JPH03159036A - Picture display unit - Google Patents

Abstract

PURPOSE:To have no influence upon signals transmitted on a printed circuit board by bonding a conductive sheet to the opposite-side plane of a glass vessel having a back metal in its floating state for constructing a vacuum vessel, via the insulating sheet and then earthing the conductive sheet. CONSTITUTION:For improvement in picture quality, a modulation signal is impressed upon a back electrode 1 to have electrostatic capacity between a back metal 11 and the back electrode 1 so that the AC component of the modulation signal appears on the back metal 11. Hereupon, the back metal 11 in its floating state is insulated by means of an insulating sheet 32 having its low dielectric constant so as to be bonded to a conductive sheet 31 an the conductive sheet 31 is subsequently earthed. As a result of this, the conductive sheet 31 is set to its zero potential to come under no influence of the modulation signal in the back electrode 1 while an increase in electrostatic capacity viewed from the back electrode 1 may be slighter than that in electrostatic capacity generated when the back metal 11 is earthed. This can lighten the interference of the modulation signal impressed upon the back electrode 1 with signals transmitted on a printed circuit board so as to improve the quality of a picture.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention generates an electron beam for each division when a screen on a screen is vertically divided into a plurality of divisions, and generates an electron beam for each division. This invention relates to an image display device that displays a television image as a whole by displaying a plurality of lines by vertically deflecting an electron beam.

[Conventional technology]

First, an example of a conventional image display device that has been proposed by the applicant will be described with reference to FIG. 2. In FIG. 2, 1 is a back electrode, 2A to 2D are linear electron beam sources formed by installing linear cathodes, 3 is an electron beam extraction electrode, 4 is an electron beam flow control bridge, and 5 is a first focusing The electrodes 6 are second focusing electrodes, 7A and 7B are horizontal deflection electrodes, and 8A and 8B are vertical deflection electrodes.

Then, these components are stored in the glass container H1O and the back metal 11 which becomes the container, and the glass container ]O
And the inside of the back metal 11 is kept in a vacuum.

The linear electron beam sources 2A to 2D are stretched in the horizontal direction so as to generate an electron flow with a substantially -like t-current density distribution in the horizontal direction, and are arranged in a plurality of linear electron beam sources (number 1) in the vertical direction at appropriate intervals. 2
In the example shown, 2A and 2B.

(Only four beams 2C and 2D are shown) are provided, and an electron beam is generated for each vertical section in which the screen of the screen 23 is vertically divided into a plurality of sections. These linear electron beam sources 2A to 2D are constructed, for example, by coating the surface of a tungsten wire with an oxide cathode material.

The back electrode 1 is made of a flat plate-shaped conductive material, is provided parallel to the linear electron beam sources 2A to 2D, and controls the amount of electron beams from the linear electron beam sources 2A to 2D.

The electron beam extracting electrode 3 has a linear electron beam 528~
Back electrode 1. via 2D. ! 44, and has a row of through holes I2 provided at appropriate intervals in the horizontal direction on a horizontal line facing each of the linear electron beam sources 28 to 2D. The second through-hole 12 serves as a separation means for separating the generated electron beam into each horizontal section and irradiating the screen 23 with the separated electron beam.
In the figure, it is circular, but it can also be oval or rectangular.
A slit-like one may also be used.

The electron beam flow side jB'R pole 4 is a row of vertically elongated conductive plates 14 arranged at predetermined intervals at positions horizontally opposite to each of the through holes 12 in the electron beam extraction electrode 3. Each conductive plate 14 has a similar through hole 13 at a position opposite to the through hole 12 of the electron beam extracting electrode 3, and the electron beam screen 23 separated by horizontal section The shape of the six through holes 13, which control the amount of light emitted from each picture element on the screen 23 by controlling the amount of irradiation, may be an ellipse or a rectangle, or may be shaped like a vertically elongated slit.

The first focusing IF pole 5 is made of a conductive plate having through holes 15 at positions facing each of the through holes 13 of the electron beam flow control electrode 4. The shape of the through holes 15 is circular.

The second focusing electrode 6 may be elliptical or slit-like.
It has a vertically connected through slit hole 16 at a position opposite to the through hole 15 of the first focusing electrode 5 . The shape of the slit hole I6 may be a round hole, an ellipse, or a rectangle like the through hole 15 of the first focusing electrode 5. control the size of light emitted on the phosphor surface.

The horizontal deflection electrodes 7A and 7B are composed of two conductive plates 18 and 19 connected by comb-like end portions that are interlocked with each other with an appropriate space between them on the same plane.
, 7B is opposed to the through hole 16 of the second focusing electrode 6. Vertical deflection electrode 8A
, 8B consists of conductive plates 20.21 connected at their ends, that is, two comb-shaped conductive plates 20.21 that are interlocked with each other at appropriate intervals on the same plane. 22, the lower conductive plate 20 and the upper conductive plate 21 form a pair of vertical deflection electrodes, which direct the electron beam in multiple steps in the vertical and horizontal directions up to the screen 23. deflect.

The screen 23 is constructed by coating the inner surface of the glass container 10 with a phosphor 24 that emits light when irradiated with the electron beam 22, and adding a metal back layer (not shown) thereon.

The operation of the image display device configured as described above will be explained.

First, a voltage v1 is applied to the back electrode 1, and a voltage V2 higher than vl is applied to the electron beam extracting electrode 3.

Further, the linear electron beam sources 2A to 2D are heated and a heater current is applied to facilitate electron emission, such that y<v
, <V2, an appropriate voltage■. When is applied to the linear electron beam a2A, the electric field on the surface of the linear electron beam fIJ2A becomes positive, and the electron beam 22 is emitted and accelerated toward the electron beam extraction electrode 3. Also, for example, V, <V
If a voltage V0 of 2 is applied to the cotton-like electron beam B2A,
The electric field on the surface of the linear electron beam tAz becomes negative, and electron emission can be suppressed.

Therefore, by individually controlling the voltages of the flocculent electron beams B2A to 2D, the linear electron beams g2B and 2C are sequentially generated from the upper linear electron beam source 2A.

. . . is repeated so that the electron beams are emitted for a certain period of time in order, and each of the linear electron beams 528 to 2D is made into a sheet-like sheet with a uniform 14 current density distribution in the horizontal direction. It can generate an electron beam.

The above-mentioned sheet-shaped electron beam is then horizontally divided into a plurality of pieces by the through hole 12 of the electron beam extraction electrode 3, and reaches the through hole 13 of the electron beam flow control electrode 4 as a further large number of electron beam rows. However, at this time, the voltage v3 of the electron beam flow control electrode 4 is set to ■3>■. If V3<V, the electron beam loses kinetic energy and cannot pass.

Therefore, by controlling the voltage V3 over time, the amount of electron beam passing is individually adjusted for each electron beam in accordance with the video signal for displaying the picture element.

The electron beam that has passed through the electron beam flow control electrode 4 then reaches the first focusing electrode 5 and the second focusing electrode 6, where it is focused and shaped by the electrostatic lens effect of the through hole 152 and through slit hole 16. , horizontal deflection 18i7A, '7E3
The potential difference (
is electrostatically deflected horizontally and vertically by a deflection voltage (referred to as a deflection voltage).

Furthermore, the metal bank layer of the screen 23 has a high voltage (
For example, 10KV) is applied, the electron beam is accelerated to high energy and collides with the metal bank, and the phosphor 2
4 to emit light.

When the television digital screen is divided vertically and horizontally into a matrix of subsections 25, one electron beam separated as described above is made to correspond to each subsection, and the electron beam is divided into each subsection. By deflecting and scanning only the inside, the entire image can be displayed on the screen. Further, by adding RGB video signals corresponding to each picture element to the electron beam flow control electrode and controlling the electron beam over time as described above, a television moving image can be reproduced.

[Invention tries to solve! l! Title]

However, in the above configuration, the cutoff characteristic of the integrated circuit for driving the beam flow control electrode is poor, so by adding a modulation signal to the back surface amount FIi1 and stopping the emission of the electron beam from the cathode, the beam flow control electrode is This has the same effect as cutting off the drive integrated circuit.

This eliminates excess electron beams that reach the anode without being canted off when the beam flow control electrode 4 is cut off, that is, when a change signal or the like is switched, thereby improving image quality.

However, the back electrode 1 and the back metal 11 are several thousand 9F
When the back metal 11 is placed in a floating state, the modulation signal of the back electrode 1 (approximately 50 VP-
F ) is applied to the back metal 11 via the capacitor, and the back metal 11 is modulated by I OVP-F. As shown in FIG. 3, the printed circuit board 33 is arranged with the back metal 11 and the insulating plate 32 sandwiched between them.
Due to changes in the electric field caused by changes in the voltage on the back metal 11, signals on the printed circuit board 33, especially video signals, are modulated and appear as noise on the screen.

When back metal 11 is connected to ground etc., the back [
The problem is that the capacitance of il becomes too large, making it impossible to obtain sufficient signal characteristics and increasing power consumption.

An object of the present invention is to provide an image display device that does not affect signals on a printed circuit board when the back metal is electrically floating.

[Means to solve the problem]

In the image display device of the present invention, a conductive plate is attached to the surface of a floating back metal constituting a vacuum container, opposite to the glass container, with an insulating plate interposed therebetween, and the conductive plate is grounded.

[For production]

With the above-described configuration, the present invention uses a conductor plate that is insulated from and bonded to the back metal to prevent interference caused by a modulation signal applied to the back electrode to a signal on the printed circuit board via the back metal that constitutes the vacuum container. This is prevented by grounding, and by floating the back metal, the increase in capacitance of the back electrode is reduced.

〔Example〕

An image display device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a part of an image display device according to an embodiment of the present invention.

In FIG. 1, 1 is a back electrode, 2A to 2D are linear electron beam sources, 10 is a box-shaped glass container with one side open, and 11 is attached to the opening of the box-shaped glass container IO. 31 is a conductor plate, 32 is an insulating plate interposed between the back metal 11 and the conductor plate 31, and 33 is a printed circuit board. Other components housed in the vacuum container are the same as those of the conventional example shown in FIGS. 2 and 3.

The operation of the image display device configured as described above will be explained below with reference to FIG.

In order to improve image quality, a modulation signal is applied to the back electrode l, and since it has a capacitance between it and the back metal 11,
The alternating current component of the modulated signal appears on the back metal 11.

Therefore, when the floating back metal 11 is insulated by an insulating plate 32 with a low dielectric constant and attached to a conductor plate 31, and the conductor plate 31 is grounded, the conductor plate 31 becomes zero potential, and the influence of the modulation signal of the back electrode 1 is reduced. Moreover, the increase in capacitance seen from the back electrode 1 is small compared to when the back metal 11 is grounded.

As described above, according to this embodiment, the insulating Fi3
By pasting the conductor plate 31 together through the conductor plate 2 and grounding the conductor plate 3, the modulation signal applied to the back electrode 1 can be connected to the printed circuit board without significantly increasing the capacitance when the back side is viewed from the pole 1. It is possible to reduce the interference caused to the above signal.

〔Effect of the invention〕

According to the image display device of the present invention, a conductive plate is attached to a floating back metal constituting a vacuum container via an insulating plate, and the conductive plate is grounded. It is possible to reduce the interference caused by the modulation signal applied to the back electrode to the signal on the printed circuit board without significantly increasing the capacitance seen from the pole, and ii! ii quality can be improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a part of an image display device according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of a conventional image display device.
3 is a partial sectional view of the image display device of FIG. 2. FIG. 1... Back electrode, 2A-2D... Linear electron beam source, 3... Electron beam extraction electrode, 4... Electron beam flow control electrode, 5... First focusing electrode, 6... ...Second focusing electrode, 7A, 7B...Horizontal deflection electrode, 8A, 8B.
...Vertical deflection electrode, 10... Box-shaped glass container, 11.
... Back metal, 31... Conductor plate, 32... Insulating plate, 33... Printed circuit board 1... Back electrodes 2A to 2D... Linear electron beam source 31... Conductor plate] Barnowameful

Claims (1)

[Claims] a screen coated with a phosphor that emits light when irradiated with an electron beam; a linear electron beam source that generates an electron beam in each vertical division of the screen divided into a plurality of vertical divisions; separating means for separating an electron beam generated by a shaped electron beam source into each horizontal section and irradiating the electron beam onto the screen; an electron beam flow control electrode that controls the amount of light emitted from each pixel on the screen by controlling the amount of electron beams separated for each horizontal section irradiated onto the screen; In each pixel, there is a focusing electrode that controls the size of light emitted by the electron beam on the phosphor surface, a back electrode that controls the amount of electron beam from the linear electron beam source, and a floating electrode that controls the opening of the box-shaped glass container that is open on one side. a vacuum container containing the screen, a linear electron beam source, a separating means, a deflection electrode, an electron beam flow control electrode, and a back electrode, with the back metal placed on the back metal side; . An image display device comprising: a conductive plate bonded to the back metal with an insulating plate interposed therebetween and grounded on the opposite side of the bonding surface with the box-shaped glass container.