JP2009042358A - Optical filter and plasma display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical filter having an antiglare function which prevents reflection of images of surrounding items and reduces a whitish image when diagonally viewed. <P>SOLUTION: The optical filter 1 has an antiglare function by dispersing black particles 30 on the surface for forming irregularities. When applied to an electromagnetic wave shield material of a PDP, an electric conductive pattern 16, a plastic film 20, an antireflection layer 24 and dispersed black particles 30 are provided on a transparent base material 10. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical filter and a plasma display device, and more particularly to an optical filter that can be suitably applied to a shielding material that shields electromagnetic waves leaking from a PDP (plasma display panel) and a plasma display device including the same.

  In recent years, PDPs (plasma display panels) having features such as a wide viewing angle, good display quality, and a large screen have been rapidly expanded in applications such as multimedia display devices. Since the PDP generates electromagnetic waves when driven, a shielding material (optical filter) is disposed on the screen of the PDP in order to shield the electromagnetic waves from the PDP.

  In such a shield material, a surface protective film is provided so that reflection of peripheral objects such as illumination does not occur on the display screen of the PDP. Examples of the surface protective film include an antireflection film and an antiglare (antiglare) film.

Patent Documents 1 and 2 disclose an electromagnetic wave shielding plate provided with a film having an antireflection function and an antiglare function.
JP 2006-196911 A JP 2003-226465 A

  In the anti-glare film, transparent particles are scattered in the hard coat resin, and reflected light due to external light is scattered by unevenness formed on the surface, thereby preventing reflection of peripheral objects such as illumination on the display screen.

  However, when such an anti-glare film is applied to a PDP shield material, when the display screen is viewed obliquely, light is scattered by the transparent particles, which causes a problem that the display screen appears cloudy.

  The present invention has been created in view of the above problems, and includes an optical filter having an anti-glare function that can prevent reflection of surrounding objects and reduce the cloudiness when viewed from an oblique direction, and the optical filter. An object of the present invention is to provide a plasma display device.

  In order to solve the above-mentioned problems, the present invention relates to an optical filter, characterized in that an optical filter having an antiglare function has the antiglare function by providing irregularities by scattering black particles on the surface.

  The optical filter of the above invention has a plastic film, a resin layer formed on the upper surface of the plastic film, and black particles scattered in the resin layer.

  In a preferred embodiment of the present invention, it is applied to an electromagnetic wave shielding material for PDP, further comprising a transparent substrate and a conductive pattern formed above the transparent substrate, and the lower surface side of the plastic film is pasted on the conductive pattern. It is worn.

  The optical filter of the present invention is disposed in front of a display device such as a PDP, and unevenness due to black particles prevents the movement of peripheral objects such as illumination (anti-glare function). In addition, since black particles are scattered, the incident external light is absorbed and reflected light is reduced, unlike the case of using transparent silica particles, which eliminates the problem of appearing cloudy when viewed obliquely. As a result, good display characteristics can be obtained in a wide viewing angle.

  In the optical filter for PDP, the light transmittance is often set to about 40% in order to improve the contrast of the display image of PDP. In order to reduce the light transmittance of the optical filter, there are methods such as adding a dye or pigment to the near-infrared absorbing film or adhesive layer, or increasing the line width of the conductive pattern, but the haze (cloudiness) increases. There is a problem that moire occurs.

  However, since the optical filter of the present invention has an antiglare function by scattering black particles, the light transmittance of the optical filter can be adjusted by the black particles. Therefore, the optical filter can be set to a desired light transmittance without causing defects (haze or moire), and the contrast of the display image on the PDP can be improved.

  In a preferred aspect of the present invention, it is preferable that the black particles are regularly arranged on a plurality of straight lines inclined at a predetermined angle from the vertical direction in order to prevent the occurrence of moire.

  As described above, in the optical filter of the present invention, it is possible to prevent the reflection of surrounding objects and to reduce the cloudiness when viewed from an oblique direction.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a configuration of an optical filter according to an embodiment of the present invention. In the present embodiment, an optical filter for a plasma display device (PDP) having an electromagnetic wave shielding function will be described as an example.

  As shown in FIG. 1, in the optical filter 1 for PDP of this embodiment, the PDP is formed on the resin layer 14 in which the adhesive layer 12 and the resin layer 14 are formed on the glass plate 10 (transparent substrate). A conductive pattern 16 made of copper or the like that shields electromagnetic waves from is formed.

  The conductive pattern 16 includes a mesh-shaped pattern portion 16a disposed in the center portion and a ground electrode portion 16b disposed in a frame shape on the peripheral side, and the pattern portion 16a is connected to the ground electrode portion 16b. The conductive pattern 16 is formed in a mesh shape with a line width of 10 μm, for example. The conductive pattern 16 may be blackened on both sides and both sides.

  In addition, a PET film may be used instead of the glass substrate 10, and the conductive pattern 16 may be formed on the PET film via an adhesive layer. In this case, the copper foil of the copper foil with PET is patterned to obtain the conductive pattern 16.

  An adhesive layer 18 is formed on the conductive pattern 16 with the ground electrode portion 16b exposed. The plastic film 20 (PET film or TAC) with the ground electrode portion 16b exposed on the adhesive layer 18 is formed. Film) is attached. A near infrared absorption layer 22 is formed on the lower surface of the plastic film 20.

  An antireflection layer 24 is formed on the upper surface of the plastic film 20. As shown in the partial cross-sectional view of FIG. 1, the antireflection layer 24 includes first, second, and third optical interference layers 24b, 24c, and 24d (resin layers) having different optical refractive indexes on the hard coat layer 24a. It is configured by stacking, and the intensity of reflected light can be reduced using optical interference.

  Further, a plurality of black particles 30 are scattered in the antireflection layer 24. The black particles 30 are scattered in a state in which the protrusions P protruding from the upper surface of the antireflection layer 34 are provided, and thereby the surface is provided with irregularities. Due to the unevenness of the protrusions P of the black particles 30, the reflected light of the external light is scattered, and reflection of surrounding objects such as illumination can be prevented. The diameter of the black particles 30 is preferably 100 μm or less, and more preferably 3 to 10 μm.

  Thus, on the surface side of the optical film 1, the plastic film 20, the near infrared absorption layer 18 formed on the lower surface thereof, and the antireflection layer 24 and the black particles 30 formed on the upper surface thereof are configured. An AG / AR / NIR film 40 is provided. The AG / AR / NIR film 40 has an antiglare (AR) function, an antireflection (AR) function, and a near infrared (NIR) absorption function.

  The protruding portion P of the black particles 30 may be covered with the third optical interference layer 24d of the antireflection layer 24 or the like. Moreover, the black particle 30 with which the whole was embedded in the antireflection layer 24 may be included, and the protrusion part P of the black particle 30 should just protrude, and the unevenness | corrugation should just be provided. Moreover, all the diameters of the plurality of black particles 30 may be the same or different.

  Furthermore, when the antireflection layer 24 is not required, the black particles 30 may be scattered in an optically isotropic resin.

  Further, the black particles 30 may be made of black particles by immersing silica particles or the like in a black color material, or may be formed of a black colored resin or the like so as to be entirely black. Further, the black particles 30 of the present embodiment can be used as long as they include particles exhibiting a color such as gray, dark brown, or dark green in addition to true black, and are dark colors that hardly reflect light.

  The optical filter 1 of the present embodiment is installed on the front surface of the display screen of the PDP 2 so that the AG / AR / NIR film 40 is on the viewer side, and the ground electrode portion 16b is connected to the ground terminal of the casing of the PDP 2. Electrically connected.

  In the optical filter of this embodiment, the unevenness caused by the black particles 30 prevents the transfer of peripheral objects such as illumination (anti-glare (anti-glare) function). Furthermore, since the black particles 30 are scattered, the incident external light is absorbed and the reflected light is reduced, unlike the case of using transparent silica particles. As a result, it is possible to obtain good PDP display characteristics in a wide viewing angle. Furthermore, since the antireflection layer 24 is provided, the reflected light intensity can be reduced and the contrast can be improved.

  By the way, in the optical filter for PDP, the light transmittance is often set to 30 to 50% (for example, about 40%) in order to improve the contrast of the display image of the PDP. External light passes through the optical filter, is reflected by the PDP, passes through the optical filter again, and is emitted to the outside. At this time, if the light transmittance of the optical filter is set high, a lot of unnecessary reflected light due to external light not related to the display image of the PDP is emitted to the outside. As a result, the contrast of the display image of the PDP is deteriorated, so that it is necessary to suppress the light transmittance of the optical filter to some extent.

  In general optical filters, in order to lower the light transmittance, dyes or pigments are included in the near-infrared absorbing film or adhesive layer, the line width of the conductive pattern (metal mesh) is increased, or the pitch is reduced. It corresponds.

  However, if a near-infrared absorbing film or an adhesive layer contains a dye or a pigment, haze (cloudiness) is increased, and if the line width of the conductive pattern (metal mesh) is increased, moire is generated.

  In the optical filter of this embodiment, the black particles 30 are scattered in the antireflection layer 24 so as to have an antiglare function. Therefore, the light transmittance of the optical filter 1 is adjusted by the black particles 30 without including a dye or pigment in the near-infrared absorbing film or the adhesive layer, or increasing the line width of the conductive pattern (metal mesh). be able to.

  That is, the light transmittance of the optical filter can be adjusted by freely setting the conductive pattern 16 to a line width (pitch) at which moire does not occur, and supplementing the black particles 30 with light shielding that is not sufficient in the conductive pattern 16.

  Thus, in this embodiment, by adjusting the amount of scattered black particles 30, the optical film can be adjusted to a desired light transmittance without causing defects (haze or moire). At this time, the light transmittance of the antireflection layer 24 is set to 90 to 50% (preferably 86 to 60%). Therefore, the contrast of the display image of the PDP can be improved without causing any harmful effects.

  Further, when referring to the arrangement of the black particles 30, particularly when the black particles 30 are randomly scattered and arranged in an optical film having a conductive pattern for PDP, moire may occur. Therefore, as shown in FIG. 2, it is preferable that the black particles 30 are regularly arranged at equal intervals on a plurality of straight lines inclined at an angle θ from the vertical (vertical) direction VD. The angle θ in FIG. 2 is set to an angle exceeding 0 ° and less than 90 ° (preferably 30 to 60 °) so that moire does not occur in consideration of the arrangement angle of the conductive pattern 16 and the like.

  Next, the manufacturing method of the optical filter of this embodiment is demonstrated.

  As shown in FIG. 3A, first, a separator 50 configured by forming a release layer 54 made of silicone or the like on the upper surface of a plastic film 52 (PET film or the like) is prepared. Next, the acrylic adhesive layer 12 and the polyester resin layer 14 are sequentially formed on the release layer 54 of the separator 50. Further, a copper foil 16 x is stuck on the resin layer 14.

  When the black conductive pattern 16 is obtained, a copper foil 16x whose one surface is blackened by electrolytic plating is used, and the blackened surface is attached to the resin layer 14. In this manner, a structure in which the adhesive layer 12, the resin layer 14, and the copper foil 16x are laminated on the separator 50 in order from the bottom is prepared.

  Next, as shown in FIG. 3B, after patterning a resist film (not shown) on the copper foil 16x, the conductive pattern 16 is formed by wet etching the copper foil 16x using the resist film as a mask. To do. Thereafter, the resist film is removed. The conductive pattern 16 includes a pattern portion 16a disposed in the central main portion and a ground electrode portion 16b connected to the peripheral portion in a frame shape.

  In this step, particularly when transported by a roll-to-roll method, the copper foil 16x is supported by the separator 50, the adhesive layer 12 and the resin layer 14, and therefore can withstand the pressure of the etching solution supplied in a spray form. The copper foil 16x can be etched stably.

  Subsequently, when the black conductive pattern 16 is obtained, the exposed surface of the conductive pattern 16 is blackened by subjecting the conductive pattern 16 to a chemical conversion treatment with a mixed solution of a sodium chlorite aqueous solution and a caustic soda aqueous solution. As a result, both sides and both sides of the conductive pattern 16 are all blackened.

  Next, as shown in FIG. 3C, the separator 50 is separated from the adhesive layer 12 by peeling from the interface between the adhesive layer 12 and the release layer 54. Thereby, as shown in FIG.3 (d), the conductive member 5 comprised by forming the resin layer 14 and the conductive pattern 16 in order on the adhesion layer 12 is obtained.

  Subsequently, as shown in FIG. 4, the surface of the adhesive layer 12 of the conductive member 5 of FIG. Further, the surface of the near-infrared absorbing layer 22 of the AG / AR / NIR film 40 described above is stuck on the conductive pattern 16 through the adhesive layer 18 so that the ground electrode portion 16b is exposed.

  The antireflection layer 24 and the black particles 30 are formed by applying a required resin material for forming the antireflection layer 24 on the plastic film 20 a plurality of times to form a resin coating layer. Further, the black particles 30 are regularly arranged and scattered in the resin coating layer by a dispenser. Furthermore, the antireflection layer 24 is obtained by curing the resin coating layer by heat treatment, and the black particles 30 are fixed therein.

  As described above, the optical filter 1 shown in FIG. 1 is obtained.

  A copper layer is formed on the glass plate 10 by a sputtering method, and the conductive layer 16 is formed by patterning the copper layer by photolithography and etching, and an AG / AR / NIR is formed thereon via an adhesive layer 18. The film 40 may be attached.

  Moreover, in this embodiment, although the optical filter for PDP was illustrated, when using for the use which does not require the conductive pattern 16, the conductive pattern 16 may be abbreviate | omitted. In this case, the AG / AR / NIR film 40 is stuck on the glass plate 10 via the adhesive layer 18. A plastic film may be used instead of the glass plate 10.

  Alternatively, an adhesive layer for sticking may be provided under the AG / AR / NIR film 40, and the optical filter may be installed by directly sticking the sticking adhesive layer to various display devices.

FIG. 1 is a cross-sectional view showing a configuration of an optical filter according to an embodiment of the present invention. FIG. 2 is a plan view showing a state of arrangement of black particles of the optical filter according to the embodiment of the present invention. FIG. 3 is a sectional view (No. 1) showing the method for manufacturing the optical filter according to the embodiment of the present invention. FIG. 4 is a sectional view (No. 2) showing the method for manufacturing the optical filter according to the embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Optical filter, 2 ... PDP, 5 ... Conductive member, 10 ... Glass plate, 12, 18 ... Adhesive layer, 14 ... Resin layer, 16 ... Conductive pattern, 16x ... Copper foil, 16a ... Pattern part, 16b ... Ground electrode Part, 20, 52 ... plastic film, 22 ... near infrared absorption layer, 24 ... antireflection layer, 24a ... hard coat layer, 24b-24d ... optical interference layer, 30 ... black particles, 40 ... AG / AR / NIR film, 50 ... separator, 54 ... release layer.

Claims (8)

In the optical filter with anti-glare function,
An optical filter having the anti-glare function by providing irregularities by dispersing black particles on a surface. Plastic film,
A resin layer formed on the upper surface of the plastic film;
The optical filter according to claim 1, comprising the black particles dispersed in the resin layer.   The optical filter according to claim 2, wherein the resin layer is an antireflection layer. A transparent substrate;
Further having a conductive pattern formed above the transparent substrate,
The optical filter according to claim 1, wherein a lower surface side of the plastic film is attached above the conductive pattern.   The optical filter according to claim 4, further comprising a near-infrared absorbing layer formed on a lower surface of the plastic film.   The optical filter according to claim 4, wherein an adhesive layer and a resin layer are provided in order from the bottom between the transparent substrate and the conductive pattern.   The optical filter according to claim 1, wherein the black particles are arranged side by side on a plurality of straight lines inclined at a predetermined angle from a vertical direction.   The plasma display apparatus which installed the optical filter as described in any one of Claims 1 thru | or 7 on the screen.

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