摘要:
In an inline electron gun for use in a color cathode ray tube (CRT), a fixed, or static, electrostatic quadrupole in the low voltage beam forming region (BFR) exerts a negative astigmatism on the electron beams in reducing beam horizontal cross-section and compensating for the horizontal under-focusing of the beams by the CRT's self-converging magnetic deflection yoke. The negative astigmatism is compensated for by a dynamic electrostatic quadrupole in the CRT's main focusing lens. The electrostatic quadrupole in the CRT's BFR includes either a plurality of spaced, horizontally oriented, aligned, elongated indentations in the G.sub.2 facing surface of the G.sub.1 control grid or a plurality of spaced, vertically oriented, elongated indentations in the G.sub.1 facing surface of the G.sub.2 screen grid, where each of the indentations has an associated through-hole circular aperture through the grid. The elongated indentations cause the cross-section of each of the electron beams to become vertically elongated particularly in the deflection region, while the dynamic electrostatic quadrupole in the main focusing lens cancels the deflection yoke's negative astigmatism without affecting electron beam cross-section shape. This invention thus incorporates a negative astigmatism and a change of beam cross-sectional shape. The negative astigmatism is later removed at the focusing lens and the benefit of the beam shape change remains.
摘要:
An electron gun for a 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 yoke for simultaneous focusing and deflection of the electron beam on the CRT's display screen. The deflection lens includes a first 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 electrode disposed either on or immediately adjacent to the inner surface of the CRT's frusto-conical funnel portion intermediate the magnetic deflection yoke and the CRT's display screen. By positioning the CRT's focus lens within the deflection field, the deflection center of the beam is disposed within the focal point of the focus lens permitting the focus lens to operate as a deflection lens to not only focus the beam, but also increase beam deflection sensitivity. The coincidence of the beam focus and deflection regions reduces beam "throw distance" (field-free zone) resulting in a corresponding reduction in beam magnification and space charge effect and improved beam spot on the CRT's display screen. Positioning a focus electrode on the CRT's neck or funnel portion increases the equivalent diameter of the main focus lens which reduces the lens spherical aberration effect on the beam, while co-locating the beam focus and deflection regions also allows for shorter CRT length.
摘要:
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. By positioning the electron gun's deflection focus lens within the deflection field, the deflection center of the electron beams is disposed within the focal point of the focus lens permitting the focus lens to operate as a deflection lens to not only focus the beam, but also increase beam deflection sensitivity. By reducing beam "throw distance" (fieldfree zone) and realizing a corresponding reduction in beam magnification and space charge effect, improved electron beam spot on the display screen is also provided. The focus lens increases the equivalent diameter of the main focus lens which reduces lens spherical aberration effect on the beams, while co-locating the beam focus and deflection regions also allows for shorter CRT length.
摘要:
For use particularly in a color cathode ray tube electron gun, means for diverting an electron beam from a straight line path. The beam diverting means has general utility, but is disclosed as part of a quadrupole lens for correcting astigmatism introduced by an associated self-converging yoke. The beam bending feature in the dynamic quadrupole compensates for convergence errors undesirably introduced by the dynamic focus voltage.
摘要:
An electron gun for a cathode ray tube includes a cathode for generating electrons; a charged element for receiving electrons from the cathode and for forming a beam crossover; and an asymmetrical unipotential-type focus lens for forming an image of the crossover at a distance from the gun, comprising a prefocus electrode arrangement for forming a prefocusing field and a main focus electrode arrangement for forming a main focusing field, the prefocus electrode arrangement being constructed, configured and adapted to be excited to cause the prefocusing field to be weaker than the main focusing field such that at low beam currents the effective focal plane of the focus lens is moved forwardly away from the cathode and beam spot size performance is thereby improved, and such that the beam exit diameter is increased for reduced space charge effects and thereby improved high beam current performance.
摘要:
An electron gun for a high resolution color display tube comprises three inline cathode assemblies, a control grid with three inline apertures, a screen grid with three inline apertures and slots at each aperture on a side facing away from the control grid, a first focusing electrode having three inline apertures facing the screen grid and three inline apertures facing away from the screen grid, and a second focusing electrode having three inline apertures facing the first focusing electrode. The diameters of the control grid apertures are in the range of 0.43 mm to 0.59 mm. The screen grid is spaced 0.13 mm to 0.26 mm from the control grid. The diameters of the screen grid apertures are in the range of 0.43 mm to 0.59 mm, and their thickness is in the range of 0.20 mm to 0.31 mm. The ratio of the depth of the slots in the screen grid to their widths is in the range of 0.13 to 0.23. The diameters of the apertures in the facing portions of both focusing electrodes are in the range of 4.06 mm to 5.44 mm, and the length of the first focusing electrode is in the range of 17.6 mm to 23.5 mm.
摘要:
An inline electron gun in a color picture tube is improved by the addition of two slots that are spaced sufficiently close to and inward from the two apertures in a portion of the screen grid electrode facing an accelerating and focusing electrode. The slots cause a distortion of the electrostatic field formed between the two electrodes at the two apertures. The field distortion compensates for an opposite distortion within the main lens of the electron gun.
摘要:
An electron beam device includes an electron beam source, plural spaced plates having aligned apertures through which an electron beam is directed, an electrostatic focusing arrangement, and plural electrostatically charged deflection plates for deflecting the beam and displacing it over a target surface. The apertures in the spaced plates are of deceasing size in the direction of travel of the electron beam for intercepting the outer periphery of the beam and providing a beam of reduced cross section. The electron beam is simultaneously deflected by the deflection plates and focused by the electrostatic focusing arrangement. The electrostatic focusing arrangement includes first and second focusing elements through which the beam is directed which are disposed along the beamline and adjacent the upper and lower end portions, respectively, of the beam deflection plates. The electron beam device is of small size, permitting plural devices to be arranged in two- and three-dimensional compact matrix arrays for dense electron beam lithography arrangements such as for use in the simultaneous manufacture of large numbers of semiconductor devices to boost the throughput in integrated circuit manufacture inexpensively.
摘要:
For use in a beam index color cathode ray tube (CRT), a multi-beam group electron gun directs first and second groups of vertically aligned electron beams on respective parallel, horizontally aligned color phosphor stripes on the CRT's display screen. Each group of electron beams includes three beams, one for each of the three primary colors of red, green and blue. The first and second electron beam groups are horizontally offset from one another, with the upper, intermediate and lower electron beams in each group tracing the same horizontal phosphor stripe as the beams scan the display screen and with a time delay provided to synchronize the video information of both electron beam groups. A color video signal is provided either to a respective cathode or to a respective segmented conductive portion containing a beam passing aperture in the electron gun's G1 control grid for individually modulating each beam with color video image information.
摘要:
An internal resistor within a color cathode ray tube (CRT) is connected to a voltage source and is coupled across a G4 grid and a G6 grid of the CRT's multi-grid quadrupole (QPF) electron gun. De-coupling the G4 grid from the G2 grid in the electron gun's prefocus lens and operating the G4 grid at a higher voltage as used in the gun's high voltage main focus lens moves the equivalent lens of the prefocus and main focus lenses toward the CRT's display screen and reduces electron beam magnification and spot size for improved video image definition and focusing.