JP2000114773A - Electromagnetic wave shielding filter and plasma display front-surface plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To discourage a moire phenomenon or make it inconspicuous by providing a non-linear lattice-like conductor or a plurality of annular conductors provided adjacently on a transparent sheet. SOLUTION: Related to a front-surface filter, a lattice-like conductor for anti-moire is pasted on a glass or resin film, or it is directly printed, or a metal foil is pasted on the resin film to manufacture a panel with high electromagnetic wave shielding characteristics. An arrangement with adjoining multiple annular lines such as circle or ellipse, as shown in the figure, makes a moire in conspicuous. The moire is effectively prevented, although, in that case, vertical and horizontal lines are not exactly arranged in lattice. A pattern where vertical lines and horizontal lines are arranged in lattice using curved lines makes moire inconspicuous. Using broken lines, with vertical and horizontal lines provided, makes the moire inconspicuous. Arranging curved lines at random further makes it inconspicuous.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a high light transmittance,
TECHNICAL FIELD The present invention relates to a matched filter having excellent electromagnetic wave shielding performance, particularly to a high-performance plasma display panel front filter.

[0002]

2. Description of the Related Art It is well known that a front filter is used in a plasma display panel for shielding electromagnetic waves. For this purpose, a light-transmitting conductive sheet is used as a front filter. Among them, those using a metal mesh have an advantage of high electromagnetic wave shielding performance.

As a front filter for shielding electromagnetic waves for a plasma display, there is a method in which a film in which conductive wires are arranged in a lattice is attached to a glass plate or a conductive film is attached to glass by sputtering.

[0004]

The front panel for shielding electromagnetic waves for a plasma display obtained by the above-mentioned method is excellent in conductivity and good in shielding electromagnetic waves, and thus has a disadvantage that a moire phenomenon occurs. The moiré phenomenon is caused by interference with the shadow of the grating itself and by interference with pixels.

It is an object of the present invention to provide a filter for shielding electromagnetic waves, in particular, a front filter for shielding electromagnetic waves for a plasma display, which makes it difficult or inconspicuous to cause moiré phenomenon.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on the occurrence of a moire phenomenon in a front filter for shielding electromagnetic waves for a plasma display, and as a result, have found the following, and have completed the present invention. .

That is, it has been found that (1) the moiré phenomenon is likely to occur due to interference between straight lines, and (2) in a grid arranged at equal intervals, moiré occurs at equal intervals, so that it is noticeable. Such a solution has been completed.

[0008] From the phenomenon (1), it has been found that it is necessary to avoid using a filter in which a grid-like conductive line composed of straight lines is arranged. In other words, it is necessary to use a filter in which a grid-like conducting wire composed of a curved line or a broken line or a plurality of adjacently arranged annular conducting wires is arranged. It has been found that it is effective to use a filter in which the diameters are randomly arranged as much as possible. For this reason, it is possible to make moire uneven at intervals by, for example, determining the grid spacing of the conductors with random numbers. Also, irregular patterns such as jigsaw buzzles do not have moiré. That is, the present invention is an electromagnetic wave shielding filter in which a lattice-shaped conducting wire that is not a straight line or a plurality of annular conducting wires arranged adjacently is arranged on a transparent sheet.

It is effective for preventing the occurrence of moire that the grid spacing of the non-linear grid-like conductors of the electromagnetic wave shielding filter is not equal or the diameter of the ring of the annular conductor is not uniform. The non-uniform lattice spacing between the non-linear grid-like conductors or the annular diameter of the annular conductor means, for example, that they are not a regular repeating pattern but a random repeating pattern.

As the conductor, a conductor obtained by attaching a conductor on a transparent sheet, or attaching a metal foil to the transparent sheet and etching to form the conductor on the transparent sheet is used. In the present invention, the transparent sheet on which the conductive wires are arranged refers to a plate, film, or sheet made of a transparent resin, glass, or the like.

With such a solution, moire can be made less noticeable. Further, the above two solutions may be applied alone or in combination.
The filter for shielding electromagnetic waves of the present invention can be used for a front panel of a plasma display, a CRT, a CRT front panel, a building glass, a window glass of a cooking appliance such as a microwave oven, and the like.

[0012]

Embodiments of the present invention will be described. The front filter according to the embodiment of the present invention is manufactured by attaching a grid-like conductive wire for preventing moiré to glass or a resin film, or is directly printed, or a metal foil is attached to a resin film to form a well-known photo filter. Etching is performed by a lingograph method to produce a balne with a conductive property and high electromagnetic wave shielding property.

Moire is noticeable in the normally used grating shown in FIG. 6, and moire is noticeable only in the horizontal or vertical lines as shown in FIG. Further, in the method of arranging the horizontal lines or the vertical lines shown in FIG. 8 at random, it was found that moire was generated at random and the moire was conspicuous. Further, even when the vertical lines and the horizontal lines are arranged in a lattice pattern as shown in FIG. 9 and are arranged at random, the occurrence of moire is conspicuous as in the pattern shown in FIG.

As shown in FIG. 1, an arrangement in which a large number of circular lines such as circles or ellipses are adjacent to each other makes moiré inconspicuous. In this case, it can be said that vertical lines and horizontal lines are always arranged in a grid pattern. No, but proved to be effective in preventing moiré.

Further, as shown in FIG. 2, in a pattern in which both vertical and horizontal lines are arranged in a lattice using curved lines, moiré becomes inconspicuous. In addition, as shown in FIG. 3, by using a polygonal line instead of a curve and providing a vertical line and a horizontal line in a grid pattern, the moire similarly becomes inconspicuous. Although the curves are randomly arranged in FIGS. 4 and 5, moire is less noticeable than in FIGS.

The following can be said from the appearance of moire due to the difference in the lattice pattern as described above. The mesh pattern is (1) not a straight line but a curve or a polygonal line, (2) a lattice pattern, not a stripe pattern (vertical stripe pattern), (3) a random repetition pattern, not a regular repetition pattern Is more preferable.

The manufacturing process of the front filter for shielding electromagnetic waves of the plasma display panel according to the present embodiment includes a laminated glass type and a filter pasting type.

First, a manufacturing process of a laminated glass type electromagnetic wave shielding filter will be described with reference to FIGS. A metal foil 3 having a thickness of about 5 to 50 μm, a PVB film 4 a having a thickness of about 10 to 100 μm, and a thickness of about 50
As shown in FIG. 10A, a polyester resin film 5 of about 100 μm is laminated and bonded in this order.

At this time, the metal foil 3 is preferably a metal foil 3 having a small electric resistance, such as aluminum, silver, nickel,
Chromium, stainless steel, etc. can be used, but copper foil is the best conductive material. It is desirable to use a copper foil which has been subjected to a blackening treatment in order to impart corrosion resistance.

PVB (polyvinyl butyral) 4 a is used as an adhesive component between the polyester resin film 5 and the metal foil 3. A precursor monomer of the PVB polymer may be applied. Although the PVB 4a is used for fixing the metal foil 3 on the polyester resin film 5, the PVB polymer is also used as an intermediate film of a laminated glass body as described later in the present invention. The nature becomes high.

The polyester resin film 5 has a function as a carrier for patterning and etching the metal foil 3, but instead of the polyester resin film, the carrier film may be made of triacetyl chloride (TAC), polyethylene (PE), polyethylene (PE), or the like. Polypropylene (PP), polyvinyl chloride (PVC), or the like can be used.

If the thickness of the metal foil 3 is smaller than 5 μm, the electric resistance increases, and if it exceeds 50 μm, the angle dependence of the light transmittance increases. The display image from the front becomes difficult to see. The thickness of the metal foil 3 is desirably 10 to 20 μm.

The three films 3 and 4 shown in FIG.
a and 5 are laminated and adhered to obtain a laminated film of FIG. At this time, each layer is bonded by heating to about 130 to 180 ° C. Polyester resin film 5 and interlayer film P
The adhesive strength between the VB 4a and the VB 4a is set high enough not to cause a problem such as peeling in the etching step, and weak enough to be easily peeled off after the etching. Adjustment of the adhesive force between the polyester resin film 5 and the intermediate film PVB4a can be adjusted by the degree of surface roughening of the polyester resin film 5.

Next, the metal foil 3 is etched by a well-known photolithography method to form a metal foil 3 as shown in FIGS.
To obtain a laminated film having a metal mesh 3a composed of conducting wires having the pattern shown in FIG. The laminated film having the obtained metal mesh 3a, the glass plate 1 and the PVB 4b (about 0.2 to 0.8 mm in thickness) are arranged as shown in FIG. And the surface of PVB4b in contact with each other at about 90 to 120 ° C. by roller pressure bonding.

After temporary bonding is performed so that the metal mesh 3a side and the intermediate film (PVB) 4b are in contact with each other, the unnecessary polyester resin film 5 is peeled off (FIG. 11).
(A)). At this time, the metal mesh 3a is an intermediate film (PV
B) Since it is sufficiently strongly adhered to 4b, there is no breakage during handling. Then, the peeled PVB film 4a
The third intermediate film (PVB) 4c (thickness of about 0.2 to
0.8 mm) and place the second glass plate 2 through
As a final bonding step, bonding is performed at about 130 to 160 ° C. for 10 to 20 minutes at a pressure of 8 to 10 kg / cm ² (FIG. 1).
1 (b)).

Here, the reason why the third intermediate film (PVB) 4c is disposed is that the extremely thin intermediate film (PB) is formed in the step of FIG.
VB) 4a to prevent air bubbles from entering between the second glass plate 2 and the second glass plate 2. Thus, the manufacturing process of the normal laminated glass body is completed. As a result, FIG.
(PVB) 4 (PVB4a-4c) in the intermediate film shown in (d)
Can be obtained as a single unit), and a front filter made of a laminated glass body for a plasma display in which the metal mesh 3a is interposed between them can be obtained.

When the metal mesh 3a is formed into laminated glass, temporary bonding is performed so that the metal mesh 3a is in contact with the intermediate film 4b, and then the unnecessary polyester resin film 5 is peeled off. At this time, the metal mesh 3a is
Since it is sufficiently strongly bonded to b, it is not damaged during handling. Thereafter, the peeled polyester resin film 5
The intermediate film 4c is also disposed on the side, the second glass plate 2 is disposed thereon, and the normal laminated glass manufacturing process of temporary bonding and final bonding is performed. Thereby, a laminated glass body in which only the metal mesh 3a is sandwiched in the intermediate film 4 can be obtained.

Here, the thickness of each of the intermediate films 4b and 4c is set to 0.2 to 0.8 μm.
If the thickness is less than 2 mm, the adhesive force between the glass plates 1 and 2 and the metal foil cannot be exhibited, and if it exceeds 0.8 mm, the light transmittance decreases. The thickness of the intermediate films 4b and 4c is preferably 0.3 to 0.5 mm.

The thickness of the intermediate film 4a is set to 10 to 100 μm. If the thickness is less than 10 μm, the adhesiveness to the polyester resin film 5 becomes weak, and if it exceeds 100 μm, it is difficult to store it in a rolled state and the handling property is reduced.

Here, when PVB is used as a film, polyvinyl alcohol obtained by saponifying polyvinyl acetate is reacted with butyraldehyde in the presence of an acid catalyst, and then neutralized, washed and dried. What is obtained as a film-like material may be used.

The glass plates 1 and 2 are 1000 mm × 6
A transparent soda-lime-silica composition having a size of 00 mm × thickness (1.1 to 1.8) mm is used, and glass obtained by a float method or the like is used.

The metal foil 3 is preferably a metal foil 3 having a small electric resistance, such as aluminum, silver, nickel, chromium,
Stainless steel or the like can be used, but copper foil is the best conductive material. It is desirable to use a copper foil which has been subjected to a blackening treatment in order to impart corrosion resistance.

The manufacturing process of the filter for shielding electromagnetic waves of the filter-bonded type of the present embodiment will be described with reference to FIG. About 50-100μ in thickness
m about 5 to 50 μm on the polyester resin film 15
12 (a). Separately, as shown in FIG. 12 (b), a PVB film 14 having a thickness of about 0.2 to 0.8 mm and glass A plate 11 is prepared, and the polyester resin film 1 is prepared.
The metal grid pattern 14 on 5 and the PVB film 14 are opposed to each other by roller pressing at about 90 to 120 ° C.

Thus, the glass plate 1 shown in FIG.
An electromagnetic wave shielding filter for a plasma display can be obtained in which the metal pattern 13 sandwiched between 1 and the polyester resin film 15 is bonded and fixed by the PVB film 14.

Here, the PVB film 14 is used as an adhesive component between the polyester resin film 15 and the metal grid pattern 13, but a precursor monomer of the PVB polymer may be applied. If the thickness of the metal grid pattern 13 is smaller than 5 μm, the electric resistance increases and the
When it exceeds, the angle dependence of the light transmittance becomes large, and when used as a front filter of a plasma display, it becomes difficult to see a display image obliquely forward of the front filter. The thickness of the metal grid pattern 13 is 10 to 20 μm
Is desirable.

The PVB film 14 has a thickness of 0.2
When it is less than 0.2 mm, the adhesive force between the glass plate 15 and the metal pattern 13 cannot be exhibited, and when it exceeds 0.8 mm, the light transmittance becomes small. P
The thickness of the VB film 14 is desirably 0.3 to 0.5 mm.

[0037]

According to the present invention, it is possible to obtain an electromagnetic wave shielding glass or a film in which the moire phenomenon hardly occurs or is not noticeable even if it occurs.

[Brief description of the drawings]

FIG. 1 is a diagram showing a pattern of a grid-like conductor in which a number of circular lines such as circles or ellipses are arranged adjacent to each other according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a pattern of a grid-like conductive wire arranged in a grid using curves for both vertical and horizontal lines according to the embodiment of the present invention.

FIG. 3 is a view showing a pattern of a grid-like conductive wire arranged using vertical lines and horizontal lines using a polygonal line according to the embodiment of the present invention.

FIG. 4 is a diagram showing a pattern of a grid-like conductive wire in which curves according to the embodiment of the present invention are randomly arranged.

FIG. 5 is a diagram showing a pattern of a grid-like conductive wire in which curves according to the embodiment of the present invention are randomly arranged.

FIG. 6 is a view showing a pattern of a grid-like conductive wire which is usually used.

FIG. 7 is a diagram showing a pattern of a grid-like conductive wire composed of only horizontal lines or vertical lines.

FIG. 8 is a diagram showing a grid-like conductor pattern in which horizontal or vertical lines are randomly arranged.

FIG. 9 is a diagram showing a pattern of a grid-like conductive wire in which horizontal and vertical lines are randomly arranged.

FIG. 10 is a diagram illustrating a manufacturing process of the front glass filter of the laminated glass type according to the embodiment of the present invention.

FIG. 11 is a diagram illustrating a manufacturing process of the front glass filter of the laminated glass type according to the embodiment of the present invention.

FIG. 12 is a diagram illustrating a manufacturing process of the film-attached plasma display front filter according to the embodiment of the present invention.

[Explanation of symbols]

1, 2, 11 Glass plate 3 Metal foil 3a Metal mesh 4, 14P
VB film 5, 15 Polyester resin film 13 Metal lattice pattern

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] October 20, 1999 (1999.10.
20)

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

[0004]

The front panel for electromagnetic wave shielding for a plasma display obtained by the above method has excellent conductivity and good electromagnetic wave shielding performance, but has a weak point of generating a moire phenomenon. The moiré phenomenon is caused by interference with the shadow of the grating itself and by interference with pixels.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

As shown in FIG. 1, when a plurality of circular lines such as circles or ellipses are arranged adjacent to each other, moiré becomes inconspicuous . This is not necessarily a vertical and horizontal lines in which arranged in a grid if it was found to be effective in anti-Moire.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5C040 GH10 MA02 MA08 5E321 AA04 BB23 BB41 CC16 GG05 GH01 5G435 AA00 AA16 BB06 GG33 HH02 HH05 KK07

Claims (5)

[Claims] 1. A filter for shielding electromagnetic waves, wherein a non-linear lattice-shaped conductor or a plurality of annular conductors arranged adjacent to each other are arranged on a transparent sheet. 2. The filter for shielding electromagnetic waves according to claim 1, wherein the lattice intervals of the non-linear lattice-shaped conductors are not equal or the diameters of the annular conductors are not uniform. 3. The method according to claim 1, wherein the lattice spacing of the non-linear grid-like conductor or the diameter of the ring of the annular conductor is not a regular repetition pattern but a random repetition pattern. Filter for shielding electromagnetic waves. 4. The method according to claim 1, wherein the conductive wire is obtained by attaching the conductive wire on a transparent sheet or by attaching a metal foil to the transparent sheet and etching the conductive wire to form the conductive wire on the transparent sheet. The filter for shielding electromagnetic waves according to any one of claims 1 to 3, wherein: 5. A plasma display front plate, wherein the filter for shielding electromagnetic waves according to claim 1 is used as a front plate of a plasma display.