JPH02183945A - Color picture tube - Google Patents

Abstract

PURPOSE:To prevent the green right drift by changing the outer size in the horizontal deflection magnetic field passing direction of at least one of thick electrodes of a main lens in response to multiple electron beam passing holes. CONSTITUTION:When a main lens is constituted of thick plate-shaped electrodes 22a and 22b, large eddy currents are generated on the electrodes 22a and 22b by the horizontal deflection rear leakage magnetic field. When the width of the portion of a center beam passing hole 25G, i.e., the outer size in the horizontal deflection magnetic field passing direction, is made smaller than those of portions of a pair of side beam passing holes 25B and 25R, the eddy current generated on the portion of the passing hole 25G is made smaller than the eddy currents generated on portions of the passing holes 25B and 25R. The delay of the horizontal deflection rear leakage magnetic field at portions of the passing holes 25B and 25R is increased. As a result, the phase of the horizontal deflection magnetic field applied to the passing hole 25G is advanced than the phase of the horizontal deflection magnetic field applied to the passing holes 25B and 25R. Correction can be performed to negate the delay of the phase of the intensity signal of the center beam, and the green right drift can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Application in Industry-1-) The present invention relates to a color picture tube, and particularly to a color picture tube that corrects convergence deviation of an in-line color picture tube.

(Prior Art) Generally, a color picture tube has an electron gun that emits three electron beams, and the three electron r beams emitted from the electron gun are applied to the horizontal deflection magnetic field of a deflection yoke attached to the outside of the envelope. The phosphor screen L is structured to display a color image on the phosphor screen L by scanning the phosphor screen made of three-color phosphor layers by deflecting the phosphor screen in the horizontal and vertical directions using a vertical deflection magnetic field.

Among such color picture tubes, especially electron guns are
For an in-line color picture tube that has a structure that emits three electron beams consisting of a center beam and a pair of side beams that pass over the surface, the horizontal deflection magnetic field (1) of the deflection yoke is set to a binction type, as shown in Figure 4. , t1
By making one deflection magnetic field (2) into a barrel-shaped non-uniform magnetic field, three electron beams (3B) can be generated without dynamic correction.
, (3G>, (3R)) can be concentrated on the phosphor screen, and when assembling the color picture tube,
It eliminates the need to assemble and install complex parts, and also eliminates the need for complex dynamic convergence correction and adjustment when incorporated into a receiver.

However, in reality, due to coma aberration based on the deflection magnetic field and its low aberration, as shown in Figure 5, the raster of the center beam (4G) and the raster of a pair of side beams (4B)
, (4R).

Therefore, in a conventional in-line color picture tube, as shown in Figure 6, three electron beams are connected to the bottom of a convergence cup provided at the phosphor screen side end (electron beam emission end side) of the electron gun. Passing hole (513)
A magnetic field control element (6) made of a high magnetic permeability material is attached to partition , (5G), and (5R), and the three electron beams are concentrated by controlling the rear leakage magnetic field of the deflection yoke. There is.

However, if the magnetic field control element (6) is used as described above,
The correction amount for the center beam and the correction amount for the side beam are different, and as shown in Figure 7, the center beam rasku (4G) shifts to the right with respect to the side beam rasku (4B>, (41?)). This phenomenon is generally referred to as green shift to the right, and is particularly noticeable in color picture tubes with a high horizontal deflection frequency and color picture tubes in which the main lens of the electron gun is a large-diameter lens.

The cause of this green shift to the right is, firstly, when the horizontal deflection frequency is increased, the eddy current generated in the electron gun electrode due to the rear leakage magnetic field of horizontal deflection increases, as shown in Figure 8. , essentially the time difference Δt between the center beam brightness signal (7G) and the pair of side beam brightness signals (7B) and (7R) of an in-line color picture tube.
This is because it becomes larger.

Second, in order to obtain good focusing performance, the main lens of the electron gun is a large-diameter lens, and in order to improve accuracy, the electrodes that make up the main lens are made into a thick integral structure by fly-blanking press processing. If the thick inner plate electrode is used, the eddy current generated in the thick inner plate electrode becomes large due to the rear leakage magnetic field of horizontal deflection, and the brightness signal of the center beam (3G) becomes smaller than that of the pair of side beams (3B), <3R. )
As shown in FIG. 9, the rasters (4B) and (4R) of the side beams are shifted to the right with respect to the center beam (4G). Moreover, if an external correction member is used so that the three electron beams are concentrated at the center of the screen, the correction effect is greater at both the left and right edges of the screen than at the center of the screen. 413), (4R)
In contrast, the center beam's Lascou (4G) will shift to the right.

In particular, in recent color picture tubes, in order to make the bending of the center beam raster relative to the side beam raster less noticeable, the side beam raster is intentionally positioned outside the center beam raster at the horizontal edge of the screen. Therefore, together with the green shift to the right, there is a large convergence shift at the left end of the screen, which is a major cause of deterioration of the characteristics of high-precision color picture tubes such as display tubes in particular.

(Problems to be Solved by the Invention) As described above, an in-line color picture tube that has an electron gun that emits three electron beams consisting of a center beam and a pair of side beams that pass on the same horizontal plane has a deflection magnetic field of a deflection yoke. By creating a non-uniform magnetic field, the three electron beams can be concentrated without dynamic correction.

However, in reality, a concentration error occurs between the raster of the center beam and the raster of the pair of side beams due to coma aberration caused by the deflection magnetic field.

Conventionally, in order to eliminate this concentration error, there is a method in which the three electron beams are concentrated by attaching a magnetic field control element to the bottom of the convergence cup and controlling the deflection magnetic field. , because the amount of correction for the center beam and the amount of correction for the side beams are different, the raster of the center beam shifts to the right with respect to the raster of the side beam, causing a green shift to the right. This phenomenon is most noticeable in color picture tubes where the main lens diameter of the electron gun is increased. Moreover, in order to make the bending of the center beam raster relative to the side beam raster less noticeable, as with recent color picture tubes, the side beam raster is intentionally positioned outside of the center beam raster at the horizontal edge of the screen. In this case, there is a problem in that, together with the green shift to the right, the convergence shift at the left end of the screen becomes large, and in particular, the characteristics of a high-precision color picture tube such as a display tube are greatly deteriorated.

This invention was made in view of the above problems, and
The purpose of the present invention is to improve the image quality of an in-line color picture tube by reducing the green right shift in which the raster of the center beam shifts to the right with respect to the raster of the side beam.

[Structure of the Invention] (Means for Solving the Problems) A main lens includes a plurality of electrodes that focus a plurality of beams passing on the same plane onto a phosphor screen, and the main lens includes a plurality of electrodes. An in-line type 'r (includes an i-element gun) consisting of at least one integrally structured thick-walled electrode with electron beam passage holes formed therein, and a plurality of beams emitted from the electron gun are deflected by the horizontal deflection magnetic field of the deflection yoke. In a color picture tube that scans the phosphor screen by being deflected in the horizontal and vertical directions by a vertical deflection magnetic field, the external dimensions of the at least one thick electrode in the direction in which the horizontal deflection magnetic field passes are set to a plurality of electron beam passing holes. I made them different accordingly.

(Function) As described above, the external dimensions of the at least one integrally structured thick electrode constituting the main lens of the in-line electron gun in the direction in which the horizontal deflection magnetic field passes are different in correspondence with the plurality of electron beam passing holes. For example, for three electron beams, the phase of the horizontal deflection magnetic field acting on the center beam is made to be different from the phase of the horizontal deflection magnetic field acting on the pair of side beams, and the brightness signal of the pair of side beams is adjusted to the brightness signal of the center beam. By correcting the phase advance of the luminance signal, it is possible to reduce the green shift to the right.

(Example) Hereinafter, the present invention will be described based on an example with reference to the drawings.

FIG. 2 shows an in-line color picture tube which is an embodiment of the present invention. This color picture tube has an envelope consisting of a panel (10) and a funnel (11) integrally joined to this panel (lO), and the inner surface of the panel (10) emits blue, green, and red light. A phosphor screen (12) consisting of a three-color phosphor layer is formed, and a shadow mask (13) having a large number of electron beam passage holes is arranged inside the phosphor screen (12), facing the phosphor screen (12). It is set up. Also, a center beam (3G) and a pair of side beams (3B) passing on the same horizontal plane within the neck (14) of the funnel (11).

The following electron gun (15) which emits 3 electron beams arranged in rows consisting of (3R) is installed, and the 3tV+ beam emitted from this electron gun (15) is
The shadow mask (13) is deflected in the horizontal and vertical directions by the horizontal and vertical deflection magnetic fields of the deflection yoke (17) attached to the outside of the boundary between the cone (16) and the neck (14). Through the phosphor screen (1
2) by scanning this phosphor screen (1).
2) It has a structure that displays a color image on top.

As shown in FIG. 1, the electron gun (15) has three independent cathodes (19) arranged in a row in the horizontal direction, and three independent cathodes (19) arranged in sequence toward the phosphor screen on the cathodes (19). The main structure includes the first to sixth grids (Gl) to (G6) and the convergence cup (2o), and the cathode (19) and the first to sixth grids (Gl) to (G6).
6) are fixed together by welding a pair of insulating supports (21), and a convergence wire is attached to the sixth grid (G6).
A cup (21) is fixed. In this electron gun configuration, the cathode (1
A lens is formed to refocus the electron beam emitted from the third to sixth grids (G3) to (G3).
G6) constitutes the main lens which ultimately focuses this electron beam onto the phosphor screen (12).

Each of the grids (Gl) to (G6) is made of non-magnetic metal and has three grids corresponding to three cathodes (19).
It consists of a unitized electrode in which several electron beam passage holes are formed. That is, the first and second grids (C1) and (02) successively adjacent to the cathode (19) consist of thin plate-shaped electrodes with three electron beam passing holes, and the third grid (G3) Similarly, the fourth grid (G4) consists of a combination of a cup electrode and a plate electrode having three electron beam passage holes, and the fourth grid (G4) consists of a combination of two plate electrodes. Additionally, the fifth and sixth grids (05)
, (Ge) are each composed of a combination of a cup electrode and a plate electrode, and the sixth grid (G6) side of the fifth grid (G5) has three thick plate electrodes (22a).
) (thick plate electrode), and the fifth grid (G5) side of the sixth grid (G6) consists of two thick plate electrodes <22b) (thick plate electrode). has been done. This fifth and sixth grid (05), (G
Thick plate-shaped electrode (22a) of O).

(22b) has three electron beam passing holes (25B), (25G), (
25R) are formed in a -row arrangement, of which at least one
The center beam passing hole (25G
) are formed with notches (2G) on both sides, and three electron beam passing holes (25B), (25G), (25R).
(
251? ) is smaller than that in ).

In addition, in this electron gun (15), (23) is fixed to the convergence cup (21) and the neck (14)
This is a valve spacer made of an elastic body that presses against the inner wall.

By the way, generally, the phosphor screen (12) side of the electron gun (15) disposed inside the neck (14) is located close to the deflection yoke (17).
) passes through the electrodes that constitute its main lens. Therefore, in particular, the main lens is connected to a thick plate electrode (22a
), (22b), the rear leakage magnetic field of horizontal deflection causes the thick plate-shaped electrodes (22a), (22b)
large eddy currents are generated. However, as mentioned above, the width of the center beam passage hole (25G) portion, that is, the external dimension in the direction in which the horizontal deflection magnetic field passes, is
2513), (25R), the eddy current generated in the center beam passage hole (25G) part will flow through the pair of side beam passage holes (25B).
, the eddy current generated in the (25R) portion is smaller than that generated in the (25R) portion. The eddy current generated in this electrode acts in a direction that obstructs the rear leakage magnetic field of horizontal deflection, so the eddy current generated in the pair of side beams is particularly large compared to the eddy current generated in the center beam passage hole (25G). Passing hole (25B)
, the lag of the rear leakage magnetic field of horizontal deflection at the (25R) portion becomes large. As a result, the phase of the horizontal deflection magnetic field that acts on the center beam passage hole (25G) relative to the side beam passage hole (25B).

(25R). Moreover, since the thick plate-shaped electrode made of non-magnetic material causes a strong phase change in the high-frequency horizontal deflection magnetic field, it can be corrected to cancel out the phase delay of the brightness signal of the center beam (3G). The screen quality of an in-line color picture tube can be improved by reducing the green shift to the right. Note that in this case, the vertical deflection magnetic field has no effect because it has a low frequency.

Note that the present invention is not limited to the electron gun shown in the above embodiment, but can be applied to various types of electron guns.

[Effect of the invention] At least one lens constituting the main lens of the in-line electron gun
By making the external dimensions of the thick electrodes, which are integrally structured, in the horizontal deflection magnetic field passage direction different, corresponding to the plurality of electron beam passage holes, it acts on the center beam of the plurality of beams emitted from the electron gun. The phase of the horizontal deflection magnetic field acting on the side beams is made different from the phase of the horizontal deflection magnetic field acting on the side beams, and the phase advance of the brightness signals of the pair of side beams with respect to the brightness signal of the center beam is corrected, thereby reducing the green shift to the right. In particular, it can be applied to color picture tubes with increased horizontal deflection frequency to improve their screen quality.

[Brief explanation of the drawing]

1 to 3 are detailed explanatory diagrams of the present invention. FIG. 1 is a diagram showing the configuration of an in-line color picture tube electron gun, which is an embodiment of the invention, and FIG. 2 is an embodiment of the invention. A diagram showing the configuration of a certain in-line type color picture tube. Figure 3 is a perspective view of a thick plate-shaped electrode that constitutes the main lens of the electron gun. Figure 4 is a diagram showing a deflection yoke attached to an in-line type color picture tube. A distribution diagram of a magnetic field consisting of a non-uniform magnetic field, Figure 5 is a raster diagram to explain the concentration error of three electron beams due to the non-uniform magnetic field of the deflection yoke, and Figure 6 is a magnetic field control element provided in the convergence cup. Figure 7 is a raster diagram to explain the concentration error of the three electron beams caused by the magnetic field control element, Figure 8 is a diagram showing the phase shift of the luminance signals of the three electron beams, and Figure 9 is a diagram of the Figure 10 is a raster diagram to explain the concentration error of the three electron beams that occurs when the main lens of the gun is configured with a thick inner plate electrode.
FIG. 6 is a raster diagram when an external correction member is used to correct the concentration error of the electron beam. 3G... Center beam 3 Skin 3R... Pair of side beams 2... Phosphor screen 13... Shadow mask 15... In-line electron gun 17... Deflection yoke 19... Cathode 22a ,
22b...Thick inner plate electrodes 25B, 25G, 25R...Electron beam passage hole 26.
...Depth of cut G1...First grid G2...Second grid G3...Third grid G4/Fourth grid G5...Fifth grid G6...Sixth Grino Dorado Dorado agent Patent attorney Dai Hu Dianfu Figure 3 Figure 2 Figure 4 Figure 1 Figure 2fJ Figure 5 Funeral diagram Figure Figure

Claims (1)

[Claims] The main lens includes an electron beam generator that emits a plurality of beams passing on the same plane and a plurality of electrodes that focus the plurality of beams emitted from the electron beam generator onto a phosphor screen. and an in-line electron gun in which the electrode constituting the main lens is composed of at least one integrally structured thick-walled electrode in which a plurality of electron beam passage holes are formed;
In a color picture tube that scans the phosphor screen by deflecting a plurality of beams emitted from the electron gun in the horizontal and vertical directions by horizontal and vertical deflection magnetic fields of a deflection yoke, the at least one thick electrode is A color picture tube characterized in that the external dimensions in the horizontal deflection magnetic field passage direction are different depending on the plurality of electron beam passage holes.