JPH0251831A - Cathode-ray tube - Google Patents

Abstract

PURPOSE:To prevent the angle of an electron beam emitted from an electron gun against a screen from being reduced and prevent the distortion of an image and the deterioration of resolution at the end sections of the screen by dividing the screen into uniform areas and arranging the electron guns of the division number at the preset positions corresponding to centers of divided faces. CONSTITUTION:Multiple electron guns 2 are arranged behind a fluorescent screen 3, multiple electron guns 2 are driven in the preset order, thus the electron beams emitted from these electron guns 2 scan the whole fluorescent screen 3. One screen is divided and shared by two electron guns 2 and 2, emission points of electron beams are increased, angles thetaa and thetab of the electron beams against the screen are not decreased. The area hit by the electron beam is not expanded, the energy of the electron beam is not reduced. The resolution at the end sections of the screen can be improved, the brightness at the end portions of the screen can be increased.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cathode ray tube used in a display section of a television receiver, etc., and more specifically to a cathode ray tube that can be made high in definition and large in size. .

[Conventional example] Conventionally, this cathode ray tube has an electron gun 2 and a phosphor screen 3 enclosed in a funnel-shaped glass outer tube (glass bulb) 1, for example, as shown in Fig. 3. It has a structure. The glass bulb 1 includes a bulging cone portion 1a at the front,
It is divided into a rear cylindrical neck part 1b and a cone part 1.
A phosphor screen 3 is coated on the bottom of a, and the inside thereof is evacuated to a vacuum.

The electron gun 2 includes a cathode 2a that emits electrons, and a cylindrical electrode 2b that emits the electrons as a beam. The final electrode of the cylindrical electrode 2b is connected to a conductive film 4 coated on the inner surface of the neck portion 1b and the cone portion 1a, and the conductive film 4 is further connected to an aluminum film 5 covering the phosphor screen 3.

Further, in order to scan the electron beam from the electron gun 2 onto the phosphor screen 3, a deflection coil 6 is disposed outside the neck portion 1b. The electron beam is magnetically deflected by the deflection coil 6, and the electron beam is scanned onto the phosphor screen 3.

Here, as shown in FIG. 4, if the fluorescent screen (corresponding to the screen) 3 is flat, the emission point of the electron beam is at one point, so the electron beam at the edge of the screen is The angle θ゛1 (〈θ,) becomes smaller, and as a result, the area hit by the electron beam becomes larger, which not only causes distortion of the image at the edge, but also reduces the electron beam per unit area at the edge. energy decreases, the image becomes darker and the resolution decreases.

By the way, the above-mentioned problem can be solved by increasing the distance between the electron gun 2 and the fluorescent screen 3, but this is not reasonable in terms of space and the like. Therefore, at present, the front of the cone portion 1a (corresponding to the phosphor screen 3) is made closer to a spherical surface, and the scanning of the electron beam in the vertical direction of the screen is controlled nonlinearly.

[Problem to be solved by the invention] However, in the structure of the cathode ray tube described above.

Since the front of the cone portion 1a is made to be close to a spherical surface, the screen to be viewed inevitably becomes smaller, and deterioration of the image at the edges of the screen cannot be avoided.Furthermore, the screens of recent cathode ray tubes are large. I started to like things,
As screens become larger, there is an urgent need to improve image quality by improving the resolution deterioration at the edges of the screen, especially when making the fluorescent screen more planar.

Furthermore, the fact that the front portion of the cone portion 1a is spherical has been an obstacle in making the cathode ray tube thinner.

This invention was made in view of the above points, and its purpose is to improve image distortion and decrease in resolution even if the front part of the cathode ray tube has a flat structure, and to make the screen larger, more compact, and thinner. The objective is to provide a cathode ray tube that can realize the following.

[Means for Solving the Problems] In order to achieve the above object, the present invention scans a fluorescent screen with an electron beam emitted from an electron gun.

In a cathode ray tube that displays an optical image by the action of the electron beam, a plurality of electron guns are arranged behind the phosphor screen, and by driving the plurality of electron guns in a predetermined order, the electron beams are emitted from the electron guns. The electron beam scans the entire phosphor screen.

[Function] With the above configuration, the video signal of the optical image to be displayed on the cathode ray tube is divided according to the receiving area of the plurality of electron guns, and the video signal of the optical image to be displayed on the cathode ray tube is divided into regions corresponding to the receiving areas of the plurality of electron guns, and the plurality of electron guns are divided based on the video signals. are driven in a predetermined order. Then, the electron beams emitted from the electron guns are deflected according to the video signal and scanned onto a predetermined area of the phosphor screen. In this way, the electron beams sequentially fired from all the electron guns,
The optical image is displayed on the screen of the cathode ray tube.

[Example] Hereinafter, an example of the present invention will be described based on the drawings. In FIG. 1, the same parts as in FIG. 3 are designated by the same reference numerals, and redundant explanation will be omitted.

In FIG. 1, a cathode ray tube 10 includes two glass bulbs 1.
(shown in Fig. 3) are joined vertically and are integrally molded. The screen of the cathode ray tube 10 is substantially planar, and therefore the fluorescent screen 3 to which the coating is applied is also substantially planar. The width-to-height ratio of the screen is the same as that of conventional cathode ray tubes. Moreover, the upper part 11 and the lower part 12 of the cathode ray tube 10
are respectively provided with neck portions 11a and 12a at the rear, and an electron gun 2 is provided inside the neck portions 11a and 12a.

Furthermore, in order to scan the electron beam from the electron gun 2 onto the upper surface A and lower surface B of the phosphor screen 3.

Deflection coils 6.6 are arranged on the outside of the neck portions 1b, lb, respectively. Therefore, the deflection coils 6.6 are controlled so that the electron beam from the upper electron gun 2 scans the upper surface A, and the electron beam from the lower electron gun 2 scans the lower surface B. It is done as it should be done.

Next, the operation of the cathode ray tube having the above configuration will be explained based on the screen diagram of FIG.

First, when an image is projected on this cathode ray tube 10, the upper half of the image is projected on the upper surface A of the phosphor screen (equivalent to a screen) 3, and the remaining lower half is projected on the lower surface B of the phosphor screen 3. It will be done. In this case, the number of scanning lines for normal television broadcasting is 5.
For example, the number of electron guns 2 in the upper part 11 is 26.
2.5 scans are performed, and the electron gun 2 in the lower part 12 has 26
2.5 scans are performed. For the scanning line in the middle of one screen, the electron guns 2 in the upper part 11 and lower part 12 are switched at the center O of the phosphor screen 3 by a horizontal synchronization signal.

In this way, since one screen is divided between the two electron guns 2 and 2 and the receiver is held, the number of emission points of the electron beam increases, and the angles θa and θb of the electron beam with respect to the screen do not become small. . Therefore, the area hit by the electron beam does not widen, and the energy of the electron beam does not decrease. Therefore, the resolution at the edges of the screen can be increased, and the edges of the screen can be made brighter. .

Also, the angle θa of the electron beam with respect to the screen.

Since θb is large, it is possible to increase the size of the screen accordingly. Furthermore, since the screen is substantially flat, the cathode ray tube 10 can be made thinner.

In the above embodiment, the case where there are two electron guns 2 has been explained, but the number of electron guns 2 may be 2"') or more. In this case, the screen may be arranged differently depending on the number of electron guns 2. It is sufficient to divide the area into areas and place the electron gun 2 corresponding to the center of the divided area.And then.

To scan the screen, divide the 11,525 beams according to the number of divisions, and use each electron gun to scan the divided number of electron beams.By doing this, one screen can be made larger.
Moreover, the cathode ray tube 1o can be made thinner.

[Effects of the Invention] As explained above, according to the cathode ray tube of the present invention, one screen is divided into equal areas, and the number of divided electron guns is arranged at predetermined positions corresponding to the centers of the divided planes. So,
Even if the screen of a cathode ray tube is flat, the angle of the electron beam emitted from the electron gun to the screen does not become small.
Image distortion and resolution degradation at the edges of the screen can be improved. Further, according to this invention, since the angle of the electron beam with respect to the screen can be increased, the screen can be enlarged.
This has the effect of making the cathode ray tube thinner.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side sectional view of a cathode ray tube showing an embodiment of the present invention, and FIG. 2 is a screen view of the cathode ray tube. FIG. 3 is a schematic side sectional view of a conventional cathode ray tube, and FIG. 4 is a diagram for explaining the relationship between the electron beam and the screen of the cathode ray tube of FIG. In the figure, 2 is an electron gun, and 3 is a fluorescent screen (corresponding to a screen). 6 is a deflection coil, IO is a cathode ray tube, 11 is an upper part (of the cathode ray tube 10), and 12 is a lower part (of the cathode ray tube 10). Figure 1 Patent applicant: Fujitsu General Co., Ltd. Agent, patent attorney Takuya Ohara Figure 2

Claims (2)

[Claims] (1) In a cathode ray tube that scans a phosphor screen with an electron beam emitted from an electron gun and displays an optical image by the action of the electron beam, a plurality of the electron guns are arranged behind the phosphor screen, and the plurality of A cathode ray tube characterized in that the electron beams emitted from the electron guns scan the entire phosphor screen by driving the electron guns in a predetermined order. (2) The cathode ray tube according to claim (1), wherein the phosphor screen is divided into equal areas with respect to the plurality of electron guns, and a neck portion having the electron guns is provided behind the center of the equal areas. .