JP2005183037A - Plasma display panel and plasma display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cell structure capable of drastically improving luminous efficiency without bringing forth dielectric breakdown even without combination of: discharge gap≥150 μm, dielectric film thickness<20 μm, and dielectric constant<8, while equally securing a margin of writing discharge. <P>SOLUTION: As to an AC plane discharge PDP, a height of the discharge cell is set at a value within the range of 180 to 210 μm, and a discharge gap between a pair of display electrodes is set at a value within the range of 125 μm to less than 150 μm. In that case, a thickness of the dielectric film is 30 μm as before, with a dielectric constant of 12 to 13. Further, it may be improved so as to reduce a discharge starting voltage by forming a thick-film metal electrode on both sides of the discharge gap. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a technique for improving luminous efficiency in an AC surface discharge type plasma display panel (hereinafter, the plasma display panel is simply referred to as PDP).

  The plasma display device is widely used as a commercial monitor or a consumer TV, but has a technical problem that the luminous efficiency of the PDP is inferior to that of a CRT.

  Regarding this problem, Patent Document 1 described later can improve the light emission efficiency by setting the discharge gap between the display electrode pairs to 150 μm or more, and further enhance the effect when the partition walls are meandering and the cell width is wide. I am proposing to be done.

  However, when the discharge gap is set to be relatively wide, the discharge start voltage becomes relatively high and the drive voltage tends to increase. According to the observation data obtained by the present inventors regarding this point, it has been obtained that when the discharge gap is increased from 75 μm to 150 μm, the discharge start voltage is increased from 200 V to 250 V.

  Regarding this new problem, Patent Document 1 described above prevents the increase of the discharge start voltage by limiting the film thickness of the dielectric covering the display electrode pair to 20 μm or less and limiting the dielectric constant to 8 or less. Insist that it is possible.

JP 2001-176405 A (FIGS. 9 and 10) JP 2001-176399 A N. Uemura et al., Proc. Of the 6th International Display Workshops 1999, Rib Height Dependence of Vacuum Ultraviolet Emission Efficiency in Surface-Discharge AC PDPs pp595-598

  However, when the film thickness of the dielectric is set to 20 μm or less, dielectric breakdown of the dielectric tends to occur.

  Moreover, the dielectric material that can be produced at low cost by screen printing and firing is usually made of lead glass, and its dielectric constant is relatively high, 12 to 13. In view of this point, it is considered difficult to form a dielectric film having a dielectric constant of 8 or less as proposed in Patent Document 1 as a thick film by the above method.

  Therefore, it can be evaluated that the structure for improving the light emission efficiency proposed by Patent Document 1 lacks practicality.

  Therefore, the present inventor proposes a structure of a PDP capable of obtaining the luminous efficiency improvement effect without setting the discharge gap to 150 μm or more in order to overcome such a matter of concern.

  A subject of the present invention is a front panel having a plurality of pairs of display electrodes, a dielectric film covering the plurality of display electrode pairs and separating each display electrode from a discharge space, and a three-dimensional intersection with the display electrode pairs A plurality of barrier ribs extending in such a manner, a phosphor layer covering the side wall of each barrier rib and adjacent barrier ribs, and a plurality of addresses located between the barrier ribs so as to cross the display electrode pair. In a plasma display panel comprising a plurality of discharge cells filled with a discharge gas, the cell height of each discharge cell being in a range of 180 μm or more and 210 μm or less. Further, the discharge gap between the pair of display electrodes is set to a value within a range of 125 μm or more and less than 150 μm.

  Hereinafter, various embodiments of the subject of the present invention will be described in detail along with the effects and advantages thereof with reference to the accompanying drawings.

  According to the subject of the present invention, while increasing the discharge gap to a value within the above range while preventing the height of the discharge cell within the above range, it is possible to prevent an increase in the discharge start voltage during display discharge. There is an effect that the margin of the driving voltage can be secured and the luminous efficiency can be increased by 10% or more.

(Embodiment 1)
The point of the present embodiment is as follows. That is, while the discharge gap between the sustain discharge pairs is defined to be 125 μm or more and less than 150 μm, the height of the cell, which has been 130 μm in the past, is set within a range of 180 μm to 210 μm. Here, the “cell height” of the discharge cell is a value obtained by subtracting the phosphor film thickness from the height of the barrier rib (bump), more strictly, the maximum between the top of the barrier rib and the exposed surface of the phosphor film. Defined as distance. In this way, the cell height is defined as a value within the range of 180 μm or more and 210 μm or less, and by combining this setting with the condition that the discharge gap is within the range of 125 μm or more and less than 150 μm, the discharge gap is simply set to 125 μm or more. It was possible to obtain an improvement in luminous efficiency that could not be obtained simply by setting the value to less than 150 μm. At this time, the conventional dielectric film thickness (for example, 30 μm or more) and the relative dielectric constant (for example, 12 to 13) are provided while preventing the increase of the discharge start voltage in the display discharge and hence the increase of the driving voltage ( It was possible to use a dielectric (on the front panel side), and to secure a margin for writing discharge as in the prior art.

  Hereinafter, the PDP of the present embodiment will be described with reference to the drawings.

  FIG. 1 is a perspective view schematically showing a cell structure of a plasma display panel (PDP) according to the present exemplary embodiment. In FIG. 1, a plurality of address electrodes extending along the second direction D2 are formed on the rear glass substrate, and a dielectric film (glaze) is formed so as to cover these address electrodes (excluding the take-out portion). Layer) is further formed on the back glass substrate. Here, the back glass substrate and the dielectric film (glaze layer) are collectively referred to as “back substrate” having the address electrodes. Note that the glaze layer need not be formed, and in this case, the rear glass substrate corresponds to the rear substrate itself. A plurality of partition walls extend and are formed along the second direction D2 so as to sandwich each address electrode, and a phosphor film is applied on the side surface of each partition wall and on the back substrate surface between adjacent partition walls.・ It is formed. Thus, the back panel is composed of the above-described back substrate, a plurality of barrier ribs, and phosphor films of R, G, B colors. On the other hand, the structure on the front panel side that is disposed opposite to the rear panel and forms discharge cells in the discharge space is as follows. That is, on the front glass substrate, a plurality of pairs of sustain electrodes x and y, both of which are transparent electrodes and mother electrodes (bus electrodes), are three-dimensionally crossed (orthogonal in plan view) with the plurality of address electrodes. Similarly, it extends and is formed along the first direction D1, and a discharge gap having a width g is formed between each sustain electrode pair x, y. Each sustain electrode pair x, y is covered with a dielectric film and a protective film (for example, an MgO film) except for the extraction portion (in FIG. 1, the front glass substrate, the dielectric film, and the protective film). Although illustration is omitted, these members are shown in FIG. 8 described later).

  The inventor first examined the change in luminous efficiency with respect to the height of the partition wall, that is, the cell height h defined above (see FIG. 1) using a panel having a conventional discharge gap of 75 μm. . The measurement results are shown in FIG. 2. As the cell height is increased, the light emission efficiency increases up to a cell height of 250 μm and becomes constant thereafter.

  As described above, when the cell height h is increased, the light emission efficiency increases. However, when the cell height h is 250 μm, the light emission efficiency tends to be saturated. The measurement results in FIG. 2 are obtained for a PDP having a discharge gap g of 75 μm, a dielectric material mainly composed of lead glass, a relative dielectric constant of 12-13, and a film thickness of 30 μm. It is a thing. At this time, the transparent electrode width is 350 μm, the mother electrode width is 60 μm, the phosphor film thickness is 20 μm, the discharge gas is Ne / Xe 5%, and the gas pressure is 66,660 Pa.

  When the cell height h is increased, the write discharge voltage between the address electrode formed in the back substrate and one sustain electrode (also referred to as scan electrode) x on the front glass substrate increases, and the drive voltage increases. . The write discharge voltage is expressed as a voltage (Vw−Vxg) from the voltage Vw applied to the address electrode and the voltage Vxg applied to the sustain electrode x. Here, FIG. 3 is a measurement showing a voltage margin of the voltage (Vw−Vxg) at the time of write discharge when each condition excluding the cell height h is set to be the same as the above conditions used in the measurement of FIG. It is a result. The write voltage lower limit in FIG. 3 is a voltage value for starting the write discharge, and the upper limit voltage is a voltage value when another cell (adjacent cell) is written. As the cell height h is increased, the distance from the phosphor to the sustain electrode becomes longer, so that the discharge start voltage to be applied to the sustain electrode does not depend on the phosphor, and as shown in FIG. In this case, the margin of the driving voltage applied to the sustain electrode (difference between the adjacent cell lighting voltage of each color and the writing voltage lower limit) is widened, and the driving voltage margin of the writing discharge becomes the maximum when the cell height h is 180 μm. Therefore, if the viewpoint of the voltage margin is also added to the measurement result of FIG. 2, it can be said that it is desirable to set the cell height h within the range of 130 μm to 210 μm as judged from FIG.

  Further, when the discharge gap g is sequentially increased from 75 μm to 100 μm, 125 μm, and 150 μm from the conventional value, the increase rate of the light emission efficiency in each discharge gap g with respect to the light emission efficiency when the discharge gap is 75 μm, the cell height h The dependency is shown in FIG. Each condition in these measurement results is the same as the corresponding condition in the measurement of FIG. 2 except for the discharge gap g. That is, the cell structure and sealed gas other than the discharge gap are the same as those already described in FIG. The luminous efficiency is a value obtained at a luminance of 300 cd / m 2 by changing the frequency with the applied voltage being constant. As shown in FIG. 4, when the cell height h is 120 μm, the increase rate is less than 5% regardless of whether the discharge gap is 100 μm, 125 μm, or 150 μm, whereas when the cell height h is 180 μm, the discharge is When the gap g is 100 μm, the increase rate is still less than 5%. However, when the discharge gap g is 125 μm and 150 μm, the light emission efficiency is well over 10%. The effect of increasing the luminous efficiency is valid even when the cell height h is 230 μm and 280 μm. As far as the measurement results in FIG. 4 are concerned, it is effective if the cell height h is 180 μm or more. I can say that. Therefore, in combination with setting the cell height h to 180 μm or more, the conventional film thickness and relative dielectric constant of the conventional film thickness and relative dielectric constant are not increased in the range of 125 μm ≦ discharge gap g <150 μm without increasing the display discharge start voltage. The luminous efficiency can be improved by 10% or more while using the dielectric film.

  On the other hand, when the discharge gap g is set to 125 μm (other conditions except for the discharge gap g and the cell height h are the same as those in FIG. 2), the write discharge when the cell height h is changed is as follows. The measurement result indicating the voltage margin is shown in FIG. As can be understood from FIG. 5, as in the measurement result of FIG. 3, it is shown that even when the discharge gap g is set to 125 μm, the write margin is expanded when the cell height h is in the range of 130 μm to 210 μm. ing.

  Therefore, it is concluded that it is desirable to set the cell height h within the range of 180 μm or more and 210 μm or less, judging from FIG. obtain. By setting within this range, it is possible to simultaneously increase the write margin while achieving an increase in light emission efficiency exhibiting an increase rate of 10% or more.

  For reference, an increase in the discharge start voltage during display discharge is shown in FIG. The discharge start voltage tends to increase with the discharge gap g. Regarding the relationship between the discharge gap g and the light emission efficiency, the wider the discharge gap g, the higher the light emission efficiency. However, as described above, when the discharge gap g increases, the discharge start voltage also increases. Therefore, the discharge gap g is determined from the upper limit of the discharge start voltage that is 125 μm or more and is allowed in the drive circuit. The result is 125 μm ≦ discharge gap g <150 μm. In this case, the film thickness and relative dielectric constant of the dielectric film covering the sustain electrode pair can be set to conventional values, and no particular problem occurs with respect to the dielectric film.

(Modification 1)
Furthermore, the structure of the sustain electrode in the PDP cell structure according to the first embodiment may be improved as shown in FIG. In the configuration of FIG. 7, the cell height is set to 200 μm, the discharge gap g is set to 125 μm, and the second thick film metal electrode 2 is provided on both sides of the discharge gap g ( The mother electrode on the opposite side of the discharge gap g corresponds to the first thick metal electrode 1). Here, for example, the electrode width of the second thick metal electrode 2 is set to 30 μm, and the film thickness thereof is set to 5 μm to 10 μm. Symbol W represents the width of the transparent electrode of each sustain electrode x, y. FIG. 8 shows a cross-sectional structure of the front panel or front substrate, and corresponds to a vertical cross-sectional view taken along line AA in FIG. As shown in FIG. 8, the second thick film metal electrode 2 protrudes on the surface of the end portion on the side forming the discharge gap g in the both end portions of each of the pair of sustain electrodes x and y. It is formed with. The second sustain electrodes x and y and the discharge gap g are covered with a dielectric film, but the dielectric film on the second thick film metal electrode 2 is thin only by the thickness of the thick film electrode 2. . For this reason, the electric field in the vicinity of the discharge gap becomes stronger than when the second thick metal electrode 2 is not provided, and the discharge start voltage during display discharge can be lowered.

  As described above, according to this modification, since the second thick metal electrode 2 is formed on both sides of the discharge gap g of the display electrode, the dielectric film thickness on each thick film metal electrode 2 is the same as that of the metal electrode 2. Since the thickness is reduced by the thickness, the electric field on the dielectric surface is increased, and the effect that the discharge start voltage in the display discharge can be lowered is obtained.

(Modification 2)
Further, as shown in FIG. 9, the PDP cell structure according to the first embodiment may be provided with a digging (groove structure) 10 in the dielectric of the discharge gap portion of the front panel. Here, the dielectric film covering the sustain electrode pair x, y and the protective film formed on the dielectric film are collectively referred to as “dielectric layer”. The formation method of the said digging part is as follows. First, a lead glass paste is printed on the surface of the front glass substrate on which the sustain electrode pair has already been formed by screen printing, a die coater, or a roll coater, and the paste is dried. Thereafter, a dry film is laminated on the surface of the dried lead glass paste, an opening is formed in the discharge gap portion by exposure and development, and the portion is scraped off by sandblasting. Thereafter, it is baked to form a glassy dielectric film on the front glass substrate surface. In this way, the groove 10 having a width of about 70 μm and a depth of about 20 μm is formed in the discharge gap portion. Thereafter, a protective film is formed thereon. Therefore, a digging portion or a groove structure corresponding to the groove 10 is also formed in the portion of the protective film formed on the groove 10.

  By adopting such a configuration, a portion where the electric field between the transparent electrodes is strong is exposed to the discharge space, so that the discharge start voltage can be lowered by about 10V to 20V.

  In addition, each partition in this Embodiment and each modification is formed by the sandblast method, for example, and the top width | variety of a partition is set in the range of 60 micrometers-70 micrometers.

(Appendix)
While the embodiments of the present invention have been disclosed and described in detail above, the above description exemplifies aspects to which the present invention can be applied, and the present invention is not limited thereto. In other words, various modifications and variations to the described aspects can be considered without departing from the scope of the present invention.

  Each of the PDPs described in the present embodiment and its modifications 1 and 2 is a driver circuit that generates and applies each signal for driving a pair of sustain electrodes and address electrodes of the PDP based on an image signal (a known drive circuit). And a plasma display device (for example, a plasma TV or a commercial monitor) can be configured.

It is a perspective view which shows typically the cell structure of PDP which concerns on this Embodiment. It is a measurement figure which shows the relationship between cell height and luminous efficiency at the time of setting a discharge gap, a dielectric film thickness, and a dielectric constant to a conventional value. It is a measurement figure which shows the relationship between a cell height and a write discharge voltage when a discharge gap, a dielectric film thickness, and a relative dielectric constant are set to conventional values. It is a measurement figure which shows the relationship between cell height and luminous efficiency increase rate in case discharge thickness is 100 micrometers, 125 micrometers, and 150 micrometers, respectively when a dielectric film thickness and a dielectric constant are set to the conventional value. It is a measurement figure which shows the margin of the write discharge voltage with respect to cell height when a dielectric gap is set to a conventional value and a discharge gap is 125 micrometers. It is a measurement figure which shows the relationship between a discharge gap and the start voltage of display discharge. 10 is a plan view schematically showing the structure of a sustain electrode pair in Modification 1. FIG. 10 is a longitudinal sectional view schematically showing the structure of a sustain electrode pair in Modification 1. FIG. 10 is a longitudinal sectional view schematically showing a part of a front panel in Modification 2. FIG.

Explanation of symbols

x sustain electrode (scan electrode), y sustain electrode (sustain electrode: common electrode), D1 first direction, D2 second direction, g discharge gap, h cell height, W width of transparent electrode, 1 first thick film metal Electrode (mother electrode), 2nd thick film metal electrode, 10 groove.

Claims (3)

A front panel having a plurality of pairs of display electrodes, a dielectric film that covers the plurality of display electrode pairs and separates each display electrode from the discharge space, and extends so as to form a three-dimensional intersection with the display electrode pairs A back panel having a plurality of partition walls, a phosphor layer covering the side surfaces of each partition wall and between adjacent partition walls, and a plurality of address electrodes located between the partition walls and extending so as to three-dimensionally intersect the display electrode pair In a plasma display panel comprising a plurality of discharge cells filled with a discharge gas,
The cell height of each discharge cell is set to a value within the range of 180 μm to 210 μm, and the discharge gap between the pair of display electrodes is set to a value within the range of 125 μm to less than 150 μm. It is characterized by
Plasma display panel. The plasma display panel according to claim 1,
Thick film metal electrodes are formed on both sides of the discharge gap between the pair of display electrodes,
Plasma display panel. The plasma display panel according to claim 1 or 2 and a circuit for driving the panel.
Plasma display device.

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