JP2006210069A - Plasma display panel and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma display panel capable of suppressing the deterioration of panel characteristics with the passage of time and manufacturing simply at low cost, and to provide its manufacturing method. <P>SOLUTION: In the plasma display panel, bus electrodes 113a, 113b are formed into approximately cross-sectionally circular arc shape using a conductive paste and a dielectric layer 114 is formed by vapor phase growth method, thereby the dielectric layer 114 becomes thinner than conventional one and a gently sloping level difference t appears on the surface of a protective layer 115. Thereby, changes in the passage of time of the panel characteristics can be suppressed, while the discharge efficiency at the time of surface discharge being improved. Furthermore, even if it is combined with a rear substrate 120 having a parallel cross-like barrier rib of a uniform height, movement of gas molecules through the gap s becomes easy, and evacuation process after pasting the front substrate 110 and the rear substrate 120 becomes short. Furthermore, since conductive paste is used, bus electrodes 113a, 113b of approximately circular arc shape can be formed simply. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a plasma display panel and a method for manufacturing the same, and more particularly to a display electrode and a method for forming the same.

  One of the thin display devices is a plasma display panel (hereinafter referred to as “PDP”), and the surface discharge type PDP is in the spotlight especially from the viewpoint of size increase and life characteristics. A surface discharge type PDP generally has a structure in which a discharge space is sandwiched between a front substrate and a back substrate. On the front substrate, a display electrode pair consisting of a transparent electrode and a bus electrode, a dielectric layer, and a protective layer are sequentially formed on the glass substrate, and the data electrode on the glass substrate is formed on the back substrate, A dielectric layer is formed in this order, and a phosphor layer and barrier ribs are formed on the dielectric layer.

  In order to reduce the power consumption of such a PDP and increase the discharge efficiency during surface discharge, it is known that the electric field strength on the surface of the dielectric layer constituting the front substrate should be increased. It is also understood that the thickness of the body layer may be reduced. FIG. 6 shows a cross-sectional view of a general front substrate. Since the dielectric layer 4 is generally formed by a liquid phase method (for example, a method of applying and baking a low melting point glass paste), the surface of the dielectric layer 4 is formed. However, it becomes flat.

  However, if the dielectric layer 4 having a flat surface is thinned, the thickness d1 of the dielectric layer 4 covering the top of the display electrode is smaller than the thickness d2 of the other part. 4 is likely to cause dielectric breakdown. In particular, if the dielectric layer 4 is to be formed thin by using the liquid phase method, the withstand voltage is lowered at the generated portion due to dust mixing or bubbles being generated, and dielectric breakdown of the dielectric layer 4 is caused. It tends to occur.

Therefore, in order to increase the electric field strength on the surface of the dielectric layer while preventing dielectric breakdown, an invention in which a part of the dielectric layer is thinned has been made. When this invention is shown in FIG. 7, since the hollow 59 having a rectangular cross section is formed in a region other than the transparent electrode 52 and the bus electrode 53 in the dielectric layer 54, a part of the dielectric layer 54 is thin. As a method for forming the depression 59 in the dielectric layer 54, for example, after a low-melting glass paste is printed flat, the low-melting glass paste is overprinted in a range excluding the portion where the depression 59 is formed, or formed flat. A method is disclosed in which a part of the dielectric layer 54 is chemically etched by exposing and developing the formed dielectric layer 54 by photolithography. Thus, by providing a rectangular recess in a part of the dielectric layer, the portion of the dielectric layer 54 where the surface discharge D1 generated by each discharge cell is generated is the transparent electrode 52 and the bus electrode. Therefore, it is possible to increase the discharge efficiency during surface discharge while preventing dielectric breakdown (see Patent Document 1).
JP-A-11-96919

  However, when the PDP having a rectangular recess formed in the dielectric layer as described above is driven for a long time, the corner portion located at the opening of the recess is sputtered by ions in the plasma, and gradually becomes a smooth shape. Change. Along with this, the discharge efficiency decreases, and the panel characteristics deteriorate with time. In particular, since the speed at which the shape of the corner portion changes with time varies among the discharge cells, there is a problem in that the discharge characteristics vary among the discharge cells, resulting in a short panel life. In addition, the manufacturing process disclosed in Patent Document 1 has a problem that it is complicated and expensive.

  In view of the above-described conventional problems, an object of the present invention is to provide a PDP that can suppress the deterioration of panel characteristics with time and can be easily manufactured at low cost, and a manufacturing method thereof.

  In order to achieve the above object, in the present invention, a PDP in which two substrates are arranged opposite to each other with a space interposed therebetween, and a display electrode pair is extended and disposed on the space side main surface on one substrate, The display electrode pairs are arranged side by side so that the two strip electrodes are spaced from each other, and the thickness of each strip electrode is gradually reduced from the inside toward the outer end on the gap side in the electrode width direction. The dielectric layer is formed to have a uniform thickness and cover the display electrode pair along the display electrode pair.

  In order to achieve the above object, the present invention provides a method for manufacturing a PDP including a step of extending a display electrode pair on a substrate and a step of forming a dielectric layer on the display electrode pair. In the step of extending the display electrode pair, two strip electrodes are arranged side by side with a certain gap, and each of the strip electrodes is directed from the inside toward the outer end on the gap side in the electrode width direction. In the step of forming the dielectric layer so that the thickness gradually decreases, the vapor phase growth method is used.

  As described above, in the PDP of the present invention, the display electrode pair is arranged side by side so that the two strip electrodes are spaced apart from each other, and each of the strip electrodes is disposed on the gap side from the inside in the electrode width direction. Since the dielectric layer is formed so that the thickness gradually decreases toward the outer end, and the dielectric layer is covered with the uniform thickness and along the display electrode pair, the space-side main surface of the dielectric layer However, when the voltage is applied to the display electrode pair by depression in the gap region, the electric field strength generated in the depression can be increased. In addition, the space-side main surface of the dielectric layer is recessed in a curved shape, so that there is no corner in the opening of the recess as compared with a rectangular recess in the space-side main surface of the dielectric layer. Therefore, even when driven for a long time, it is possible to suppress the change of the shape of the space side main surface of the front substrate by sputtering. In addition, since the thickness of the dielectric layer is uniform, the dielectric layer is not extremely thin at the portion covering the display electrode pair, and therefore, it is difficult to cause dielectric breakdown.

Therefore, it is possible to achieve a configuration in which the panel characteristics hardly change over time while improving the discharge efficiency during the surface discharge, and thus a long-life PDP can be realized while reducing power consumption.
In the above-mentioned strip electrode, the cross section perpendicular to the electrode extending direction is a chevron that is thicker toward the center, and the thickness is changed so as to gradually decrease in a quadratic or exponential manner from the top to the bottom. If so, the above-described depression becomes deeper, and thus the above-described effect can be more preferably achieved.

In the case where the strip electrode has a laminated structure including a resistance film electrically connected to each other and a conductive film containing a metal material, the above effect is achieved while ensuring responsiveness by including the conductive film. be able to.
In the case where the conductive film constitutes a gradually decreasing portion of the strip electrode, the taper angle between the conductive film containing a metal material and the base layer in contact with the conductive film is perpendicular to the extending direction of the display electrode. When the angle is 30 ° or more, a large cross-sectional area per width of the conductive film can be secured, so that the line resistance can be suppressed. Accordingly, it is possible to suppress the rounding of the driving waveform. In addition, when the taper angle is set to 80 ° or less, it is possible to suppress the generation of sharp corners in the conductive film. Therefore, a conductive film having the above structure can be easily realized.

When the thickness of the dielectric layer of the front substrate is in the range of 3 μm or more and 20 μm or less, it is easy for the main surface on the space side of the dielectric layer to have substantially the same shape as the main surface on the space side of the strip electrode. Therefore, the above-described effects can be achieved more preferably.
Of the two substrates, in the rear substrate corresponding to the other substrate, when a partition wall is arranged in a direction intersecting with the pair of display electrodes arranged in parallel on the front substrate, the dielectric layer of the front substrate has the above-mentioned Since the depression is formed, a gap is always formed between the top of the partition wall and the dielectric layer of the front substrate, so that the evacuation process after bonding can be performed in a short time, and particularly uniform. When a rear substrate having a high cross-shaped partition wall is adopted, the time of the vacuum exhausting process can be greatly reduced as compared with a combination with a conventional front substrate.

  In order to achieve the above object, in the method of manufacturing a PDP of the present invention, in the step of extending the display electrode pair, two strip electrodes are juxtaposed with a certain gap between each of the strip electrodes. Is formed so that the thickness gradually decreases from the inner side toward the outer end on the gap side in the electrode width direction, and in the step of forming the dielectric layer, a vapor phase growth method is used. Since a dent can be formed in the gap region on the side main surface, and a dent can be formed in a curved surface, a PDP having the above-described effects can be manufactured.

  Furthermore, by using the vapor phase growth method, the dielectric layer can be formed so that the thickness of the dielectric layer on the top of the display electrode and the thickness of the dielectric layer on the top of the display electrode are uniform. In addition, it is possible to prevent only the thickness of the dielectric layer on the top of the display electrode from becoming extremely thin, and the dielectric layer can be densely formed. It can prevent the dielectric breakdown of the body layer.

In the step of extending and forming the display electrode pair, the surface of the conductive paste applied on the front substrate when including a sub-step of forming a conductive film by applying a conductive paste containing a metal material on the substrate Since the conductive film can be easily formed in a substantially circular arc shape by tension, the above-mentioned curved depression can be more preferably formed.
In the sub-step of forming the conductive film, when any one of a dispenser method, a photolithography method, an ink jet method, and a screen printing method is used, the conductive film having the cross-sectional shape can be easily formed on the front substrate. . In particular, according to the dispenser method, a conductive film having a generally arcuate cross section can be easily formed. Therefore, a PDP can be easily manufactured.

In the step of forming the dielectric layer, the dielectric layer is formed by vapor-phase growth of the dielectric layer material using a method selected from plasma CVD, sputtering, reactive sputtering, and vapor deposition. In this case, a more preferable dense dielectric layer can be formed thinly and uniformly.
When a front substrate corresponding to one substrate on which the display electrode pair and the dielectric layer are formed is bonded to a rear substrate corresponding to the other substrate in which a partition is arranged in a direction intersecting the display electrode pair, As described above, by forming a depression in the dielectric layer of the front substrate, a gap can be formed between the top of the partition wall and the dielectric layer of the front substrate. The evacuation process can be performed in a short time, especially when a rear substrate with a uniform-height grid wall is adopted, the time required for the evacuation process is significantly longer than when combined with a conventional front substrate. Can be shortened.

Embodiments of the present invention will be described below with reference to the drawings.
(Embodiment 1)
Hereinafter, Embodiment 1 of the present invention will be described with reference to FIGS.
<Configuration of PDP>
FIG. 1 is a schematic configuration diagram of a PDP in the present embodiment. Fig.1 (a) is a principal part perspective view of PDP in this Embodiment, FIG.1 (b) is a schematic sectional drawing of PDP in the A surface of Fig.1 (a).

In FIG. 1 (a), a front substrate 110 having a configuration described below has a grid-shaped partition wall 122 formed so as to surround a discharge space 121 corresponding to each discharge cell arranged in a matrix in the PDP. It is attached to the rear substrate 120 arranged.
In FIG. 1B, the display electrode pair 101 is formed on the glass substrate 111 of the front substrate 110.

  The display electrode pair 101 includes a scan electrode 102 and a sustain electrode 103. The scan electrode 102 and the sustain electrode 103 include wide transparent electrodes 112a and 112b (thin films mainly composed of ITO), and transparent electrodes 112a, The bus electrodes 113a and 113b having a narrow width are formed on the gate 112b. The transparent electrodes 112a and 112b function as resistance films, and the bus electrodes 113a and 113b function as conductive films made of a metal material.

A dielectric layer 114 is formed so as to cover the glass substrate 111, the scan electrode 102, and the sustain electrode 103, and then a protective layer 115 is formed on the dielectric layer 114.
The bus electrodes 113a and 113b are formed in a stripe shape so as to form a substantially arc shape in the cross section in the width direction, and the thickness at the top is 5.2 μm. However, the present invention is not limited to this, and may be approximately 2 to 20 μm in consideration of the line resistance of the bus electrodes 113a and 113b.

  The dielectric layer 114 is made of a silicon oxide film having a relative dielectric constant of about 3.5 to 4.5, and is formed thin and uniform in thickness by using a formation method described later. The dielectric layer 114 preferably has a thickness of 3 to 20 μm in consideration of the capacitance between the paired display electrodes and the withstand voltage. As described above, since the dielectric layer 114 is thinly formed so as to cover the scan electrode 102 and the sustain electrode 103, the dielectric layer 114 is formed of the bus electrodes 113a and 113b and the transparent electrodes 112a and 112b. The shape along the undulations of the surface of the electrode pair 101, that is, substantially the same shape.

  The thickness of the protective layer 115 is preferably about 0.3 to 2 μm in consideration of the damage received by the protective layer 115 during panel operation, the lifetime of the panel, the formation time (cost), etc. The surface shape of the protective layer 115 is also dielectric. Since the shape of the surface of the display electrode pair 101 is substantially the same as that of the body layer 114, the protective layer 115 is a portion corresponding to the skirts of the bus electrodes 113a and 113b from the portion corresponding to the tops of the bus electrodes 113a and 113b. As a result, the shape becomes concave and a step t is formed on the surface of the protective layer 115. The step t is approximately equal to the thickness of the tops of the bus electrodes 113a and 113b. In the present embodiment, the level difference t is approximately 4.9 μm.

<Taper angle of bus electrode to transparent electrode>
Here, the taper angle of the bus electrodes 113a and 113b with respect to the transparent electrodes 112a and 112b as the underlying layers in contact with the bus electrodes 113a and 113b will be described with reference to FIG. Here, the taper angle refers to a contact angle of the bus electrodes 113a and 113b with respect to the transparent electrodes 112a and 112b after the firing process in the manufacturing method described below.

  FIG. 2 shows a transparent electrode and a bus electrode constituting the scan electrode. As shown in FIG. 2, a PDP in which a bus electrode 113a having a substantially arc shape in cross section is formed on a transparent electrode 112a, with various taper angles θ changed, and its characteristics were examined. However, it has been found that when the taper angle θ is not less than 30 ° and not more than 80 °, it has good characteristics. When the taper angle θ is smaller than 30 °, it is preferable that when the taper angle θ is smaller than this, the thickness at the top of the bus electrode 113a cannot be increased while the width of the bus electrode 113a is kept narrow. This is because the taper angle θ is good when the angle is 80 ° or less. When the taper angle θ is larger than this, the initial characteristic of the PDP is good, but a sharp corner is generated at the step t existing in the protective layer. For this reason, the shape change of the corner portion is remarkably caused by long-time driving of the PDP. The taper angle θ can be adjusted by a manufacturing method described later.

In the above description, the taper angle is described using the scan electrode, but the taper angle of the sustain electrode is also preferably in the above range.
<Manufacturing method of PDP>
Hereinafter, a method for manufacturing the PDP in the first embodiment will be described.
(I) Step of forming transparent electrode First, a transparent electrode material is deposited on a glass substrate using a sputtering method or the like, and then patterned using a photolithography technique to form a transparent electrode.

(Ii) Bus Electrode Formation Step Then, after forming the transparent electrode, the bus electrode is formed on the transparent electrode so as to have a stripe shape and a substantially arc shape in cross section. For example, when a silver paste is applied as a conductive paste with a narrow width on a transparent electrode using a dispenser, the applied silver paste has a generally arcuate cross section. The reason why the cross section is generally arc-shaped is that the silver paste has surface tension. In order to use an appropriate surface tension, it can be freely set to some extent by changing the ratio of components such as paste viscosity and solvent. This will be described later. By heating and drying the applied silver paste, bus electrodes are formed so as to form a generally arc shape in the cross section.

The dispenser used in the present embodiment is generally well known, and is disclosed in detail in, for example, Japanese Patent No. 2671361. Therefore, the description of the dispenser structure is omitted here.
FIG. 3 is a schematic process diagram illustrating a process of forming bus electrodes using a dispenser. Hereinafter, the process of forming a bus electrode using a dispenser will be described with reference to FIG.

[Bus electrode forming process using dispenser method]
As shown in FIG. 3 (a), a glass substrate 111 on which transparent electrodes 112a and 112b are formed is placed on a table (not shown), the table is moved, and the tip of the dispenser is placed above the starting position where silver paste is applied. Place them facing each other.
The dispenser tip is lowered while detecting the relative position between the surface of the glass substrate 111 and the tip of the dispenser by a position sensor (not shown) so that a predetermined gap is provided between the tip of the dispenser and the surface of the glass substrate 111. Position the dispenser tip in the height direction. This gap is appropriately set depending on the relative movement speed between the tip of the dispenser and a table (not shown), the viscosity of the silver paste, the cross-sectional dimension of the drawing pattern to be formed, and is usually about several tens of μm.

  Next, as shown in FIG. 3B, while the silver paste 113P mainly composed of silver particles is discharged from the tip of the dispenser from the glass substrate 111 to the transparent electrodes 112a and 112b, the tip of the dispenser is moved at a predetermined moving speed. When the relative movement is performed along the drawing pattern to be formed, the silver paste can be applied in a predetermined drawing pattern. At that time, even if the gap between the tip of the dispenser and the surface of the glass substrate 111 slightly changes, the discharge amount of the silver paste 113P is constant, so that a highly accurate drawing pattern can be formed. Moreover, since it is non-contact, it cannot be overemphasized that the surface of the glass substrate 111 and transparent electrode 112a, 112b is not damaged.

  In addition, when apply | coating a silver paste with a dispenser, it is desirable that the viscosity of a silver paste is 10 Pa.s or more and 1000 Pa.s or less. The reason why the viscosity range of the silver paste is defined as described above is that when a silver paste having a relatively high viscosity of 10 Pa · s or more is used, the taper angle of the formed bus electrode is different even if the material of the substrate surface is different. However, when the viscosity is less than 10 Pa · s, it is not preferable because the thickness after firing is not sufficient and the wiring resistance becomes high. On the other hand, when the viscosity is higher than 1000 Pa · s, there is a problem that the nozzle of the dispenser is clogged, which is not preferable.

[Bus electrode formation process using photolithography]
In addition to using the dispenser, there is also a method using photolithography as a method for forming the bus electrode on the transparent electrode. FIG. 4 is a schematic process diagram showing a process of forming a bus electrode using photolithography. Hereinafter, a description will be given with reference to FIG.
A silver paste 113P is applied on the transparent electrodes 112a and 112b (FIG. 4A), masked with the silver paste 113P, and then exposed and developed in this order to form a bus electrode component 113Q having a desired width ( FIG. 4 (b)).

Then, the silver paste 113P is again applied on the bus electrode component 113Q (FIG. 4C), and the masking, exposure and development are again performed in this order on the silver paste 113P, and the width of the bus electrode component 113Q is smaller than the width of the bus electrode component 113Q. Bus electrode component 113R is formed to form bus electrodes 113a and 113b (FIG. 4D).
By repeating the above steps, the bus electrodes 113a and 113b in which the thicknesses of the bus electrodes 113a and 113b decrease from the center to the end in the cross section perpendicular to the extending direction of the bus electrodes 113a and 113b are changed to the transparent electrodes 112a. , 112b. In this case, when viewed microscopically, corners are formed in the cross section, but as viewed macroscopically, the cross sectional shapes of the bus electrodes 113a and 113b are substantially circular as shown in FIG. It can be regarded as an arc shape, and can be identified with the cross-sectional shape of the bus electrode 113a shown in FIG.

Note that the number of steps is determined in consideration of both the productivity and the effect because the labor is increased even if the steps are repeated.
When the glass substrate coated with the silver paste is heated and dried and fired by the above method, the silver paste is cured while slightly reducing its volume, and a bus electrode is formed. The application amount of the silver paste is set so that the top thickness of the bus electrode is approximately 2 to 20 μm in consideration of the line resistance of the bus electrode to be formed. In the present embodiment, the top thickness of the bus electrode is set to 5.2 μm.

In addition to the use of photolithography, the bus electrode can be preferably formed in the same manner by applying a silver paste by screen printing and drying and baking it.
In addition, in the cross section perpendicular to the extending direction of the bus electrode, the taper angle of the bus electrode with respect to the transparent electrode corresponding to the base layer of the bus electrode is after firing as described above, but this taper angle θ is When applying the conductive paste using a dispenser, the viscosity of the conductive paste, the contact angle of the conductive paste with respect to the transparent electrode, the moving speed of the dispenser, etc. change accordingly. By adjusting appropriately, it can be set as a desired value.

(Iii) Dielectric layer forming step After the bus electrode is cured, a silicon oxide film having a relative dielectric constant of about 3.5 to 4.5 is formed so as to cover the glass substrate, the transparent electrode, and the bus electrode. The layer is formed using, for example, a plasma CVD apparatus. Thereby, a dielectric layer can be formed along the bus electrode.

Since a general plasma CVD apparatus is used, a description of its configuration is omitted.
[Dielectric layer forming process using plasma CVD]
Hereinafter, a process of forming a silicon oxide film as a dielectric layer using a plasma CVD apparatus will be described. A glass substrate used as a PDP material is placed on the lower electrode provided in the vacuum vessel, and, for example, TEOS, He, O ₂ gas is supplied as a source gas from a gas supply device through a shower head provided at the lower part of the upper electrode. While the vacuum vessel is evacuated with a pump and the inside of the vacuum vessel is kept at a predetermined pressure, for example, high frequency power of 13.56 MHz is supplied from the upper electrode high frequency power source to the upper electrode, and the lower electrode high frequency power source is supplied to the lower electrode. For example, by supplying a high frequency power of 1 MHz, for example, the raw material gas is turned into plasma to increase its reactivity, and a silicon oxide film is formed as a dielectric layer on the glass substrate.

According to the plasma CVD method, a silicon oxide film is formed with a uniform thickness along the surface shape of the display electrode. For this reason, the shape of the display electrode can be prevented from being buried in the dielectric layer as before, and the surface of the dielectric layer can be prevented from being flattened. The surface shape of the silicon oxide film is the surface shape of the display electrode. Therefore, it is suitable for the present invention.
A silicon oxide film used as a dielectric layer is an insulating material that has an excellent transmittance for visible light and an excellent withstand voltage. The thickness (thickness of the flat portion) is determined in consideration of the capacitance between the bus electrodes, the withstand voltage, etc., but is generally in the range of 3 to 20 μm.

(Iv) Step of forming protective layer After forming the dielectric layer, when the magnesium oxide thin film is formed as a protective layer on the dielectric layer by sputtering, electron beam evaporation, etc., the surface of the dielectric layer is formed. A protective layer having a uniform thickness is formed along the.
When the front substrate is formed as described above, a step appears because the protective layer is formed along the shape of the display electrode surface. This step appears due to the shape of the cross section perpendicular to the extending direction of the bus electrode, and the dimension of the step is substantially equal to the thickness of the top of the bus electrode. The level difference is caused because the plasma CVD method is used for forming the dielectric layer, so that the flattening action at the time of formation as seen in the liquid phase method hardly occurs. In the present embodiment, the thickness of the protective layer (thickness of the flat portion) is determined in consideration of damage to the protective layer during panel operation, the lifetime of the panel, the formation time (cost), and the like. It is in the range of 3 to 2 μm. The dimension of the step is approximately 4.9 μm.

(V) Sealing step After the front substrate is formed as described above, the front substrate and the separately formed rear substrate are bonded to each other with the discharge space interposed therebetween, and bonded together and evacuated. A PDP is produced by containing a discharge gas (for example, a mixed gas of Ne and Xe). As the back substrate, a substrate having a stripe-shaped partition structure may be used, but a substrate having a cross-shaped partition structure may be used. When using a rear substrate having a grid-like barrier rib structure, a step t is generated on the front substrate side even if a vertical barrier rib structure having the same height as the horizontal barrier rib is used. A gap s is always generated between the front substrate and the top of the partition wall (see FIG. 1B), and the above-described evacuation process can be performed satisfactorily.

<< Effect of PDP in this embodiment >>
In the PDP employing the front substrate configured as described above, since the dielectric layer is formed with a uniform thickness along the surface shape of the bus electrode, the dielectric layer is sandwiched between the pair of display electrodes. A depression is formed in the discharged discharge gap region. Therefore, the electric field strength in the discharge gap is increased when the PDP is driven, and the discharge efficiency during the surface discharge is increased. In addition, since the step portion of the surface of the protective layer from the portion corresponding to the bus electrode top portion of the protective layer to the portion corresponding to the bus electrode skirt portion has a smooth curve, it is not a sharp corner portion, Even if the PDP is driven for a long time and subjected to sputtering by ions in the plasma, the shape of the step hardly changes with time. Furthermore, since the dielectric layer is formed with a uniform thickness and does not become extremely thin at the portion covering the top of the bus electrode, it is difficult for dielectric breakdown to occur. Therefore, the PDP in the present embodiment can suppress changes in panel characteristics over time while reducing power consumption. Further, since the panel characteristics do not change with time, the panel life can be extended.

Furthermore, since the rear substrate having a cross-granular barrier structure is used for the front substrate having the above-described configuration, the movement of electrons between discharge cells is significantly larger than when a rear substrate having a striped barrier rib structure is used. Since it is suppressed and crosstalk is less likely to occur, a high-definition panel can be realized.
<< Effects of PDP Manufacturing Method in Present Embodiment >>
As described above, the bus electrode having a substantially arc-shaped cross section is formed by a dispenser method or the like, and the dielectric layer is formed by a thin film method, whereby the main surface of the dielectric layer on the discharge space side is easily curved as described above. A depression can be provided.

  In addition, since the dielectric layer can be formed thin by forming the dielectric layer by plasma CVD, the electric field strength in the discharge gap sandwiched between the pair of display electrodes can be increased, and the discharge during surface discharge Efficiency can be increased. In addition, according to the plasma CVD method, the dielectric layer can be densely formed, and dust can be prevented from being mixed and bubbles can be prevented from being generated at the time of formation. Therefore, it is possible to form a dielectric layer that hardly causes dielectric breakdown. Furthermore, since the dielectric layer can be formed with a uniform thickness according to the plasma CVD method, the thickness of the dielectric layer covering the top of the bus electrode is not extremely reduced, and a dielectric layer that does not easily cause dielectric breakdown is formed. Can do.

  Further, since the depression is formed on the surface of the dielectric layer of the front substrate, when manufacturing the PDP, if the front substrate and the rear substrate are bonded together, a gap is formed between the front substrate and the rear substrate partition. Is surely formed, and the movement of gas molecules is facilitated through this gap in the process of evacuating the inside of the panel thereafter. Therefore, the evacuation process can be performed in a short time (in the same time as in the case of the staggered partition wall structure).

Therefore, a PDP that exhibits the above effects can be easily manufactured at a low cost in a short time.
<Consideration of bus electrode thickness h>
Further, when the PDP was formed and examined under various conditions, when the top thickness of the bus electrode on the glass substrate was h and the step difference due to the bus electrode on the glass substrate was t, the top thickness h was 2 μm or more and 20 μm or less. When the level difference t is 0.5 times or more and 1 time or less of the apex thickness h, it is possible to achieve both a reduction in driving voltage and a reduction in the exhaust time of the bonded panels. This is because if the top thickness h is smaller than 2 μm, the line resistance of the bus electrode is large and the driving waveform is rounded. If the top thickness h is larger than 20 μm, the viscosity of the conductive paste used in the bus electrode coating process is considerably reduced. This is because a problem arises that the nozzle of the dispenser is clogged because it needs to be set high. In addition, it is difficult to find a condition for forming a dielectric layer in which the level difference t is larger than the top thickness h, while a condition for forming a dielectric layer in which the level difference t is smaller than 0.5 times the top thickness h is found. It is also difficult. In order to form the step t smaller than 0.5 times the top thickness h and the step t larger than the top thickness h, an extremely complicated manufacturing process is required by adding a plurality of types of formation processes. Because it becomes.

Note that as an example of a method for forming a bus electrode, an example in which a conductive paste is applied by dispenser, photolithography, or screen printing is described in this embodiment mode; however, the present invention is not limited thereto. A similar shape can be formed even by coating using another liquid phase direct drawing method such as a method.
In this embodiment, the plasma CVD method is shown as a method for forming the dielectric layer. However, the present invention is not limited to this, and other vapor phase growth methods such as sputtering of silicon oxide with a sputtering gas are used. Then, a method of depositing a silicon oxide film on a substrate (sputtering method), a method of depositing a silicon oxide film on a substrate by sputtering silicon using a sputtering gas in an oxygen-containing atmosphere (reactive sputtering method), silicon oxide A dielectric layer can be formed densely, uniformly, and thinly by a method (evaporation method) in which a silicon oxide film is deposited on a substrate (evaporation method) by applying energy such as heat, electron beam, or laser light to an object to evaporate it. .
(Embodiment 2)
The second embodiment of the present invention will be described below with reference to FIG.

<Configuration of PDP>
FIG. 5 is a cross-sectional view showing a schematic configuration of the front substrate of the PDP in the second embodiment. The front substrate of the PDP shown in FIG. 5 has substantially the same configuration as that of the front substrate of the PDP shown in FIG. 1 in the first embodiment, and the bus electrodes 113a and 113b are glass substrates rather than the transparent electrodes 112a and 112b. Since only the points arranged on the 111 side are different, the description of the items overlapping with those described in the first embodiment is omitted.

In this embodiment, since the glass substrate 111 corresponds to the base layer in contact with the bus electrodes 113a and 113b, an angle corresponding to the contact angle of the bus electrodes 113a and 113b with respect to the glass substrate 111 is a taper angle. A preferable range of the taper angle is the same as that of the first embodiment.
<Manufacturing method of PDP>
Hereinafter, a method for manufacturing the PDP in the second embodiment will be described.

The manufacturing method of the PDP in the second embodiment is almost the same as the manufacturing method of the PDP in the first embodiment. In the first embodiment, the bus electrode is formed after the transparent electrode is formed. Since the second embodiment is different only in that the transparent electrode is formed after the bus electrode is formed, the bus electrode forming step and the transparent electrode forming step will be described in detail below.
(I) Bus electrode formation step First, a bus electrode is formed on a glass substrate so as to have a stripe shape and a generally arc shape in cross section. For example, a thin wire made of a conductive paste is applied onto a glass substrate using a dispenser and heated to form a bus electrode so as to form a generally arc shape in cross section.

Since the usage of the dispenser is the same as the usage in the first embodiment, the description thereof is omitted here. The silver paste used as the conductive paste is the same as that in the first embodiment, and has the same viscosity range as that in the first embodiment.
In addition to using the dispenser, there is a method using photolithography. Since the manufacturing method by photolithography is the same as the manufacturing method described in Embodiment 1, the description thereof is omitted.

Similarly to the first embodiment, the bus electrode can be preferably formed by screen printing as well as photolithography.
(Ii) Transparent electrode formation process After forming the bus electrode, the transparent electrode material is deposited using a sputtering method, and then patterned using a photolithography technique to form the transparent electrode on the bus electrode. To do.

After completing the transparent electrode forming step, a dielectric layer and a protective layer are formed in the same manner as shown in the first embodiment, and a PDP is manufactured through a sealing step.
<< Effect of PDP in this embodiment >>
The PDP employing the front substrate configured as described above also has the same effect as the PDP shown in the first embodiment. That is, a depression is formed in the dielectric gap in the discharge gap region sandwiched between the pair of display electrodes, and the dielectric layer is thin, so that the electric field strength in the discharge gap sandwiched between the pair of display electrodes is increased. Further, since the discharge efficiency during surface discharge can be increased, and the surface of the protective layer is curved, the shape of the step hardly changes over time even when the PDP is driven for a long time. Since the layer has a uniform thickness and does not become extremely thin at the portion covering the bus electrode, it is difficult to cause dielectric breakdown.

Therefore, also in the PDP in the present embodiment, it is possible to suppress changes in panel characteristics over time while reducing power consumption. Further, since the panel characteristics do not change with time, the panel life can be extended.
Furthermore, the PDP in which the front substrate having the above-described configuration is combined with the rear substrate having a cross-granular barrier rib structure having vertical barrier ribs and horizontal barrier ribs having the same height also has the same effect as the PDP described in the first embodiment. .

<< Effects of PDP Manufacturing Method in Present Embodiment >>
By forming the bus electrode having a substantially arc-shaped cross section as described above by the dispenser method or the like and forming the dielectric layer by the thin film method, it is very easy to provide a curved recess on the discharge space side of the front substrate. In addition, since the dielectric layer is formed by plasma CVD, a PDP having the above effects can be manufactured as in the first embodiment. In addition, since the gap due to the depression is also formed in this embodiment, the process of evacuating the inside of the panel after pasting the front substrate and the rear substrate is performed in a short time (equivalent to the case of the staggered grid structure). Can be done in time).

Therefore, if the above process is adopted in the manufacture of a PDP, as in the first embodiment, a PDP that exhibits the above effects can be easily manufactured at low cost in a short time.
<Consideration of bus electrode h>
Further, the relationship between the top thickness h of the bus electrode on the glass substrate and the level difference t caused by the bus electrode on the glass substrate is the same as that in the first embodiment, and thus the description thereof is omitted.

In the embodiment of the present invention, the case where the dispenser method or the like is used in the step of forming the bus electrode using the conductive paste is exemplified, but the other liquid phase direct drawing method such as the inkjet method is used. Also good. By using these liquid phase direct drawing methods, it becomes possible to obtain a generally arcuate cross-sectional shape by utilizing the surface tension of the paste.
In addition to the plasma CVD method, the dielectric layer is formed by a sputtering method, a reactive sputtering method, and a vapor deposition method in the same manner as in the first embodiment. it can.

In order to improve the adhesion between the laminated films, a thin film such as Cr, Ti, or TiN is used in contact with the bus electrode, or a silicon nitride film, an alumina film, or silicon oxynitride is used in contact with the dielectric layer. It is also possible to use a film or the like.
In any of the above embodiments, the bus electrode has a generally arcuate cross-sectional shape. However, the present invention is not limited to this, and the facing region of the display electrode that forms at least a pair from the top to the bottom of the bus electrode is not limited thereto. If the bus electrode is formed so that the shape is curved, the same effect can be obtained.

  In each of the above-described embodiments, the description has been given using the PDP in which the protective layer is provided on the dielectric layer. However, the present invention is not limited to this, and the present invention can be similarly implemented even without a protective film on the dielectric layer. .

  The present invention is a PDP having excellent characteristics and a manufacturing method thereof, and can be used for a display used for image display of a television or a computer and a manufacturing method thereof.

(A) is a principal part perspective view of PDP in Embodiment 1, (b) is a schematic sectional drawing of PDP in Embodiment 1. FIG. FIG. 3 is a schematic cross-sectional view showing a taper angle of a bus electrode with respect to a transparent electrode in the first embodiment. It is the schematic process drawing which showed the process of forming a bus electrode using a dispenser. It is the schematic process drawing which showed the process of forming a bus electrode using photolithography. 6 is a schematic cross-sectional view of a front substrate of a PDP in Embodiment 2. FIG. It is a schematic sectional drawing which shows the front substrate of the conventional PDP. It is a schematic sectional drawing which shows the front substrate of PDP described in patent documents.

Explanation of symbols

101 Display electrode pair 102 Scan electrode 103 Sustain electrode 1, 111 Glass substrate 2, 52, 112a, 112b Transparent electrode 3, 53, 113a, 113b Bus electrode 113P Silver paste 113Q, 113R Bus electrode component 4, 54, 114 Dielectric Layers 5 and 55 Protective layer 59 Recess 110 Front substrate 120 Rear substrate 121 Discharge space 122 Partition

Claims (11)

A plasma display panel in which two substrates are arranged opposite to each other with a space interposed therebetween, and a display electrode pair is extended and arranged on the space side main surface on one substrate,
The display electrode pair includes two strip electrodes arranged in parallel with a gap between each other,
Each of the strip electrodes is formed so that the thickness gradually decreases from the inner side toward the outer end on the gap side in the electrode width direction,
The plasma display panel, wherein the dielectric layer has a uniform thickness and covers the dielectric electrode layer along the display electrode pair. In the strip electrode,
The cross section perpendicular to the electrode stretching direction has a chevron shape that is thicker toward the center.
2. The plasma display panel according to claim 1, wherein the thickness of the plasma display panel is changed so as to gradually decrease in a quadratic function or an exponential function from the peak to the bottom. The strip electrode is
3. The plasma display panel according to claim 1, wherein the plasma display panel has a laminated structure including a resistance film electrically connected to each other and a conductive film containing a metal material. The conductive film constitutes a gradually decreasing portion of the strip electrode;
4. The plasma display panel according to claim 3, wherein a taper angle of the conductive film with respect to a base layer in contact with the conductive film is 30 ° or more and 80 ° or less in the cross section.   5. The plasma display panel according to claim 1, wherein the dielectric layer has a thickness in a range of 3 μm to 20 μm.   6. The plasma display panel according to claim 1, wherein a partition wall is disposed in a direction intersecting with the display electrode pair on the other of the two substrates. 7. A method of manufacturing a plasma display panel, comprising: extending a display electrode pair on a substrate; and forming a dielectric layer on the display electrode pair,
In the step of extending the display electrode pair,
Two strip electrodes are arranged side by side with a certain gap,
Each of the strip electrodes is
In the electrode width direction, formed so that the thickness gradually decreases from the inside toward the outer end on the gap side,
In the step of forming the dielectric layer, a vapor phase growth method is used. In the step of extending the display electrode pair,
8. The method of manufacturing a plasma display panel according to claim 7, further comprising a sub-step of forming a conductive film by applying a conductive paste containing a metal material to the substrate.   9. The method of manufacturing a plasma display panel according to claim 8, wherein the sub-step of forming the conductive film uses a dispenser method, a photolithography method, an ink jet method, or a screen printing method.   As the vapor phase growth method, a dielectric layer is formed by vapor phase growth of a dielectric layer material using a method selected from a plasma CVD method, a sputtering method, a reactive sputtering method or a vapor deposition method. A method for manufacturing a plasma display panel according to any one of claims 7 to 9.   11. The substrate according to claim 7, wherein the substrate on which the partition is arranged in a direction crossing the display electrode pair is bonded to the substrate on which the display electrode pair and the dielectric layer are formed. A method for producing the plasma display panel according to claim 1.

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