Patent Application
20070236120
The above and other features and advantages of the present invention will become more apparent to those of ordinary skill in the art by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which:
Korean Patent Application No. 10-2006-0032665, filed on Apr. 11, 2006, in the Korean Intellectual Property Office, and entitled: “Filter Assembly and Plasma Display Device Adopting the Same,” is incorporated by reference herein in its entirety.
The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are illustrated. The invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
In the figures, the dimensions of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when a layer or element is referred to as being “on” another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. Further, it will be understood that when a layer is referred to as being “under” another layer, it can be directly under, and one or more intervening layers may also be present. In addition, it will also be understood that when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. Like reference numerals refer to like elements throughout.
Hereinafter, the present invention will be described in detail by explaining embodiments of the invention with reference to the attached drawings.
Referring to
The panel assembly 210 may include a first substrate 211 and a second substrate 212. A space between the first and second substrates 211 and 212 may be sealed.
The chassis base assembly 230 may include a chassis base 231, which may be attached to the rear surface of the panel assembly 210, e.g., using adhesive materials. The adhesive materials may include a thermal conductive sheet 232 at the center of the rear surface of the second substrate 212, the thermal conductive sheet 232 adapted to transfer heat generated from the panel assembly 210 during operation thereof to the chassis bass 231, and double-sided tape 233 along edges of the rear surface of the second substrate 212.
A plurality of driving circuit boards 234 may be disposed on the rear surface of the chassis base 231. A plurality of circuit elements 235 may be included on the driving circuit boards 234. The circuit elements 235 may be electrically connected to one end of a signal transfer unit 236, e.g., a flexible printed cable. The other end of the signal transfer unit 236 may be electrically connected to an electrode terminal of the panel assembly 210, and may be adapted to transfer electrical signals between the panel assembly 210 and the driving circuit board 235. The signal transfer unit 236 may include a driving integrated circuit (IC) 236a, a plurality of leads 236b, and a flexible film 236c to cover the leads 236b.
A chassis reinforcing member 237 may be attached at the top and bottom of the rear surface of the chassis base 231 to strengthen the chassis base 231. A cover plate 238 may be disposed to protect the signal transfer unit 236 from damage. In other words, the signal transfer unit 236 may be between the chassis base 231 and the cover plate 238. Thermal grease 239 may be provided between the driving IC 236a and the chassis reinforcing member 237, and a silicon layer 240 may be between the driving IC 236a and the cover plate 238.
The filter assembly 250 may be attached to the front surface of the first substrate 211. The filter assembly 250 may be a multi-layer structure including a plurality of layers stacked on one another to block electromagnetic waves and infrared (IR) light generated from the panel assembly 210, to block visible emission from the discharge gas and to block reflection of external light. Here, the filter assembly 250 is directly attached to the front surface of the panel assembly 210.
The case 270 may house the panel assembly 210, the chassis base assembly 230 and the filter assembly 250. The case 270 may include a front cabinet 271 in front of the filter assembly 250 and a back cover 272 behind the chassis base assembly 230. A plurality of air holes 273 may be on the top and bottom of the back cover 272.
Hereinafter, the present invention will be described in greater detail.
Referring to
The near IR shielding film 254 may reduce or prevent emission of near IR light generated by plasma of an inactive gas used in a light emitting process. The transmittance control film 255 may control an amount of light transmitted through the filter assembly 250. In an embodiment of the present invention, a transmittance of 40% may be maintained. The wavelength selective absorption film 256 may block visible light emitted from the discharge gas, e.g., when neon is used, may block light within a wavelength region of about 590 nm. In the present example, a maximum absorption may be in a wavelength range of about 560˜610 nm. The near IR shielding film 254, the transmittance control film 255 and the wavelength selective absorption film 256 may be sequentially attached to each other. The base film 251 may further include additional films performing various functions.
The electromagnetic wave shielding filter 252 may be disposed between the first substrate 211 and the base film 251. The electromagnetic wave shielding filter 252 may be attached directly to the front surface of the first substrate 211. That is, a separate space need not be formed between the first substrate 211 and the filter assembly 250, i.e., the electromagnetic wave shielding filter 252 may contact the first substrate 211.
Electromagnetic waves, generated by the panel assembly 210 or circuit elements 235 of the driving circuit boards 234, during operation of a plasma display device 200 may cause functional errors of other electronic devices and may be harmful to humans. Accordingly, the electromagnetic waves should to be blocked, and the electromagnetic wave shielding filter 252 blocks the electromagnetic waves.
The electromagnetic wave shielding filter 252 may include fine metal meshes 252a and a conductive sheet 252b. The metal meshes 252a may be patterned in the central area of the conductive sheet 252b corresponding to the first substrate 211.
The electromagnetic wave shielding filter 252 may be formed of a material having high electrical conductivity, e.g., Cu, Ag, Al, Pt, Au, Fe or an alloy thereof. A ceramic material having conductivity or carbon nanotubes may also be used.
The conductive sheet 252b may be connected to an edge of the chassis base 231 by a conductive line 301, as illustrated in
The metal meshes 252a of the electromagnetic wave shielding filter 252 may be patterned using a variety of methods, however, coating or etching may simplify the manufacturing method and standardize the pattern.
Alternatively, the electromagnetic wave shielding filter 252 may be formed of a transparent conductive layer, e.g., an indium tin oxide (ITO) layer, and a metal layer, e.g., a copper layer which may be oxidized and stacked on the transparent conductive layer.
Referring again to
The surface reflection film 253 may include at least one of an anti-glare film (AG film) 257 and an anti-reflection film (AR film) 258, which may be attached to the front surface of the AG film 257, to prevent reduction of visibility due to reflection of external light.
The AG film 257 may include protrusions having a diameter of about 1 nm˜1 mm, e.g., about 0.5˜20 μm, on the surface of the AG film 257. These protrusions may diffuse light. The distribution area of the protrusions may be less than or equal to about 50% of the total surface area of the AG film 257. If the distribution area of the protrusions is greater than about 50% of the total surface area of the AG film 257, reflection of external light by the AG film 257 may be reduced, but a haze of the AG film 257 may increase when an image formed on a panel passes through the AG film 257 such that a high-contrast image may not be obtained.
The AR film 258 may reduce light reflection using a phase difference due to a stacking of a low refractive index layer and a high refractive index layer on one another. The surface reflection film 253 including the AG film 257 and the AR film 258 may have a haze of less than or equal to about 20%, e.g., about 0.5˜10%. If the haze of the surface reflection film 253 is greater than about 20%, image contrast may be reduced. A mirror reflectivity of the surface reflection film 253 may be less than about 1%.
The AG film 257 may include a transparent substrate and a plurality of beads on a surface of the transparent substrate. The transparent substrate of the AG film may be formed of a transparent material, e.g., glass, PET(Polyethylene Terephthalate) film, TAC(tri-acetyl-cellulose) film, PVA(polyvinyl alcohol) film, PE(polyethylene) film. The thickness of the transparent substrate may be about 10 μm to about 1000 μm. A plurality of beads may be formed of a light transmittable material, e.g., stylene, melanin, acrylic resin, acrylic-stylene, polycarbonate, polyethylene, polyvinyl chloride, or a metal oxide, e.g., SiO2, AlSiO2, ZrO2, GeO2 or Al2O3. The light transmittable material may have an average particle size of about 0.1 μm to about 20 μm.
The AR film 258 may include a transparent substrate and a stacked structure of a low refractive index layer and a high refractive index layer formed on the surface of the transparent substrate. The transparent substrate of the AR film may be the same as the transparent substrate of the AG film. A low refractive index layer and a high refractive index layer may be formed by stacking at least two materials selected from, e.g., acrylate resin, cellulose series resin, epoxy resin, urea-melamine resin and urethane resin.
A combined film having the AG film 257 and the AR film 258 may include a transparent substrate and a stacked structure of a low refractive index layer and a high refractive index layer on one another on the surface of the transparent substrate, and a plurality of beads formed on a surface of the low refractive index layer.
The films 251 to 253 may be combined in different ways to form variations on the filter assembly, as illustrated, for example, in
Referring to
Referring to
Referring to
Electromagnetic waves may be generated from the panel assembly 210 or circuit elements 235 of the driving circuit boards 234 during operation of the plasma display device 200 having the structure described above. The electromagnetic waves may impinge on the electromagnetic wave shielding filter 252 attached directly to the front surface of the first substrate 211 and may be grounded to the chassis base 231 through the conductive line 301, which is electrically connected to the electromagnetic wave shielding filter 252.
Furthermore, near IR light may be blocked by the near IR shielding film 254, visible light emitted by the discharge gas may be blocked by the wavelength selective absorption film 256 and reduction of visibility due to reflection of external light may be improved by a surface reflection film 253.
Features of the filter assembly 250 according to an embodiment of the present invention were investigated by experiments performed by the present applicant, the results of which are shown in the following Table 1. In Table 1, all of the examples are directly on the first substrate 211. Comparison example 1 is an AR film, comparison example 2 is an AG film, and each of examples 1 and 2 is a combined film including the AG film and the AR film.
Here, a haze meter NPH 2000 of Nippon Denshoku Kogyo may be used as the haze meter 1000 and a method of measuring haze using the haze meter 1000 is illustrated as shown in
Referring to
Here, light is divided into diffuse light and parallel light which are reflected in the integrating sphere 1100. The diffuse light is incident on a photodetector 1040. A whole internal surface of the integrating sphere 1100 may be coated with a reflective material, e.g., BaSO4, such that light is reflected on the whole internal surface of the integrating sphere 1100.
A signal generated due to the light being incident on the photodetector 1040 is transferred to a measuring portion 1050 to display data results. Also, the amount of parallel light may be calculated using a motor 1030. In the motor 1030, light is reflected by white circles 1031 and transmitted through black circles 1032 such that the light is divided into transmitted light and parallel light. The motor 1030 is rotated throughout the measuring.
The haze may be calculated using Equation 1 below:
haze(%)=(diffused light/total transmitted light)×100 (1)
parallel light=total transmitted light−diffused light (2)
Mirror reflectivity may be calculated by measuring an amount of light incident at 30° and reflected using, e.g., Darsa pro-5000 (PSI, Korea).
Meanwhile, copper meshes having an aperture ratio of 90% may be used for a electromagnetic wave shielding filter 252, a total transmittance of the filter assembly 250 is maintained at 40%, the AR film 258 (comparison example 1) or the AG film 257 (comparison example 2) or a combined film (example 1 or 2) including the AG film 257 or the AR film 258 is used for a surface reflection film 253 having a haze of X1%, wherein the filter assembly 250 has a haze of X2%. An absolute value of mirror reflectivity of glass to which the filter assembly 250 is attached is 4.2%.
Referring to TABLE 1, in comparison example 1, the haze of the filter is 2.3%, the haze of the surface reflection film is 0.6%, mirror reflectivity is 1.08%, reflection of objects occurs, and visibility passes the standard. In comparison example 2, the haze of the filter is 32.3%, the haze of the surface reflection film is 30%, mirror reflectivity is 0.03%, reflection of objects does not occur, and visibility does not pass the standard.
On the other hand, as shown in TABLE 1, in example 1, the haze of the filter is 4.7%, the haze of the surface reflection film haze is 2.95%, mirror reflectivity is 0.87%, reflection of objects by mirror reflection does not occur, and visibility passes the standard. In example 2, the haze of the filter is 8.87%, the haze of the surface reflection film is 5.7%, mirror reflectivity is 0.44%, reflection of objects by mirror reflection does not occur, and visibility passes the standard.
It may be preferable that the haze of the filter, the haze of the surface reflection film, and mirror reflectivity have as small values as possible. In examples 1 and 2 according to embodiments of the present invention, the hazes of the filters are 4.7% and 8.87%, respectively, the hazes of the surface reflection films are 2.95% and 5.7%, respectively, and the mirror reflectivities are 0.87% and 0.44%, respectively. Compared to comparison example 2 in which the haze of the filter is 32.3%, the haze of the surface reflection film is 30%, and mirror reflectivity is 0.03%. Thus, the hazes of the filter and the surface reflection film are smaller and the mirror reflectivities are greater in examples 1 and 2 than in comparison example 2. Reflection of objects does not occur and visibility is excellent in examples 1 and 2, while visibility is not excellent in comparison example 2.
In comparison example 1, the haze of the filter is 2.3%, the haze of the surface reflection film is 0.6%, and mirror reflectivity is 1.08%. The haze of the filter and the surface reflection film is larger and the mirror reflectivities are smaller in examples 1 and 2 than in comparison example 1. Reflection of objects does not occur and visibility is excellent in examples 1 and 2, while reflection of objects does occur in comparison example 1.
As described above, in the filter assemblies 250 according to the present invention, reflection of objects by mirror reflection does not occur and visibility passes the standard.
A filter assembly and a plasma display device adopting the filter assembly according to embodiments of the present invention may provide at least one or more of the following advantages.
First, mirror reflection of objects may be reduced or eliminated while allowing visibility to be excellent by adopting a surface reflection film having a haze value in a predetermined range.
Second, quality of a plasma display device can be increased by including at least one of an AG film and an AR film having a haze value in a predetermined range.
Third, since a filter assembly may be attached directly to the front surface of a panel assembly, an additional supporting medium may not be needed, and the filter assembly may have fewer components and may be thinner.
Exemplary embodiments of the present invention have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. Accordingly, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2006-0032665 | Apr 2006 | KR | national |
