JPH0762985B2 - Color image receiver - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a color image receiving device, and more particularly to a shadow mask type color image receiving device using one electron beam.

[Technical Background and Problems of the Invention] In a general color image receiving device for television, three electron guns are arranged at predetermined intervals in an in-line or delta shape, and electron beams are generated, controlled, accelerated, and focused, respectively, and The three electron beams are converged on the screen surface. Since the three electron beams are incident on the shadow masks arranged near the screen at predetermined angles,
A predetermined fluorescent body selected and provided at a predetermined position on the screen is bombarded to emit light. These three electron beams are deflected and scanned on the entire screen by the action of the magnetic field by the deflection yoke. At this time, respective video signals are applied to the control electrodes of the three electron guns in synchronization with the deflection scanning. In such a color image receiving device, three electron beams must be properly converged on the entire screen, distortion of the scanning area (raster) on the screen surface and distortion due to deflection of the beam spot must be removed. This makes the deflection yoke design extremely demanding. These are greatly affected by the distance between the three electron beams incident on the deflecting surface. The smaller the electron beam distance is, the easier the design of the deflection yoke is, and the distortion due to the deflection of the beam spot is remarkably improved. On the other hand, in order to improve the resolution, it is necessary to reduce the beam spot diameter on the screen. For this purpose, it is most effective to make the electron lens aperture of each electron gun as large as possible to form a large aperture lens. Is the way. However, reducing the electron beam spacing, that is, the electron gun spacing, and increasing the electron lens aperture, that is, the electron gun electrode aperture diameter, are contradictory and cannot be improved at the same time.

As one attempt to eliminate such conflicting contradictions, a system as disclosed in JP-A-60-12652 has been proposed. That is, in the shadow mask, slit holes that are long in the horizontal direction are arranged in horizontal rows, and stripe-shaped fluorescent bodies that are continuous in the horizontal direction are provided corresponding to the horizontal rows of slit holes. Then, the horizontal scanning line of one electron beam is made to correspond to one horizontal row of slit holes to generate horizontal stripe-shaped light emission of one color. However, such a method also has many other problems and has a large problem in practical use. For example, three horizontal scans will produce a color trio with a set of red, blue, and green.
With this method, there are 525 horizontal scanning lines, so only 175 pairs of color trios can be obtained in the vertical direction of the screen, which makes it difficult to call it a color image as a whole. If the horizontal scanning lines are tripled to 1575 lines, then in the case of a 20-inch type, the horizontal row of shadow masks, that is, the vertical pitch must be about 190 μm. Row pitch of conventional slit-hole type shadow mask is 500 μm
It is about 800 μm to about 800 μm, and it is technically extremely difficult to etch and punch a thin metal plate for a shadow mask with a row pitch of 190 μm with high precision. Furthermore, the trajectory of the horizontal scanning line of the electron beam and the horizontal alignment line of the shadow mask and the screen must be exactly aligned at any time. This shows that the linearity of the sawtooth wave of the drive current of the deflection yoke is maintained with high accuracy including the change over time.
Extremely complicated circuit system.

[Object of the Invention]

The present invention has been made in view of the above points, and the electrode aperture diameter of the electron gun can be made sufficiently large and the electron beam interval incident on the deflecting surface can be made arbitrarily small, so that high resolution and high convergence can be achieved over the entire screen. It is an object of the present invention to provide a highly practical color image receiving device capable of obtaining a quality color screen.

[Outline of Invention]

According to the present invention, the electron gun diameter is made sufficiently large by using one electron gun, and the first small deflection is performed in three steps before the electron beam is incident on the deflection center plane. The electron beam spacing is made sufficiently small as substantially three electron beams, and a second small deflection for concentrating the substantially three electron beams is performed on the screen, and further electron gun control is performed. The above object is achieved by switching the signals applied to the electrodes to three types of signals in synchronization with the first small deflection.

Example of Invention

 Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 3 is a schematic block diagram of a color image receiving device as an example of the color image receiving device embodying the present invention. FIG. 3 shows a horizontal section including the axis of the electron beam. In FIG. 3, a color image receiving device (1) includes a face plate (3) having a screen (2) on an inner surface thereof and a neck (5) connected to a side wall portion of the face plate (3) through a funnel (4). An electron gun (6) installed inside the neck (5), a deflection yoke (7) as a main deflection unit mounted on an outer wall from the funnel (4) to the neck (5), and the screen ( 2) A shadow mask (9) having a large number of apertures (8) oppositely arranged at a predetermined interval, and a metal back made up of three fluorescent stripes formed on the screen (2) as one group. And a large number of fluorescent bodies (10). The inner and outer walls of the funnel portion (5) have conductive films (11),
(12) is uniformly applied, and an anode button (13) is provided on a part of the funnel portion (4). Through this anode button (13), the anode high voltage is externally applied to the screen (2) and shadow. Mask (9), internal conductive film (11)
And to the final electrode of the electron gun (6). An enlarged perspective view of the electron gun (6) is shown in FIG.

In FIG. 2, the electron gun (6) comprises a plurality of electrodes (to be described later) and four insulating supports (20a), (20b) supporting them.
Is fixed to the stem pin (34) and enclosed in the neck (5). The plurality of electrodes are used for controlling, accelerating, and focusing the electron beam generated from the cathode (22) having a heater (21) for generating one electron beam (15) and the cathode (22). A plurality of electrodes, that is, a first grid (23), a second grid (24) and a third grid (2
5), the fourth grid (2
6), a fifth grid (27) and convergence electrodes (29a) and (29b) as second deflecting means. The first grid (23) and the second grid (24) are plate-like electrodes that are arranged in close proximity, the third grid (25) is a cylindrical electrode that is arranged in close proximity to the second grid (24), and the fourth The grid (26) is separated from the third grid (25) by a predetermined distance and is composed of two divided cylindrical electrodes (26a) and (26b), and the fifth grid (27) is separated from the fourth grid (26). Cylindrical electrodes arranged at a predetermined distance, and a valve spacer (28) is attached to the side wall of the cylindrical electrode to make contact with the internal conductive film (11) and an anode high voltage Eb of about 25 kV to 30 kV is applied. It has become like. Convergence electrodes (29a) and (29b) are arranged at a predetermined distance from the fifth grid (27). The central electrode (29
a) is connected to the fifth grid (27) by the connector (31), and the electrodes (29b) on both sides are connected by the connector (32) at the back of the insulating support (20a). 33)
And is capable of supplying an appropriate electric potential as disclosed in Japanese Patent Laid-Open No. 53-89360. The third grid (25) and the fifth grid (27)
Are connected by a connector (30), and the two electrodes (26a), (26b) and other electrodes of the fourth grid (26) are connected to the stem pin (34) at the bottom of the neck so that a predetermined comparison can be made from the outside. A relatively low voltage is applied.

In the above electrode structure, the cathode (22) is kept at a cutoff voltage of about 150 V, and three kinds of video signals are applied thereto at a predetermined cycle. Ground potential is applied to the first grid (23), about 700V is applied to the second grid (24), and the third grid (25)
An anode high voltage of about 25 kV is applied to the fifth grid (27) and the central convergence electrode (29a). Also the fourth
In the grids (26a) and (26b), an appropriate potential difference is generated between the fourth grids (26a) and (26b) in accordance with the periods of the three types of video signals, and the average potential is about 4kV
A medium potential is applied. A potential of about 23 kV, which is slightly lower than the high voltage of the anode, is applied to the convergence electrodes (29b) on both sides. Therefore, one electron beam (15) generated from the cathode (22) is controlled by the cathode (22), the first grid (23) and the second grid (24), and the third grid (25) and the fourth grid ( 26), the unipotential electron lens of the 5th grid (27) accelerates and focuses the light to reach the screen, but at the same time when it passes through the 4th grid (26), the Z-axis (tube axis ) Is subjected to two-stage electrostatic deflection in the direction away from. In this case, the electron beam (15) which is not subjected to the small deflection passes through the center of the convergence electrode and thus reaches the screen as it is, but the electron beam (16) or (17) which is subjected to the small deflection is transferred to the center electrode (29a) of the convergence electrode. ) And the outer electrode (29b), it is electrostatically deflected by this convergence electrode in the direction approaching the Z axis (paraxial direction). That is, the fourth
Substantially three electron beams (15), (16), (17) concentrated on the screen by the first small deflection by the grid (26) and the second small deflection by the convergence electrode (29)
Is present, and as shown in FIG. 1, these substantially three electron beams respectively enter the shadow mask (9) at a predetermined angle, are selected, and are provided at positions corresponding to the incident angle. The fluorescent substance on the screen is struck and the light is emitted. At this time, the first small deflection by the fourth grid portion and the periods of the three types of video signals applied to the cathode are synchronized. These three electron beams (15 '), (1
Deflection device (7) deflects and scans 6 ') and 17'.

FIG. 1 schematically shows only the main part of the above embodiment. At this time, the distance Sg between the three electron beams at the deflection center plane (18) is substantially equal to the fourth grid (26) and the convergence electrode (29).
It is determined by the degree of small deflection due to a) and (29b) and can therefore be made arbitrarily small. In practice, if the distance Sg between the three electron beams is made too small, the distance q between the shadow mask (9) and the screen (2) must be made extremely large in accordance with the basic principle of the shadow mask type color picture tube. In Sg should be chosen. On the deflection surface, if the electron beam interval Sg is small, the unbalance of the deflection magnetic field that the three electron beams receive is reduced, so that the deflection aberration can be similarly reduced for the three electron beams, and the deflection aberration can be reduced around the screen. A good three beam spots can be obtained.

Next, FIG. 4 shows a time chart of the current flowing through the deflection yoke, the deflection voltage applied to the fourth grid, and the three video signals. In FIGS. 1 to 3, the video signal Svideo is applied to the cathode (22), the small deflection voltage vag is applied to the fourth grid (26), and the horizontal and vertical deflection coils of the deflection yoke (7) are applied. A horizontal deflection current iH and a vertical deflection current iv are passed respectively. Vertical deflection current i in FIG.
In v, a sawtooth current flows once for a predetermined time Tv, and the electron beam is deflected and scanned once in the vertical direction. Corresponding to this, horizontal deflection scanning is performed as shown in FIG. Correspondingly, the horizontal horizontal deflection current iH shown in FIG. 4 (b) is a sawtooth current flowing once for a time TH which is much shorter than TV, and the electron beam is horizontally deflected for one scanning. Therefore, horizontal deflection is scanned a predetermined number of times during one vertical deflection. (However, in FIG. 4, the blanking period at the time of deflection scanning is omitted.) In the conventional scanning method of the video signal, 3 corresponding to red, green, and blue are provided.
Using the electron beam of the book, three colors are simultaneously generated during one horizontal deflection period. However, in the present invention, since only one electron beam is used, it is impossible in principle to emit three colors at the same time. Therefore, during one horizontal deflection period, it is possible to perform small deflection one after another, for example, by the fourth grid (26) in accordance with the aperture of the shadow mask to perform color switching. However, since the small deflection switching frequency becomes too high, in this embodiment, as shown in FIG. 4, the small deflection switching frequency Δt becomes equal to one horizontal scanning line period TH, and the small deflection switching frequency becomes high. It prevents you from going too far. In addition, with this, the fourth
As in the horizontal scanning period TH, the red, green and blue color image signals are sequentially switched in synchronism with the small deflection switching as shown in FIGS. (B), (c) and (d).

As described above, in the present invention, the horizontal deflection frequency is three times that in the conventional case because the horizontal deflection frequency is equal to the single horizontal deflection of the conventional three-electron gun color picture tube device in the present invention. In the current NTSC system, the horizontal deflection frequency is 15.75kHz, so three times this
Although it is 47.25 KHz, there is no practical problem at this level of frequency from either circuit technology or deflection yoke technology. Further, the design of the deflection yoke in this case can be realized without any new technology, and at the same time, the electron beam interval on the deflection surface in the deflection yoke is much smaller than that of the conventional three-electron gun type. This is an extremely easy condition. That is, since the unbalance of the magnetic field distribution in the deflection yoke is reduced, the deflection aberration can be similarly reduced for the three electron beams, and good three beam spots can be obtained in the peripheral portion of the screen as well as the convergence quality. It is also clear that this will be much improved.

Although the unipotential type electron gun is used as the electron gun in the above embodiments, the present invention is not limited to this, and any type of lens type electron gun may be used. Further, in the above-mentioned embodiment, the case where substantially three electron beams are arranged in a horizontal row has been shown, but the present invention is not limited to this, and a small deflection is performed so that the substantially three electron beams become a delta arrangement. It goes without saying that you can go. Further, in the above-mentioned embodiment, the color image receiving device having one electron gun for one screen has been described, but the present invention is not limited to this, and is incorporated in Japanese Utility Model Publication No. 47-9349, Japanese Utility Model Publication No. 39-25641, and It goes without saying that each of the color image receiving devices having a large number of electron guns by dividing one screen, such as Japanese Patent Publication No. 42-4928, can also be applied individually.

〔The invention's effect〕

As described above, according to the present invention, by using one electron gun, the electrode aperture diameter, that is, the electron lens aperture diameter can be set regardless of the beam intervals of a plurality of electron beams substantially formed on the deflection surface. It is possible to increase the size and obtain a high-resolution image, and at the same time, the beam intervals of a plurality of electron beams can be arbitrarily reduced regardless of the aperture of the electron lens, resulting in excellent convergence quality on the entire screen. High-quality images can be obtained. Furthermore, since the beam interval can be made small, only the vicinity of the central axis of the deflection magnetic field can be used. Therefore, the imbalance of the deflection magnetic field received by multiple electron beams is reduced, and a good beam spot can be obtained around the screen. can get.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a color image receiving apparatus of an embodiment of the present invention, FIG. 2 is an enlarged perspective view showing an electron gun unit applied to the embodiment of FIG. 1, and FIG. 3 is a system of the color image receiving apparatus. And FIG. 4 is a time chart showing signals to respective parts in the embodiment of FIGS. 1 to 3. (1) …… Color image receiving device (2) …… Screen (5) …… Neck (6) …… Electron gun (7) …… Main deflection part (9) …… Shadow mask (10) …… Fluorescent body (15), (16), (17), (15 '), (16'), (1
7 ') ... electron beam (18) ... deflection center plane (22) ... cathode (26) ... first auxiliary deflection means (29a), (29b) ... second deflection means

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takashi Nishimura 1-9-2 Harara-cho, Fukaya-shi, Saitama Inside Fukaya CRT factory, Toshiba Corp. (56) Reference JP-A-51-135432 (JP, A) JP Showa 44-7867 (JP, B1) Japanese Patent Sho 47-1411 (JP, B1) Showa 43-1072 (JP, Y1)

Claims (1)

[Claims] 1. An electron gun, a shadow mask, a screen, and a main deflection unit arranged on the tube axis in the neck, and are provided in accordance with three types of video signals of red, green and blue generated from the electron gun. The electron beam controlled and deflected and scanned in the horizontal direction and the vertical direction by the main deflecting unit causes a predetermined fluorescent body disposed on the screen to impact and emit light through the shadow mask, and one electron gun is provided. Image receiving means for generating an electron beam, a first auxiliary deflecting means and a second deflecting means, and a plurality of electrodes for controlling, accelerating and focusing the electron beam generated from the cathode. In the apparatus, by switching the potential of the auxiliary deflection electrode, the electron beam is subjected to the first small deflection in three steps in synchronization with the horizontal deflection scanning, and three electron beams separated in the horizontal direction are generated. In addition, the first auxiliary deflecting unit that sequentially switches the three types of video signals applied to the electron gun, and the first auxiliary deflecting unit and the main deflecting unit are provided between the first auxiliary deflecting unit and the first auxiliary deflecting unit. 3 by the auxiliary deflection means of 3
Two electron beams on both sides of one electron beam are slightly deflected in the paraxial direction, the three electron beams are made to have a predetermined interval in the main deflection section, and are made incident on the shadow mask, and are concentrated on the screen. A color image receiving device comprising: