JPS61124042A - Picture display apparatus - Google Patents

Abstract

PURPOSE:To reduce coma aberration, equalize spot diameter and obtain uniform and high grade picture by controlling electron beam at the initial generating stage of electron in such a way as it is deflected and focused in the vertical direction. CONSTITUTION:This picture display apparatus uses five rear electrodes of 33a-33e per line. Electron group generated from the line cathode 36 is vertically deflected and vertically focused by selecting adequately a voltage applied to the seven electrodes including vertical deflection electrodes 34a, 34b. The dotted lines indicate the electron beams where all electrons generated are vertically deflected while being focused. As explained above, since the speed component can be given to the upper part of vertical direction when the electrons are generated, generation of aberration can be controlled to the utmost and the spot diameter can be equalized. Thereby, almost all electrons generated can be guided, realizing improvement in power efficiency and increase in brightness.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is an image display device in which an electron beam emitted from a hot cathode is controlled by an electron beam control electrode, accelerated and collided with a phosphor surface to display an image. It is related to the device.

Conventional Structure and Its Problems FIG. 1 shows an example of a basic structure of an image display/element that the inventors have been experimenting with.

This display element includes, in order from the back to the front, a back electrode 1, a line cathode 2 as an electron beam source, a vertical focusing electrode 3,
4, 5, a vertical deflection electrode 6, an electron beam flow control electrode 7, horizontal focusing electrodes 8, 9, a horizontal deflection electrode 10, an electron beam acceleration electrode 11, and a screen plate 12 are arranged. are housed within the evacuated interior of a flat glass pulp (not shown). A plurality of line cathodes 2 as electron beam sources (only three line cathodes 2a to 2C are shown here) are provided at appropriate intervals in the vertical direction (Y direction). In this embodiment, it is assumed that 15 pieces are provided. The line cathodes 2 are controlled to sequentially emit electron beams for a fixed period of time starting from the upper line cathode 2a. The back electrode 1 creates a potential gradient between the vertical focusing electrode 3 and the line cathode 2 which is controlled to emit an electron beam for a certain period of time.
It functions to suppress the generation of electron beams from other line cathodes and to push out the generated electron beams only in the forward direction. The vertical focusing electrode 3 is a conductive plate 14 having a large number of through holes 13 arranged at small intervals (so that they almost touch each other) in the horizontal direction facing each of the line cathodes 2. The electron beam emitted from the cathode 2 is taken out through the through hole 13 and focused in the vertical direction.

The vertical focusing electrode 4.5 is similar.

A plurality of vertical deflection electrodes 6 are arranged horizontally at intermediate positions between the through holes 13, and each one has a vertical deflection electrode 6,
The conductor 16 and 16' are arranged on the upper and lower surfaces of an insulating substrate 15. And facing 1
A vertical deflection voltage is applied between e and 1d' to deflect the electron beam in the vertical direction. In this configuration example, the electron beam from one line cathode 2 is vertically deflected to a position corresponding to 16 lines by a pair of conductors 16, 16''.

The 16 vertical deflection electrodes 6 constitute 16 pairs of conductors corresponding to each of the 16 line cathodes 2, so that 240 horizontal lines are drawn on the screen 12. Deflect the electron beam.

Next, the control electrode 7 extracts each n electron beam horizontally by dividing it into one picture element at a time, and controls the amount of the electron beam passing therethrough in accordance with a video signal for displaying each picture element. Therefore, by providing 32,020 control electrodes 7, it is possible to display v320 picture elements per horizontal line. Also,
In order to display images in color, each picture element is displayed using phosphors of three colors, R, G, and E, and the R, G, and I image signals are sequentially applied to each control electrode 7. It will be done. Also, 3
When 20 sets of video signals are applied simultaneously, one line of video is displayed at one time. The horizontal focusing electrode 8 is long in the vertical direction (Y direction) facing the slit of the control electrode 7, and has a large number of through holes (not shown, similar to the through holes 18) arranged horizontally at small intervals. It is composed of a conductive plate 17 having a conductive plate 1, which is divided horizontally, and focuses the electron beam for each pixel in the horizontal direction into a thin electron beam.The horizontal focusing electrode 9 is also similar. belongs to.

The horizontal deflection electrode 1o is composed of a plurality of conductive plates 19 arranged vertically in the middle of the through holes of the horizontal focusing electrode 80. When a voltage is applied, the electron beam for each pixel is deflected in the horizontal direction, and the R, G, and B phosphors are sequentially irradiated on the screen 12 to emit light. Make it. In this embodiment, the deflection range is one pixel wide for each electron beam. Consists of 20 n
The electron beam is focused on screen 1 with sufficient energy.
It plays an auxiliary role in accelerating the electron beam so that it collides with the electron beam 2 and deflecting the electron beam in the vertical direction.

The screen 12 is illuminated by electron beam irradiation.The control electrode 70 has three phosphors 21 for one slit, that is, for each one electron beam divided in the horizontal direction, R, G, and B. A pair of colored phosphors are provided.
It is applied in vertical stripes. In FIG. 1, the two-dot chain lines drawn on the screen 12 indicate the divisions in the vertical direction that are displayed corresponding to each of the plurality of line cathodes 2, and the broken lines indicate the sections of the plurality of control electrodes 7. Shows the horizontal divisions displayed corresponding to. In one partition partitioned by these two, there is R for one picture element in the horizontal direction.
There are oG and B phosphors 21, and the width is 16 lines in the vertical direction. The size of one section is, for example, 1 square inch in the horizontal direction and 16 square meters in the vertical direction. Also,
In this embodiment, for one control electrode 7, that is, for one electron beam, the R, G, and B phosphors 21 are divided into one pixel.
Although only a pair is provided, it is of course possible to provide two or more pairs for two or more picture elements. In that case, the control electrode 7 has R, G, and B for two or more picture elements. Video signals are applied sequentially, and in synchronization with them, horizontal deflection is eliminated.

The above is an outline of the image display device, and the problems of this conventional example will be explained using FIGS. 2 and 3.

FIGS. 2a and 2s are vertical cross-sectional views of the configuration of one line of the display device shown in FIG. 1.

FIG. 2a shows the case where the center of the line is irradiated without vertically deflecting the electron beam, and FIG. 2a shows the case where the top end of the line is irradiated with the electron beam vertically deflected. Figure 3a shows the outline of the spot shape on the screen in the case of the non-deflected beam shown in Figure 2a, and Figure 3a shows the outline of the spot shape on the screen in the case of the vertically deflected beam shown in Figure 2a. An outline of the spot shape is shown. In the case of an undeflected beam, the spot shape is as shown in Figure 3a because the electrons fly vertically symmetrically with respect to the central axis, as shown in Figure 2a, the electron beam trajectory 22&.
It becomes a concentric ellipse shape. In contrast, in the case of a vertically polarized beam, coma aberration occurs because the electrons fly vertically asymmetrically with respect to the central axis, as shown in Figure 2, which shows the electron beam trajectory 22b, and the spot shape is As shown in the figure, it becomes a star shape, and as a whole, the vertical spot diameter φb of the deflected beam becomes smaller than the vertical spot diameter φ of the non-deflected beam, resulting in difficulty in focusing.

Since the vertical spot diameter is unevenly distributed from the center of the line to the end of the line as described above, the image display apparatus has drawbacks such as uneven brightness and uneven resolution of the image on the screen.

OBJECTS OF THE INVENTION The present invention eliminates the above-mentioned drawbacks and provides a high-quality image display device.

DESCRIPTION OF THE INVENTION The present invention has a function of focusing the electron flow at the initial stage of generation in the vertical direction and guiding it to the high voltage side by controlling the combination of the voltages applied to the back electrode and the vertical deflection electrode. This configuration V
Coaxialization of the CLv beam is promoted, and as a result of a reduction in deflection aberration, the beam spot diameter on the screen is made more uniform.

Example An embodiment of the present invention will be described with reference to the fourth factor, FIG. 6.

In Fig. 4, for one line in the vertical direction, 23a
A set of three back electrodes, 23b, 23c, are installed for each line cathode 24a, 24b. Further, the vertical deflection electrode 26 is installed so as to surround the upper and lower sides of the line cathodes 24a and 24b, and the vertical focusing electrode 26 shown in FIG.
, 4 are omitted. The dotted line in the figure is the trajectory of the vertically deflected electron beam.

In the conventional embodiment shown in Fig. 1, the electron beam generated in the horizontal direction from the line cathode was taken out by a vertical focusing electrode 3.4 and then vertically deflected by a vertical deflection electrode e, but coma aberration occurred during this deflection. This causes the spot diameter to be non-uniform as described above. However, in the method of the present invention, the back electrodes 24a, 24b, 24(!
Then, by appropriately setting the voltage applied to the vertical deflection electrode 26, the electron beam axis path as shown by the point le in FIG. 5 can be determined. FIG. 6 shows and explains the control mechanism at the initial stage of electron generation. In the embodiment shown in FIG. 4, three back electrodes were used per line, but in the embodiment shown in FIG.
Five back electrodes of 33θ are used. and 34a
, 34b, the electron group generated from the line cathode 36 can be vertically deflected and vertically focused. The dotted line in the figure shows an electron beam that is vertically deflected while focusing all the returned electrons, and the solid line in the figure is the distribution of equipotential lines. In this way, since it is possible to give a vertically upward velocity component already at the time of electron generation, it is possible to suppress the occurrence of coma aberration as much as possible and to achieve a uniform spot diameter. In addition, another major feature of this method is that the vertical focusing electrode 3,
I'm glad that step 4 could have been omitted. As mentioned above, in the conventional embodiment, a part of the generated electrons is taken out and guided to the screen, but in the embodiment of the present invention,
It becomes possible to guide almost all the generated electrons,
It has advanced features in terms of power efficiency and increased brightness, and also has the advantage of reducing the number of parts.

In Figure 5, only the case where the vertical deflection is fully deflected is shown, but
Even when the beam is deflected in the middle between non-deflection and the like, a good spot shape can be created by individually controlling the voltages applied to the back electrode and the vertical deflection electrode.

Effects of the Invention As described above, the present invention is effective in controlling the electron beam to be vertically deflected and focused in the initial stage of electron generation in a flat panel image display device in which a plurality of line cathodes are installed in the vertical direction. By reducing the spot diameter and making the spot diameter uniform, it is possible to obtain a homogeneous and high-quality image. At the same time, there are fewer difficulties in assembling the electrode, and the number of parts can be reduced, which is a unique advantage.

[Brief explanation of drawings]

Figure 1 is an exploded perspective view of a conventional image display device, Figure 2a,
3b is a vertical cross-sectional view of one line portion in a conventional image display device, FIGS. The figure is an exploded perspective view of an image display device according to an embodiment of the present invention, and FIG. 5 is a vertical cross-sectional view of the vicinity of a line cathode of the image display device. 1, 23a to 23a, 33a to 33e
... = back electrode, 2.24a, 24b, 36--
--= Line cathode, 3.4, 5, 25.35... Vertical focusing electrode, 6° 26.34a, 34b ---
Vertical deflection electrode, 7°27...Electron beam flow control electrode, 8,9,28°29...Horizontal focusing electrode,
10.30...Horizontal deflection electrode, 11.31...
...Electron beam accelerating electrode, 12゜32...
screen. Name of agent: Patent attorney Toshio Nakao and 1 other person
2 Figure α Figure 3

Claims (1)

[Claims] A plurality of linear hot cathodes each having a linear shape in the horizontal direction and being installed parallel to each other in the vertical direction and capable of emitting electron beams;
Other wires other than the linear hot cathode, which are approximately flat plate-shaped, are installed parallel to the linear hot cathode in a plurality equivalent to each one of the linear hot cathodes, and are controlled to emit an electron beam for a certain period of time. a plurality of sets of back electrode means for blocking the electron beam from the linear hot cathode and pushing out the generated electron beam only in the forward direction; and a plurality of through holes for extracting the electron beam from the linear hot cathode. a focusing electrode means arranged in a flat plate shape and located parallel to the back electrode means on the opposite side of the back electrode means via the linear hot cathode; and deflection electrode means for deflecting the electron beam. a control electrode means for controlling the electron beam; an accelerating electrode means for accelerating the electron beam; and a display coated with a phosphor that emits light upon collision of the electron beam; An image display device that controls a combination of voltages applied to electrode means and the deflection electrode means.