JP3625007B2 - Plasma display panel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to various PDPs (Plasma Display Panels).
[0002]
Among PDPs, a surface discharge type PDP in which a pair of display electrodes for generating a main discharge are arranged adjacent to each other on the same substrate is widely used in applications such as televisions and computer monitors, with the practical use of color screens. It has come to be used. It is also attracting attention as a large-screen flat device for HDTV. In order to further popularize such PDPs, development of brighter and higher contrast screens is underway.
[0003]
[Prior art]
FIG. 5 is a cross-sectional view of the main part showing the internal structure of a conventional surface discharge type PDP 90.
The PDP 90 is a PDP having a matrix display type three-electrode structure, and is referred to as a reflection type in terms of classification according to the arrangement form of phosphors. In the PDP 90, a pair of display electrodes X and Y for generating surface discharge along the substrate surface are arranged on the inner surface of the glass substrate 11 on the front side for each line (row) of the matrix display. Each of the display electrodes X and Y includes a transparent conductive film 41 having a large width and a metal film 42 having a small width. These display electrodes X and Y are covered with a dielectric layer 17 for AC driving, and a protective film 18 is deposited on the surface of the dielectric layer 17. Both the dielectric layer 17 and the protective film 18 are translucent. Address electrodes A are arranged on the inner surface of the glass substrate 21 on the back side so as to be orthogonal to the display electrodes X and Y. A phosphor layer 28 is provided so as to cover the glass substrate 21 including the upper part of the address electrode A. In addressing for setting display contents, a cell (display element) is selected by the address electrode A and the display electrode Y. The phosphor layer 28 is locally excited by ultraviolet UV generated by surface discharge and emits visible light of a predetermined color. Of this visible light, the light that passes through the glass substrate 11 becomes display light.
[0004]
The gap S1 between the display electrode X and the display electrode Y in each display line is called a “discharge slit”, and the width (dimension in the arrangement direction of the display electrodes X and Y) w1 of the discharge slit S1 is about 100 to 200 volts. It is selected so that surface discharge is generated by the application of the driving voltage. In contrast, the gap S2 between the display electrode X and the display electrode Y between adjacent lines is called “reverse slit”, and the width w2 of the reverse slit S2 is sufficiently larger than the width w1 of the discharge slit S1. The value is selected. That is, the discharge between the display electrodes X and Y arranged with the reverse slit S2 therebetween is prevented. Thus, by providing the discharge slits S1 and the reverse slits S2 and arranging the display electrodes X and Y, each line can be made to emit light selectively. In addition, the part (area | region between electrodes) corresponding to reverse slit S2 of a display screen turns into a non-light-emission area | region.
[0005]
[Problems to be solved by the invention]
The conventional panel structure is a structure in which the non-light-emitting phosphor layer 28 can be seen from the front side through the reverse slit S2. The phosphor layer 28 in the non-light emitting state has a whitish color such as white or light gray. For this reason, when used in a particularly bright place, external light is scattered by the phosphor layer 28 and the non-light emitting area between the lines becomes whitish, and the display contrast is impaired.
[0006]
As a means for solving this problem, it is conceivable to provide a darker film on the inner surface side or outer surface side of the front glass substrate 11 than the phosphor. The area corresponding to the reverse slit S2 in the display screen is made to appear dark. In other words, the dark film is a film that absorbs visible light. By providing such a film, the inside is hidden and the reflection of external light is suppressed, and the contrast is improved. However, the overall brightness of the display screen is reduced.
[0007]
An object of the present invention is to increase display contrast while suppressing a decrease in luminance.
[0008]
[Means for Solving the Problems]
A light shielding layer for concealing the inside is provided in a region where light is not emitted on the display screen, and a layer of a material having a high reflectance is provided on the back side of the light shielding layer. For example, in a surface discharge type, when a light shielding layer is provided in a region corresponding to a reverse slit, the planar pattern of each light shielding layer is strip-shaped, and a striped (stripe) light shielding pattern is formed on the entire display screen. become. The light shielding layer shields visible light that is transmitted through or is transmitted through the reverse slit. As a result, a phenomenon in which the non-light-emitting area appears bright due to outside light and leakage light of each line is prevented, and display contrast is increased. Moreover, the light traveling from the inside toward the light shielding layer is reflected by a layer made of a material having a high reflectivity and returned to the inside, and a part of the light returning to the inside is reflected by the inner wall and emitted as display light to the outside. That is, by providing a layer of a material having a high reflectance, the display light is not absorbed by the light shielding layer, and a decrease in the amount of light emission seen from the outside is reduced.
[0009]
A plurality of pairs of PDPs according to the first aspect of the present invention are arranged on the inner surface of the substrate on the front surface side with a predetermined non-discharge region in which display electrode pairs for surface discharge along the row direction of display are not discharged. A surface discharge type plasma display panel in which a discharge space is continuous in each column and a phosphor layer continuous in each column of the display screen is arranged on the inner surface of the substrate on the back side, and between the rows in the display screen non-discharge Oite the region, dark shading layer made of a strip-shaped pattern on the inner surface of the front substrate are provided, the reflectance of visible light than the light blocking layer between the light-shielding layer and the discharge space between A light absorption preventing layer comprising a belt-like pattern which is a large layer is provided, and the display electrode, the light shielding layer and the light absorption preventing layer are covered with a dielectric layer made of low melting glass .
[0010]
In a PDP according to a second aspect of the present invention, the light shielding layer and the light absorption preventing layer are made of a pigment.
[0011]
In the PDP according to a third aspect of the present invention, the light shielding layer and the light absorption preventing layer are provided apart from each other in the substrate facing direction.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a perspective view showing a basic structure of a PDP 1 according to the present invention. In FIG. 1, components corresponding to those in FIG. 5 are denoted by the same reference numerals regardless of differences in shape and material. The same applies to the other figures below.
[0013]
The PDP 1 is a surface discharge type PDP having a three-electrode structure of a matrix display system called a reflection type like the conventional PDP 90. On the inner surface of the glass substrate 11 on the front side of the pair of substrates facing each other with the discharge space 30 interposed therebetween, linear display electrodes X and Y for generating surface discharge along the substrate surface are provided for each line L of the matrix display. Are arranged in pairs. The display electrodes X and Y are each composed of a wide linear transparent electrode 41 made of an ITO thin film and a narrow linear bus electrode 42 made of a metal thin film having a multilayer structure. The bus electrode 42 is an auxiliary electrode for ensuring appropriate electrical conductivity, and is disposed at the edge of the transparent electrode 41 on the side far from the surface discharge gap. A dielectric layer (low melting point glass layer) 17 for AC driving is provided so as to cover these display electrodes X and Y with respect to the discharge space 30, and magnesia (MgO) is provided as a protective film 18 on the surface. A film is deposited.
[0014]
On the other hand, the inner surface of the glass substrate 21 on the back side is uniformly covered with a base layer 22 made of low-melting glass. The address electrodes A are arranged on the base layer 22 at a constant pitch so as to be orthogonal to the display electrodes X and Y. The underlayer 22 prevents the electromigration of the address electrode A. By the counter discharge between the address electrode A and the display electrode Y, the wall charge accumulation state in the dielectric layer 17 is controlled. The address electrode A is also covered with a dielectric layer 24 made of low-melting glass having the same composition as the underlayer 22. On the dielectric layer 24, a plurality of linear partitions 29 having a height of about 150 μm in plan view are provided between the address electrodes A. The three primary colors R (red), G (green), and B (blue) for full-color display so as to cover the surface of the dielectric 24 and the side surfaces of the partition walls 29 including the upper portion of the address electrode A are covered. Phosphor layers 28R, 28G, and 28B (hereinafter referred to as phosphor layer 28 when it is not necessary to distinguish colors) are provided. These phosphor layers 28 emit light when excited by ultraviolet rays generated by surface discharge.
[0015]
The discharge space 30 is partitioned for each unit light emitting region in the line direction by the barrier ribs 29, and the gap size of the discharge space 30 is defined. A part of the structure corresponding to each unit light emitting area is a cell constituting the display screen. In the PDP 1, there is no partition that partitions the discharge space 30 in the column direction of matrix display (the arrangement direction of the display electrodes X and Y). However, the distance between the display electrodes X and Y between the lines L (reverse slit width) is selected to be 100 to 400 μm, which is sufficiently larger than the surface discharge gap (discharge slit width) of about 50 μm in each line L. There is no discharge interference between the lines.
[0016]
In the PDP 1, one pixel (pixel) for display is composed of three adjacent unit light emitting regions (subpixels) in each line L. The emission color of each line L in the same column is the same, and the phosphor layers 28R, 28G, 28B of each color are provided by screen printing so as to be continuous in the column.
[0017]
2 is a cross-sectional view of the main part of the PDP 1, and FIG. 3 is a plan view of the display screen SC.
As shown in FIG. 2, in the PDP 1, a light shielding layer 47 that blocks visible light is provided for each reverse slit S <b> 2 so as to be in direct contact with the inner surface of the glass substrate 11. A light absorption preventing layer 48 having a large visible light reflectance is provided so as to overlap the back side of each light shielding layer 47. Each light shielding layer 45 is patterned in a strip shape extending in the line direction as shown in FIG. The light shielding layers 47 separated from each other form a light shielding pattern having a stripe shape (stripe shape) on the entire display screen (screen) SC, and the phosphor layer 28 is hidden between the lines L to increase display contrast.
[0018]
Each light absorption preventing layer 48 is patterned in a strip shape so as to cover almost the entire back surface of the light shielding layer 47. Light emitted from the phosphor layer 28 and traveling toward the light shielding layer 47 is reflected by the light absorption preventing layer 48 and scattered. Of the scattered light, light reflected in an appropriate direction on the phosphor surface or the like is emitted to the outside as display light. That is, if there is no light absorption preventing layer 48, part of the light absorbed by the light shielding layer 47 contributes to display.
[0019]
According to the stripe pattern, unlike the matrix pattern surrounding the sub-pixels or the pixels, there is no fear of the positional deviation in the line direction, so that the alignment of the two glass substrates 11 and 21 in the manufacture of the PDP 1 is facilitated.
[0020]
The PDP 1 having the above structure is manufactured by separately providing predetermined constituent elements for the glass substrate 11 and the glass substrate 21, and then arranging the glass substrates 11 and 21 to face each other and joining the peripheral portions.
[0021]
In manufacturing the front side, a light shielding layer 47 and a light absorption preventing layer 48 are formed on the surface of the glass substrate 11 provided with the display electrodes X and Y. The light shielding layer 47 is formed using a paste added with a black pigment, and the light absorption preventing layer 48 is formed using a paste added with a white pigment. Examples of binders for these pastes include ethyl cellulose and acrylic resin. You may mix a low melting glass powder as needed. Examples of black pigments include manganese dioxide (Mn ₂ O ₂ ), chromium oxide (Cr ₂ O ₃ ), copper oxide (CuO), iron oxide (FeO), and cobalt oxide (Co ₃ O ₄ , CoO). Examples of white pigments include titanium oxide (TiO ₂ ), silicon dioxide (SiO ₂ ), alumina (Al ₂ O ₃ ), barium titanate (BaTiO ₃ ), barium sulfate (BaSO ₄ ), magnesia (MgO), and trioxide. Examples include yttrium (Y ₂ O ₃ ) and tantalum oxide (Ta ₂ O ₅ ).
[0022]
The paste to which the black pigment is added is subjected to pattern printing using a screen mask and dried to form the light shielding layer 47. Instead of pattern printing, a solid film of paste may be provided by printing, slot coater, roll coater or the like, and patterning may be performed by photolithography. In that case, a photosensitive material is mixed in the paste. When the low melting point glass is mixed, baking is performed as necessary after drying. The firing here is carried out in the case where “when the white pigment paste is fired in a lump in the subsequent step, the pigments are mixed and desired optical characteristics cannot be obtained”.
[0023]
Subsequent to the formation of the light shielding layer 47, a paste to which a white pigment is added is printed and dried to form the light absorption preventing layer 48. Also in the light absorption preventing layer 48, pattern printing or lithography can be appropriately used as a pattern forming technique. Firing as necessary is the same as the formation of the light shielding layer 47.
[0024]
After the light shielding layer 47 and the light absorption preventing layer 48 are formed in this way, the dielectric layer 17 is formed by printing and baking a low melting point glass paste, and magnesia is deposited by vacuum deposition or the like to form the protective film 18. Form.
[0025]
FIG. 4 is a cross-sectional view of the main part of the second PDP 2 and shows the structure of the front side portion of the discharge space.
Display electrodes X and Y are arranged on the inner surface of the glass substrate 11 on the front side, and these display electrodes X and Y are covered with a first dielectric layer 17a. Shielding layer 4 7 so as to overlap with the reverse slit S2 is provided in a plan view, the second dielectric layer 17b and is interposed light absorbing prevention layer 4 8 is provided on the back side of the light-shielding layer 4 7. Light absorption preventing layer 4-8 is covered with a third dielectric layer 17c. Incidentally, the third dielectric layer 17c is omitted, it may be a second dielectric layer 17b of the exposed surface and the light absorption prevention layer 4 8 of the surface protection film 18 to cover the provided.
[0026]
In the substrate-facing direction (vertical direction in the figure), since the light-shielding layer 4 7 and the light-absorbing prevention layer 4 8 are separated from each other, there is no possibility that the black pigment to white pigment in PDP2 resulting in mixed, the pigment selected High degree of freedom. Further, the influence of the change in dielectric constant accompanying the addition of the pigment in the dielectric, for example, the increase in the stray capacitance between the lines can be minimized.
[0028]
【The invention's effect】
According to the first to third aspects of the invention, it is possible to increase the display contrast while suppressing a decrease in luminance.
[0029]
According to invention of Claim 3, the freedom degree of material selection in manufacture becomes large.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a basic structure of a PDP according to the present invention.
FIG. 2 is a cross-sectional view of a main part of a PDP.
FIG. 3 is a plan view of a display screen.
FIG. 4 is a cross-sectional view of a main part of a second PDP.
FIG. 5 is a cross-sectional view of the main part showing the internal structure of a conventional PDP.
[Explanation of symbols]
1, 2 PDP (Plasma Display Panel)
11 Glass substrate (front side substrate)
21 Glass substrate (substrate on the back side)
17 Dielectric layer 30 Discharge space 4 7 Light shielding layer 4 8 Light absorption prevention layer S2 Reverse slit (electrode gap between rows)
SC display screen X, Y display electrode

Claims (3)

A plurality of pairs of display electrodes for surface discharge along the row direction of display are arranged on the inner surface of the substrate on the front side across a predetermined non-discharge region where discharge does not occur, and discharge spaces are continuous in each column of the display screen, A surface discharge type plasma display panel in which phosphor layers that are continuous in each row of the display screen are arranged on the inner surface of the substrate on the back side,
Oite the non-discharge area between the to what line of the display screen, a dark light-shielding layer is provided made of a strip-shaped pattern on the inner surface of the front substrate, the light shielding layer between the light-shielding layer and the discharge space A light absorption preventing layer composed of a belt-like pattern that is a layer having a higher visible light reflectance than the display electrode, the light shielding layer, and the light absorption preventing layer are covered with a dielectric layer made of low-melting glass. A plasma display panel characterized by that. The light shielding layer and the light absorption preventing layer are made of a pigment.
The plasma display panel according to claim 1. The light shielding layer and the light absorption-preventing layer and the plasma display panel of claim 1 wherein the provided apart from each other in the substrate-facing direction.

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