JPH0229756Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is an electromagnetic wave shielding method used in cathode ray tubes (abbreviated as CRT) used in video display terminals, which are terminal display devices for computers, etc. The present invention relates to a functional anti-glare filter.

Prior Art and Problems In order to avoid visual impairment for workers operating computers, etc., it has become popular to attach anti-glare filters to the surface of CRTs. On the other hand, video display terminals use a large number of ICs, LSIs, etc., which generate high-frequency pulses and cause radio interference in peripheral electronic equipment, so the case should be electromagnetically shielded and the CRT surface should also be electromagnetically shielded. There is a need to. The above anti-glare filter is made of a black synthetic fiber net and does not have an electromagnetic shielding effect.As an alternative, a filter made of a blackened metal fiber net that has an electromagnetic shielding function has been proposed. The anti-glare effect is inferior due to the size.
Further, in Japanese Patent Application Laid-open No. 188038/1983, a filter is proposed in which a mesh is formed using synthetic fibers and conductive fibers as threads, and which has anti-glare and electromagnetic shielding functions. However, although it has anti-glare and anti-static functions, unlike metal fiber mesh, its electromagnetic shielding function is not sufficient, and at present,
I have not found anything that has sufficient anti-glare and electromagnetic shielding functions.

Measures to Solve the Problems In view of the above circumstances, the inventor of the present invention has repeatedly studied filters with excellent anti-glare and electromagnetic shielding properties, and has developed a filter that can be used by superimposing a black fiber filter and a blackened metal fiber filter. , discovered that even if the necessary image brightness can be maintained and a metal fiber mesh is used, electromagnetic shielding properties are not good if there is insufficient electrical continuity between the periphery of the mesh and the conductive frame,
We investigated a method for treating the edges and came up with the present invention.

The electromagnetic shielding anti-glare filter according to the present invention is constructed by attaching a black fiber net and a blackened metal fiber net to a conductive frame so that the metal fiber net faces the CRT side, and the black fiber net and the metal fiber The metal fiber mesh is characterized in that the meshes intersect with each other at an angle, and the peripheral edge of the metal fiber mesh is treated to be electrically conductive and is fixed to the conductive frame.

An embodiment of the present invention will be explained based on the drawings.
FIG. 1 is a partially cutaway perspective view showing a conductive frame 1 with a black fiber mesh 2 on the outside and a black metal fiber mesh 3 on both sides of the CRT.
The conductive frame 1 is made of a metal such as aluminum or a conductive hard plastic such as ABS resin kneaded with fine aluminum fibers, and is made into a neat rectangular shape that fits the CRT surface. For example, it is made by knitting and weaving nylon fibers mixed with carbon black, and the thread diameter is
The mesh size is preferably 10 μm to 100 μm and 5 times or less the thread diameter. If the thickness is less than 10 μm, the transmittance of light from the CRT will be low and the image will become dark, and if it is greater than 100 μm, the anti-glare effect will decrease. Next, the metal fiber net 3 is preferably made of metal fibers of stainless steel, monel metal, copper, etc., dyed black. The fiber diameter is
The mesh size is preferably 50 μm or less, and the mesh size is preferably 10 times or less the fiber diameter. If the mesh size is 50 μm or more, the anti-glare property will be poor, and if the mesh size is 10 times or more the fiber diameter, the mesh will be coarse and the electromagnetic shielding property will be insufficient. Further, the fibers of the black fiber network and the metal fibers of the metal fiber network preferably intersect at an intersection angle of 5 to 45 degrees, thereby preventing moiré phenomena caused by overlapping of the networks.

Next, the periphery of the metal fiber mesh is subjected to electrical conduction treatment and bonded to the conductive frame 1. That is, the tip of each metal fiber forming the metal fiber network has a conductive treatment part 4 made of a conductive adhesive, such as silver paste, so that all of the metal fibers forming the metal fiber network are electrically conductive. It is fixed to the conductive frame 1 using the conductive adhesive. Therefore, unlike the case where the metal fiber network is simply fixed to the conductive frame with an adhesive or the like, complete electrical continuity is achieved between the metal fiber network and the conductive frame.

The filter of the present invention thus formed is mounted on the video display terminal housing with the CRT surface covered using a mounting member (not shown) molded from conductive synthetic resin or conductive rubber into an appropriate shape. Mounted under electrical continuity.

Further, as shown in FIG. 2, the conductive frame 1 is made of, for example, plastic fibers treated with a metal compound such as nickel or copper, such as acrylic fibers treated with copper sulfide, to reduce the surface resistance to below 1Ω. By attaching the static eliminating tape, static electricity on the filter caused by the electromagnetic shield can be removed by self-discharging into the air from the erected fiber tips of the static eliminating tape.

Effects of the invention In the filter of this invention, a metal fiber mesh is used, and the periphery of the metal fiber mesh is completely electrically connected to the conductive frame, so the electromagnetic shielding property is very good. In the region of ~30MHz
It has a shielding effect of 30dB or more, and since it has a black fiber mesh on the surface, it has an anti-reflection effect with a reflected light attenuation rate of 75% or more, and the mesh of the metal fiber mesh is larger than that of the black fiber mesh. , even if the nets are overlapped
The CRT's fluoroscopic image does not darken, and the nets intersect at appropriate angles, avoiding moire phenomena and not obstructing the view. Furthermore, a frame with static eliminating tape pasted thereon allows discharge into the air without attaching a ground, which is advantageous since there is no need for a ground when installing a video display terminal. Since the frame of the filter of the present invention is rigid, difficult to deform, and conductive, it has the advantage that it can be easily attached to a video display terminal housing subjected to electromagnetic shielding using a mounting member.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view of a filter according to the present invention, and FIG. 2 is a partially cutaway perspective view of another embodiment. 1... Conductive frame, 2... Black fiber network, 3
...Metal fiber mesh, 4...Continuity treatment section, 5...Static elimination tape.

Claims (1)

[Scope of utility model registration request] A black fiber mesh and a blackened metal fiber mesh are attached to a conductive frame so that the metal fiber mesh faces the CRT surface side, and the black fiber mesh and the metal fiber mesh intersect each other at an angle, and the metal fiber mesh 1. An electromagnetic shielding anti-glare filter, characterized in that the periphery of the fiber network is treated to be electrically conductive and is fixed to the conductive frame.