JPS616683A - Crt display - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a CRT display device, and more particularly to a structural improvement of the device for reducing radiation noise from the device.

[Conventional technology]

Recently, CRT display devices have been widely used as computer terminal devices or personal computer display units, but radiation noise leaking from these CR and T display devices to the outside has become a problem, and improvements are urgently needed. ing. In particular, a video signal is output from the main body of a personal computer, and this output signal is amplified by the video signal amplification circuit in the neck of the CRT and input to the CRT. At this time, radiation noise is generated, and this noise is transmitted to the case. There are problems such as leakage to the outside and causing malfunction of other electronic devices. In particular, the radiation noise level is high in the frequency range of 30 to 100 M)1z, and it is desired to suppress this radiation noise.

Conventionally, in order to suppress such radiated noise, a film of conductive paint was applied to the inside of the casing in which the CRT is installed, and this film was grounded to prevent the radiated noise from leaking outside the plastic casing. However, such a method is insufficient and it is difficult to suppress the radiation noise within a specified value.

[Problem that the invention seeks to solve]

The problem to be solved by the present invention is radiation noise generated from the video signal amplification printed circuit board disposed in the neck of the CRT of the CRT display device.

[Means for solving problems]

A means for solving the above problem is to arrange a conductive member opposite to the back side of a video signal amplification printed circuit board disposed on the neck of the CRT body installed in the casing, and to is electrically connected to the ground pattern of the printed circuit board.

[Effect]

That is, a conductive member for shielding is arranged opposite to the back side opposite to the component mounting surface of a printed circuit board for video signal amplification arranged in the neck of the CRT, and this conductive member and the printed circuit board are grounded. By electrically connecting it to the pattern, radiation noise generated from the printed circuit board is removed.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail using the drawings.

FIG. 1 is a conceptual diagram showing a first embodiment of the CRT display device of the present invention, FIG. 2 is a conceptual diagram of main parts of the first embodiment of the CRT display device of the present invention, and FIG. 3 is a conceptual diagram showing the first embodiment of the CRT display device of the present invention. FIG. 2 is a conceptual diagram of main parts of a second embodiment of the CRT display device of FIG.

As shown in FIGS. 1 and 2, the CRT display device of the present invention includes a CRT 2 in a casing 1 having a conductive film formed on the inner surface.
Further, a conductive conductive plate made of a metal plate such as copper (Cu) is placed opposite to the ground pattern on the back side of the printed circuit board 4 on which the electronic circuit for video signal amplification is mounted, which is disposed on the neck 3 of the CRT. The sex sheet 5 has four Cs separated by a predetermined interval.
It is supported by a metal support 6 such as u. This conductive sheet 5 is electrically connected to the ground pattern of the printed circuit board 3 by four metal supports 6 made of copper or the like, so that the ground potential of the printed circuit board 4 and the conductive sheet 5 are at the same potential. This metal support 6 has a structure in which, for example, a screw is passed through a steel pipe, and the steel pipe is used as a spacer for connection and spacing setting. , is appropriately determined to have the function of electrically connecting the conductive sheet 5. Of course, the video signal amplification printed circuit board 4 is connected to the main board 8 by a cable 7 with a connector, including a ground connection.

In this way, the radiation noise generated mainly from the ground pattern side of the printed circuit board 4 is shielded by the conductive sheet 5, and as a result of measurement, the radiation noise level is 4db to 8db.
was found to decrease over a range of b.

Further, a second embodiment of the CRT display device of the present invention is shown in FIG. As shown in the figure, the second embodiment is different from the first embodiment in that the electronic components forming the video signal amplification circuit are mounted at a predetermined interval opposite to the ground pattern of the printed circuit board 4. A rectangular parallelepiped box-shaped shielding member 1) made of a conductive material such as Cu and having an open top is attached by four metal supports 6 so as to surround the printed circuit board 4. electrically connects the printed circuit board 4 and the shielding member 1), so that the printed circuit board 4 and the shielding member 1) are electrically at the same potential.

In this way, the effect of shielding the radiation noise generated from the printed circuit board 4 is further increased, and there is an effect that the radiation noise can be shielded more efficiently than in the first embodiment.

Further, the material forming the metal support or the conductive sheet is not limited to Cu or the like, but any material with good electrical conductivity such as aluminum (All), nickel (Ni), iron (Fe), etc. may be used.

〔Effect of the invention〕

As described above, according to the CRT display device of the present invention, C
The radiation noise generated by the printed circuit board for video signal amplification installed in the neck of the RT is shielded by the conductive shield plate installed opposite to the back of the printed circuit board, so it is less noise than the CRT display device. This kind of CRT eliminates the possibility of noise leaking to the outside.
If the display device is used as a display section of an electronic device such as a personal computer, the personal computer main body can operate without any inconvenience such as malfunction, resulting in a highly reliable electronic device.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing a first embodiment of the CRT display device of the present invention, FIG. 2 is a conceptual diagram of main parts of the first embodiment of the CRT display device of the present invention, and FIG. 3 is a conceptual diagram showing the first embodiment of the CRT display device of the present invention. FIG. 2 is a conceptual diagram of main parts of a second embodiment of the CRT display device of FIG. In the figure, 1 is a housing, 2 is a CRT, 3 is a neck, 4 is a printed circuit board for video signal amplification, 5 is a conductive sheet, 6 is a metal support, and 1) is a box-shaped shielding member. Figure 1 Figure 3

Claims (3)

[Claims] (1) A conductive member is disposed opposite to the back side of a printed circuit board for video signal amplification disposed on the neck of the CRT body installed in the casing, and the conductive member is connected to the ground pattern of the printed circuit board. CR characterized by electrical connection
T display device. (2) The CRT display device according to claim (1), wherein the conductive member is in the form of a sheet. (3) The CRT display device according to claim (1), wherein the conductive member has a box shape with an open top so as to surround the printed circuit board at a predetermined interval.