JPS61279043A - Image display device - Google Patents

Abstract

PURPOSE:To reduce unevenness of color at the edge of a screen, by extending and fixing plural accelerating electrodes at a rectangular metal frame with plural conductors stuck at the surface of the inside brim through an insulating layer. CONSTITUTION:According to the equipotential line distribution shown on a section square to the screen, at the central portion well apart from the metal frame 23, patterns of conductive plates 26a to 26d to be stuck at the inside brim of the metal frame are produced. By giving adequate potentials to those conductive plates to make them into electrodes, an electric field distribution same as at the central portion of the screen can be secured even near the metal frame, and the landing on the screen in the condition of almost same pitches horizontally can be acquired, without electrons pulled to the metal frame directions. Therefore, reduction of unevenness of color can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an image display device for video equipment.

Conventional technology Conventionally, cathode ray tubes have been mainly used as display elements for displaying color television images, but conventional cathode ray tubes have a much longer depth than the screen, making it difficult to manufacture thin television receivers. It was impossible to do so.

In addition, in recent years, EL elements, plasma display devices, liquid crystal display elements, etc. have been developed as flat display elements, but all of them have low brightness.

It is insufficient in terms of performance such as contrast and color reproducibility of color display, and has not been put into practical use. Therefore,
The purpose is to achieve a device that can display color television images on a flat display device using electron beams, and the screen is divided vertically into multiple sections and each section is divided into two sections. The electron beam is deflected vertically to display multiple lines, and then divided horizontally into multiple sections and phosphors such as R, G-B, etc. are emitted sequentially in each section. A television image is displayed as a whole by controlling the amount of electron beam irradiation to the R, G, B, etc. phosphors using color video signals. An example of a conventional image display element will be described below with reference to the drawings. Figures 2 and 3 are
This shows a conventional image display element. In FIG. 2, from the back to the front, 1 is a back electrode, 2 is a line cathode as an electron beam source, 3 and 31 are vertical focusing electrodes,
4 is a vertical deflection electrode, 6 is an electron beam flow control electrode, 6 and 6' are horizontal focusing electrodes, 7 is a horizontal deflection electrode, 8 is an electron beam acceleration electrode, and 9.22 is a glass container. Then, the components are housed in the glass container 22 and evacuated.

The operation of the image display device configured as described above will be described below. First, 2 as an electron beam source.
The line cathodes are stretched horizontally so as to generate electron beams distributed linearly in the horizontal direction, and a plurality of such 20 line cathodes are arranged vertically at appropriate intervals (here, 2 to 2 lines). (Only four of the two are shown). In this embodiment, it is assumed that 16 pieces are provided, and 2I to 2Y are provided. These wire cathodes 2 are constructed by coating the surface of a tungsten wire with a diameter of 10 to 20 μm, for example, with an oxide cathode material. Then, as will be described later, the electron beams are controlled to be emitted sequentially from the upper line cathode 2 for a fixed period of time. The back electrode 1 suppresses the generation of electron beams from other line cathodes 2 other than the line cathode 2 which is controlled to emit electron beams for a certain period of time, which will be described later, and directs the generated electron beams only in the forward direction. It has the effect of pushing out. This back electrode 1 may be formed by a coating film of a conductive material adhered to the inner surface of the rear wall of the glass pulp. Furthermore, a planar electron beam emitting cathode may be used in place of the back electrode 1 and the line cathode 2. The vertical focusing electrode 3 is the line cathode 2i~
2 horizontally long slits 10 facing each of the
The electron beam emitted from the line cathode 2 is taken out through the slit 1o by the conductive plate 11 having a
Focus vertically. The slit 10 may be provided with crosspieces at appropriate intervals in the middle, or may be a row of through holes provided horizontally at small intervals (so that they almost touch each other). It may be configured with a slit. The vertical focusing electrode 3' is also similar. A plurality of vertical deflection electrodes 4 are arranged horizontally at intermediate positions of the slits 10, and conductors 13 and 13 are provided on the upper and lower surfaces of the insulating substrate 12, respectively.
' is provided. Then, a vertical deflection voltage is applied between the opposing conductors 13 and 13' to deflect the electron beam in the vertical direction.

In this configuration example, the pair of conductors 13 and 13'
The electron beam from the book line cathode 2 is vertically deflected to a position corresponding to 16 lines. And 16 vertical deflection electrodes 4
Thus, 15 conductor pairs corresponding to each of the 16 wire cathodes 2 are constructed, and in the end, 24 conductor pairs are formed on the screen 21.
The electron beam is deflected so as to draw a zero horizontal line.

Next, the electron beam flow control electrodes 6 are composed of conductive plates 16 each having a vertically long slit 14, and a plurality of electron beam flow control electrodes 6 are arranged in parallel in the horizontal direction at predetermined intervals.

In this configuration example, 320 control electrode conductive plates 15a to
15n (only 10 are shown in the figure). Each of the electron beam flow control electrodes 5 divides the electron beam horizontally into one picture element and takes out the electron beam, and controls the amount of electron beam passing therethrough according to a video signal for displaying each picture element. . Therefore, if 32,020 electron beam flow control electrodes 6 are provided, 320 pixels can be displayed per horizontal line. In addition, in order to display images in color, each picture element is displayed with phosphors of three colors, R, G, and B, and each electron beam flow control electrode 6 is provided with the R, G, and B phosphors.
, B are sequentially applied. Furthermore, 320 sets of video signals for one line are simultaneously applied to the 320 electron beam flow control electrodes 6, so that one line of video is displayed at one time. The horizontal focusing electrode 6 has a plurality of vertically long electrodes (32
Consisting of a conductive plate 17 having 0 slits 16,
The electron beams for each picture element divided in the horizontal direction are focused in the horizontal direction to form fine electron beams.

The horizontal deflection electrode 7 is composed of a plurality of conductive plates 18 arranged vertically in the middle of each of the slits 16, and a horizontal deflection voltage is applied between each of the conductive plates 18, so that a horizontal deflection voltage is applied to each pixel. The electron beams are respectively deflected in the horizontal direction, and the R, G, and E phosphors are sequentially irradiated on the screen 21 to cause them to emit light. In this embodiment, the deflection range is the width of one picture element for each electron beam. The accelerating electrode 8 is composed of a plurality of conductive wires 19 provided horizontally at the same position as the vertical deflection electrode 4, and accelerates the electron beam so that it collides with the screen 21 with sufficient energy. The screen 21 is constructed by coating the back surface of the glass container 9 with a phosphor 2o that emits light when irradiated with an electron beam, and adding a metal back layer (not shown). The phosphor 20 has three color phosphors of R, G, and B for one slit 14 of the electron beam flow control electrode 6, that is, for each one electron beam divided in the horizontal direction. They are provided in pairs and are applied in stripes in the vertical direction. Screen 2 in Figure 3
The broken lines drawn in 1 indicate the vertical divisions displayed corresponding to each of the plurality of line cathodes 2, and the two-dot chain lines are displayed corresponding to each of the plurality of electron beam flow control electrodes 5. Indicates the horizontal division. As shown in the enlarged view in Figure 3, one compartment divided by these two has
In the horizontal direction, there are R, G, and B phosphors 2o for one picture element, and in the vertical direction, they have a width for 16 lines. In addition,
In the figure, A is one section in the vertical direction, and B is one section in the horizontal direction. The size of one section is, for example, one block in the horizontal direction and 16 blocks in the vertical direction. Also, please note that in FIG. 3, the horizontal length is greatly expanded relative to the vertical direction to make it easier to see. In this embodiment, only one pair of R, G, and H phosphors 20 is provided for each picture element for one electron beam flow control electrode 6, that is, for one electron beam. However, it is of course possible to provide two or more picture elements, and in that case, R, G, and B video signals for two or more picture elements are sequentially applied to the electron beam flow control electrode 6. Horizontal deflection is performed synchronously.

Problems to be Solved by the Invention However, when a voltage is applied to each electrode in the configuration as described above, there are problems such as color unevenness occurring in the image at the edge. Figure 4 shows this.

This will be explained with reference to FIG. Figure 4 shows the accelerating electrode 1
9 shows an example of the holding method in which the accelerating electrode 19 is stretched and fixed to a rectangular metal frame 23 with high rigidity under high tension. The reason for using this holding method is that the parallelism and linearity of the accelerating electrodes contribute to the vertical deflection sensitivity of the electron beam generated from the upper and lower two line cathodes, and this contributes to the joining accuracy of the upper and lower boundaries of the screen. Don't let it affect you,
This is because it is necessary to maintain the parallelism and linearity of the accelerating electrodes with high precision. In particular, since a high voltage is usually applied to the accelerating electrode 8, a Coulomb force is generated due to the potential difference between the accelerating electrode 8 and the horizontal focusing electrode 6'.
Since the accelerating electrode is subjected to a force in the direction of
3 is required.

However, as shown in the horizontal cross section near the metal frame 23 in FIG. 6, in such a configuration, the same high voltage is applied to the accelerating electrode 19, the metal frame 23, and the metal back layer on the screen 21, so the electric field distribution changes. The two-dimensionality in the horizontal direction is impaired, and the equipotential lines 24 are distorted near the metal frame 23. As a result, the electron beam trajectory 26 is bent near the metal frame, and the electron beams do not land on the screen at an equal pitch. Therefore, the spot of the electron beam is misaligned with respect to the R, G, and B phosphors, causing color unevenness, so that there is a problem that the image near the metal frame cannot be used as an effective screen.

The present invention has been made in view of the above-mentioned problems, and provides an image display device having high quality image quality without color unevenness even at the edges of the image.

Means for Solving the Problems In order to solve the above problems, the image display device of the present invention includes:
It has a structure in which a plurality of accelerating electrodes are stretched and fixed to a rectangular metal frame with a plurality of conductors attached to the inner edge surface via an insulating layer.

Function The present invention suppresses the distortion of the electric field even in the vicinity of the metal frame, maintains the two-dimensionality of the electric field in the horizontal direction, and arranges the electron trajectory in the vicinity of the metal frame.
This makes it possible to reduce the occurrence of color unevenness at the edges of the image.

In other words, a pattern of conductive plates to be attached to the inner edge of the metal frame is created according to the distribution of equipotential lines that appear in a cross section perpendicular to the screen at a central area that is sufficiently far away from the metal frame, and an appropriate potential is applied to each conductive plate. If the electrodes are given with This makes it possible to reduce color unevenness.

Embodiment Hereinafter, an image display device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a method for holding accelerating electrodes of an image display device in one embodiment of the present invention. In FIG. 1, 19 is an accelerating electrode, 23 is a metal frame, and 28a, 28b.

28o and 26d are conductive plates, and 27 is an insulating layer. 6 is a plan view of the inner edge of the metal frame in FIG. 1, and FIG. 7 is a sectional view taken along line 8-A' in FIG. 1.

The pattern of the conductive plates 26a to 26d simulates the equipotential line distribution formed by the accelerating electrode 19 and the metal back layer of the screen, and in this embodiment, four types of conductive plates are used. The more you increase the number of potentials and subdivide the potential, the more precise control becomes possible.

By applying an appropriate potential to each conductive plate 26a to 26d, the distribution of equipotential lines 28 as shown in FIG.
By keeping the electron beams substantially parallel to the screen, the electron beams can land on the screen 21 at substantially equal pitches without bending the electron trajectory 29 toward the metal frame. In particular, since the landing accuracy of most electron beams is stable, except for the electron beams that pass directly near the conductive plates 26a to 26d, it is possible to expand the effective screen area to close to the metal frame. ing.

For other electrode configurations in this example, see 1.
, is similar to the prior art embodiment shown in FIG. Furthermore, the equipotential diagrams and electron beam trajectories shown in Figures 1 and 2 were all created by three-dimensional numerical analysis simulation.

Effects of the Invention As described above, the present invention includes attaching a plurality of conductive plates via an insulating layer to the inner edge of a metal frame that holds an accelerating electrode among a plurality of electrodes placed between a back electrode and a screen, By applying a predetermined potential to each conductive plate, it is possible to correct disturbances in the electric field near the metal frame and organize the electron beam, creating a high-quality effective screen over a wide range up to the area immediately adjacent to the metal frame. It has the unique effect of being expandable.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an accelerating electrode of an image display device according to an embodiment of the present invention and a metal frame for supporting and fixing the accelerating electrode;
FIG. 2 is an exploded perspective view showing the internal basic configuration of an embodiment of the present invention and a conventional image display device, FIG. 3 is a plan view showing the phosphor of the image display device, and FIG. 4 is a conventional image display device. FIG. 5 is a perspective view showing an accelerating electrode in the device and a metal frame that supports and fixes it; FIG. 5 is a horizontal sectional view showing the electric field distribution and electron trajectory near the metal frame of a conventional image display device; FIG. 6 is a perspective view showing an example of the present invention. FIG. 7 is a plan view showing the structure of the inner edge of the metal frame in the embodiment, and a horizontal sectional view showing the electric field distribution and electron trajectory near the metal frame in the embodiment of the present invention. 19...t... Catenary conductor, 23... Metal frame, 26a, 26b, 26a, 26d----
--Conductor, 27...Insulating layer. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure c+J GJ cq
Figure 3 Figure 5 C'

Claims (1)

[Claims] A space surrounded by two sets of opposite sides of a rectangular metal frame with a plurality of conductors pasted to the surface of the inner edge via an insulating layer is formed by attaching a plurality of catenary conductors to the metal frame in parallel to one set of opposite sides. An electrode means which is fixedly stretched and divided into a plurality of spatial regions, and the overhead wire-like conductor and the metal frame are electrically connected to each other, a plurality of linear hot cathodes, and an electrode means for extracting an electron beam from the hot cathode. , electrode means for focusing the electron beam, electrode means for controlling the electron beam, electrode means for deflecting the electron beam, and display means coated with a phosphor that emits light upon collision of the electron beam. An image display device contained within a transparent vacuum container.