JPH11121974A - Electromagnetic wave shielding plate and mesh pattern plate for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic wave shielding plate provided with meshes composed of metallic thin films, having superior see-through property and electromagnetic wave shielding property. SOLUTION: An electromagnetic wave shielding plate 100, which is used in a state such that the plate 10 is placed on the front face of a display and has an electromagnetic wave shielding property, is formed by laminating meshes composed of metallic thin films 117 upon another on one surface of a transparent substrate 130. Each mesh is composed of a plurality of lines 150 arranged in parallel with each other in the X-direction at prescribed pitch Py intervals and with a plurality of segments 170 which respectively connect adjacent lines 150 to each other and cross the lines 150 at a prescribed angle θ, and the segments 170 between each line 150 is provided at prescribed pitch Px intervals in the X-direction and used mesh-shaped prescribed regions which are randomly arranged in the X-direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic wave shielding plate using a metal thin film mesh, and a pattern plate for forming the metal thin film mesh. More specifically, the present invention relates to an electromagnetic wave shielding plate using a metal thin film mesh for shielding an electromagnetic wave generated from an electromagnetic wave generation source such as an electron tube for a display, and a mesh pattern plate for producing the metal thin film mesh.

[0002]

2. Description of the Related Art Conventionally, an electronic device for generating an electromagnetic wave used directly by a person in close proximity, for example, an electronic tube for a display such as a plasma display, has a standardized intensity of electromagnetic wave emission in consideration of the adverse effect of the electromagnetic wave on the human body. It is required to keep within. Further, in a plasma display panel (hereinafter also referred to as a PDP), light emission uses plasma discharge, so that the frequency band is 30 MHz to 13 MHz.
In order to leak unnecessary electromagnetic waves of 0 MHz to the outside, it is required to suppress the electromagnetic waves as much as possible so as not to adversely affect other devices (for example, information processing devices and the like). In response to these demands, generally, in order to remove or attenuate electromagnetic waves flowing out of the device from an electronic device that generates electromagnetic waves,
An electromagnetic wave shield that covers an outer peripheral portion of an electronic device or the like that generates an electromagnetic wave with a suitable conductive member is employed. In a display panel such as a plasma display panel, an electromagnetic wave shielding plate having good transparency is generally provided on the front surface of the display.

The basic structure of the electromagnetic wave shielding plate is relatively simple. For example, a transparent conductive film such as an indium-tin oxide film (ITO film) is formed on a transparent glass or plastic substrate by vapor deposition or sputtering. A transparent glass or plastic substrate on which a suitable metal screen such as a wire mesh is adhered, or a transparent glass or plastic substrate with a metal thin film on the entire surface by electroless plating or evaporation. Is formed, and the metal thin film is processed by a photolithography method or the like to provide a mesh made of a fine metal thin film.

An electromagnetic wave shielding plate in which an ITO film is formed on a transparent substrate is excellent in transparency, generally has a light transmittance of about 90%, and can form a uniform film on the entire surface of the substrate. Therefore, when used for a display or the like, there is no concern about occurrence of moire or the like due to the electromagnetic wave shielding plate. However, in an electromagnetic wave shielding plate in which an ITO film is formed on a transparent substrate, since a vapor deposition, a sputtering, and a technique are used to form the ITO film, a manufacturing apparatus is expensive, and productivity is generally poor. Therefore, there is a problem that the price of the electromagnetic wave shielding plate itself as a product becomes high. Further, the electromagnetic wave shielding plate having an ITO film formed on a transparent substrate has a conductivity that is at least one order of magnitude lower than that of an electromagnetic wave shielding plate having a mesh made of a metal thin film, and therefore, the electromagnetic wave emission is relatively weak. Although effective for target objects, when used for strong objects, there is a problem that the shielding function becomes insufficient, leaked electromagnetic waves are emitted, and it may not be possible to satisfy the standard value. is there. In the electromagnetic wave shielding plate in which the ITO film is formed on the transparent substrate, the conductivity is improved to some extent by increasing the thickness of the ITO film in order to increase the conductivity, but in this case, the transparency is significantly reduced. The problem occurs. In addition, there is a problem that the manufacturing cost becomes higher due to the further increase in thickness.

When an electromagnetic wave shielding plate in which a metal screen is attached to a transparent glass or plastic substrate surface is used,
Alternatively, when an appropriate metal screen such as a wire mesh is directly adhered to the display surface, it is simple and the cost is low, but the transmittance of an effective mesh (100-200 mesh) metal screen is 50%. % Or less,
It has the serious drawback of extremely dark displays.

[0006] In addition, since a mesh formed of a metal thin film is formed on the surface of a transparent glass or plastic substrate, the outer shape is processed by etching using photolithography, so that fine processing is possible and a high aperture ratio (high transmittance) is obtained. rate)
Since the mesh can be formed and the mesh is formed by a metal thin film, the conductivity is very high as compared with the above-mentioned ITO film and the like, and an advantage that strong electromagnetic wave emission can be shielded. Have. However, the manufacturing process is complicated and complicated, the productivity is low, and the production cost is inevitable.

[0007] As described above, each electromagnetic wave shielding plate has advantages and disadvantages, and is selected and used according to the application. Among them, an electromagnetic wave shielding plate in which a mesh made of a metal thin film is formed on the surface of a transparent glass or plastic substrate is good in terms of electromagnetic wave shielding and light transmission, and has recently been placed on the front of a display panel such as a plasma display panel. , And has been used for electromagnetic wave shielding. However, when the electromagnetic shielding plate provided with the metal thin film mesh is used in front of a plasma display panel (PDP), moire is noticeable to an observer due to the interaction between the metal thin film mesh and the scanning lines of the display. There was a problem. In addition, the moiré generated when installed in front of the display body displaying an image in an orthogonal matrix structure is as follows.
In general, display scan lines and 15 degrees, 30 degrees, or 22.
There is a minimum when the mesh crosses at 5 degrees or the like, but it still gives the viewer discomfort. Although this is the minimum moiré, it is due to the fact that the images are displayed regularly at regular intervals.

[0008]

Under such circumstances, even if an electromagnetic shielding plate provided with a metal thin-film mesh is used in front of a display such as a PDP or the like, and the electromagnetic shielding plate is used in front of a display such as a PDP, the distance between the metal thin-film mesh and the scanning lines of the display is reduced. There has been a demand for an electromagnetic shielding plate that does not generate moiré due to interaction or makes moiré less noticeable. The present invention corresponds to this, and is an electromagnetic shielding plate provided with a metal thin film mesh, and even when used on the front of the display, generation of moire due to the interaction between the metal thin film mesh and the scanning line of the display. It is an object of the present invention to provide an electromagnetic shielding plate in which the shape of a metal mesh is devised so as not to be noticeable or moire is inconspicuous. At the same time, it is intended to provide a pattern plate for producing such a metal thin film mesh shape.

[0009]

The electromagnetic wave shielding plate of the present invention is an electromagnetic wave shielding plate which is used on the front of a display and has an electromagnetic wave shielding property in which a mesh made of a metal thin film is laminated on one surface of a transparent substrate. The shape of the mesh connects a plurality of lines provided along the X direction in parallel with each other at a predetermined pitch Py and each adjacent line of the plurality of lines, and intersects the line at a predetermined angle θ. It is composed of a plurality of line segments, and the line segments between the lines are provided at a predetermined X-direction pitch Px and use a predetermined mesh-shaped region whose X-direction position is random. It is assumed that. In the above, a grounding frame portion made of the same metal thin film as the mesh is provided around the periphery of the mesh portion so as to surround the screen area of the display when used on the front surface of the display. Things. Further, in the above, when used in front of the display, an angle between a horizontal scanning line of the display and a line direction of the mesh is in a range of 15 degrees to 45 degrees. . The transparent substrate referred to here includes a plastic film in addition to a rigid substrate made of glass, polyacrylic resin, or polycarbonate resin.

[0010] The mesh pattern plate of the present invention is used for forming the mesh on an electromagnetic wave shielding plate having an electromagnetic wave shielding property in which a mesh made of a metal thin film is laminated on one surface of a transparent substrate and used on the front surface of a display. A pattern version, which has all the patterns of the mesh area to be created in at least one pattern version,
The pattern shape is formed by connecting a plurality of lines provided along the X direction in parallel with each other at a predetermined pitch Py and each adjacent line of the plurality of lines, and a plurality of line segments crossing the line at a predetermined angle θ. And a line segment between each line is provided at a predetermined pitch Px in the X direction, and a predetermined area of a mesh shape whose X direction position is random is used. is there. As described above, the transparent substrate referred to here includes a plastic film in addition to a rigid substrate made of glass, polyacrylic resin, or polycarbonate resin.

[0011]

According to the electromagnetic wave shielding plate of the present invention having such a structure, even when the electromagnetic wave shielding plate is used in front of a display such as a PDP, moire is generated due to the interaction between the metal thin film mesh and the scanning lines of the display. It is possible to provide an electromagnetic shielding plate provided with a metal thin film mesh having no or no noticeable moiré. This makes it possible to provide an electromagnetic wave shielding plate having both good transparency and electromagnetic wave shielding properties for a display such as a PDP. Specifically, the mesh shape is X parallel to each other at a predetermined pitch Py interval.
A plurality of lines provided along the direction, and a plurality of line segments connecting the adjacent lines of the plurality of lines and intersecting the lines at a predetermined angle θ. This is achieved by using a predetermined mesh-shaped region provided at intervals of the direction pitch Px and having a random position in the X direction in the X direction. That is, by randomizing the X direction position of the line segment between the lines, the regularity of the mesh arrangement is lost, and no moire is generated due to the interaction between the metal thin film mesh and the scanning line of the display, or the moire is reduced. They are not noticeable. Further, when used on the front surface of the display, the angle between the horizontal scanning line of the display and the line direction of the mesh is set in the range of 15 to 45 degrees, which is more effective. In addition, a grounding frame made of the same metal thin film as the mesh is provided around the outside of the mesh so as to surround the screen area of the display when used on the front of the display. I have.

The mesh pattern plate of the present invention, by adopting such a constitution, enables fine processing of a metal mesh used for the electromagnetic wave shielding plate of the present invention by photolithography. This makes it possible to create the plate itself relatively easily. Specifically, it has all the patterns of the mesh area to be created in at least one pattern plate, and the pattern shape is X parallel to each other at a predetermined pitch Py interval.
A plurality of lines provided along the direction, and a plurality of line segments connecting the adjacent lines of the plurality of lines and intersecting the lines at a predetermined angle θ. This is achieved by using a predetermined mesh-shaped region provided at intervals of the direction pitch Px and having a random position in the X direction in the X direction.

[0013]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an electromagnetic wave shielding plate according to a first embodiment of the present invention.
2 (a) and 2 (b) are examples of a mesh pattern plate of the present invention. FIG. 3 is a partially enlarged view for explaining the pattern shape of the mesh pattern, and FIG. It is a figure for explaining a manufacturing method of a pattern version.

First, an embodiment of an electromagnetic wave shielding plate according to the present invention will be described with reference to FIG. The example shown in FIG.
An electromagnetic wave shielding plate for electromagnetic wave shielding placed on the front surface of a display such as P, and having a grounding frame portion and a mesh portion formed on one surface of a transparent substrate. In FIG. 1, 100
Is an electromagnetic wave shielding plate, 110 is a mesh portion, 115 is a ground frame portion, 117 is a metal thin film, 130 is a transparent substrate, 150 is a line, and 170 is a line segment. 1A is a plan view, FIG. 1B is a cross-sectional view taken along line A1-A2 in FIG. 1A, and FIG. 1C is an enlarged view of a part of a mesh portion. FIG.
1A and 1C show the X direction and the Y direction for clarifying the positional relationship and the mesh shape. FIG.
(B), as shown in the cross section, a mesh section 110 and a grounding frame section 115 are provided on one surface of a transparent substrate 130. The grounding frame portion 115 is formed of the same metal thin film as the mesh portion around the outer periphery of the mesh portion 110 so as to surround the screen area of the display when used on the front of the display. The mesh part 110 has a plurality of lines 150 provided along the X direction in parallel with each other at a predetermined pitch Py as shown in FIG. A plurality of line segments 17 connecting each adjacent line and intersecting the line at a predetermined angle θ
The predetermined area of the mesh shape consisting of
It is the one surrounded by 5. In the above mesh shape, the line segments 170 between the lines 150 are provided at a predetermined pitch Px in the X direction, and the positions in the X direction are random.

Although the aperture ratio of the mesh portion 110 is more advantageous as it approaches 100%, it is in a technically practical range of 65 to 65%.
It may be 95%. Light is a line 1 consisting of a metal thin film 117
The light passes through a region where the transparent substrate 130 surrounded by the line 50 and the line segment 170 is exposed. The angle γ between the line in the X direction and the direction of the horizontal scanning line of the display is, in particular, in the range of 15 ° to 45 ° from the moire plane observed when used on the front of a display such as a PDP. Is preferred.

As the transparent substrate 130, a glass, polyacrylic resin or polycarbonate resin substrate is preferably used, but if necessary, a plastic film may be used. Examples of plastic film materials include triacetyl cellulose film, diacetyl cellulose film, acetate butyrate cellulose film, polyether sulfone film, polyacrylic resin film, polyurethane resin film, polyester film, polycarbonate film, polysulfone film, and polysulfone film. An ether film, a trimethylpentene film, a polyetherketone film, a (meth) acrylonitrile film and the like can be used, and a biaxially stretched polyester is particularly preferable because it has excellent transparency and durability. Usually, the thickness is preferably about 8 μm to 1000 μm. In addition, 1 to large displays
A rigid substrate having a thickness of 10 mm is used. For a small display for a character display tube, a plastic film having an appropriate flexibility and a thickness of 0.01 mm to 0.5 mm is attached to the display. . The light transmittance of the transparent substrate 130 or the plastic film in place of the transparent substrate is ideally 100%.
It is preferable to select one having 0% or more. In general, as the metal thin film forming the grounding frame 115 and the mesh 110, a metal is preferably a material which is preferably inexpensive and easy to process, and more preferably a material having good electromagnetic wave shielding properties. Specific examples of materials used include Au, Ag, Cu, Ni, Fe, Al, Zn, and S.
n, Ti, Ta, Mo, Co, various other simple metals,
Alternatively, a single layer or a multilayer of various alloys may be used. The thickness of the metal thin film 117 for effectively shielding electromagnetic waves is preferably as large as possible in terms of electromagnetic wave shielding, but is preferably about 0.2 to 20 μm from the viewpoint of workability.

The example shown in FIG. 1 has such a configuration, so that when used on a front surface of a display such as a PDP, an observer can see the interaction between the metal thin film mesh and the scanning lines of the display. Moiré is no longer observed or moiré is inconspicuous. That is, it is possible to provide an electromagnetic wave shielding plate having both good transparency and electromagnetic wave shielding.

Next, an embodiment of the mesh pattern plate of the present invention will be described with reference to FIG. 2 (a) and 2 (b) are diagrams each showing an enlarged part of the mesh portion of the pattern plate. FIG. 3A is an enlarged view of a part of the pattern plate shown in FIG. still,
FIG. 2 shows only a part of the mesh portion in an enlarged manner, and does not show a frame portion for grounding. 2, reference numerals 210 and 211 denote pattern plates, 221 denotes a black portion, 222 denotes a white portion.
50 is a line, 170 is a line segment, and θ is an intersection angle. FIG.
An example shown in FIG. 1 is a pattern plate for etching a mesh portion of an electromagnetic wave shielding plate for electromagnetic wave shielding used for placing on the front surface of a display such as a PDP shown in FIG. 1 by a photolithography method, and includes at least one pattern plate. It is provided with all the pictures of the mesh area to be created, and the pattern shape connects a plurality of lines provided along the X direction in parallel with each other at a predetermined pitch Py interval and each adjacent line of the plurality of lines. , A plurality of line segments intersecting the line at a predetermined angle θ, and a line segment between the lines is provided at a predetermined pitch in the X direction Px, and the position in the X direction is random. This is based on a region. The pattern 210 shown in FIG.
Is composed of a line 150 and a line segment 170 that are orthogonal to each other, and corresponds to a case where the intersection angle θ between the line 150 and the line segment 170 is 90 degrees. Pattern 2 shown in FIG.
Numeral 11 indicates a case where the crossing angle θ between the line 150 and the line segment 170 is smaller than 90 degrees.

FIG. 3A shows a partially enlarged shape of the pattern plate 210 shown in FIG. 2A. By the way, as for the pattern of the repetitive shape formed by the combination of the line and the line segment as shown in FIG. 3A, the m-th line in the Y direction as shown in the equation of FIG. Lm and the (m + 1) th line Lm + in the Y direction
1, the position Pn of each n-th line segment Lnm in the X direction
m is determined. Here, Rm is a variable that changes randomly every time m changes in the range of 0 to Px, and α, in the X and Y directions from the origin position (point P0 in FIG. 3) of each line segment Lnm.
A predetermined position of β is a position Pnm of the line segment Lnm.
In addition, the origin position of each line segment may be set to the corresponding position as the origin position. It goes without saying that the values of α and β also change depending on how the origin position is set. For the pattern plate 201 shown in FIG.
2A is different from that of the pattern plate shown in FIG. 2A, but when the position of the nth line segment Lnm in the X direction and the mth line segment Lnm in the Y direction is Pnm, FIG. 3), the X coordinate of Pnm is (Rm + α + (n−1) P
The x and Y coordinates are represented by β + (m−1) py).

Next, an example of a method of manufacturing the pattern plates 210 and 211 will be briefly described. First, the creation of the pattern of the mesh portion is performed as follows. FIG.
As described above, the X coordinate of the position Pnm of each line segment 170 is (Rm + α + (n−1) Px, and the Y coordinate is β + (m−
1) py), and the line 150 is provided at a predetermined pitch P in the Y direction.
It can be seen that the picture position of the entire pattern area can be expressed by sending the data corresponding to 0 and the data corresponding to one line at a predetermined pitch. That is, although the pattern of the entire area of the pattern plate can be expressed by designating the pitch, first of all, in order to create image data for drawing by CAD using this characteristic, it is necessary to use the number of pitch feeds. Is flattened as drawing data.
Next, with respect to the pattern of the grounding frame portion, drawing data is created directly by CAD by specifying coordinates. Thus, the drawing data of the mesh part and the grounding frame part is obtained. Then, the obtained drawing data is converted into raster type electron beam exposure machine data, and the electron beam exposure machine coats the above-mentioned metal thin film formed on one surface of the transparent substrate by vapor deposition or sputtering. The exposed pattern area of the resist is collectively exposed. Next, this is developed to form a resist image corresponding to the pattern on the metal thin film, and the exposed metal thin film portion is removed by etching using the resist image as a mask to obtain a pattern plate.

Using the pattern plate thus obtained, an etching process is performed by a photolithography method to produce an electromagnetic wave shielding plate. A resist applied on a metal thin film (corresponding to 117 in FIG. 1) formed on one surface of a transparent substrate (corresponding to 130 in FIG. 1) by vapor deposition, sputtering, electrodeposition, or the like, is subjected to close contact exposure with the above pattern plate. Then, by developing this, a resist image corresponding to the pattern plate is formed on the metal thin film, and the exposed metal thin film portion is removed by etching using the resist image as a mask, whereby the electromagnetic wave shielding plate shown in FIG. 1 is formed. Can be made.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the electromagnetic wave shielding plate of the present invention will be described. In the embodiment shown in FIG. 1, an acrylic plate is 5 mm thick as the transparent substrate 130, and Cu is 6 μm as the metal thin film 117.
The electromagnetic wave shielding plate 100 having a thickness and a blackened copper surface and having a mesh shape shown in FIG.
Electromagnetic wave shielding properties and transparency were confirmed on the front surface of the PDP. The attenuation rate of the electromagnetic waves was about 30 dB, and almost no moiré was seen, so that it was practically usable. In the mesh section 110, the line width of the metal thin film 117 is 15 μm, and the feed pitch Py of the line in the Y direction and the feed pitch Px of the line in the X direction are 160 μm. The mesh crossing angle θ was 30 degrees.

[0023]

As described above, even when the present invention is used in front of a display such as a PDP, moire does not occur or is not noticeable due to the interaction between the metal thin film mesh and the scanning line of the display. With good transparency,
It is possible to provide an electromagnetic wave shielding plate having electromagnetic wave shielding properties.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of an embodiment of an electromagnetic wave shielding plate of the present invention.

FIG. 2 is a diagram showing an example of an embodiment of a mesh pattern plate of the present invention.

FIG. 3 is an enlarged view for explaining a pattern shape of the mesh pattern shown in FIG. 2;

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 electromagnetic wave shielding plate 110 mesh part 115 grounding frame part 117 metal thin film 130 transparent substrate 150 line 170 line segment 210, 211 pattern plate 221 black part (light shielding part) 222 white part (transparent part) θ crossing angle

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01J 17/04 H01J 17/04

Claims (4)

[Claims] 1. An electromagnetic wave shielding plate, which is used on a front surface of a display and has an electromagnetic wave shielding property in which a mesh made of a metal thin film is laminated on one surface of a transparent substrate, wherein the mesh has a predetermined pitch Py. A plurality of lines provided along the X direction in parallel with each other at intervals, and a plurality of line segments that connect each adjacent line of the plurality of lines and intersect the line at a predetermined angle θ. The electromagnetic wave shielding plate is characterized in that the line segments are provided at predetermined X-direction pitches Px and use a predetermined mesh-shaped region whose X-direction position is random. 2. The grounding frame portion made of the same metal thin film as the mesh around the outer periphery of the mesh portion so as to surround the screen area of the display when used on the front surface of the display. An electromagnetic wave shielding plate, characterized in that: 3. The display device according to claim 1, wherein an angle between a horizontal scanning line of the display and a line direction of the mesh is 15 degrees or more when used in front of the display.
An electromagnetic wave shielding plate having a range of 45 degrees. 4. A pattern plate for forming a mesh on an electromagnetic wave shielding plate having an electromagnetic wave shielding property in which a mesh made of a metal thin film is laminated on one surface of a transparent substrate and used on a front surface of a display, At least one pattern plate is provided with all the patterns of the mesh area to be created, and the pattern shape includes a plurality of lines provided along the X direction in parallel with each other at a predetermined pitch Py interval, and the plurality of lines. A plurality of line segments connecting the adjacent lines of the line and intersecting the line at a predetermined angle θ are provided, and the line segments between the lines are provided at a predetermined pitch Px in the X direction, and the positions in the X direction Wherein a predetermined region of a random mesh shape is used.