JPS5845136B2 - Denshijiyuusouchi - Google Patents

Description

[Detailed description of the invention] The present invention relates to an electron gun device.

FIG. 1 shows an example of a conventional electron gun device, in which reference numerals 1, 2, and 3 indicate an electron gun formed of a plurality of electrodes.

The electron guns 1, 2, and 3 are arranged to form an equilateral triangle at intervals of 120 degrees, and the axes of these three electron guns are arranged so that their extension corresponds to the center of the screen. The electrodes, for example, intersect at a point on the surface -L of the shadow mask 4, so that each electrode is tilted by approximately 1 degree so as to form a triangular gun.

The electron beams emitted from each of the electron guns 1.2.3 pass through the shadow mask 4 and impinge on the fluorescent surface 5, forming desired waves.

However, according to the above-mentioned conventional electron gun device, in order to achieve high resolution image quality, the axial length of each electron gun 1°2.3 is lengthened, and the tube diameter is increased. The cathode side of guns 1, 2, and 3 (X side in Figure 1) is each electron gun 1,
2.3, the glass inner wall that houses the picture tube comes close to or comes into contact with the inner wall of the glass, which causes strays and sparks, resulting in extremely poor performance as a color picture tube.

In order to eliminate this drawback, other ideas as shown in FIG. 2 have been made.

In the same figure, 6, 7.8 is an electron gun, which is 12
They are arranged in parallel to form an equilateral triangle with an interval of 0 degrees.

As shown in FIG. The configuration has a constant slope with respect to the above.

Therefore, the electron beams a, b, and c emitted from the cathodes of the electron guns 6, 7.8 pass through the inclined electron lens L formed between the electrodes 10 and 11, and are bent at this portion. , passes through the hole in the shadow mask 4 and strikes a predetermined phosphor dot t on the phosphor surface 5.

Therefore, since the electron guns are arranged in parallel in this conventional design, the problems such as stray and sparks can be solved and the tube diameter can be increased.

However, according to such a conventional device, the electron beam entering the aperture 12 at the bottom of the third grid electrode 10 in a circular shape (see FIG. The electron beam collides with the central axis of the electron gun in a circular shape with its long axis in the direction of bending (the third
(See figure m).

This is because the main lens L has a certain inclination with respect to the tube axis, so the electron beam incident on the electron lens L), which is the main lens of this electron gun, is not uniformly focused, and the cross section of the electron beam is distorted. arise.

This is called astigmatism.

For this reason, conventional electron gun devices have the drawback of not being able to obtain good images and significantly deteriorating resolution.

The present invention aims to eliminate such drawbacks, and will be explained in detail below using actual winding examples.

FIG. 4 shows an electron gun device according to the first invention.

In the present application, the hole 12 in the bottom aperture part of the electrode 10 in the electron gun device shown in FIG. 3 is made into a circular hole 22 as shown in FIG.

More specifically, the hole 22 is formed as a circular shape having a long axis in the same direction as the long axis of the ellipse (see FIG. 3m) of the electron beam impinging on the phosphor surface.

By forming the hole 22 in this way, the electron beam entering the third grid electrode 10 is distorted through the hole 22 in the bottom aperture of this electrode 10, and becomes a circular shape (see FIG. 4, n). ), enters the main lens L in this state.

This electron beam then causes astigmatism in the main lens L,
Distortion in the cross section of the electron beam and distortion in the electron lens can be canceled out by adjusting the voltage applied to the electrode position so that the best focus is obtained at the center of the fluorescent surface. At the top, one phosphor dot is projected in a substantially circular shape.

(See Figure 4C).

Therefore, the image becomes good without deterioration.

Next, the relationship between the shape of the aperture 22 at the bottom of the third grid electrode 10 and the shape of the beam after passing through this aperture 22 will be explained.

In FIG. 5, the cathode 13. The first grid electrode 14, the second
1 shows an example of an electron gun device according to the present invention comprising a grid electrode (beam accelerating electrode) 15°, a third grid electrode (focusing electrode) 10, and a fourth grid electrode (anode electrode) 11.

An example of the voltage applied to each electrode is 25 KV for the fourth grid electrode 11, 7 KV for the third grid electrode, and 7 KV for the third grid electrode 11.
Since the grid electrode is a beam power low speed electrode, it has a lower value than the third grid K[j, so it is 650V, the first grid electrode 14 has a ground potential of 0V, and the cathode electrode has a voltage of 650V for controlling the beam amount according to the image signal. The voltage is, for example, 50V.

Next, in order to examine the electron lens action near the aperture 22 in Fig. 5, we will calculate the quadratic attack of the on-axis potential near the aperture d2 (--, V: Z2 potential, z: FIG. 6 shows the values calculated for the above applied voltage example.

Here, the electron lens action, that is, the force acting on the electron beam in the direction perpendicular to the electron gun axis, that is, in the radius r direction, is -e - (e: electron charge amount) or dZ2, d2 (i) - In the region >O, the electron beam is acted upon by a focusing lens which is focused in the axial direction Z2.

d2■ (2) In the region -<O, the electron beam is subjected to a force acting in a direction Z2 away from the axis, that is, a diverging lens.

When this is applied to FIG. 6, it is clear that the vicinity of the aperture 22 of the third electrode 10 acts as a diverging lens, and the influence of the shape of the aperture 22 is also that of a diverging lens.

FIG. 7a) FIG. 7 shows the result of calculating the beam shape within the third grid electrode 10 for a single example of the aperture 22 of the third grid electrode 10 shown above.

If the aperture 22 is a circular shape with the long axis in the X-axis direction, the beam shape, which was a perfect circle before passing through the aperture 22, will have a long axis in the y-axis direction, contrary to the shape of the aperture 22. It can be seen that it has changed to an ellipse with .

This is because the vicinity of the aperture 22 acts as a diverging lens as described above.

Therefore, if the distortion of the electron beam caused by the electron lens L tilted with respect to the tube axis as shown in Fig. 3 f becomes an ellipse with its long axis in the X-axis force direction, an aperture is needed to cancel this distortion. It can be seen that the shape of 22 may be an ellipse having the long axis in the X-axis force direction.

Here, although the electron gun device explained in this actual estimation is a △ arrangement type electron gun device, the present invention is not limited to this, and can of course be applied to an in-line type electron gun device. be.

In this case, there is no security in forming the main lens shown in FIG. 3 with the electron gun 1 located at the center, and there is no security in forming the hole 12 in an elliptical shape.

Further, in the present invention, although the electron gun has been described as having a main lens system composed of a single electron lens, it is not limited to this, but is composed of a plurality of electron lenses. Of course, the present invention can be applied to any electron gun having a main lens.

As explained above, according to the electron gun device according to the present invention,
Since each electron gun can be arranged in parallel, the electron gun can be made longer even if the tube diameter is increased, and the electron beam can be projected onto the screen in a good shape, resulting in good image quality. Become something.

[Brief explanation of drawings]

FIGS. 1, 2, and 3 are simplified configuration diagrams showing an example of a conventional electron gun device, and FIGS. 4 and 5 are simplified configuration diagrams showing an example of an electron gun device according to the present invention 1. Figure, Figure 6, Figure 7a
+b is a diagram explaining the effects of the present invention. 1-3, 6-8...electron gun, 4...shadow mask, 5...fluorescent surface, 10...
...Third grid electrode, 11... Anode electrode, 12, 22... Hole.

Claims (1)

[Claims] 1 at least a cathode, a first grid electrode, respectively;
It consists of an electron gun having a second grid electrode, a third grid electrode, and a fourth grid electrode, and whose central axis is arranged approximately parallel to the tube axis of the cathode ray tube, and the second grid electrode of each electron gun has a third grid electrode. By applying a voltage lower than the electrode voltage, a diverging lens is formed in a part of the bottom aperture of the third grid electrode, and the opposing surface of the electrodes of the main lens part consisting of the electrodes after the third grid electrode is aligned with the central axis of the electron gun. In an electron gun device in which each electron beam emitted from each electron gun is concentrated at one point on a phosphorescent surface by tilting the electron gun against Therefore, a hole in a part of the bottom aperture of the third grid electrode of each electron gun is formed into an elliptical shape having a long axis in a direction in which the electron beam is bent from the middle upper sleeve by the main lens part. An electron gun device characterized in that when the electrode voltage is adjusted so that the best focus can be obtained at the center of the phosphor surface of each of the electron beams, each electron beam collides in a circular shape.