JPS5933932B2 - Gazouhiyoujisouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image display device, particularly a thin image display device.

FIG. 1 is an exploded perspective view showing the constituent electrodes of a conventional thin image display device of this type, in which 1 is a plane cathode that emits electrons; Control electrodes for controlling the amount of electrons; 3 and 4 are row electrodes and column electrodes having a large number of insulated conducting wire groups arranged in directions orthogonal to each other; 5 is a metal made of a thin aluminum film on the side that is exposed to electrons; This is a fluorescent screen electrode with a background.

The electrodes 1 to 5 are arranged in parallel and housed in a vacuum container (not shown) made of a transparent glass material and having at least a transparent section on the front surface. In the conventional image display device configured as described above, a heater (not shown) is now ignited to stand by so that thermionic electrons can be uniformly emitted from the surface cathode 1 at ground potential.

On the other hand, as shown in FIG. 2, numbers are assigned to the conductive wire groups of the row electrodes 3 and column electrodes 4, that is, the grid thin wire groups, and, for example, only "AN" and "Bj" are selected as "positive" potentials, respectively. Set all other thin wires to "negative" potential. With these settings, by selecting the optimal conditions,
It is possible to generate only the image of the selected point 6, which is the intersection of the above-mentioned "AN" and "BN", on the fluorescent surface electrode 5.

Needless to say, the electrons in other parts are cut off due to the negative potential. In addition, the above-mentioned "optimum Jogawa" means that, for example, the potential of "A" and "B" is a few tens of volts to several hundreds of volts, respectively), and the potential of the remaining grid thin lines is a few hundred volts, and the potential of the control electrode 2 and the fluorescent The potential of the surface electrode 5 varies depending on the brightness.
~several 100, and the fluorescent surface electrode 5 has a voltage of several KV. When using the image projected on the fluorescent surface electrode 5 in the manner described above for displaying a television image, the grid thin line group "
It goes without saying that the potentials of "A" and "B" may be switched at the horizontal and vertical scanning cycles of the television, respectively.

Furthermore, when modulating the brightness, the potential of the control electrode 2 may be modulated as described above.

Therefore, when using the above-mentioned conventional image display device for displaying television images, it is sufficient to switch the potentials of the row electrodes 3 and the grid thin line groups of the column electrodes 4 at the scanning period of the television. However, if a high phosphor surface anode potential is required (for example, when using a red-emitting phosphor, 5K or more is required), the row electrode 3 and column electrode 4 are
For example, the switching potential of the switch becomes E5O゛0.1200V, and a switching device using an ordinary IC or a transistor has insufficient withstand voltage, which may cause not only dielectric breakdown but also the inability to switch.

The present invention has been made with this point in mind, and attempts to eliminate the above-mentioned drawbacks by providing a shield electrode between the column electrodes 4 and the fluorescent surface electrodes 5.

That is, FIG. 3 shows one embodiment of this invention.
In the figure, the same reference numerals as those of the conventional image display device (FIG. 1) refer to the same constituent members, and the explanation thereof will be omitted.

Reference numeral 7 denotes a thin shield electrode interposed between the column electrode 4 and the fluorescent surface electrode 5 in parallel with these electrodes. The shield electrode 7 has a potential gradient between the shield electrode 7 and the row/column electrodes 3 and 4 that is the same as the potential when the shield electrode 7 is not present. A potential is given that is smaller than the slope.

Generally, in this type of image display device, when the potential of the fluorescent surface electrode 5 is set high, the fluorescent surface electrode 5 and the control electrode 2
As a result, the switching potential between row electrode 3 and column electrode 4 becomes significantly higher.

In this invention, a shield electrode 7 is interposed between the fluorescent surface electrode 5 and the control electrode 2. . Since the electrons passing through the selection point 6 are allowed to reach the fluorescent surface electrode 5, even if the potential of the fluorescent surface electrode 5 is set high, the distance between the fluorescent surface electrode 5 and the shielding electrode 7 is small. The potential gradient between the shield electrode 7 and the column electrode 4 becomes large, but the potential gradient between the shield electrode 7 and the column electrode 4 is independent of the potential of the fluorescent surface electrode 5.
Therefore, the switching potential between the row electrodes 3 and the column electrodes 4 can be set low and freely.

Therefore, according to the present invention, even if a high potential of, for example, 5 KV or more is required for the fluorescent surface electrode 5 in order to obtain sufficient luminance, the switching potential of the row electrode 3 and column electrode 4 is as follows. For example, as low as 150V, e100V,
Moreover, it can be set freely and has the excellent effect of not being unable to switch as in the conventional case.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing only each electrode of a conventional image display device, FIG. 2 is an explanatory diagram of the operation of row electrodes and column electrodes, and FIG. 3 is a perspective view of only electrodes showing an embodiment of the present invention. be. In the drawing, 1 is a surface cathode, 2 is a control electrode, 3 is a row electrode, 4 is a column electrode, 5 is a fluorescent surface electrode, 6 is a selection point, and 7 is a shield electrode.

Claims (1)

[Claims] 1. A flat planar cathode capable of emitting thermoelectrons uniformly over the entire surface, a control electrode provided parallel to the electron emitting surface of this planar cathode to control the amount of electrons, and an insulated electrode provided parallel to this control electrode. row electrodes and column electrodes consisting of a large number of groups of conductive wires arranged in directions orthogonal to each other; flat fluorescent screen electrodes provided parallel to these electrode surfaces; A vacuum container having a see-through portion is provided on a surface facing the surface electrode, and a synchronous voltage for line scanning is sequentially applied to the row electrodes, and a synchronous voltage for surface scanning is sequentially applied to the column electrodes. In the image display device, the row electrodes and
A shielding electrode is interposed between the column electrode and the phosphor screen electrode, and when there is no potential gradient between the shielding electrode and the row electrode/column electrode. An image display device characterized in that a potential is applied that is smaller than a potential gradient of the image display device.