JP3618448B2 - Electromagnetic wave leakage prevention filter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electromagnetic wave leakage prevention filter, and more particularly to an optical filter that shields an electromagnetic wave from an image display unit.
[0002]
[Prior art]
A gas discharge display panel used in an image display device, for example, a plasma display panel (PDP), excites gas molecules enclosed inside by discharge between electrodes (specifically, xenon gas and neon gas are excited). Mixing and helping the excitation of xenon gas molecules), the fluorescent material coated inside is excited by the generated ultraviolet light, light in the visible light region is emitted, and an image is displayed. An electromagnetic wave is generated, and the electromagnetic wave leaks to the outside although it is slight. In order to prevent leakage of this electromagnetic wave, an electromagnetic wave leakage prevention function is provided in an optical filter disposed on the front surface of the PDP in order to block wavelengths in the near infrared region emitted by the PDP. This function is achieved, for example, by disposing a mesh-shaped conductor (referred to as a conductive mesh) on a synthetic resin plate surface such as acrylic as a base material of an optical filter. The conductive mesh covers the frequency range where leakage should be prevented, and the conductor width and conductor spacing of the grid of the conductive mesh are optimally set so as not to hinder the image light, and the conductive mesh is connected to the PDP housing. In addition, the charges induced by the electromagnetic waves are grounded, and the direction of the mesh is set obliquely as shown in FIG. 5 so that the PDP pixel matrix and the mesh conductor do not interfere with the image light.
[0003]
By the way, the PDP applies a pulse of about 350 V between the electrodes at a required period for lite toilets (in order to write new video data to each pixel, the data of all pixels are erased at once). Since the filter is disposed close to the front surface of the PDP, the front glass of the PDP and the filter are capacitively coupled, and the pulse voltage for the lye toilet is applied to the conductive mesh of the filter through the coupling capacitance with the required period. A charge is generated. This electric charge instantaneously generates a voltage (maximum of about 140 V according to actual measurement) between the conductive mesh and the ground due to the impedance of the ground circuit, but the voltage of the conductive mesh becomes 0 V by conducting to the ground. On the other hand, as shown in FIG. 6, this instantaneous voltage (about 140 V) is charged in the portion 41 (the acrylic adhesive is present) surrounded by the lattice of the conductive mesh 12, and the conductive mesh 12. This charge remains even after the voltage becomes 0V. Since the charged portion is at a short distance from the conductive mesh 12, it exceeds the withstand voltage, and at the same time the voltage of the conductive mesh 12 drops to 0 V, this charge is instantaneously discharged (sparked) toward the conductive mesh 12. This discharge is an AC (alternating current) drive type PDP. For example, when the video signal is of the NTSC system, when driving is performed with six subfields in one field, voltage generation of the conductive mesh 12 is repeated (required). ) The period is about 360 Hz (60 fields × 6 subfields = 360 Hz), the discharge is repeated at about 360 Hz, and a spark sound is heard as an abnormal sound.
[0004]
[Problems to be solved by the invention]
In view of such a point, the present invention does not charge a charge induced by a pulse voltage applied to the PDP in order to prevent leakage in the grid of the conductive mesh formed on the optical filter surface in order to prevent electromagnetic wave leakage of the PDP. Thus, it is intended to prevent the generation of abnormal noise due to the discharge of the charged charge.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention provides a light-transmitting conductive mesh on an optical filter disposed on the front surface of a PDP (image display unit), and provides a transparent antistatic layer on the conductive mesh. The present invention provides an electromagnetic wave leakage prevention filter that is attached to the front surface of a PDP with the antistatic layer side facing the PDP.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
In the electromagnetic wave leakage prevention filter according to the present invention, a pigment for correcting the emission color of PDP is appropriately mixed with a synthetic resin such as acrylic or polycarbonate which is colorless and transparent and has impact resistance, and a line in the near infrared region emitted by PDP. A near-infrared absorption layer for absorbing the spectrum is provided as a filter base, and an external light antireflection treatment layer, that is, an AR (Anti-Reflection) coating layer (AR film), is provided on the outer surface side to prevent reflection of external light. In addition, a conductive mesh is provided on the inner surface side (PDP side) to prevent leakage of electromagnetic waves radiated from the PDP to the outside, and light scattering treatment, that is, AG (Anti-Glare) treatment, and antistatic treatment on the conductive mesh. In other words, an AS (Anti-Static) -treated AG / AS-treated film is adhered to prevent glare on the screen (anti-glare). Performed Rutotomoni antistatic, it constitutes an electromagnetic wave leakage preventing filter. The conductive mesh is connected to the housing of the PDP, converts the electromagnetic wave from the PDP into a current with the conductive mesh, and conducts to the ground.
[0007]
【Example】
Embodiments of an electromagnetic wave leakage prevention filter according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic view of an example of a state in which an electromagnetic wave leakage prevention filter according to the present invention is attached, FIG. 2 is a side sectional view of an essential part of an embodiment of an electromagnetic wave leakage prevention filter according to the present invention, and FIGS. FIG. 5 is an explanatory view of a conductive mesh, and FIG. 6 is an enlarged view of the conductive mesh.
[0008]
In FIG. 1, 1 is a PDP, 2 is an electromagnetic wave leakage prevention filter (hereinafter abbreviated as a filter), 3 is a front part of the housing, and 4 is a rear part of the housing. The mounting bracket 7 is brought into contact with the peripheral edge of the filter 2, and the mounting bracket 7 is fastened to the mounting boss 5 of the housing front portion 3 with a screw 6, and the filter 2 is attached to the housing front portion 3. The PDP 1 is fixed to the housing rear part 4 with the screw 9 through the mounting boss 8, and the housing rear part 4 is attached to the housing front part 3 so that the peripheral edge of the PDP 1 is brought into contact with the mounting metal 7, and the mounting metal 7 is filtered. 2 is brought into strong contact with a conductive mesh, which will be described later, led to the peripheral edge of the filter. The mounting boss 5, the inner surface of the housing front portion 3, the inner surface of the housing rear portion 4, the mounting boss 8, etc. are subjected to conductive treatment processing, thereby connecting the conductive mesh to the metal portion (ground) on the back surface of the PDP 1. The electric charge induced in the conductive mesh 12 by the electromagnetic wave radiated more is conducted to the ground.
[0009]
In FIG. 2, 11 is a filter base, 12 is a conductive mesh disposed on one surface of the filter base 11, 13 is an antistatic layer, for example, an AG / AS treatment film, and 14 is an AG / AS treatment film. 13 is an adhesive for adhering 13 on the conductive mesh 12. The filter base 11 is a colorless and transparent synthetic resin having impact resistance, such as acrylic or polycarbonate, mixed with a pigment for a selective absorption filter that absorbs a red component for correcting the emission color of the PDP, and emits blue light. The fluorescent material for use absorbs a red component that emits light in addition to blue. A near-infrared absorption filter layer (not shown) is provided on this to absorb the line spectrum in the near-infrared region (800 nm to 1000 nm) emitted from the PDP, and to operate an infrared remote control device or an optical communication device installed in the vicinity. Try not to cause trouble.
[0010]
For example, the conductive mesh 12 performs a necessary treatment on the surface of the filter base 11, electrolessly plating a metal such as copper to a required thickness (for example, 0.1 μm), and a metal such as nickel thereon. Electroless plating is performed to a required thickness (for example, 100 mm), a photoresist is formed thereon, ultraviolet rays are irradiated to remove the resist other than the mesh conductor portion, and a conductive mesh is generated by etching. Then, considering the screen size of the PDP, the pixel pitch, etc. so as to transmit visible light well and shield electromagnetic waves in the frequency range of 30 MHz to 130 MHz, for example, as shown in FIG. ) And conductor spacing (127 μm) to shield electromagnetic waves in the above frequency range, and the direction of the mesh is inclined 45 ° as shown in FIG. Make sure that the mesh does not interfere with the image. The conductive mesh 12 is made of a synthetic resin mesh fabric electrolessly plated with a high conductivity metal such as copper or copper nickel to form a metal woven fabric, and adheres to the filter base 11 or the filter base 11 It may be divided into two sheets and sandwiched between layers. Metal woven fabrics are not suitable for small-diameter PDPs because of the limited mesh fineness (that is, conductor width), but they are effective for large-diameter types such as 40-50 types. Alternatively, instead of mesh as described above, a metal such as silver or gold is sputtered to form a thin film that transmits light, or the filter base is made of a glass material, and a metal such as tin oxide is vacuum deposited. Thus, a thin film that transmits light may be formed.
[0011]
The antistatic layer 13 is obtained by dissolving a conductive metal oxide, for example, fine particles of tin oxide and antimony in a required solution, for example, a mixed solution of pure water, alcohol, and a surfactant, and is colorless. It is an antistatic film formed by applying to a transparent film. Alternatively, it is an AG / AS (light scattering / antistatic) treated film formed by subjecting the surface of a colorless and transparent film to light scattering treatment and applying the antistatic agent thereon. This antistatic layer 13 is formed to have a surface resistance of about 10 8 ohm / square cm, adheres to the conductive mesh 12 (PDP 1 side) with the adhesive 14, and charges are not easily charged between the lattices of the conductive mesh 12. To be.
In addition, the AG treatment forms fine irregularities on the surface of a colorless and transparent film, diffuses and diffuses light from lighting fixtures, etc., and prevents glare and overlaps with the image of the PDP so that the screen is not difficult to see. To. Then, with the antistatic layer 13 side set to the PDP side, it is attached to the front surface of the PDP 1 as shown in FIG. 1, and the mounting metal 7 is brought into contact with the lead-out portion of the conductive mesh 12 to conduct electricity. Connect mesh 12 to ground.
[0012]
FIG. 3 shows an example in which an AR film 21 is adhered to the outer surface side (downward in the drawing) of the filter base 11. The AR film 21, for example, deposits a plurality of films made of materials having different refractive indexes on the surface of a transparent film, or forms a film by applying a fluororesin, and refracts light incident on the filter body in a complicated manner. This makes it difficult to return to the front and prevents the contrast of the image from being lowered due to reflection of external light.
[0013]
In FIG. 4, a transparent antistatic agent 31 is applied to the surface of the filter base 11 where the conductive mesh 12 is disposed, and the AG / AS-treated film 13 is adhered to the application surface of the antistatic agent 31 with an adhesive 14. It is an example. The surface resistance of the coating layer of the antistatic agent 31 is about 10 6 ohm / square cm, and the coating of the antistatic agent 31 makes it more difficult to charge the lattice between the conductive meshes 12 of the filter base 11. It becomes. The AR film 21 is the same as that shown in FIG.
[0014]
When the AG / AS treatment film 13 or the layer of the antistatic agent 31 is not provided, as described above, a charge of about 140 V is induced in the conductive mesh 12 by the lye toilet of the PDP 1, and the portion 41 ( This charge is charged in the presence of an acrylic adhesive, and the charge of the conductive mesh 12 flows to the ground via the mounting bracket 7 and becomes 0 V. As shown in the figure, this electric charge remains and discharges toward the conductive mesh 12 having a voltage of 0 V. However, by providing an antistatic layer between the PDP 1 and the conductive mesh 12, an electrode is interposed between the PDP 1 and the conductive mesh 12. The 140V is divided by the capacitance between the PDP 1 and the antistatic layer and the capacitance between the antistatic layer and the conductive mesh 12 (voltage inversely proportional to the capacity ratio). ) Is the charge induced on the conductive mesh 12 is lower than the 140V value, i.e., decreases the voltage of the discharge disabled, the discharge is not performed, and that no abnormal sounds.
[0015]
【The invention's effect】
As described above, according to the electromagnetic wave leakage prevention filter according to the present invention, since the antistatic layer is provided between the conductive mesh provided in the optical filter and the PDP in order to prevent the electromagnetic wave leakage of the PDP, Even if a charge is induced in the conductive mesh by the pulse voltage applied to, the voltage becomes a low value, so that no discharge is performed and no abnormal noise is generated.
[Brief description of the drawings]
FIG. 1 is a schematic view of a state in which an electromagnetic wave leakage prevention filter according to the present invention is attached.
FIG. 2 is a side sectional view of an essential part of an embodiment of an electromagnetic wave leakage preventing filter according to the present invention.
FIG. 3 is a side sectional view of an essential part of another embodiment of the electromagnetic wave leakage preventing filter according to the present invention.
FIG. 4 is a side sectional view of an essential part of another embodiment of the electromagnetic wave leakage preventing filter according to the present invention.
FIG. 5 is an explanatory diagram of a conductive mesh of an electromagnetic wave leakage prevention filter according to the present invention.
FIG. 6 is a partially enlarged view of a conductive mesh of the electromagnetic wave leakage prevention filter according to the present invention.
[Explanation of symbols]
1 PDP
2 Electromagnetic wave leakage prevention filter 7 Mounting bracket 11 Filter base 12 Conductive mesh 13 AG / AS treatment film 14 Adhesive 21 AR film 31 Antistatic agent

Claims (8)

An optical filter disposed in front of the image display unit of a plasma display panel (PDP) is provided with a light-transmitting conductive mesh, a transparent antistatic layer is provided on the conductive mesh, and the antistatic layer side is disposed on the image. electromagnetic wave leakage prevention filter to attach to the front of the image display unit to face the display unit. 2. The electromagnetic wave leakage prevention filter according to claim 1, wherein the antistatic layer is an antistatic film formed by applying a transparent antistatic agent to a colorless and transparent film, and is adhered to the conductive mesh with an adhesive. 3. . The antistatic layer is a light scattering / antistatic film produced by applying a light scattering treatment to the surface of a colorless and transparent film and applying a transparent antistatic agent so that it adheres to the conductive mesh with an adhesive. The electromagnetic wave leakage prevention filter according to claim 1. The electromagnetic wave leakage prevention according to claim 3, wherein a transparent antistatic agent is applied to a conductive mesh-arranged surface of the optical filter, and the light scattering / antistatic film is adhered to the antistatic agent application surface by an adhesive. filter. The optical filter, the emission color of the correcting function of the image display unit to the filter base of the colorless transparent synthetic resin, made of a one provided line spectral cutoff function in the near-infrared region emitted from the image display unit, one face The electromagnetic wave leakage prevention filter according to claim 1, wherein the conductive mesh and the antistatic layer are provided on the electromagnetic wave leakage prevention filter. The optical filter, the emission color of the correcting function of the image display unit to the filter base of the colorless transparent synthetic resin, made of a one provided line spectral cutoff function in the near-infrared region emitted from the image display unit, one face The electromagnetic wave leakage prevention filter according to claim 3 or 4, wherein the conductive mesh and the antistatic layer are provided on the antistatic layer, and the light scattering / antistatic film is adhered to the antistatic layer with an adhesive. The electromagnetic wave leakage prevention filter according to claim 5 or 6, wherein an antireflection layer is provided on the other surface of the optical filter to prevent reflection of external light. Said conductive mesh connected to the housing of the image display unit, according to claim 1 electromagnetic wave by the induced charge (voltage) and be grounded from the image display unit, according to claim 2, claim 3, claim 4 The electromagnetic wave leakage prevention filter according to claim 5, claim 6 or claim 7.

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