JPH03142900A - Fluorescent indication panel - Google Patents

Abstract

PURPOSE:To enable troubleshooting of unnecessary radiation without interrupting a visual field of the surface by laying out a metal net or a metal mesh having an opening section corresponding to dots which constitute an indication screen on the front of an electron-ray indicator panel. CONSTITUTION:A fluorescent screen protection glass 3 has an opening section of 0.55mm high X 0.5mm wide in conformity with dots of a fluorescent element wherein a metal mesh is laid out at an inter opening span of 0.20mm and it is connected with a frame ground 5. Generally, the shield effect of metal mesh is indicated by the maximum dimension of 20l og (lambda/2L):L<=lambda/2 wavelength [m], L: frame. The metal mesh (L=0.70mm) provides an excellent shield effect which meets the noise regulations specified by U.S. Federation Communication Committee or Japan Radio wave Interruption Self regulation, say, 46 [dB] to 76 [dB] in a frequency ranging from 30 [MHZ (hertz) to 1 [GHZ (hertz).

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a fluorescent display tube device used, for example, in a display section of a desktop electronic computer.

2. Description of the Related Art It is well known that when a fluorescent display tube operates, unnecessary radiation is generated from the display surface. Shielding can be considered as a measure to prevent this unnecessary radiation.

Generally, the effect of shielding is as follows: Shielding effect = A + R + B [dB] A = absorption loss = 131.7 f・μ,・σ, x t[
d BlR=reflection loss=168-10 log(μ,・
f/ (7,) [d B ] B = Correction term f: Frequency μr = Relative permeability σ with vacuum permeability as 1
r: It is expressed as a specific conductivity with the conductivity of copper as 1, and is found to be effective for materials with high conductivity such as metals.

3 and 4 show conventional examples of fluorescent display tube devices. Second
In the figure, 2 is a fluorescent element, 3 is a fluorescent surface protective glass, and 4 is a fluorescent display surface. Conventionally, since the field of view of the display surface cannot be blocked, materials with high conductivity such as metals cannot be used, and no measures have been taken to prevent unnecessary radiation.

Problem to be Solved by the Invention Conventionally, no measures have been taken to prevent unnecessary radiation from the display surface of a fluorescent display tube device, so it is necessary to reduce the unnecessary radiation of a device including a fluorescent display tube device to below noise regulations. The problem was that it was difficult.

To solve the above problems, the present invention aims to take measures against unnecessary radiation without blocking the field of view of the display surface of a fluorescent display tube device.

Means for Solving the Problems and In order to achieve this object, the present invention arranges a metal net or metal mesh having openings corresponding to the dots constituting the fluorescent display surface on the front surface of the fluorescent display tube. It is configured to do this.

Effect of the Invention With the above-described structure, the present invention makes the shielding material correspond to the dots constituting the fluorescent display surface, so a metal with high conductivity can be used without blocking the field of view, and the display surface of the fluorescent display tube device can be made of a metal with high conductivity without blocking the field of view. It is possible to take effective measures against unnecessary radiation from

Embodiment FIGS. 1 and 2 show an embodiment of the fluorescent display tube device of the present invention. Note that the same parts as in FIGS. 3 and 4 are given the same numbers.

In FIG. 1, 1 is a metal mesh, 5 is a frame ground, and the others are the same as the conventional example. The fluorescent surface protection glass 3 has a vertical dot of 0.55 mm to correspond to the dot of the fluorescent element 2.
A metal mesh 1 having openings of [mml, width 0.5 [nvsl] and a distance between the openings of 0.20 [mml] is arranged and connected to the frame ground 5.

In general, the shielding effect of metal mesh is 201og (λ/2LIL≦λ/2 λ: wavelength [ml, L: maximum dimension [ml], L of the metal mesh used this time (=0.70 [+m
l) The noise effect is required by the noise regulations of the Federal Communications Commission (hereinafter referred to as FCC) in the United States and the Japan Voluntary Regulation on Interference with Information Processing Equipment (hereinafter referred to as VCCR). frequency from 30 [MHz] to 1 [GHz]
40r+Inl or +, 7n "rl 1
11 Toi Uni,,'11. :f; Sufficient effect can be obtained.

Effects of the Invention According to the present invention, the effect of shielding unnecessary radiation from the display surface of the fluorescent display tube device can be achieved without blocking the field of view of the display surface of the fluorescent display tube device. MHz] to 1 [GHz, ], 46
[dB] to 76 [dB]. This makes it easy to reduce unnecessary radiation from devices including fluorescent display tube devices to below noise regulations.

Furthermore, in contrast to the display screen protective glass of the conventional fluorescent display tube device, the present invention uses a metal mesh, so that the strength can be increased.

[Brief explanation of the drawing]

Fig. 1 is a front view of a fluorescent display tube device according to an embodiment of the present invention, Fig. 2 is a longitudinal cross-sectional view of the same, Fig. 3 is a front view of a conventional fluorescent display tube, and Fig. 4 is a cross-sectional view of the same. Show the diagram. DESCRIPTION OF SYMBOLS 1... Metal mesh, 2... Fluorescent element, 3... Screen protection glass, 4... Fluorescent display surface, 5... ...Frame ground.

Claims (1)

[Claims] A fluorescent display tube device in which a metal net or metal mesh having apertures corresponding to the dots forming the fluorescent display surface is arranged on the front surface of the fluorescent display tube.