JP3674146B2 - Optical filter device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical filter device, and more particularly to an optical filter device that shields electromagnetic waves leaking from a plasma display panel (PDP) and blocks near infrared rays.
[0002]
[Prior art]
A gas discharge display panel used in a video display device, for example, a PDP, excites gas molecules enclosed inside by discharge between electrodes (specifically, mixing neon gas with xenon gas, Exciting the fluorescent material coated inside with the generated ultraviolet rays, and emitting light in the visible light region to display an image, but this discharge etc. generates electromagnetic waves due to the discharge. Leak outside. Xenon gas generates a line spectrum in the near-infrared region in addition to ultraviolet light when excited, and the wavelength of this line spectrum is the center wavelength (800 nm) of the emission spectrum of an LED (light emitting diode) used for a remote control device or optical communication. May be disturbed when these devices are operated in the vicinity of the PDP.
[0003]
For this reason, an optical filter is provided on the front surface of the PDP to block these electromagnetic waves leaked from the PDP and the line spectrum in the near infrared region, but the electromagnetic waves are shielded by a synthetic resin such as acrylic. On the surface of the optical filter, for example, an electromagnetic wave shielding layer is formed by forming a mesh of conductors to cover a frequency range in which leakage should be prevented, and so as not to disturb image light. Suppose that the interval and mesh direction (the PDP pixel matrix and the mesh conductor are slanted so that they do not overlap) are set, and for blocking the line spectrum in the near infrared region, for example, A layer made of infrared absorbing glass or a plastic-based infrared absorbing filter is provided. Separately produced a layer of, respectively, there is a problem that increase the production cost to combine these. Note that the electromagnetic wave shielding layer in which the conductor is formed in a mesh shape inevitably prevents the image light from being blocked by the mesh, and causes a problem of darkening the screen.
[0004]
[Problems to be solved by the invention]
In view of these points, the present invention is capable of shielding electromagnetic waves leaked from the PDP and blocking transmission of the line spectrum in the near infrared region, and achieving these at a lower cost.
[0005]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a near-infrared region emitted from the PDP in an optical filter provided on the front surface of the PDP and having a function of preventing reflection of external light and a function of correcting the emission color of the PDP. A layer for blocking the electromagnetic spectrum leaking from the PDP, for example, a layer formed by transparently forming a thin film made of silver and an inorganic oxide by sputtering on a transparent film, and the thickness of this layer Is formed to approximately 100 mm.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
In the optical filter device according to the present invention, an optical filter base is formed by mixing a pigment for correcting the emission color of the PDP with a colorless and transparent synthetic resin such as acrylic or polycarbonate having impact resistance to reflect external light. A light reflection preventing layer for preventing light is provided on the surface, and a layer for blocking electromagnetic waves leaking from the PDP while blocking the near-infrared line spectrum emitted from the PDP is provided on the other surface. This near-infrared line spectrum and electromagnetic wave shielding layer is formed by transparently forming a thin film made of silver and an inorganic oxide on a transparent film by sputtering or the like. It connects to the housing which accommodates PDP by the contact part which contact | abutted, and earth | grounds the voltage induced by electromagnetic waves.
[0007]
【Example】
Hereinafter, embodiments of an optical filter device according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing an example of a state in which an optical filter device according to the present invention is attached, FIG. 2 is a side sectional view showing the configuration of the optical filter device according to the present invention, and FIG. 3 shows a cutoff characteristic of a line spectrum in the near infrared region. It is a figure explaining.
[0008]
In FIG. 1, 1 is a PDP, 2 is an optical filter device (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 portion 4 with the screw 9 through the mounting boss 8, and the housing rear portion 4 is attached to the housing front portion 3 so that the peripheral portion of the PDP 1 is brought into contact with the mounting bracket 7, and the mounting bracket 7 is attached to the filter 2. In contact with a ground electrode (electrode for connecting the electromagnetic wave shielding layer to the ground), which will be described later, provided on the periphery 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 electromagnetic wave shielding layer to the metal portion (ground) on the back surface of the PDP 1, The voltage induced in the electromagnetic wave shielding layer by the electromagnetic wave radiated from the PDP 1 is conducted to the ground.
[0009]
In FIG. 2, 11 is a filter base, 12 is a silver sputter film disposed on one surface of the filter base 11, 13 is an AR (Anti-Reflection) film for preventing reflection of external light, and 14 is a Newton ring (light and dark). AN (Anti-Newton Ring) film 15 for preventing the concentric circles) is an earth electrode provided for connecting the silver sputtered film 12 to the earth, and is formed by printing a conductive metal. The silver sputter film 12, the AR film 13, and the AN film 14 are each adhered with a transparent adhesive or the like.
[0010]
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 1. The fluorescent material for blue light emission absorbs a red component that emits light in addition to blue.
[0011]
The sputtered silver film 12 is, for example, a thin film having a thickness of about 100 mm so that the surface resistance is about 2.7 ohm / square cm by sputtering silver or silver and an inorganic oxide on one side of a transparent PET (Polyethlene terephthalate) film. The film is formed. This sputtering layer shields electromagnetic waves in the frequency range of 30 MHz to 130 MHz leaking from the PDP 1 and blocks the line spectrum in the near infrared region (800 nm to 1000 nm) emitted from the PDP. The reason why the inorganic oxide fine particles are deposited is to prevent the appearance of the back surface from being reflected by the mirror surface in the case of depositing only silver, for example, white inorganic oxide. The fine particles are deposited on the front side (the lower side in FIG. 2) and silver is deposited on the rear side, or silver and an inorganic oxide are sputtered at the same time, and the light from the front is inorganic. Diffuse reflection with fine oxide particles.
[0012]
According to the experiment, the shielding amount (attenuation) of the electromagnetic wave is at least 10 decibels or more in the above frequency range, and the total of the electromagnetic wave shielding performance of the PDP 1 itself is controlled by the information processing apparatus or the like. The leakage level can be cleared. In addition, the near-infrared line spectrum shielding characteristic transmits about 60% in the wavelength range of 400nm to 700nmn, the transmittance at 800nm is about 10%, and less than 4% at 850nm. Interference with the infrared remote control device or optical communication equipment can be prevented.
[0013]
An electrode for ground connection is formed on the periphery of the silver sputtered film 12 by printing or the like, and the mounting bracket 7 is brought into contact with this portion to conduct with the silver sputtered film 12, and the surface is electrically connected via the mounting bracket 7. The treated mounting boss 5 → the inner surface of the housing front portion 3 → the inner surface of the housing rear portion 4 → the connection boss 8 is connected to the ground on the back surface of the PDP 1.
[0014]
The AR film 13 is formed by, for example, depositing a plurality of films of materials having different refractive indexes on the surface of a transparent film, or applying a fluororesin to form a film, thereby refracting incident light in a complicated manner. It makes it difficult to return to the front, and prevents a decrease in contrast of the image due to reflection of external light. In addition, the AN film 14 forms fine irregularities on the surface of a transparent film, and when the filter 2 is disposed in contact with the PDP 1, the irregularities prevent the filter 2 from coming into close contact with the surface of the PDP 1, and a Newton ring. Prevents the occurrence of light and dark concentric circles.
[0015]
【The invention's effect】
As described above, according to the optical filter device according to the present invention, the sputtered silver film layer of approximately 100 Å thick, with shielding electromagnetic waves in the frequency range of 30 MHz ~ 130 MHz leaking from PDP, released from PDP The line spectrum in the near-infrared region ( 800 nm to 1000 nm ) can be cut off, reducing the leakage level of electromagnetic waves and preventing interference with remote control devices or optical communication equipment due to the emission of the near-infrared line spectrum. It can be effective.
In addition, the cost can be greatly reduced as compared with the case where the electromagnetic wave leakage prevention process and the near-infrared shielding are separately performed.
[Brief description of the drawings]
FIG. 1 is a schematic side view of a state in which an optical filter device according to the present invention is attached.
FIG. 2 is a cross-sectional view of a main part of an optical filter device according to the present invention.
FIG. 3 is a diagram for explaining a cutoff characteristic of a line spectrum in a near infrared region.
[Explanation of symbols]
1 PDP
2 Optical filter 7 Mounting bracket
11 Filter base
12 Silver sputter film
13 AR film
14 AN film
15 Ground electrode

Claims (1)

The near-infrared line spectrum emitted from the plasma display panel is blocked by an optical filter that is provided in front of the plasma display panel and has the function of preventing reflection of outside light and correcting the emission color of the plasma display panel. In the optical filter device provided with a layer that shields electromagnetic waves leaking from the plasma display panel ,
The optical filter device is characterized in that the layer is formed by forming a silver thin film to a thickness of about 100 mm.

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