KR100360534B1 - Color picture tube having an inline electron gun - Google Patents

Abstract

The present invention is arranged inside the neck 14 of the fluorescent screen 22 and the receiving tube to generate three inline electron beams consisting of one center beam and two side beams and directing these electron beams to the fluorescent screen. It is related with the color water pipe provided with (26). The electron gun includes a plurality of electrodes in which the focusing electrode G5 is incorporated. The neck of the water tube is configured to accommodate the scan rate modulation coils 54 and 56 surrounding it. The focusing electrode comprises two spaced apart portions 44, 46 which are electrically connected and adapted to connect the same focusing voltage V _FOCUS . The space 45 between the parts is surrounded by the neck position for the coil.

Description

COLOR PICTURE TUBE HAVING AN INLINE ELECTRON GUN}

For color picture tubes, the resolution of the image depends on having a small electron beam spot size on the fluorescent screen of the picture tube. In such a color picture tube, the electron gun generates three electron beams, which must be simultaneously focused on a small spot on the fluorescent screen. It is known to provide scan rate modulation (SVM) using a coil in the neck of the water tube. SVM coils are bipolar devices arranged to produce a vertical magnetic field, which induces horizontal deflection of the electron beam. This SVM coil improves the image quality of the picture tube by modulating the horizontal deflection speed of the electron beam. The SVM coil is driven as a function of the video signal. As video rates increase from NTSC rate to VGA and SVGA rate, the SVM coils must operate at the corresponding high frequency. These high frequencies eventually change the magnetic field quickly. According to Faraday's law derivation, the changing magnetic flux will generate an internal closed loop current path in any conductor. In addition, Lenz's law explains that the induced eddy currents generate induced magnetic flux that opposes changes in the incident field, reducing the magnitude of the magnetic field reaching the electron beam. The magnitude of these currents depends on the rate of change of frequency, such as magnetic flux. In order to reduce the size of such a magnetic field, a high power circuit or a high sense coil is required, resulting in an undesirable problem of high cost.

The present invention relates to an improved color water tube with an inline electron gun, and more particularly to a color water tube with an inline electron gun with a split focusing electrode.

BRIEF DESCRIPTION OF THE DRAWINGS The sectional view of the axial direction of the color water pipe which implements this invention.

FIG. 2 is a partial side view in axial direction of the electron gun of FIG. 1 disposed in a water tube neck having an SVM coil located on the neck; FIG.

3 is a schematic view of the electron gun of FIG. 2 showing electrical connection of electrodes of the electron gun;

4 is a front view of the side surface of the G5B electrode portion opposite the G5T electrode portion in the electron gun of FIG. 2;

Fig. 5 is a front view of the side of the G5B electrode portion opposite the G5T electrode portion in another electron gun.

The present invention provides a color receiver tube having a fluorescent screen and an electron gun disposed inside the neck of the receiver tube and generating three inline electron beams consisting of one central beam and two side beams and directing the electron beams to the fluorescent screen. It is about. The electron gun includes a plurality of electrodes including a focusing electrode. The neck of the water pipe is configured to accommodate the scan rate modulating coils surrounding it. The focusing electrode includes two spaced apart portions that are electrically connected and adapted to connect the same focusing voltage. The space between the parts is surrounded by the neck position for the coil. This space provides an area free of eddy currents, thereby increasing the magnetic field by the electron beam.

1 shows a rectangular colored water tube 10 having a glass envelope comprising a tubular neck 14 connected by a rectangular faceplate panel 12 and a rectangular funnel 15. The funnel 15 has an internal conductive coating layer (not shown) that extends from the anode button 16 to the neck 14. The faceplate panel 12 includes a peripheral flange, ie sidewall 20, which is sealed to the funnel 15 by the viewing faceplate 18 and the glass frit 17. The tricolor fluorescent screen 22 is supported by the inner surface of the viewing faceplate 18. The screen 22 is preferably a line screen with phosphor lines arranged in three triads, each three suits each comprising three colored phosphor lines. Also, the screen may be configured as a dot screen. The multi-opened color selection electrode, i.e., the shadow mask 24, is detachably mounted to the screen 22 in a predetermined space spaced state by a conventional method. The electron gun 26, schematically depicted in dashed lines in FIG. 1, generates three electron beams along a path that converges through the shadow mask 24 and directs these electron beams inside the neck 14 to direct them towards the screen 22. It is mounted in the center.

The water tube of FIG. 1 is designed for use with an external magnetic deflection yoke (not shown) attached to the water tube near the junction of the funnel and neck. In operation of the water tube, the yoke subjects the three beams to a magnetic field that causes the beam to be scanned horizontally and vertically into a rectangular raster on the screen 22.

Details of the electron gun 26 are shown in FIGS. 2, 3 and 4. The electron gun 26 includes three spaced apart inline cathodes 34 (only one is shown in FIG. 2) arranged in a named order, control grid electrodes 36 (G1), screen grid electrodes 38 (G2) ), An acceleration electrode 40 (G3), a plate-shaped electrode 42 (G4), two focusing electrodes, for example, a first focusing electrode 44 (G5B) and a second focusing electrode 46 (G5T) Focused focus electrode G5 and final electrode 48 (G6). Each of the G1 to G6 electrodes has an opening therein to allow three electron beams to pass therethrough. The electrostatic main focusing lens of the electron gun 26 is formed by the contact portion of the G5T electrode 46 and the G6 electrode 48. G5B electrode 44 and G5T electrode 46 are formed by two portions 44B and 44T, 46B and 46T, respectively.

All electrodes of the electron gun 26 are connected directly or indirectly to the two insulating support bars 50, 52. Preferably the support rod is made of glass heated and pressed on the rings extending from the electrode to fit the rings to the rods.

Two scan modulation (SVM) coils 54 and 56 are shown in neck 14 of FIG. Each coil is rectangular and has an outline to match the cylindrical shape of the neck. Each coil also includes a large central window disposed on the top and bottom of the neck facing each other. While such SVM coils have been used on water tubes with electron guns of fixed focusing voltage, the inventors have found that this can be accomplished by incorporating additional space 45 within the electron gun to allow the SVM system to operate in an unobstructed manner on the electron beam. It has been found that the effect of the SVM coil on the correlation can be increased. The space 45 enables the fast changing magnetic flux generated by the SVM coil to reach the electron beam without incurring the losses caused by the generation of eddy currents at the electrodes. This additional space 45 is formed by vertically dividing the G5 focusing electrode into two electrode portions, namely the G5B electrode portion 44 and the G5T electrode portion 46. The coil should enclose the space between the two electrode portions 44, 46, but preferably this space should be located closer to the longitudinal center of the coil than close to their ends as shown in FIG. 2.

The electrical connection of the electrode of the electron gun 26 is shown in FIG. The G1 electrode is connected to ground. The G2 and G4 electrodes are connected to each other and to the G2 voltage (V _G2 ), the G3, G5B and G5T electrodes are all connected to each other and to a fixed focusing voltage (V _FOCUS ), and the G6 electrode is connected to the anode voltage (V). _ANODE ).

In the electron gun 26, the opposing pieces 44T, 46B of the two electrode portions 44, 46 each have a single extended opening 47 therein as shown for the portion 44T of FIG. do. The spaced fragments 44B, 46T of the two electrode portions 44, 46 are respectively shown with three openings 60, 62, for the passage of three electron beams, as shown for the portion 44T of FIG. 4. 64) is provided inside. 5 shows another embodiment of portions 44T and 46B, each of which is denoted by a prime symbol for the same reference numeral. This alternative embodiment shows how the shape and size of all openings in the electrode portions 44, 46 can be changed to achieve a certain level of performance. In the portion of the embodiment shown in FIG. 5, a larger extended opening 47 ′ is included in portion 44T ′, and three larger openings 60 ′, 62 ′, 64 ′ are portion 44B ′. )

One set of electrode space dimensions for the electron gun 26 is provided in Table 1 below.

TABLE 1

Spacing between cathode and electrode G1 = 0.003 "(0.076 mm) *

Space between electrodes G1 and G2 = 0.009 "(0.229 mm)

Space between electrodes G2 and G3 = 0.030 "(0.762 mm)

Spacing between electrodes G3 and G4 = 0.050 "(1.270 mm)

Spacing between electrodes G4 and G5B = 0.050 "(1.270 mm)

Space between electrodes G5B and G5T = 0.070 "(1.778 mm)

Space between electrodes G5T and G6 = 0.050 "(1.270 mm)

* At operating temperature

Claims (3)

An electron gun 26 disposed inside the fluorescent screen 22 and the neck 14 of the water tube to generate three inline electron beams consisting of one center beam and two side beams and directing these electron beams to the fluorescent screen. A color receiving tube (10) with a focusing electrode (G5) having two spaced apart portions (44, 46, 44 ') electrically connected for connection to the same focusing voltage (V _FOCUS ); And a plurality of electrodes (44T, 46B) of the two spaced apart portions of the focusing electrode each have three openings (60, 62) therein for the passage of the three electron beams. , 64; 60 ', 62', 64 ') wherein at least one of the two spaced apart portions the three openings have a single extended opening therein for passage of the three electron beams; 47, 47'a leading edge porti on) (43, 43 '), characterized in that the color of the water tube is set. An electron gun 26 disposed inside the fluorescent screen 22 and the neck 14 of the water tube to generate three inline electron beams consisting of one center beam and two side beams and directing these electron beams to the fluorescent screen. A color receiving tube (10) having a plurality of electrodes including a focusing electrode (G5), and a neck of the receiving tube having scan rate modulation coils (54, 56) at the position of the focusing electrode; Surrounded by, wherein the focusing electrode comprises two spaced apart portions (44, 46, 44 ') electrically connected for connection to the same focusing voltage (V _FOCUS ). 3. The opposing portions of the two spaced apart portions 44, 46, 44 ′ of the focusing electrode G5 each have three openings 60, respectively, for the passage of the three electron beams. 62, 64; 60 ', 62', 64 ', wherein the three openings in at least one of the two spaced apart portions have a single extended opening therein for the passage of the three electron beams. A color water tube, which is set on the rear side of the leading edge portions 43, 43 'forming (47, 47').