This application is the U.S. National Phase under 35 U.S.C. §371 of International Application No. PCT/JP2008/002445, filed on Sep. 4, 2008, the entire contents of which application is incorporated by reference herein by reference.
The present invention relates to a plasma display panel, a plasma display panel unit, and a manufacturing method of a plasma display panel.
A plasma display panel (PDP) is made up by adhering two pieces of glass plates (a front glass plate and a back glass plate) with each other, and displays an image by generating discharge light in a space (discharge space) formed between the glass plates. Cells corresponding to pixels in the image are in a self-luminescence type, and phosphors emitting visible lights in red, green, and blue by receiving ultraviolet ray generated by the discharge are coated thereon.
For example, a PDP in a three-electrode structure having X, Y electrodes and address electrodes displays images by generating a sustain discharge between the X electrodes and the Y electrodes. The cells generating the sustain discharge (cells to be lighted) are selected by, for example, selectively generating an address discharge between the Y electrodes and the address electrodes.
In a general PDP, the X and Y electrodes are disposed on a front glass plate while having intervals with each other, and the address electrodes disposed between barrier ribs extending in an orthogonal direction of the X electrodes and between the barrier ribs adjacent each other are disposed at the back glass plate. A general barrier rib is formed to be transparent relative to the visible light. Accordingly, for example, in a plasma display device (PDP device) made up by using this kind of PDP, there is a possibility in which outside light incident on the PDP penetrates the barrier rib, reflects in the PDP device, and this reflected light is incident on the PDP again. In this case, the light penetrating the barrier rib and reflected in the PDP device is emitted from the PDP together with the visible light emitted from the phosphors, and a contrast when the image is displayed on the PDP is lowered. A PDP in which the barrier ribs are made a dark color is proposed to improve the contrast (for example, refer to Patent Document 1).
In recent year, a PDP in which the three electrodes of the X electrodes, Y electrodes, and address electrodes are disposed at the front glass plate is proposed (for example, refer to Patent Document 2). In this kind of PDP, the address electrodes provided at the front glass plate are disposed along the barrier ribs formed at the back glass plate.
In Patent Document 2, the barrier ribs are integrally formed with the back glass plate. In the PDP in which the barrier ribs are integrally formed with the back glass plate, a material choice of the back glass plate is limited and there is a possibility in which a cheap material cannot be used when the barrier ribs are made the dark color. When the cheap material cannot be used for the back glass plate, a manufacturing cost of the PDP increases. Note that an invention to improve the contrast of the image is not proposed in the PDP having the three electrodes at the front glass plate.
A proposition of the present invention is to improve the contrast of the image in the PDP having the three electrodes at the front glass plate.
A plasma display panel has a first plate and a second plate facing each other via a discharge space. A plurality of first electrodes and a plurality of second electrodes extending in a first direction, and a plurality of address electrodes extending in a second direction intersecting with the first direction are provided at the first plate. Also, a plurality of first barrier ribs extending in the second direction are integrally formed with the second plate at the first plate side of the second plate. Further, the plasma display panel has, for example, an antireflective film formed on a surface of the second plate at an opposite side of a surface facing the first plate.
According to the present invention, it is possible to improve a contrast of an image in a PDP having three electrodes at a front glass plate.
Hereinafter, embodiments of the present invention are described by using the drawings.
The front plate part 12 has X bus electrodes Xb and Y bus electrodes Yb formed in parallel along the first direction D1 and formed alternately along the second direction D2 on a glass base FS (first plate) (at a lower side in the drawing). The glass base FS is formed by a material penetrating visible light. Besides, X transparent electrodes Xt extending in the second direction D2 from the X bus electrodes Xb to the Y bus electrodes Yb are coupled to the X bus electrodes Xb. Y transparent electrodes Yt extending in the second direction D2 from the Y bus electrodes Yb to the X bus electrodes Xb are coupled to the Y bus electrodes Yb. In an example in the drawing, the X transparent electrode Xt and the Y transparent electrode Yt face along the second direction D2. Note that the transparent electrodes Xt, Yt may be provided to face along the first direction D1, and may be provided to face along a diagonal direction relative to the first direction D1 (or the second direction D2).
Here, the X bus electrode Xb and the Y bus electrode Yb are opaque electrodes formed by a metallic material and so on, and the X transparent electrode Xt and the Y transparent electrode Yt are transparent electrodes penetrating visible light formed by an ITO film and so on. An X electrode XE (first electrode, sustain electrode) is made up of the X bus electrode Xb and the X transparent electrode Xt, and a Y electrode YE (second electrode, scan electrode) is made up of the Y bus electrode Yb and the Y transparent electrode Yt. Discharge (sustain discharge) is repeatedly generated at an electrode pair made up of the X electrode XE and the Y electrode YE (more specifically, between the X transparent electrode Xt and the Y transparent electrode Yt).
Besides, the transparent electrodes Xt and Yt may be disposed on a whole surface between the bus electrodes Xb and Yb to which they are respectively coupled and the glass base FS. Note that electrodes which are made of the same material (metallic material and so on) as the bus electrodes Xb and Yb, and integrated with the bus electrodes Xb and Yb may be formed instead of the transparent electrodes Xt and Yt.
The electrodes Xb, Xt, Yb, Yt are covered by a dielectric layer DL. For example, the dielectric layer DL is an insulating film such as a silicon dioxide film formed by a CVD method. Plural address electrodes AE extending in an orthogonal direction (second direction D2) of the bus electrodes Xb, Yb are provided on the dielectric layer DL (at a lower side in the drawing). For example, the address electrode AE is formed by the metallic material and so on, and a surface at a side on which outside light is incident is made black. As stated above, the front plate part 12 has the glass base FS in which the plural electrodes XE, YE extending in the first direction D1 and the plural address electrodes AE extending in the second direction D2 are provided. Namely, the PDP according to this embodiment has three electrodes (electrodes XE, YE, AE) at the front plate part 12.
The address electrodes AE and the dielectric layer DL are covered by a protective layer PL. For example, the protective layer PL is formed by an MgO film of which emission characteristic of secondary electrons resulting from collision of a positive ion is high to make the discharge easy to occur. Note that a dielectric layer other than the dielectric layer DL may be provided between the address electrodes AE, the dielectric layer DL and the protective layer PL.
The back plate part 14 has a glass base RS (second plate) facing the glass base FS via the discharge space DS. For example, the glass base RS is formed by a material penetrating visible light. A barrier rib in grid state made up of first barrier ribs BR1 extending in the second direction D2 and second barrier ribs BR2 extending in the first direction D1 is formed on the glass base RS (on a surface of the glass base RS facing the glass base FS). In this embodiment, the barrier ribs BR1, BR2 are the same material as the glass base RS, and integrally formed with the glass base RS.
For example, the barrier ribs BR1, BR2 are integrally formed with the glass base RS by selectively removing a portion of the glass base RS where the discharge space DS of the glass base RS is formed by a sand blast method and so on. Namely, the first ribs BR1 are provided at the glass base FS side of the glass base RS to extend in the second direction D2, and integrally formed with the glass base RS. Besides, the second barrier ribs BR2 are provided at the glass base FS side of the glass base RS to extend in the first direction D1, and integrally formed with the glass base RS and the first ribs BR1.
For example, in this embodiment, the second barrier ribs BR2 are disposed between the bus electrodes Xb, Yb adjacent each other when they are seen from the image display surface side (an upper side of the drawing). Note that the second barrier ribs BR2 may be disposed at a position overlapping with only either of the bus electrodes Xb, Yb adjacent each other, or disposed at a position overlapping with both of the bus electrodes Xb, Yb adjacent each other when they are seen from the image display surface side (the upper side of the drawing). Otherwise, the second barrier ribs BR2 may be respectively disposed at a position overlapping with the bus electrode Xb and a position overlapping with the bus electrode Yb when they are seen from the image display surface side (the upper side of the drawing).
Sidewalls of a cell are made up by the barrier ribs BR1, BR2. Phosphors PHr, PHg, PHb emitting visible lights in red (R), green (G), blue (B) exited by ultraviolet ray are respectively coated at side surfaces of the barrier ribs BR1, BR2 and on the glass base RS at a portion surrounded by the barrier ribs BR1, BR2.
The antireflective film AR is provided on a surface of the glass base RS at an opposite side of a surface facing the glass base FS (the lower side in the drawing). For example, the antireflective film AR is disposed at a position at least overlapping with all over a display area of an image (for example, an area surrounded by the barrier ribs BR1, BR2 disposed at the outermost side) when it is seen from the image display surface side (the upper side of the drawing). Outside light penetrating the barrier ribs BR1, BR2 is absorbed by the antireflective film AR. In this embodiment, it is thereby possible to reduce a reflection amount of the outside light incident on the PDP 10, and to improve the contrast of the image.
Here, the antireflective film AR is formed by, for example, coating a black pigment (dark color pigment) on the surface of the glass base RS at the opposite side of the surface facing the glass base FS after adhering the glass base RS and the glass base FS. Namely, in this embodiment, the antireflective film AR is formed by a nonmetal material, and is made black. As stated above, in this embodiment, the back plate part 14 including the antireflective film AR is made up without using the metallic material, and therefore, it is possible to make a manufacturing process of the back plate part 14 and an assembly process of the PDP (the process adhering the glass base RS and the glass base FS and so on) easy.
One pixel of the PDP 10 is made up of three cells emitting lights in red, green, and blue. Here, one cell (one color pixel) is formed at an area surrounded by, for example, the barrier ribs BR1, BR2. As stated above, the PDP 10 is made up by disposing the cells in matrix state and by alternately arranging plural kinds of cells emitting lights of which colors are different from one another to display the image. A display line is made up of the cells formed along the bus electrodes Xb, Yb, though it is not illustrated in particular.
The PDP 10 is made up by adhering the front plate part 12 and the back plate part 14 so as to bring the protective layer PL into contact with the first barrier ribs BR1, and so on, and by encapsulating discharge gas such as Ne, Xe into the discharge space DS.
At least a part of the address electrode AE positions above the discharge space DS. Namely, at least a part of the address electrode AE are disposed in the cell CL. The transparent electrode Yt is disposed in each cell CL so as to be adjacent to the address electrode AE, and the transparent electrode Xt is disposed in each cell CL so as to be adjacent to the transparent electrode Yt. It is thereby possible to generate an address discharge at a focused cell CL by applying a voltage between the address electrode AE and the transparent electrode Yt. Besides, it is possible to generate the sustain discharge at a cell CL selected by the address discharge by applying a voltage between the transparent electrode Xt and the transparent electrode Yt.
Besides, as stated above, the antireflective film AR is provided at a rear surface side of the glass base RS (the opposite side of the image display surface, the lower side of the drawing) in this embodiment, and therefore, a part of the outside light OPT incident on the PDP 10 (the outside light OPT penetrating the barrier ribs BR1, BR2) is absorbed by the antireflective film AR, to thereby enable to reduce an amount of the outside light OPT penetrating the PDP 10. Namely, in this embodiment, it is possible to reduce the reflection amount of the outside light OPT incident on the PDP 10 because a part of the outside light OPT incident on the PDP 10 is absorbed by the antireflective film AR.
Further, the reflection amount of the outside light OPT incident on the address electrode AE decreases because the address electrode AE is made black. As a result, it is possible to reduce the reflection amount of the outside light OPT incident on the PDP 10, and to improve the contrast of the image in this embodiment. Namely, an image quality can be improved.
Note that the visible light VL2 emitted from the phosphors PHr, PHg, PHb toward the barrier ribs BR1, BR2 side penetrates the barrier ribs BR1, BR2 to be emitted from the PDP 10 together with the visible light VL1 because the barrier ribs BR1, BR2 penetrate the visible light VL. The visible light VL1 is the visible light emitted from, for example, the phosphors PHr, PHg, PHb toward the discharge space DS side. Accordingly, it is possible to make the visible light VL emitted from the phosphors PHr, PHg, PHb effectively contribute to the display of the image in this embodiment. Namely, it is possible to reduce the reflection of the outside light without incurring the deterioration of luminance, and to improve the image quality in this embodiment.
The optical filter 20 is adhered to a protection glass (not-illustrated) attached to an opening part 32 of the front case 30. For example, the optical filter 20 has a function to lower a penetrable rate of the visible light so as to improve the contrast of the image of the PDP device. Note that the optical filter 20 may have a function to shield electromagnetic waves. Besides, the optical filter 20 may be adhered not to the protection glass but to the image display surface 16 side of the PDP 10 directly. Here, for example, a plasma display panel unit (hereinafter, called also as a PDP unit) 80 is made up by including the PDP 10, the base chassis 50, the circuit unit 60, and the double-faced adhesive sheet 70.
In this embodiment, a part of the outside light OPT incident on the PDP 10 is absorbed by the antireflective film AR illustrated in the above-stated
Accordingly, it is possible to prevent that the visible light other than the visible light emitted from the phosphors PHr, PHg, PHb illustrated in the above-stated
In this case, the amount of the visible light absorbed by the optical filter 20 decreases among the visible light emitted from the phosphors PHr, PHg, PHb, and therefore, it is possible to improve the luminance of the image displayed by the PDP device. Namely, the image quality can be improved. Besides, it is possible to manufacture the optical filter 20 easily and in low cost when the contrast of the image displayed by the PDP device is maintained to be the same as the conventional level, because a layer and so on to lower the penetrable rate is not necessary to be provided at the optical filter 20.
As stated above, the antireflective film AR is provided at the rear surface side of the glass base RS (on the surface of the glass base RS at the opposite side of the surface facing the glass base FS) of the PDP 10 in this embodiment. Besides, the barrier ribs BR1, BR2 are integrally formed with the glass base RS with the same material as the glass base RS. Accordingly, it is possible to reduce the reflection amount of the outside light OPT incident on the PDP 10 without incurring the deterioration of the luminance in this embodiment. Namely, it is possible to improve the contrast of the image without incurring the deterioration of the luminance and to improve the image quality in this embodiment.
A back plate part 14A has the glass base RS, the barrier ribs BR1, BR2, the phosphors PHr, PHg, PHb, and the black filter BF. The glass base RS, the barrier ribs BR1, BR2, the phosphors PHr, PHg, PHb are the same as the above-stated
The black filter BF is a filter in black to absorb the outside light, and it is adhered to the rear surface of the glass base RS (the surface at the opposite side of the surface facing the glass base FS). For example, the black filter BF is adhered to the rear surface of the glass base FS by a not-illustrated double-faced adhesive sheet and so on after the glass base RS and the glass base FS are adhered. Namely, the black filter BF functions as an antireflective film absorbing the outside light penetrating the barrier ribs BR1, BR2, and so on. As stated above, the similar effect as the embodiment described in the above-stated
The PDP 10B has the front plate part 12 and a back plate part 14B. The front plate part 12 is the same as the above-stated
In this embodiment, the double-faced adhesive sheet 70 is formed by, for example, a material penetrating the outside light. Otherwise, the double-faced adhesive sheet 70 may be formed by a material absorbing the outside light as illustrated in a later-described
The PDP unit 80B has the PDP 10B, the base chassis 50, the circuit unit 60 and a double-faced adhesive sheet 70A. The PDP 10B is the same as the above-stated
Incidentally, the example in which one pixel is made up of three cells (red (R), green (G), blue (B)) is described in the above-stated embodiments. The present invention is not limited to the embodiments. For example, one pixel may be made up of four or more cells. Otherwise, one pixel may be made up of cells emitting colors other than red (R), green (G), blue (B), or one pixel may include a cell emitting a color other than red (R), green (G), blue (B).
The example in which the second direction D2 is orthogonal to the first direction D1 is described in the above-stated embodiments. The present invention is not limited to the embodiments. For example, the second direction D2 may intersect with the first direction D1 in approximately orthogonal direction (for example, 90 degrees±5 degrees). The similar effect as the above-stated embodiments can be obtained also in this case.
The example in which the barrier rib in the matrix state made up of the first barrier ribs BR1 and the second barrier ribs BR2 is integrally formed with the glass base RS is described, in the above-stated embodiments. The present invention is not limited to the embodiments. For example, the second barrier ribs BR2 are not formed, and a barrier rib in a stripe state made up by the barrier ribs BR1 may be integrally formed with the glass base RS. In this case, the cell is formed at an area surrounded by, for example, the bus electrodes Xb, Yb paired with each other and a pair of the first barrier ribs BR1 adjacent each other. The similar effect as the above-stated embodiments can be obtained also in this case.
The example in which the antireflective film AR is formed to be black is described in the above-stated embodiments. The present invention is not limited to the embodiments. For example, the antireflective film AR may be formed to be a dark color other than black. Similarly, the black filter BF, the surface 52 of the base chassis 50A at the PDP side and the surface of the double-faced adhesive sheet 70A at the PDP side may be the dark color other than black. The similar effect as the above-stated embodiments can be obtained also in this case.
The example in which the antireflective film AR is formed after the glass base RS and the glass base FS are adhered is described in the above-stated embodiments. The present invention is not limited to the embodiments. For example, the antireflective film AR may be formed by providing a black layer (dark color layer) at the rear surface of the glass base RS (the surface at the opposite side of the surface facing the glass base FS) before the glass base RS and the glass base FS are adhered. The similar effect as the above-stated embodiments can be obtained also in this case.
The example in which the antireflective film AR is formed by the nonmetal material is described in the above-stated embodiments. The present invention is not limited to the embodiments. For example, the antireflective film AR may be formed to be black or the dark color by sputtering a metallic material such as chromium to the rear surface of the glass base RS. In this case, the antireflective film AR is formed by sputtering the metallic material to the rear surface of the glass base RS (the surface at the opposite side of the surface facing the glass base FS) before the glass base RS and the glass base FS are adhered. The similar effect as the above-stated embodiments can be obtained also in this case.
The example in which the antireflective film AR is disposed at the position overlapping with all over the display area of the image when it is seen from the image display surface side is described in the above-stated embodiments. The present invention is not limited to the embodiments. For example, the antireflective film AR illustrated in
The example in which the base chassis 50A or the double-faced adhesive sheet 70A is functioned as the antireflective member is described in the above-stated embodiments. The present invention is not limited to the embodiments. For example, an antireflective member 72 may be provided between the PDP 10B and the double-faced adhesive sheet 70 as illustrated in
The many features and advantages of the embodiment are apparent from the detailed specification and, thus, it is intended by the appended claims to cover all such features and advantages of the embodiment that fall within the true spirit and scope thereof. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the inventive embodiment to exact construction and operation illustrated and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope thereof.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2008/002445 | 9/4/2008 | WO | 00 | 11/15/2010 |
Publishing Document | Publishing Date | Country | Kind |
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WO2010/026617 | 3/11/2010 | WO | A |
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