JPH06208834A - Reflection type flat cathode-ray tube - Google Patents

Abstract

PURPOSE:To restrict generation of luminescent line at the time of displaying a window signal by providing a grounded low resistance conductive film, on the outer surface of a screen panel. CONSTITUTION:A low resistance conductive layer 11 such as copper foil, for example, of the resistivity of 10<-7>OMEGA, is provided on the outer surface of a screen panel 2, and is grounded, to form a reflection type flat cathode-ray tube 9. A capacitor of low impedance is formed by an ITO conductive layer 3 of the inner surface of the panel 2 and by a copper foil 11 of the outer surface, in the tube 9. When a window signal is input therein, a phosphor surface 4 on which an electron beam scans, and the panel 2 are to be charged negative, however, since the panel 2 is ac-connected with a GND, fluctuation in the load is absorbed by the GND at low resistance. Variation in the electric field in a CRT is thus almost eliminated, and a luminescent line can be minimized. When a window signal, for which fluctuation in current is large, the luminescent line can be restricted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection type flat cathode ray tube, and more particularly to a reflection type flat cathode ray tube in which a bright line generated when a window signal is displayed is suppressed.

[0002]

2. Description of the Related Art A conventional reflective flat cathode ray tube (CRT) having no conductive film such as ITO (indium tin oxide) on the inner surface of a front panel is shown in FIG. An ITO conductive film 3 applied to the inner surface of the panel 2 to which a high voltage (HV) is applied, a fluorescent screen 4 applied to the ITO conductive film 3, a deflection yoke 5 for horizontal and vertical deflection, and a video signal. It is equipped with an electron gun 6 to be obtained.

[0003]

In such a conventional reflection type flat cathode ray tube, when the grounded low resistance conductor is not provided on the outer surface of the screen panel 2, as shown in FIG.
As shown in, the fluorescent screen 4 scanned by the electron beam and the screen panel 2 are negatively (-) charged when the window signal is displayed. On the other hand, the front panel 1 is in a high resistance state because there is no ITO conductive film, and the high voltage potential is maintained as it is. At this time, an electric field E other than the magnetic field of the deflection yoke 5 is generated from the front panel 1 in the direction of the screen panel 2 inside the CRT, and the trajectory of the electron beam is deviated in the direction of the front panel 1 (upward). Then, the window of the fluorescent screen 4 shifts to the upper side of the screen, and as shown in FIG.

Further, as shown in FIG. 5, exterior carbon is applied to the outer surface of the screen panel 2 to be grounded (GND).
Even in the conventional reflection type flat cathode ray tube having such a configuration, the specific resistance of the exterior carbon is relatively high, such as several hundreds of Ω / cm, and it is insufficient to absorb the charge fluctuation inside the CRT by grounding (GND). Therefore, as in the case described above, FIG.
The bright line 10 shown in FIG.

FIG. 6 is an equivalent circuit diagram of the conventional reflection type flat cathode ray tube shown in FIG. 5, and the HV becomes unstable due to the high specific resistance of the exterior carbon as described above.

Therefore, the present invention has been made in consideration of the above problems.
An object of the present invention is to provide a reflective flat cathode ray tube capable of suppressing the generation of bright lines when displaying a window signal.

[0007]

According to the present invention, there is provided a reflection type flat panel comprising a front panel, a screen panel facing the front panel, and a transparent conductor film and a fluorescent surface on the inner surface of the screen panel. In the cathode ray tube, a reflection type flat cathode ray tube characterized in that a grounded low resistance conductor film is provided on the outer surface of the screen panel.

[0008]

According to the reflective flat cathode ray tube of the present invention,
For example, a transparent conductor film 3 such as ITO (indium tin oxide)
Is provided on the inner surface of the screen panel 2 facing the front panel 1, not on the inner surface of the front panel, together with the phosphor screen, and on the outer surface of the screen panel 2, a grounded low-resistance conductor film is provided. It is possible to stabilize the internal charge of the CRT by absorbing a sudden change in the beam current at the upper part of the window during display. Therefore, even when the window is displayed, the electron beam trajectory does not receive any electric field other than the deflection yoke (DY) magnetic field, and the generation of bright lines can be suppressed.

In the present invention, the low resistance conductor film preferably has a specific resistance of 10 ^-4 Ω / cm or less, and a specific resistance of 10 Ω / cm or less.
^-7 Ω / cm copper foil is preferred.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a schematic view for explaining an embodiment of a reflection type flat cathode ray tube according to the present invention. As shown in FIG. 1, the reflection type flat cathode ray tube 9 of the present invention has a low resistance such as a copper foil having a specific resistance of 10 ⁻⁷ Ω / cm on the outer surface of the screen panel 2 of the conventional cathode ray tube shown in FIG. The conductor layer 11 is provided and grounded. That is, in the cathode ray tube 9 of this embodiment, the ITO conductive layer 3 on the inner surface of the screen panel 2 and the copper foil 11 on the outer surface form a low-impedance capacitor and are grounded. 2 is an equivalent circuit of the reflection type flat cathode ray tube of the present invention shown in FIG.

In the above embodiment, when the window signal is input, the fluorescent screen 4 scanned by the electron beam and the screen panel 2 try to be negatively charged, but the screen panel 2 is AC-coupled with GND, so that the change in charge does not occur. It has low resistance and is absorbed by GND. Therefore, the change in the electric field inside the CRT is almost eliminated, and the generation of bright lines can be suppressed to the minimum.

[0013]

As described above, according to the present invention,
It is possible to suppress the generation of bright lines when displaying a window signal whose current changes drastically.

[Brief description of drawings]

FIG. 1 is a schematic view for explaining an embodiment of a reflective flat cathode ray tube according to the present invention.

FIG. 2 is an equivalent circuit diagram of the embodiment shown in FIG.

FIG. 3 is a schematic partial cross-sectional view of a conventional reflective flat cathode ray tube.

FIG. 4 is a schematic diagram for explaining the operation of the CRT in FIG.

5 is a schematic diagram for explaining the operation of a conventional reflective flat cathode ray tube in which the screen carbon of the cathode ray tube in FIG. 4 is coated with exterior carbon.

6 is an equivalent circuit diagram of the structure of FIG.

FIG. 7 is a diagram showing a bright line which is a display defect when a window signal is displayed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front panel 2 Screen panel 3 ITO conductive film 4 Fluorescent surface 5 Deflection yoke 8 Exterior carbon 9 Reflective flat cathode ray tube of the present invention 10 Bright line 11 Low resistance conductor layer (copper foil) 12 Window signal

Claims (3)

[Claims] 1. A reflection type flat cathode ray tube comprising a front panel, a screen panel facing the front panel, and a transparent conductor film and a fluorescent surface on the inner surface of the screen panel, wherein the outer surface of the screen panel has a low resistance grounded. A reflective flat cathode ray tube characterized by having a conductor film. 2. The specific resistance of the low resistance conductor film is 10 ⁻⁴ Ω /
The reflective flat cathode ray tube according to claim 1, wherein the reflective flat cathode ray tube is less than or equal to cm. 3. The reflection type flat cathode ray tube according to claim 1, wherein the low resistance conductor film is copper.