JPH0320861Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an optical filter for the screen of a picture tube (also referred to as a cathode ray tube or CRT). In recent years, with the advancement of office automation, the health problems of so-called VDT (visual display terminal) workers have become a focus of social concern. The present invention relates to a filter that makes the screen easier to see and blocks electromagnetic waves.

(Prior Art) Various types of filters have been commercially available that make picture tubes easier to view and shield electromagnetic waves. For example, one known method is to weave thin wire into a mesh shape and sandwich it between glass plates on both sides.

(Problems to be Solved by the Invention) However, the wire mesh of the above type is extremely expensive. Therefore, the present invention aims to provide a filter that is inexpensive and has good performance.

(Means for solving the problem) The above problem is a material in which conductive metal plating is applied to the surface (outer surface, inner surface, and pore surface) of a mesh-like cloth woven from hollow porous chemical fibers. This is realized by a picture tube filter that is sandwiched between two transparent plates.

(Function) According to the filter having the above configuration, the conductive mesh-like cloth can be manufactured at low cost, so that the manufacturing cost of the filter is low. Furthermore, since the thickness of the fibers and the size of the mesh can be freely adjusted as required, a filter that is easy to see and has excellent electromagnetic shielding properties can be obtained. Moreover, since the surface area is very large, a sufficient amount of metal can be plated, and a high electromagnetic shielding effect can be obtained.

(Embodiment) FIG. 1 shows an embodiment of the present invention. However, section C shows a virtual state in which the synthetic resin cover body 1 is removed, and section B shows a virtual state in which the metal wire 5a is also removed.In reality, the state in section A is B,
It also extends to section C.

The filter body 2 has a cross section shown in FIG. That is, a mesh cloth 4 in which hollow porous Tetoron fibers are plain-woven is sandwiched in the center. Here, the hollow porous Tetoron fiber has a hollow center 15c and a large number of holes 15, as shown in a partially enlarged view in FIG.
a and 15b are open. Some of the holes are independent like 15a, and some are penetrating like 15b. In this embodiment, this thread is plain-woven into a mesh-like cloth, and conductive metal plating is applied to the surface of this mesh-like cloth (not only the outer surface but also the inner surface of the hollow 15c and the hole surface of the through hole 15b). There is. Compared to a normal Tetron, in this case, the surface area is significantly increased because surfaces are also formed on the circumferential surfaces of the hollow hole 15c and the through hole 15b. Therefore, if the plating thickness is the same, a significantly larger amount of metal can be plated. Therefore, a superior electromagnetic shielding effect can be achieved compared to the case of plating a normal Tetron system.

In this example, the thickness for color display is
There are 160 15-denier fibers per inch, and for monochrome displays, there are 135 20-denier fibers per inch. The thickness and number of threads are determined taking into consideration both the electromagnetic shielding effect and the ease of viewing the screen.

In the case of this embodiment, the mesh-like cloth is sandwiched in such a manner that the perpendicular threads are oriented at an angle of 45 degrees from the horizontal. This is effective in preventing moiré and blurring on the screen.

As shown in FIG. 2, ultraviolet absorbing films 8 and 9 are arranged on both sides of the mesh-like plating cloth 4. In this embodiment, a vinyl acetate polymer membrane (trade name: Dumilan) having a thickness of 150 microns is used. Furthermore, glass plates 7, 10 are arranged on the outside of the membrane. The glass plates 7, 10 are coated with an anti-reflection coating, as is the case with many optical glasses.

In this embodiment, by applying pressure with heated rollers from both sides of the glass plates 7, 10, the ultraviolet absorbing films 8, 9 and the glass plates 7, 10, and the ultraviolet absorbing films 8 and 8
9 or the ultraviolet absorbing films 8, 9 and the mesh-like plating cloth 4 are realized.

In this embodiment, the left, right, and lower portions of the filter body 2 are cut so that the mesh-like plating cloth does not protrude from the glass plate. However, the upper part is
As shown in FIG. It's stuck in place. The end of the metal wire 5a is connected to a grounding connector 6 via a coated wire 5b. The upper part of the filter body 2 is covered with a cover body 1 made of synthetic resin. The cover body 1 made of synthetic resin is provided with unevenness in the longitudinal direction, and is used as shown in FIG. 3 by being combined with a synthetic resin member 12 having grooves that engage with the unevenness. When in use, earthing is taken from the grounding connector 6.

The performance of this filter will be explained below. FIG. 5 is a diagram showing the electromagnetic wave shielding performance of the filter of the present invention, and shows that a shielding effect of at least 30 dB or more can be obtained. FIG. 6 is a diagram showing the reflectance of the filter of the present invention, and is compared with data for surface-untreated glass for reference. This has been shown to significantly prevent reflections and improve the visibility of the VDT screen. FIG. 7 shows the light transmittance of the filter of the present invention. This shows that the present invention can moderate the light and prevent screen glare. Although it is difficult to show numerically, blurring and flickering of images are also reduced, and eye fatigue can be greatly reduced.

Furthermore, since the VDT is grounded via the ground electrode, even if an electrostatic phenomenon such as frictional electricity occurs on the VDT housing body, it will not be charged, and problems caused by static electricity can be prevented.

(Effects) The filter of the present invention can provide a filter that is cheaper than the case where a conventional metal mesh is used. Furthermore, since the thickness of the threads constituting the mesh and the size of the mesh can be freely adjusted, a filter that is easy to see and has a good electromagnetic shielding effect can be freely designed.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the entire filter of the present application;
However, sections B and C are shown with some members omitted. FIG. 2 is a sectional view of the filter, and FIG. 3 is a sectional view showing the filter in use. FIG. 4 is an enlarged perspective view showing one fiber, FIG. 5 is a characteristic diagram showing the electromagnetic wave shielding effect of the present filter, FIG. 6 is a light reflectance, and FIG. 7 is a characteristic diagram showing light transmission performance.

Claims (1)

[Claims for Utility Model Registration] (1) A material made of hollow porous chemical fibers woven into a mesh shape and having conductive metal plating applied to the surface (outer surface, inner surface, and pore surface). A picture tube filter that is sandwiched between two transparent plates. (2) A practical product in which a material made of hollow, porous chemical fibers woven into a mesh shape with conductive metal plating applied to the surface is sandwiched between an ultraviolet absorbing film and then between two transparent plates. Scope of patent registration request No. 1
The picture tube filter described in . (3) A material made of hollow porous chemical fibers woven into a mesh shape with conductive metal plating on the surface is sandwiched between ultraviolet absorbing films, and two sheets of glass with anti-reflection treatment. A picture tube filter according to claim 1 or 2, which is sandwiched between plates. (4) Utility model registration claims Paragraphs 1 to 3, consisting of a cloth woven in a mesh-like manner from hollow porous chemical fibers, sandwiched in such a way that the perpendicular threads are inclined at 45 degrees from the horizontal. The picture tube filter according to any one of the above. (5) Utility model registration claim No. 1 characterized in that a grounding electrode is connected to a material made of hollow porous chemical fibers woven into a mesh shape and having conductive metal plating applied to the surface. The picture tube filter according to any one of items 1 to 4.