Abstract: An electron gun for a color cathode ray tube includes a triode having a cathode, a control electrode and a screen electrode for producing an electron beam, and first, second, third and fourth focus electrodes and a final accelerating electrode for accelerating and focusing the electron beam. A predetermined static focus voltage is supplied to the first and third focus electrodes, a dynamic focus voltage synchronized with a deflection signal is supplied to the second and fourth focus electrodes, and an anode voltage higher than the highest dynamic focus voltage is supplied to the final accelerating electrode. Thus, by means of a dynamic and axially symmetrical lens, astigmatism of the electron beam spot on the periphery of the screen is improved, thereby forming an almost circular beam spot.

Abstract: A magnetic focusing system has a pair of disc-shaped pole pieces between which several permanent rod magnets are mounted, their north poles in contact with one pole piece and their south poles in contact with the other pole piece. The permanent rod magnets are equally spaced around the outer perimeters of the pole pieces, and are separated from one another so that they do not create a ring. The pole pieces have central holes, between the rims of which a symmetric magnetic lens is formed for focusing an electron beam.

Abstract: A dynamic focus amplifier, comprising: a first circuit responsive to a vertical rate sawtooth waveform for generating at the vertical rate a modulating waveform having a desired component of a given shape during trace intervals and an undesired time compressed version of the given shape during retrace intervals; a second circuit responsive to the sawtooth waveform for generating a pulse waveform at the vertical rate, substantially corresponding in width and phase to a vertical retrace blanking waveform; and, a differential amplifier stage, formed by Darlington pairs, for combining the modulating waveform and the pulse waveform to remove the undesired time compressed version of the given shape from the modulating waveform. The second circuit may comprise a capacitor which is charged in a first direction by the sawtooth waveform during vertical trace and charged in an opposite direction during vertical retrace.

Abstract: A color cathode ray tube (CRT) includes a multi-beam electron gun capable of operating in two or more modes for use as either a television receiver display or as a high resolution video monitor. The electron gun directs a plurality of electron beams onto the CRT's display screen, with the electron beams arranged in two or more groups. In one group of electron beams, the beam forming portion of the electron gun provides small diameter electron beams having reduced spot size on the CRT's display screen for high video image resolution when used as a monitor for graphics and/or character display. In another group of electron beams, the beam forming portion of the electron gun provides electron beams having a larger diameter and current for increased video image brightness when used as a television receiver. Each group of electron beams includes a plurality of horizontally aligned electron beams, with each beam providing one of the primary colors of red, green, or blue.

Abstract: A screen grid voltage or a focus voltage for a cathode ray tube is controlled via a digital-to-analog converter. The voltage variation range of the screen grid or focus voltage that can be obtained for the entire variation range of an output signal of the digital-to-analog converter is not significantly larger than that required for the type of cathode ray tube that is utilized.

Abstract: Dynamic focus circuits for generating a dynamic focus signal for focusing an electron beam on a CRT, the signal being proportional to a function of the vertical deflection Y and horizontal deflection X of the beam according to X.sup.2 +Y.sup.2 +X.sup.2 f(Y) or X.sup.2 +Y.sup.2 +Y.sup.2 f(X), where f(Y) or f(X) is a positive symmetric function. The resultant dynamic focus signal has increased magnitude as the beam moves away from the center of the screen, thus providing proper focusing at the corners of the screen as well as at the center and sides of the screen.

Abstract: In a color cathode ray tube apparatus including an electron gun assembly having a main electron lens section constituted by a plurality of electrodes for focusing three electron beams arranged in a line on a target and a deflection unit for deflecting the three electron beams, at least an electrode to which a voltage obtained by superposing a variable voltage changed in accordance with a deflection amount of the electron beams on a predetermined DC voltage and an electrode which substantially opposes the electrode and to which a voltage obtained by superposing a variable voltage induced through a capacitance between the opposing electrodes on a predetermined voltage applied through a resistor arranged in a tube is applied are arranged in a main electron lens section, and the main electron lens section is made into an electron lens for changing the focusing state of the electron beams in synchronism with deflection of the electron beams.

Abstract: A cathode ray tube having an electron gun for relatively low beam currents (less than 1 mA) is shown. The electron gun has a G1 and a G2 electrode. The voltage difference between these electrodes is more than 800 Volt and the electrical field strength E.sub.12 between said electrodes is more than 4 keV/mm. An improvement in spot size is thereby obtained.

Abstract: A focus voltage control apparatus adapted for a color CRT and capable of achieving a just focused state of any desired color even in monochromatic display. Red, green and blue color signals R, G, B are integrated per horizontal line period in integrating/peak holding circuits and then are weighted respectively in weight control circuits. Subsequently the maximum one of the color signals is detected in a comparator, and one of color selection signals SR, SG, SB is outputted in accordance with the result of such detection and then is supplied to focus voltage converters for the individual colors. A reference focus voltage refV is converted into a color focus voltage VR, VG or VB on the basis of the color selection signal SR, SG or SB for just focusing the color signal R, G or B.

Abstract: A current transformer has a primary side winding coupled to a source of horizontal rate sawtooth yoke current and a secondary side in which a horizontal rate AC signal is developed. A rectifier has at least one capacitor, the rectifier receiving the horizontal rate AC signal and energizing a DC voltage across the at least one capacitor. A modulator for the DC voltage generates a first deflection rate waveform. A capacitor coupled to the modulator and to the secondary side of the transformer generates a second deflection rate waveform. The first and second deflection rate waveforms are combined to define a vertical dynamic focus voltage signal.

Abstract: A method and apparatus for generating a dynamic focus signal for focusing an electron beam on a CRT, the signal being proportional to a function of the vertical deflection Y and horizontal deflection X of the beam according to X.sup.2 +Y.sup.2 +X.sup.2 f(Y) or X.sup.2 +Y.sup.2 +Y.sup.2 f(X), where f(Y) or f(X) is a positive symmetric function. The resultant dynamic focus signal has increased magnitude as the beam moves away from the center of the screen, thus providing proper focusing at the corners of the screen as well as at the center and sides of the screen.

Abstract: Known display devices include a video signal processing circuit with a black level setting circuit. This black level setting circuit measures the black level of the video signal, for example, during the field retrace interval by making use of an extra output of the video output stage. However, the measured black level has a line-frequency interference component which is caused by a parasitic capacitance in the display tube. The line-frequency interference component is fully compensated for by coupling one side of a secondary winding of a transformer, required for the focusing voltage to be generated, to a first capacitor, the other terminal of which is connected to the measuring input of the black level setting circuit, and by coupling at least a second and a third capacitor across the secondary winding of the transformer.

Abstract: In a pulse beam forming apparatus, there are disposed in order a beam generating device for generating a charged particle beam having a circular cross section, a beam elongating device for elongating the charged particle beam in cross section, a deflecting device for deflecting the charged particle beam in a direction perpendicular to the longitudinal direction of the cross section, an aperture for cutting the charged particle beam, and a beam reshaping device for reshaping the charged particle beam into one having a circular cross section.

Abstract: A dynamic focusing electron gun is provided which includes a cathode and first and second grids which collectively form a triode, a plurality of electrodes for forming an auxiliary lens, and an anode installed adjacent to the final electrode of the auxiliary lens for forming a main lens. Electron beam passing holes are formed in the electrodes of the auxiliary lens so that an electron beam is repeatedly and alternately deformed in the sequence of the vertically-elongated and then horizontally-elongated (or horizontally-elongated and then vertically-elongated) shapes, constituting more than two quadrupole lenses of opposing polarities.

Abstract: In a dynamic focus electron gun, a horizontal dynamic focus voltage is varied according to those portions of a screen where the electron beam arrives and is applied so that the peak-to-peak amplitude of the horizontal dynamic focus voltage in one horizontal deflection period for the upper and lower portions of the screen is greater than that for the screen's center, thereby accomplishing uniform beam spots throughout the screen.

Abstract: A magnetic focusing device is disposed around the neck of a cathode ray tube. The device comprises a magnetic frame formed by constituent pieces having different magnetic permeabilities and having a gap in a portion thereof radially closest to the neck. A static focusing coil is enclosed in the frame and energized by a direct current. A dynamic focusing coil is energized by a periodically variable current and disposed between the static coil and the neck of the tube. The dynamic focusing coil is disposed near the gap and uses as a magnetic circuit the portion of the frame consisting of the material whose imaginary component of magnetic permeability is the lowest.

Abstract: An electron gun for a color cathode ray tube having sequentially formed a cathode, a control electrode, a screen electrode, a focus electrode and a final accelerating electrode, wherein the focus electrode is constituted by first and second focus electrodes. The first focus electrode includes an evenly formed electron beam inlet plane and an electron beam outlet plane in which a portion for shaping a central electron beam passing hole is formed convexly in respect to portions for shaping outer electron beam passing holes, while the second focus electrode comprises an evenly formed electron beam outlet plane and an electron beam inlet plane in which a portion for shaping a central electron beam passing hole is formed concavely in respect to portions for shaping outer electron beam passing holes. The quadruple lens formed between outer electron beam passing holes is formed asymmetrically, to improve the convergence characteristic.

Abstract: A focus control circuit for a CRT includes a focus bias voltage setting device for setting a focus bias voltage, a bias voltage control device for controlling the focus bias voltage and the focus bias voltage setting device in response to control information, a first amplifier for amplifying a luminance setting voltage with an amplification factor determined by an amplification factor control voltage and for supplying the amplified luminance setting voltage to a transistor, and a resistor network and a second amplifier for dividing a voltage applied to a control grid and applying it to the first amplifier as a control voltage.

Abstract: An electron gun for a color cathode ray tube includes a cathode, control and screen electrodes forming a triode, 1st to 3rd focus electrodes forming a first unipotential prefocus lens, 4th and 5th focus electrodes forming a second unipotential prefocus lens with the 3rd focus electrode, a 6th focus electrode forming a bipotential prefocus lens with the 5th electrode adjacent thereto, and an accelerating electrode for forming a bipotential main focus lens with the 6th focus electrode. Vertically-elongated electron beam passing holes are respectively formed in the outgoing planes of the 1st, 3rd and 5th electrodes and horizontally-elongated electron beam passing holes are respectively formed in the incoming planes of the 3rd, 5th and 6th focus electrodes.

Abstract: An electron beam focusing device is provided for apparatus such as cathode ray tubes wherein an electron beam is scanned on a flat surface normal to the beam and converged at a point on the flat surface using magnetic fields. The focusing device includes a static field generator for converging the beam, and a dynamic focus device. The dynamic focus device is comprises a first winding coupled to a power supply, for example a current supply, for providing a magnetic field substantially defining a parabola during a trace interval of the beam to account for the variation in beam path length which occurs with scanning, and a second winding magnetically coupled to the first winding. An energy storing circuit coupled to the first and second windings stores energy during the trace interval and releases energy during the retrace interval such that the second winding induces a reverse current in the first winding, thereby returning current to the power supply during retrace.

Abstract: A focus coil for a television is disposed between scanning electron beam generator and a planar screen and has a winding coupled between a power supply and a current sink for providing a magnetic focusing field due to current in the coil. A focusing circuit comprises a resonant circuit coupled to the focus coil for generating a parabolic current in the focus coil to account for variations in the distance between the focusing device and the screen during scanning. The resonant circuit stores a portion of the energy developed during trace intervals and returns this energy to the power supply during retrace intervals. The resonant circuit includes a capacitor and an additional coil, in series with one another, and together in parallel with the focus coil. The additional coil is magnetically coupled to the focus coil and induces a reverse current in the focus coil during the retrace interval for returning energy to the power supply.

Abstract: A display device comprising a deflection unit and a cathode ray tube having an in-line electron gun. The electron gun comprises a main lens portion having means to generate a main lens field and a quadrupole field. During operation, the intensity of the fields is dynamically varied. The electron gun comprises a prefocusing lens portion having means of generating a prefocusing lens field and a further quadrupole field. During operation, the intensity of said fields is controlled so that a dynamic cylindrical lens is formed in the prefocusing lens portion. By virtue thereof, an improved picture reproduction can be obtained.

Abstract: An electron gun for a color cathode ray tube includes a cathode, a control electrode and a screen electrode constituting a prepositioned triode. First, second, third and fourth focus electrodes form two pre-focus lenses and a final accelerating electrode positioned adjacent to the fourth focus electrode forms a main focus lens. The first pre-focus lens is synchronous with a deflection signal. Variation of the focussing intensity of the main focus lens is compensated for by the first pre-focus lens.

Abstract: A circuit for driving a focus coil with a constant amplitude current in response to receiving a focus control signal and a horizontal scan rate signal, comprising: (a) a variable capacitance circuit connected to the focus coil to form a series combination of the focus coil and the variable capacitance circuit; (b) an amplifier circuit for receiving and amplifying the focus control signal and in response applying an amplified focus control signal to the series combination; and (c) a control circuit for receiving the horizontal scan rate signal and in response setting a predetermined capacitance of the variable capacitance circuit to obtain minimal voltage of the amplified focus control signal applied to the series combination of the focus coil and the variable capacitance circuit while maintaining constant current amplitude.

Abstract: A focus yoke used for an electromagnetically focused CRT display comprises: a cylindrical permanent magnet unit which is disposed around a neck portion of a CRT and is spaced from the circumference of the neck portion; a core unit which defines a toroidal space together with the cylindrical magnet unit for substantially surrounding the neck portion, the core unit forming a magnetic path to guide magnetic lines of force generated by the cylindrical magnet unit; a dynamic focus winding unit disposed in the toroidal space; and a winding unit disposed externally of said toroidal space for eliminating an undesired magnetic field of an inverse polarity generated due to the cylindrical magnet unit.

Abstract: An improved cathode-ray tube includes a viewing screen and an electron gun for generating and directing three electron beams toward the screen. The gun includes at least eight electrodes spaced in order from three cathodes, with the furthest electrode from the cathodes being interconnected to a tube anode. The electrodes form a beam forming region, a first quadrupole lens, a main focus lens and a second quadrupole lens in the path of each electron beam. In the improvement, the second quadrupole lens is positioned on the anode side of main focus lens, with the first quadrupole lens being diverging for defocusing the beams, and the second quadrupole lens being converging for focusing the beams in the horizontal plane.

Abstract: An electron gun for a color cathode ray tube is formed such that parallel vertical blades are extending toward cathodes formed at both edges of each electron beam passing hole in the outgoing plate of a focus electrode. Horizontal blades extending toward the cathodes at a predetermined length are formed at the edges of the top and bottom portions of electron beam passing holes in the incoming plate of a dynamic focus electrode. Thus, the horizontal blades are inserted into the electron beam passing holes of the focus electrode, which reduces astigmatism due to deflection aberration and improves the focusing characteristics.

Abstract: A Dynamic Color Separation (DCS) color display system employs signals which provide timing, luminance, and chrominance information of the display output. The display system includes a timing circuit which produces unique signals for correcting errors produced when hue is controlled by the phase of the (S) signal and the degree of saturation with its amplitude. The signals may be applied to known CRT beam guns, and modified guns specific to the generated signals are also disclosed.

Abstract: An improved resolution electron gun for a cathode ray tube(CRT) is provided having a cathode, a control grid and an anode. A positive voltage is applied to the anode for the purpose of drawing the electron beam from the cathod, which emits the electron beam along its principal axis. The control grid between the cathode and the anode has a modulating drive voltage to modulate the emitted beam. The anode and the grid are aligned along the principal axis of the cathode and are adjacent to one another. A limiting aperture is mounted along the principal axis to clip the beam and reduce its diameter. A screen is provided along the principal axis within the CRT to receive the projected beam. To obtain increased resolution, the modulating drive voltage is increased while the aperture size is decreased. More specifically, the modulating drive voltage is increased beyond 25% of a predetermined maximum cutoff value, and the limiting aperture permits less than 50% of beam current to transmit.

Abstract: An electron gun for a color cathode ray tube includes cathodes, a control electrode and a screen electrode which form a front triode, first, second, third, fourth and fifth focus electrodes which form a plurality of auxiliary electrostatic lenses, and a final accelerating electrode installed adjacent to the fifth focus electrode to form a main electrostatic lens, wherein vertically-elongated electron beam passing holes are formed on the fourth focus electrode, a predetermined focus voltage is applied to the first, second and fifth focus electrodes, a dynamic focus voltage lower than the focus voltage and synchronized with a deflection synchronizing signal is applied to the fourth focus electrode, a static voltage higher than the focus voltage is applied to the second focus electrode, and an anode voltage higher than the focus voltage is applied to the final accelerating electrode.

Abstract: An image detecting device is disclosed wherein an image detector is mounted within a rare earth permanent magnet structure with a hollow cavity and an access port that passes through the structure and thereby accessing the cavity. The shell is permanently magnetized to produce a substantially uniform magnetic field in the cavity. The shell's magnetization is the resultant of two magnetization components M1 and M2. M2 components are uniform in both magnitude and direction while M1 components are uniform in magnitude but not uniform in direction. Preferably, the magnitudes of the M1 and M2 components are substantially equal to each other but aligned in opposite directions in regions adjacent to the access port. The image detector located within the cavity of the magnet is oriented such that the magnetic flux in the cavity flows in the same direction as the electron beam passing through the cavity.

Abstract: In an electron gun assembly, electron beams emitted from cathodes are focused in first cross-over and accelerated and controlled by grids along three axes arranged in-line. The controlled electron beams are weakly converged by unipotential lenses and are converged in a vertical plane by a common single electron lens having a lens power which is varied in accordance with a horizontal or vertical deflection of the electron beams. The converged electron beams form second cross-over on the axes which are shifted along the axes are diverged from the second cross-overs. The diverged electron beams are further focused and converged onto a screen by a main lens.

Abstract: A horizontal focus circuit in an image display for improving the focus characteristics at the edges of a planar CRT screen or a CRT screen used in a multi-sync mode.

Abstract: An electron gun in which at least two of a plurality of electrodes constituting the electron gun are endowed with structures for generating rotationally-asymmetric electric fields, in electron-beam apertures of the electrodes or around the electron-beam apertures, and a cathode-ray tube which comprises the electron gun can enhance focus characteristics and attain favorable resolutions over the whole area of a screen and in all the current ranges of electron beams, and they do not give rise to moire in the small current range of the electron beams, without supplying a dynamic focus voltage.

Abstract: A method and apparatus for generating a dynamic focus correction voltage signal for a cathode ray tube which comprises the steps of: generating horizontal and vertical scan counter signals, and inputting the counter signals to a dynamic output voltage generating means which produces an output voltage that is proportional to the distance the scan is from the center of the image on the CRT in both the vertical and the horizontal directions.

Abstract: A focus voltage correction circuit for cathode ray tubes is disclosed in which a flyback pulse is generated by switching a supply voltage to be applied to a primary side of a flyback transformer, and the flyback pulse being is rectified and smoothed so as to develop a focus voltage in cathode ray tubes. A correction voltage capable of minimizing an error in the focus voltage to be caused by an error in the supply voltage is superimposed on the flyback pulse. In addition, the focus voltage correction circuit for cathode ray tubes may be provided with a device for regulating the correction voltage such that the focus voltage regulation can be performed.

Abstract: An electron gun has one first-type electron lens in the focusing electrode which changes the cross-sectional shape of the electron beam into a nonaxisymmetric shape with increase in the degree of the electron beam deflection by applying a first voltage varying in synchronism with deflection, and one second-type axisymmetric electron lens in the focusing electrode which weakens the lens power with increase in the degree of the electron beam deflection by applying a second voltage increasing with the degree of deflection.

Abstract: An electron gun for a color cathode ray tube for realizing a high-quality image includes a triode having a cathode, a control electrode, and a screen electrode, and a main lens system having first to fourth focusing electrodes and an anode. The first focusing electrode and the fourth focusing electrode are electrically connected to each other, and the second focusing electrode and the third focusing electrode are electrically connected to the control electrode and the screen electrode, respectively. By forming a multistep auxiliary lens, the influence of spherical aberration and astigmatism on the electron beams are decreased and, in turn, a high-quality image can be realized.

Abstract: An electron gun for a color cathode ray tube (CRT) includes a cathode, a low voltage beam forming region (BFR), and a high voltage deflection focus lens disposed in the beam deflection region of the CRT's magnetic deflection yoke for simultaneous and coincident focusing and deflection of the electron beams on the CRT's display screen. The deflection lens includes a first focus electrode either in the form of a cylindrical metal grid or a conductive coating disposed on the inner surface of the CRT's neck portion and extending into the magnetic deflection field. The deflection lens further includes a second focus electrode either in the form of a conductive coating or a frusto-conical metallic grid disposed on or immediately adjacent to the inner surface of the CRT's funnel portion intermediate the magnetic deflection yoke and the CRT's display screen.

Abstract: In an electron gun for cathode ray tubes in which the second of three focusing electrodes is divided into first, second, and third auxiliary electrodes, applying a first dynamic voltage synchronous with vertical and horizontal deflection signals to the first and third auxiliary electrodes, a second dynamic voltage synchronous with the deflection signals to the second auxiliary electrode, and a static focusing voltage higher than the maximum of the first and second dynamic voltages to the first and third focusing electrodes. The electron gun uses two dynamic focusing voltages in a low voltage driving method for low dynamic focusing voltages, thereby greatly reducing the possibility of an arc discharge between electrodes and compensating for astigmatism of the electron beam due to the non-uniform magnetic field of the deflection yoke. A sharp picture is achieved by improving the focusing of the electron beam.

Abstract: A diode modulation circuit provides a horizontal yoke coil current which is modulated in a manner to correct for side pin cushion distortion in the resultant CRT television picture tube display. The modulation circuit includes two parallel capacitance-inductance resonant circuits coupled in series. One coil of the parallel resonant circuits is the horizontal yoke coil of the picture tube. A modulation circuit is applied to the coil of the other parallel resonant circuit to generate a modulation current in the yoke coil. The modulation current flowing through the yoke coil is applied to the primary winding. Another modulated current in the diode modulator circuit is applied to a secondary winding of a transformer, the windings being coupled to each other via a common core. The turns ratio of the primary winding to the secondary winding of the transformer are such as to add the fluxes generated by the windings to produce a net flux in the transformer core that exhibits negligible modulation.

Abstract: A flyback transformer constituted such that a focus pack incorporating a circuit board having a resistor circuit including a variable resistor for focus voltage supply is mounted on a transformer case, comprising an outer case to be mounted on a transformer case, and an inner frame, formed inside the outer case to be integral with the outer case for incorporating the circuit board, wherein an opening path is formed between the outer case and the inner frame, a shaft hole extending through the opening path is provided for the outer case and the inner frame, the shaft hole is defined from the opening path by an insulating cylinder wall, and a rotational operation shaft for the variable resistor is inserted in a cylinder hole of the insulating cylinder wall.

Abstract: A single power amplifier is provided both the horizontal and vertical focussing coils of each CRT of a red, blue and green CRT projection television system. Each amplifier includes an amplitude adjustment network to minimize spot size, an adder circuit for superimposing horizontal and vertical parabolic focussing voltages and a power amplifier stage for amplifying the superimposed voltages. The amplifier stage includes a differential amplifier comparator for converting with high gain the horizontal superimposed parabolic voltage into a saw tooth voltage superimposed on a vertical parabolic voltage which is applied to the vertical focussing coil. A passive capacitive filter filters out the vertical parabolic voltage, applies only the filtered saw tooth voltage to a transformer for stepping up the voltage. The stepped up saw tooth voltage is then applied to the horizontal focussing coil.

Abstract: A projection television receiver has a cathode ray tube with an electron gun for emitting an electron beam incident on a screen, an electromagnetic deflection yoke and an electromagnetic focusing coil. A horizontal deflection driving circuit is coupled to a horizontal deflection coil and provides deflection current to the horizontal deflection coil for scanning the beam repetitively on the screen. The focusing coil is driven from a current step-down transformer having a primary winding coupled in series with the horizontal deflection coil. A secondary winding of the transformer is coupled to the focusing coil for driving the focusing coil with a horizontal rate parabolic current. A capacitor-resistor circuit is coupled in parallel with the focusing coil and with the secondary winding of the transformer for adjusting a phase relationship of the parabolic current relative to the horizontal deflection current and for adjusting the amplitude of the parabolic current.

Abstract: A method of determining display parameters of an electron beam picture tube. An image pattern is produced on the display screen of the tube by frequency modulating the electron beam. The frequency component of the image pattern having a frequency equal to the beam modulation frequency, that being the fundamental wave of the pattern, is determined. Information about the sharpness of focus can be derived from the modulation depth of the fundamental wave, and information about the position of the electron beam and raster distortion can be derived from the phase of the fundamental wave.

Abstract: A unit for adjusting the focusing voltage of a cathode ray tube by controlling the high voltage of a flyback transformer comprising a main body unit (400) consisting of an interior face having a rail (402) extending therefrom, a knob (3) journaled in the main body, a variable shaft means (417) connected to turn with the knob, a contact terminal support (412) having a cylindrical protrusion (414) extending through an elongate opening in the variable shaft means, the protrusion having a rail groove (413) therein for sliding over the rail and a contact pin (411) carried by the contact terminal support.

Abstract: A CRT dynamic focus system, having independent corner adjustment, processes horizontal and vertical rate signals derived from the horizontal and vertical deflection systems of the CRT display. The composite horizontal output and vertical rate focus signals are supplemented by additional horizontal rate corner focus signals by separate top and bottom gated amplifiers. The phase and amplitude of the supplemental focus signals are independently adjustable.

Abstract: The invention provides an in-line electron gun in which first astigmatic lens fields that are convergent in a horizontal direction and divergent in a vertical direction are produced between a first focusing grid and a second focusing grid, and second astigmatic lens fields that are divergent in a horizontal direction and convergent in a vertical direction are produced upstream of the first focusing grid. The lens magnifications in both horizontal and vertical directions can be made substantially equal, so that it is possible to achieve a satisfactory resolution over the entire area of the phosphor screen and also to prevent moire occurrences.

Abstract: Apparatus in a three-beam inline electron gun system for a color cathode ray tube, wherein the tube has a screen and a partially self-converging yoke which partially, but incompletely, converges the three beams and undesirably imparts astigmatism to the beams in off-center regions of the screen, applies a field-strength-dependent asymmetrical field to the two outer beams to provide partial dynamic convergence. The apparatus includes an electron beam source for developing three electron beams, a focusing lens portion for focusing the three electron beams at the tube screen, an astigmatism correcting lens portion for developing an astigmatic field component in the path of each of the beams, and a modulated voltage source for modulating the strength of the astigmatic field component as a function of beam deflection angle to at least partially compensate for the yoke-induced astigmatism and for modulating focus field strength in providing partial dynamic electron beam convergence.

Abstract: At least one of the focusing electrodes stages disposed between an acceleration electrodes stage and a rear focusing electrodes stage is constituted by first and second grid electrodes, confronting portions thereof having asymmetrical construction with respect to an electron beam axis. A constant focusing voltage is applied to the first grid electrode, and a dynamic focusing voltage gradually increasing or decreasing from the constant focusing voltage as the degree of beam deflection increases is applied to the second grid electrode.