JP2011014286A - Plasma display panel and method of manufacturing the same, and plasma display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protective layer technology which enables a high resolution plasma display panel to achieve both a reduction of address discharge delay time throughout a wide temperature range and a reduced voltage fluctuation by suppressing a reduction of wall charges during a rest period, leading to a realization of stable address discharge and high contrast.SOLUTION: The protective layer includes MgO containing impurity element, and actual priming electron emission source numbers in MgO are ≥1.4x10/cell and ≤8.1x10/cell. The protective layer is formed by using MgO containing the priming electron emission source in this range, so that the reduction of the address discharge delay time is reduced as well as the voltage fluctuation during the rest period is reduced. The stable address discharge is possible in the high resolution plasma display panel, thereby a high contrast plasma display device is obtained.

Description

  The present invention relates to a plasma display panel (hereinafter also referred to as PDP) and a plasma display device, and more particularly to a technique that is effective when applied to a high-definition plasma display panel.

  The PDP is one of flat panel displays having features of good moving image performance, a wide viewing angle, and easy enlargement. PDPs are classified into a DC (direct current) type and an AC (alternating current) type because of the difference in structure and driving method. Among them, the AC type AC surface discharge type PDP is the most practically used system because of its simple structure and high reliability.

  An AC surface discharge type PDP having a general box structure is mainly composed of a front plate and a back plate, the front plate and the back plate are arranged opposite to each other with the discharge space interposed therebetween, and a discharge gas is sealed in the discharge space. A mixed gas such as He—Xe, Ne—Xe, or He—Ne—Xe is used as the discharge gas.

  The back plate is a striped address electrode (hereinafter also referred to as A electrode) formed on the back substrate, a dielectric layer covering the address electrode, and formed on the dielectric layer to maintain a discharge distance and between adjacent cells. The barrier ribs prevent crosstalk and form discharge cells, and the phosphor layers that emit light in red, green, and blue colors formed between the barrier ribs. The phosphor layer is made of a phosphor that is excited by ultraviolet rays generated by discharge and emits light in red (R), green (G), and blue (B) colors.

  The front plate is formed with a plurality of display electrodes made of pairs of stripe-like sustain electrodes (hereinafter also referred to as X electrodes) and scan electrodes (hereinafter also referred to as Y electrodes) so as to intersect the address electrodes on the front substrate. The display electrode includes a transparent electrode and a bus electrode. The display electrode is covered with a dielectric layer, and a protective layer is formed on the surface of the dielectric layer.

  This protective layer is required to have characteristics such as protection of the dielectric layer by ion bombardment of the discharge gas, secondary electron emission, and wall charge retention. In PDP, a material mainly composed of magnesium oxide (hereinafter referred to as MgO) having these characteristics is widely used.

  As a general image gradation display method in the PDP, there is ADS (Address Display-Period Separation). In the ADS system, one TV field (1/60 s) is divided into a plurality of subfields having a predetermined luminance ratio, and these subfields are selectively made to emit light according to an image, and gradations are expressed by differences in luminance. ing. Further, the subfield includes a reset period, an address period, and a sustain period. In the reset period, in order to make the wall voltages in all the discharge cells arranged in a matrix substantially uniform, a sustain voltage higher than the discharge start voltage is applied between the sustain discharge electrode pairs, and reset discharge is performed in all the discharge cells. In the address period, address discharge that generates an appropriate amount of wall charges is performed only on the discharge cells to be lit among all the discharge cells. In the sustain period, sustain discharge (display discharge) is performed a number of times according to the gradation value of the display data using the wall charges.

  The plasma display device using this PDP is expected as an image display device corresponding to high-quality image quality such as digital broadcasting, and high image quality such as high definition, high brightness, and high contrast is required. Has been. In addition, display image reliability such as a reduction in the occurrence rate of black noise is also required.

  High definition of the PDP is achieved by reducing the pixel pitch and the discharge cell size. Higher brightness can be achieved by increasing luminous efficiency and increasing the number of sustain discharges. Higher contrast is achieved by increasing the number of subfields with different numbers of sustain discharges and reducing the luminance during black display by reducing discharges that do not contribute to display discharge such as reset discharge.

The address period of each subfield is determined by the number of PDP scan lines and the address pulse width. The address pulse width is set in consideration of an address discharge delay time t _d (hereinafter also referred to as a discharge delay time) from when the address voltage is applied until the address discharge occurs. At this time, when the address pulse width for the address discharge delay time t _d is insufficient, it does not occur address discharge between the application of the address voltage. Therefore, black noise is generated due to erroneous discharge such that subsequent sustain discharge is not performed. Furthermore, in the case of higher definition, the number of scan lines increases with the increase in the number of pixels. Thereby, in the high-definition PDP, the ratio of the address period in each TV field is increased, and the ratio of the sustain period that is important in increasing the brightness and the contrast is decreased.

The address discharge delay time t _d is also related to the efficiency of the PDP. As a high-performance television device, an improvement study of the PDP structure for the purpose of increasing the light emission efficiency of the PDP device is underway, and the Xe gas generated by increasing the composition ratio of the Xe gas in the discharge gas mainly containing Ne. study to try to actively use the ₂ molecular beam has been actively conducted. In general, studies have been made to achieve such high emission efficiency of the PDP in a composition ratio region larger than the xenon gas composition ratio (about 5%) in the discharge gas. However, it is also known that when the Xe partial pressure is increased, problems such as an increase in discharge start voltage and an increase in discharge delay time occur.

From the above, in order to achieve the performance of the PDP, it is essential to shorten the address discharge delay time t _d and the address period. There are two main methods for shortening the discharge delay time and the address period. There are two main methods for shortening the address period. One is a method of increasing the data driver IC. For example, if the data driver IC is doubled and the scan line is divided into two at the top and bottom of the panel and the scan is simultaneously changed to the dual scan method, the apparent address period is halved. However, the dual scan method has a problem in terms of productivity and cost due to an increase in the number of circuits related to driving of the data driver IC and the like and complicated wiring.

The other is to reduce the address discharge delay time t _d, is a method of shortening the address pulse width. Address discharge delay time t _d is, Y electrodes, X electrodes and applied voltage and formation delay time depending on the residual wall charges after the reset discharge of the A electrodes t _f, and the electrons become discharge pilot light (priming electrons) statistical delay time until released from the protective layer (hereinafter, also referred to as a release time constant of the priming electrons) consists of the sum of t _s. If priming electron emission characteristics of the protective layer is excellent, it is possible to reduce the statistical delay time t _s and the address discharge delay time t _d, it is possible to perform a stable address discharge.

In order to realize shortening of the address discharge delay time t _d, technical development of the MgO is being performed is a protective layer. Technological development of MgO can be broadly divided into two techniques: a technique of adding an impurity element in MgO and a technique of providing a layer made of fine particles such as MgO crystals on the protective layer.

  As a technique for adding an impurity element into MgO, for example, in Patent Document 1, silicon (hereinafter referred to as Si) is used as the impurity element, and in Patent Document 2 and Patent Document 3, scandium (hereinafter referred to as Sc) is used as the impurity element. It also describes the concentration of each additive element with respect to MgO, which is optimal.

  For example, Patent Document 4 discloses a technique for providing a layer made of fine particles such as MgO crystal on the protective layer.

JP-A-10-334809 JP 2006-169636 A JP 2006-207013 A JP 2006-54160 A WO2005 / 098890A

IDW '06, PDP2-4 2006, p359-362 IDW'08, PDP3-3 2008, p. 1869-1872

  However, it is difficult to say that countermeasures against discharge delay due to MgO as a protective layer are still sufficiently taken. Regarding the technique of adding an impurity element into MgO, in Patent Document 1, generation of erroneous discharge can be suppressed to some extent by adding Si to MgO, but it is insufficient in improving PDP characteristics. It is described in.

  Furthermore, the guaranteed operating temperature of the PDP has a temperature range of a minimum temperature of 0 ° C., more preferably −15 ° C., a maximum temperature of 60 ° C., more preferably 80 ° C., depending on the manufacturer. Therefore, the present inventors evaluated the discharge delay time in a wide temperature range of −10 ° C. to 60 ° C. As a result of studies on the technique of adding Si to MgO by the present inventors, it has been clarified that the discharge delay time is temperature-dependent and the discharge delay time increases in a low temperature region. Therefore, when the Si addition method to MgO is not appropriate, it is necessary to sufficiently lengthen the address period in order to perform stable address discharge in a wide temperature range, and it is necessary to secure a sustain period that is important in improving image quality. It becomes difficult.

As a result of evaluating the discharge delay time in a wide temperature range of −10 ° C. to 60 ° C. with respect to the technique of adding Sc to MgO, the inventors of the present invention have a temperature dependency, and particularly before the discharge delay measurement. last time from discharge to discharge delay measurements (hereinafter, rest referred to as period or t _i) it is long, when driving at a high temperature, that the discharge delay time increases are revealed. Therefore, as in the technique of adding Si to MgO, when the method of adding Sc to MgO is not appropriate, it is necessary to sufficiently lengthen the address period in order to perform stable address discharge in a wide temperature range.

  The techniques of Patent Documents 1 to 3 described above also show the concentration of the impurity element added to these MgO. However, as a result of studies by the present inventors, it has been found that the discharge delay time varies depending on the film forming conditions even at the same concentration. It can be seen that the film forming conditions greatly affect the activation rate of the impurity element in MgO, that is, the probability that the impurity element forms a priming electron emission source related to statistical delay in MgO.

  For this reason, it is necessary to add a large amount of impurity element to MgO in order to realize a desired discharge delay time under film formation conditions with a low activation rate. However, addition of a large amount of an impurity element to MgO causes defects, segregation, and cracks in MgO, and may adversely affect the crystal structure, sputtering resistance, electrical characteristics, and the like of MgO. Furthermore, the use of large amounts of impurity elements increases material costs associated with the impurity elements.

  Regarding the technique of providing a layer made of fine particles such as MgO crystal on the protective layer, Patent Document 4 shows that the discharge delay is improved by controlling the characteristics and particle size of the fine particles.

  However, in such a technique, in order to form a layer made of fine particles on the protective layer, it is necessary to add a complicated process in the manufacturing process of the PDP, and there are problems in terms of manufacturing cost including materials and yield. .

  Furthermore, as a result of the evaluation by the present inventors, the technique of providing a layer made of fine particles such as MgO crystals on the protective layer improves the discharge delay, but the xenon gas in the discharge gas is aimed at improving the light emission efficiency of the PDP. When the composition ratio is increased, the sputtering of MgO, which is a protective layer due to ion bombardment at the time of discharge, is promoted, and there are cases where the operation guarantee time (product life) of the PDP is shortened and the reliability related to each characteristic is remarkably lowered. It has also been clarified that the occurrence frequency of black noise and the appearance of non-lighting lines increases during high temperature operation of 20 ° C. or higher. The deterioration of the PDP characteristics during high-temperature operation occurs similarly to the technique of adding an impurity element in MgO if the concentration of the impurity element with respect to MgO is equal to or higher than a threshold value.

One of the causes, during the suspension period t _i from after the reset discharge ends until applies address voltage, the discharge space side surface of the dielectric layer and the phosphor layer covering the address electrodes (A electrodes) and scan electrodes ( The voltage difference between the dielectric layer covering the Y electrode) and the surface of the protective layer on the discharge space side (that is, the voltage applied to the discharge space between the A-Y electrodes) V _AY is considered to decrease. Non-Patent Document 1 and the like are reported. Hereinafter, the decrease of the voltage difference _{V AY} dormant period _{t i} referred to as voltage variation [Delta] V _AY.

As a factor of the voltage fluctuation ΔV _AY , it is considered that priming electrons emitted from the protective layer between the end of the reset discharge and the application of the address voltage cancel the wall charge on the discharge space side surface. According to Non-Patent Document 1, the voltage fluctuation [Delta] V _AY dormant by priming electrons period _{t i} is described as being 300~10000V / s.

This voltage variation ΔV _AY reduces the effective voltage applied to the discharge space when the address voltage is applied. For this reason, when a predetermined voltage is not applied to the discharge space, the address discharge fails and erroneous discharge is likely to occur.

Therefore, not only shorten the address discharge delay time t _d, it is necessary to suppress the protective layer technology voltage variation [Delta] V _AY dormant period t _i.

An object of the present invention, a wide and shortening the address discharge delay time t _d in the temperature range, by both inhibiting the decrease of the wall charges in the rest period t _i and voltage variations [Delta] V _AY, stable address discharge and high contrast It is to provide a protective layer technology that realizes a PDP.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  That is, a plasma display device according to a typical embodiment forms a discharge space by arranging a pair of substrates to face each other, a plurality of electrodes on one substrate, a dielectric layer on the electrode, and the dielectric layer A PDP filled with a discharge gas in the discharge space, a reset period for aligning the charged state of the entire display surface of the PDP, an address period for selecting a discharge cell for performing display discharge, and display discharge And a driving device that realizes a driving method including a sustain period for performing the above.

  Specifically, in the PDP, a space between the front plate and the back plate facing the PDP is partitioned by a partition provided on the back plate, and the space is filled with a discharge gas. The front plate includes a first substrate, a display electrode pair provided on the first substrate, a first dielectric layer covering the display electrode pair, and a protective layer on the first dielectric layer. Yes. The back plate includes a second substrate, an address electrode provided on the second substrate, a second dielectric layer covering the address electrode, and the partition provided on the second dielectric layer. And a phosphor layer in contact with the space and provided on the second dielectric layer.

Here, in order to solve the above-mentioned problem, the protective layer has an intrinsic depth of 400 to 1200 meV from the bottom of the conduction band (that is, an energy range of 400 to 1200 meV from the bottom of the conduction band to the valence band). The total number _Nee of the effective number of priming electron emission sources (hereinafter also simply referred to as effective number), which is a physical property value, is 1.1 × 10 ⁶ cells / cell or more and 8.1 × 10 ⁶ cells / cell or less (specifically, 1.1 × 10 ⁶ cells / cell to 5.4 × 10 ⁶ cells / cell or 1.4 × 10 ⁶ cells / cell to 8.1 × 10 ⁶ cells / cell) did.

  The priming electron emission source is formed by using MgO as a main component of the protective layer and adding an impurity element to the MgO. At least one of the impurity elements contained in the main component MgO is Sc. Here, the Sc concentration contained in MgO as a main component is 45 mass ppm or more and 735 mass ppm or less (specifically, 45 mass ppm or more and 520 mass ppm or less, or 55 mass ppm or more and 735 mass ppm or less). It is characterized by being.

  Further, the protective layer is formed by using MgO as a main component and adding an impurity element to the MgO. Here, the impurity element contained in the main component MgO is Si, aluminum (hereinafter referred to as Al), yttrium (hereinafter referred to as Y), cerium (hereinafter referred to as Ce), calcium (hereinafter referred to as “Al”). , Ca), lanthanum (hereinafter referred to as La), samarium (hereinafter referred to as Sm), tin (hereinafter referred to as Sn) and hydrogen (hereinafter referred to as H). It is characterized by being at least one element selected.

The protective layer may be formed by depositing a deposition source pellet to which the impurity element is added with a pressure gradient plasma gun (hereinafter also referred to as a plasma gun). Here, the vapor deposition is performed in an atmosphere containing water (H ₂ O). Further, the vapor deposition is performed in an atmosphere containing oxygen (O ₂ ).

  Further, the PDP is characterized in that the discharge gas is a gas containing Xe in an amount of a composition ratio of 8% or more. The composition ratio means that the discharge gas contains Xe gas, the molar concentration of the discharge gas is ng, the molar concentration of the Xe gas is nXg, the Xe molar concentration ratio in the discharge gas is aXe, and the Xe molar concentration ratio It is expressed as aXe = nXg / ng.

In the above problem, since the address discharge delay time t _d that is expressed by the sum of the statistical delay time t _s of the formation delay time t _f, the shortening of the address discharge delay time t _d to shorten the statistical delay time t _s It is realized with.

The statistical delay time t _s is the priming electron emission characteristics of the protective layer (hereinafter, also referred to as electron emission characteristic) because it is related to, the energy state density of the priming electron emission source in the protective layer in addition to measuring Can also be obtained.

Energy state density separates the statistical delay time t _s the address discharge delay time t _d, is determined by analyzing the measurement condition dependency of priming electron emission characteristics. The outline of the analysis system and the analysis method is as follows, and the analysis method is described in Non-Patent Document 2. Details will be described later.

(1) The measurement data of the address discharge delay time t _d with respect to the measurement conditions of the pause period t _i and the temperature T is input.

(2) Based on the measurement data for each pause period t _i and temperature T, the cumulative number for each address discharge delay time is calculated, and the discharge probability frequency and the already discharged probability are calculated.

(3) statistical delay time _{t s} when priming electrons of the electron emission related to constant _{t s} ^exp _(t i, T) is calculated.

  (4) A function of the energy state density of the electron emission source is set, and an average value, a dispersion value, and an effective number search range and search width of the activation energy with respect to the energy state density are set.

(5) The electron emission time constant t _s ^th (t _i , T) of the priming electrons is calculated by the overlap integral with respect to the energy state density of the electron emission source and the energy of the window function.

(6) Mean square of t _s ^exp (t _i , T) obtained from the measurement data and t _s ^th (t _i , T) obtained from the calculation with respect to the total number of measurement conditions of the suspension period t _i and the temperature T The average value, dispersion value, and effective number of activation energies that minimize the error are determined.

Thereby, the energy state density of one or a plurality of electron emission sources can be analyzed. Furthermore, the electron emission time constant t _s ^th (t _i , T) for each measurement condition can be calculated from the energy state density of the electron emission source from (5).

Voltage variation [Delta] V _AY between the rest period t _i is related to the priming electron emission amount N _em emitted from the protective layer. Priming amount of electrons emitted per unit time is given by the inverse of the discharge time constant t _s of priming electrons. With the temperature T of the PDP being constant, the priming electron emission amount N _em during the rest period t _i is

Given in. The electric charge Q _em to be emitted is expressed using the elementary quantity q.

Given in. Wall charges formed by reset discharge are emitted from the protective layer, assuming that the surface of the dielectric layer and phosphor layer on the A electrode side is positive and the surface of the dielectric layer and protective layer on the Y electrode side is negative. It is considered that the charge Q _em reaches the surface of the dielectric layer and the phosphor layer on the A electrode side. As a result, the wall charges on the surface of the dielectric layer and phosphor layer on the A electrode side are reduced by −Q _em , and the wall charge on the surface of the dielectric layer and protective layer on the Y electrode side is reduced by Q _em .

The capacitance of the A electrode side and the Y electrode side of one discharge cell C _A, when the C _Y, the voltage fluctuation [Delta] V _AY accompanying variation in the wall charges due to priming electron emission,

And is related to the priming electron emission amount N _em . Furthermore, if the voltage difference V _AY is large, the emitted priming electrons ionize the discharge gas in the discharge space, and secondary electrons are emitted from the protective layer to the discharge space, which may increase the voltage fluctuation ΔV _AY .

The priming electron emission amount N _em depends on the number of priming electron emission sources N _ee caused by the trap level in MgO. Since the trap level serving as the priming electron emission source can be formed by adding an impurity element into MgO, the priming electron emission amount N _em can be controlled by adjusting the effective number N _ee and the impurity concentration. In the conventional product MgO, when operated at a high temperature, the black noise due to the voltage fluctuation ΔV _AY is not practically problematic in the rest period t _i = 16 ms corresponding to 1 TV field. Therefore the upper limit of the priming electron emission amount _{N em} is normalized by the conventional product MgO for rest period _t i = voltage fluctuations in 16 ms [Delta] V _AY and priming electron emission _{N em,} voltage variation [Delta] V _AY of each condition 1 below Is the value.

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

That is, according to a typical embodiment, the effective number N _ee priming electron emission source disclosed in the present _application, by using a protective layer formed by _j in PDP, statistical delay time in a wide temperature range t _s In addition, by reducing the address discharge delay time t _d and suppressing the voltage fluctuation ΔV _AY during the pause period t _i , stable address discharge and high contrast can be realized in a high-definition PDP.

It is a disassembled perspective view which shows typically the principal part of AC surface discharge type PDP which the present inventors examined. It is sectional drawing of the xz plane of the discharge cell of FIG. It is sectional drawing of the yz plane of the discharge cell of FIG. It is explanatory drawing which shows the structure of the plasma display apparatus using PDP of FIG. FIG. 2 is a diagram for explaining a configuration of one field and subfield in ADS that is a gradation display method in the PDP of FIG. 1. FIG. 5 is a diagram for explaining a driving method for selecting a discharge cell and performing address discharge in the address period in FIG. 4. It is a figure which shows the voltage waveform used for the measurement of the address discharge delay time as a premise of this invention. It is a figure which shows the accumulated number with respect to the measurement data of the address discharge delay time examined as a premise of this invention, and the analysis method of the statistical delay time and formation delay time using the already-discharge probability. It is a block diagram which shows an example of the structure and procedure in the analysis system and analysis method of the electron emission characteristic used by this invention. FIG. 2 is a block diagram illustrating an example of a hardware configuration of an analysis system in an analysis system and an analysis method for electron emission characteristics used in the present invention. It is explanatory drawing of the electron emission time-constant analysis of the priming electron using the already discharge probability in the analysis system and analysis method of the electron emission characteristic used by this invention. It is a plot figure which shows the electron emission time constant of the priming electron calculated | required from the measurement data of the address discharge delay time examined as a premise of the present invention in the electron emission characteristic analysis system and analysis method used in the present invention. It is a figure which shows the energy in which the window function with respect to an idle period and temperature becomes the maximum in the analysis system and analysis method of the electron emission characteristic used by this invention. It is explanatory drawing of the energy overlap density of the energy state density of an electron emission source and a window function in the analysis system and analysis method of the electron emission characteristic used by this invention. It is a figure which shows the search range and search width | variety of the average value, dispersion value, and effective number of activation energy in the analysis system and analysis method of the electron emission characteristic used by this invention. In the electron emission characteristic analysis system and analysis method used in the present invention, in the electron emission characteristic analysis system and analysis method, the electron emission time constant and measurement data of the priming electrons obtained from the calculation (solid line) for the electron emission source It is explanatory drawing regarding the comparison of the electron emission time constant of the priming electron calculated | required from (plot). It is a figure which shows the energy state density of an electron emission source in the analysis system and analysis method of an electron emission characteristic in the analysis system and analysis method of an electron emission characteristic used by this invention. It is a block diagram which shows an example of the structure and procedure in the case where there are a plurality of types of electron emission sources in the electron emission characteristics analysis system and analysis method used in the present invention. FIG. 6 is a plot diagram showing electron emission time constants of priming electrons obtained from measurement data when there are a plurality of types of electron emission sources in the electron emission characteristic analysis system and analysis method used in the present invention. In the electron emission characteristic analysis system and analysis method used in the present invention, electrons of priming electrons obtained from calculation (solid line) with respect to the first type of electron emission source when a plurality of types of electron emission sources exist. It is a comparison figure of the electron emission time constant of the priming electron calculated | required from the emission time constant and measurement data (plot). It is a figure which shows the energy state density with respect to the 1st type electron emission source in the analysis system and analysis method of the electron emission characteristic used by this invention. In the electron emission characteristic analysis system and analysis method used in the present invention, the electron emission time constant and measurement data (plot) of the priming electrons obtained from the calculations (solid lines) for the first and second electron emission sources It is a figure regarding the comparison of the electron emission time constant of the priming electron calculated | required from FIG. It is a figure which shows the energy state density with respect to the 1st type and the 2nd type electron emission source in the analysis system and analysis method of the electron emission characteristic used by this invention. FIG. 4 is a plot diagram showing electron emission time constants of priming electrons obtained from measurement data of Embodiment 1 in the electron emission characteristic analysis system and analysis method used in the present invention. In the electron emission characteristic analysis system and analysis method used in the present invention, the electron emission time constant of priming electrons obtained from calculation (solid line) for the first type and second type electron emission sources in the first embodiment It is a figure regarding the comparison of the electron emission time constant of the priming electron calculated | required from measurement data (plot). In the electron emission characteristic analysis system and analysis method used in the present invention, it is a diagram showing the energy state density for the electron emission source of the first embodiment. It is a figure which shows the relationship between Sc density | concentration with respect to MgO in a protective layer, and the effective number of a priming electron emission source in the analysis system and analysis method of the electron emission characteristic used by this invention. 5 is a graph showing a range of the total effective number of priming electron emission sources capable of performing good address discharge in the plasma display device according to the first exemplary embodiment of the present invention. FIG. 6 is a plot diagram showing electron emission time constants of priming electrons obtained from measurement data of Embodiment 2 in the electron emission characteristic analysis system and analysis method used in the present invention. In the electron emission characteristic analysis system and analysis method used in the present invention, the electron emission time constant of the priming electrons obtained from the calculations (solid lines) for the first type and second type electron emission sources in the second embodiment It is a figure regarding the comparison of the electron emission time constant of the priming electron calculated | required from measurement data (plot). In the electron emission characteristic analysis system and analysis method used in the present invention, it is a diagram showing the energy state density for the electron emission source of the second embodiment. 6 is a graph showing the range of the total effective number of priming electron emission sources capable of performing good address discharge in the plasma display device according to the second embodiment of the present invention. 6 is a plot diagram showing electron emission time constants of priming electrons obtained from measurement data of Embodiment 3 in the electron emission characteristic analysis system and analysis method used in the present invention. FIG. In the electron emission characteristic analysis system and analysis method used in the present invention, the electron emission time constant of the priming electrons obtained from the calculation (solid line) for the first type and second type electron emission sources in the third embodiment It is a figure regarding the comparison of the electron emission time constant of the priming electron calculated | required from measurement data (plot). In the electron emission characteristic analysis system and analysis method used in the present invention, it is a diagram showing the energy state density for the electron emission source of the third embodiment. 10 is a graph showing a range of the total effective number of priming electron emission sources capable of performing good address discharge in the plasma display device of Embodiment 3 of the present invention. In the analysis system and analysis method for electron emission characteristics used in the present invention, it is a plot diagram showing the electron emission time constant of priming electrons determined from the measurement data in the PDP in which Si is added to MgO in the fourth embodiment. . In the electron emission characteristic analysis system and analysis method used in the present invention, calculation is performed for the first and second electron emission sources in the PDP in which Si is added to MgO of the fourth embodiment (solid line). It is a figure regarding the comparison of the electron emission time constant of the priming electron calculated | required from (1) and the electron emission time constant of the priming electron calculated | required from measurement data (plot). In the electron emission characteristic analysis system and analysis method used in the present invention, it is a diagram showing an energy state density for an electron emission source of a PDP in which Si is added to MgO of the fourth embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments, and the repetitive description thereof may be omitted.

<Basic form of implementation>
(PDP basic structure)
First, in order to facilitate understanding of the present invention, a basic structure of an AC surface discharge type PDP will be described as an example of a PDP studied by the present inventors. In this application, the “front plate” and the “back plate” of the two substrates constituting the PDP are the front plate, which is the display plate through which light emission from the phosphor passes when both are assembled into a panel. The direction which does not become a display surface is demonstrated as a backplate. In the present application, the “front plate” and the “back plate” will be described based on a front substrate and a back substrate each made of a glass substrate.

  FIG. 1 is an exploded perspective view schematically showing a main part of a so-called box-type AC surface discharge type PDP 15 examined by the present inventors. 2 is a cross-sectional view of the discharge cell CL of FIG. 1 in the xz plane after assembly. FIG. 3 is a cross-sectional view of the discharge cell CL of FIG.

  First, the front plate 12 and the formation method thereof will be described. A display electrode 6 composed of striped transparent electrodes 4a and 5a and bus electrodes 4b and 5b is disposed on the front substrate 1, and the display electrode 6 is a sustain electrode (X electrode) 4 and a scan electrode (Y electrode). It consists of 5 pairs. The transparent electrodes 4a and 5a are formed of a film made of indium tin oxide (ITO) which is a transparent conductor, and bus electrodes 4b and 5b made of a single silver film are provided on the transparent electrodes 4a and 5a with a narrower width than the transparent electrodes 4a and 5a. Has been. The transparent electrodes 4a and 5a may be formed of tin oxide, zinc oxide or the like, and the bus electrodes 4b and 5b may be formed of a single layer film of aluminum or a laminated film of chromium / copper / chromium.

  The transparent electrodes 4 a and 5 a and the bus electrodes 4 b and 5 b constituting the display electrode 6 are covered with the dielectric layer 2. The dielectric layer 2 is formed of a dielectric glass film. Then, the protective layer 3 is formed on the surface of the dielectric layer 2. Details of the protective layer 3 will be described in each embodiment.

  Next, the back plate 13 and its forming method will be described. Striped address electrodes (A electrodes) 10 orthogonal to the display electrodes 6 are disposed on the back substrate 11. The back substrate 11 is a glass substrate, and the address electrode (A electrode) 10 is formed of a single layer film of aluminum or a laminated film of chromium / copper / chromium.

The address electrode (A electrode) 10 is covered with a dielectric layer 9, on which a partition wall 7 is formed for maintaining a discharge distance and preventing crosstalk between adjacent cells. The dielectric layer 9 is formed of a dielectric glass film. The partition wall 7 is disposed in parallel with the display electrode 6 and the address electrode (A electrode) 10 of the front plate 12, and the address electrode (A electrode) 10 is located between the partition walls 7. A region (space) surrounded by each partition wall 7 facing the display electrode 6 is a discharge space 14, and a phosphor layer 8 is formed on the dielectric layer 9 so as to be in contact with the discharge space 14. The phosphor layer 8 is formed of (Y, Gd) BO ₄ : Eu ²⁺ in red, BaMgAl ₁₀ O ₁₇ : Eu ²⁺ in blue, and Zn ₂ SiO ₄ : Mn ²⁺ in green.

  The front plate 12 and the back plate 13 are arranged opposite to each other so that the display electrode 6 and the address electrode (A electrode) 10 are orthogonal to each other, and the non-display areas of both plates are sealed with a sealing agent. Thereby, the discharge space 14 isolated from the outside air is formed. The discharge space 14 is filled with a mixed gas having neon (Ne) -xenon (Xe) as a discharge gas as a gas base at a predetermined pressure and partial pressure. The discharge gas in the present invention is a gas that has a total pressure of 450 Torr and contains Xe in such an amount that the composition ratio is 8% or more.

(PDP device)
FIG. 4 is an explanatory diagram showing a configuration of a plasma display device (hereinafter also referred to as a PDP device) 20 including the PDP 15. The plasma display apparatus 20 includes an address electrode (A electrode) 10, a scan electrode (Y electrode) 5, a PDP 15 having a sustain electrode (X electrode) 4, and an address drive circuit 21 for driving the address electrode (A electrode) 10. A scan pulse output circuit 22 for driving the scan electrode (Y electrode) 5, a sustain pulse output circuit 23 for driving the sustain electrode (X electrode) 4, and a drive control circuit for controlling these output circuits 24, a signal processing circuit 25 for processing an input signal, a driving power source 26 for applying a voltage to the PDP 15 and the like, and a driving device including a video source 27 for generating a video signal.

  In the plasma display device 20, after the PDP 15 is completed, the electrodes of the PDP 15 and the flexible substrate are joined by an anisotropic conductive film. Thereafter, in order to prevent deformation of the PDP 15 and improve heat dissipation, for example, a plate made of aluminum or the like is attached. On the plate, a driving device such as a drive power source 26 or an address drive circuit 21 is incorporated, and the plasma display module is mounted. Complete. Thereafter, the plasma display device 20 is completed by performing further inspection and attaching an exterior case.

(PDP driving method)
A case where ADS (Address Display-Period Separation) is applied to the PDP 15 as an image gradation display method will be described. FIG. 5 is a diagram for explaining the configuration of 1 TV field and subfield in ADS which is a gradation display method. FIG. 6 is a diagram for explaining a driving method in which discharge cells are selected and address discharge is performed in the address period shown in FIG. Note that GND in FIG. 6 is a reference voltage (reference potential).

  As shown in FIG. 5I, one field (1/60 s≈16.67 ms) is divided into a plurality of subfields having a predetermined luminance ratio. These subfields are selectively made to emit light according to the image, and the gradation is expressed by the difference in luminance. Each subfield basically includes a reset period, an address period, and a sustain period shown in FIG.

  In the reset period, a voltage equal to or higher than the discharge start voltage is applied between the display electrodes, and reset discharge occurs in all the discharge cells. Thereby, the wall voltage in all the discharge cells, that is, the charged state can be made substantially uniform.

In the address period, a voltage is applied to the address electrode (A electrode) and the scan electrode (Y electrode) of the discharge cell selected based on the image data. FIG. 5 shows three consecutive scan electrodes (Y electrodes). When (Y _i electrode) and (Y _{i + 2} electrode) are selected, and (Y _{i + 1} electrode) is not selected, the voltage applied to each electrode It is a waveform. The address voltage of voltage Va is applied to the address electrode (A electrode) in synchronization with the application of the scan pulse of −Vy to the (Y _i electrode) and (Y _{i + 2} electrode) of the selected discharge cell. Address discharge (selective discharge) occurs. In the selected discharge cell in which the address discharge has occurred, wall charges necessary for performing the sustain discharge (display discharge) performed in the sustain period are formed. On the other hand, in the (Y _{i + 1} electrode) of the discharge cell that is not selected, no address discharge occurs because the address voltage is not applied to the address electrode (A electrode) when the scan pulse of −Vy is applied. As a result, wall charges necessary for display discharge are not formed, and no sustain discharge occurs during the sustain period. When the address period of each subfield is constant regardless of the number of display electrode pairs, the width of the scan pulse becomes shorter as the number of display electrode pairs increases. Therefore, the address delay time t _d that is acceptable according to the display electrode pairs are different.

In the sustain period, sustain pulses are alternately applied to the sustain electrode (X electrode) and the scan electrode (Y electrode), and a sustain discharge occurs in the selected discharge cell. For example, when eight subfields having luminance weights based on the binary system are provided, red (R), green (G), and blue (B) discharge cells each have 2 ⁸ (= 256) gradations. Luminance display is obtained, and color display of about 16.78 million colors is possible.

  Next, the address discharge delay time measuring method and analysis method that the present inventors have reached the present invention will be described.

(Address discharge delay time measurement method)
The address discharge delay time _{t d} with measured driving waveform shown in FIG. 7, for measuring the tube surface temperature T of the PDP as -10 to 60 ° C.. The repetition period of this measurement drive waveform is 100 ms. The width of each pulse in the reset discharge period and the preliminary discharge period is 30 μs.

In the reset discharge period, a reset discharge is generated between the sustain electrode (X electrode) and the scan electrode (Y electrode) constituting the display electrode pair, and the wall voltage in the discharge cell, that is, the charged state is made substantially uniform. This eliminates the effects of previous discharges. In the preliminary discharge period, in order to select a discharge cell to be measured, a voltage is applied to the address electrode (A electrode) and then a voltage is applied to the sustain electrode (X electrode) and the scan electrode (Y electrode). ) And the scan electrode (Y electrode) are discharged four times. At this time, the voltage applied to the sustain electrode (X electrode) and the scan electrode (Y electrode) thereafter is a voltage value at which stable discharge occurs in the discharge cell measured in the preliminary discharge period. Once the sustain electrode during the start idle period and (X electrode) to generate a discharge between the scan electrodes (Y electrodes), after the lapse of the dead time t _i of 10μs~50ms while applying a voltage, the address electrodes in the address discharge period A voltage is applied to (A electrode), and the time from when the voltage is applied until when the discharge is actually started is measured 1000 times. The voltage applied to the address electrode (A electrode) during this address discharge period is a voltage value at which stable discharge occurs in the measurement cell.

  In this measurement drive waveform, the protective layer is excited by each discharge, whereby electrons are trapped in the trap level, and a part of these electrons are emitted as priming electrons to the discharge space.

(analysis method)
The address discharge delay time t _d, Y electrodes, X and A electrodes forming the delay time t _f that depends on the residual wall charges after the applied voltage and the reset _discharge, as well as priming electrons from the protective layer serving as the discharge of the pilot light consisting of the sum of the statistical delay time t _s until it is released.

Because the priming electrons are emitted into the discharge space from the protective layer is a statistical phenomenon, the fluctuation occurs in the statistical delay time t _s. 8, the measurement data measured repeatedly address discharge delay time t _d in the same discharge cell, which is an example of a frequency distribution of the discharge delay time is displayed in the address discharge delay time t _d cumulative number for each (2001). Reference numeral 2002 denotes the already discharged probability G. Regardless of the same discharge cell, the peak is about 500 ns, 400 ns when the discharge time is early, and 1000 ns or more when the discharge time is slow, indicating an asymmetric shape. Calculated by the repeated following method using the measurement data measured by analyzing the priming electron emission characteristics of the protective layer related to the statistical delay time t _s, release time constants ^{_{t s th (t i, T}} ) priming electrons To do.

  FIG. 9 is a block diagram showing an example of the configuration and procedure in the priming electron emission characteristic analysis system and analysis method, and FIG. 10 is a block diagram showing an example of the hardware configuration of the analysis system.

  First, the configuration of the priming electron emission characteristic analysis system used in the present invention will be described with reference to FIGS. The analysis system used in the present invention is an analysis system for electron emission characteristics with respect to the electron emission source in the protective layer, and includes a personal computer 2200, a calculation device 102, and the like. The personal computer 2200 includes an input device 101 including a storage device, an output device 103 including an image processing device, and the like. The computing device 102 includes a CPU device 2201 and a storage device 2202, and the CPU device 2201 and the storage device 2202 are connected by a data transfer coupling bus 2204.

  In FIG. 10, a plurality of computing devices 102 are connected in a matrix by a data transfer coupling bus 2205. However, the present invention is not limited to this, and the number of computing devices 102 may be one. Alternatively, it may be provided in the personal computer 2200.

  Next, an example of the operation of the electron emission characteristic analysis system used in the present invention will be described with reference to FIGS. In the calculation device 102, an analysis program for electron emission characteristics is stored (held) in the storage device 2202, and the CPU device 2201 reads out the program and performs arithmetic processing according to an instruction from the personal computer 2200. The result of the arithmetic processing is stored in the storage device 2202. Data necessary for arithmetic processing is transmitted from the personal computer 2200 via the data transfer coupling bus 2205. The result of the arithmetic processing in the computing device 102 is transmitted to the personal computer 2200 via the data transfer coupling bus 2205. In the personal computer 2200, data necessary for the arithmetic processing is input from the input device 101, and the result of the arithmetic processing is output / displayed by the output device 103.

  As shown in FIG. 9, the arithmetic processing in the computing device 102 is executed according to the following procedure.

First, in step S102-1, measurement data of an address discharge delay time t _d with respect to a pause period t _i from the sustain voltage application to the address voltage application and the MgO temperature T measured from the PDP is measured from the input device 101. Input to the computing device 102. The MgO temperature T is the panel surface temperature.

Next, in step S102-2, the calculation device 102 calculates the cumulative number for each address discharge delay time based on the measurement data for each pause period t _i and the MgO temperature T, and the discharge probability frequency P (t ) Is calculated.

  FIG. 11 shows a discharge probability frequency P (t) 201 in which the maximum value of the discharge probability frequency is normalized to 1. The discharge probability frequency P (t) is a Gaussian function type on the short time side, but has an asymmetric shape with a tail on the long time side. The discharge probability G (t) is calculated using the discharge probability frequency P (t) and the equation (1). FIG. 11 shows the already discharged probability G (t) 202. The already discharged probability G (t) shows a convex shape from convex downward to upward and has a gentle slope on the long time side.

In step S102-3, in order to remove the fluctuation of the formation delay time t _f and obtain the electron emission time constant t _s ^exp of the priming electrons,

The already discharged probability G (t) and its time t in a long time region satisfying the above are used. Here, t _f ^ave is an average value of the formation delay time t _f , and σ _tf is a variance value of the formation delay time t _f . The average value t _f ^ave of the formation delay time and the dispersion value σ _tf of the formation delay time are the average of the address discharge delay time with respect to the measurement data of the short pause period t _i in which the priming electrons exist when the address voltage is applied. It can be obtained from the value and the variance value. As shown in FIG.

Of t _a satisfying long region 203, t _b, with its already-discharge probability G (t _a) G (t _b), and, using equation (2), a constant _{t s} ^exp priming electrons of the electron emission calculate.

For example, in the measurement data of the address discharge delay time for a short rest period of t _i = 0.1 ms and T = 25 ° C., the average value of the address discharge delay time t _f ^ave = 0.59 μs and the variance value σ _tf = 0.09 μs. It is. Then, the time t _63.2 and t _{95 at which} the measured discharge probability G (t) at the measurement target condition t _i = 50 ms and T = 25 ° C. becomes 63.2% and 95% are 0.84 μs and 1.45 μs, respectively. It is. The t _s ^exp (t _i = 50 ms, T = 25 ° C.) obtained using equation (3) is 0.31 μs. Therefore,

Is 0.71 μs,

It can be seen that the long-time region condition is satisfied.

Similarly, in FIG. 12, t _i = 1 ms, 10 ms, 50 ms and T = −10 ° C. (263.15 K), 10 ° C. (283.15 K), 25 ° C. (298.15 K), 60 ° C. (333.30). The electron emission time constant t _s ^exp of the priming electrons obtained from the measurement data for 12 measurement conditions (15K) is shown by a plot 301. In this way, the electron emission time constant t _s ^exp at the pause period t _i and the temperature T of MgO can be obtained.

Next, a method for analyzing the energy state density D _j (E) of the electron emission source type j will be described. The electron emission time constant t _s ^th obtained from the calculation is related to the energy state density D _j (E) by the equations (4) and (5).

Here, E is the energy depth of the priming electron emission source (hereinafter also referred to as energy), f _ph is the phonon frequency of the electron emission source, and k _B is the Boltzmann constant. In addition, W _j (E, t _i , T) is equal to the measurement condition of the rest period t _i and the temperature T of MgO.

Is a window function having a maximum value e ⁻¹ t _i ⁻¹ and an energy width ± several k _B T. As a measurement condition, in the measurement in which the pause period t _i is constant and the temperature T of MgO is changed, the window function is such that the energy E _m (t _i , T) changes with the maximum value e ⁻¹ t _i ⁻¹ being constant. . On the other hand, in the measurement in which the temperature T of MgO is constant and the pause period t _i is changed, the maximum value e ⁻¹ t _i ⁻¹ changes while E _m (t _i , T) changes.

FIG. 13 shows the rest periods t _i = 0.01 ms, 0.1 ms, 1 ms, 10 ms, 100 ms, 1000 ms and the MgO temperatures T = −10 ° C. (263.15 K), 0 ° C. (273.15 K), 10 ° C. 283.15K), energy that maximizes the window function at 25 ° C (298.15K), 40 ° C (313.15K), and 60 ° C (333.15K)

showed that. Here, the phonon frequency f _ph of the electron emission source was 3.1 × 10 ¹³ Hz. In the rest period t _i = 0.01 ms and the MgO temperature T = −10 ° C., the energy at which the window function is maximized is 443 meV. In the rest period t _i = 1000 ms and the MgO temperature T = 60 ° C., the energy at which the window function is maximized represents 892 meV.

As shown in FIG. 14, the reciprocal of the electron emission time constant t _s ^th is the window function W _j (E, t _i , T determined by the energy state density D _j (E) 401 of the unknown electron emission source and the measurement conditions. It can be seen that the overlap integral for the energy of 402) is calculated and is equivalent to taking the sum for all electron emission source types j.

In step S102-4, when the Gaussian function of Equation (6) is set as the energy state density D _j (E) of the electron emission source, according to the conditions of FIG. , Effective number N _{ee, j} , activation energy average value ΔE _{a, j} , and activation energy variance σ _{E, j} . At this time, the search range, search width, and number to be input to search for these parameter values will be described.

With respect to the measurement conditions t _i = 1 ms, 10 ms, 50 ms, T = −10 ° C., 10 ° C., 25 ° C., and 60 ° C., the energy at which the window function is maximized is in the range of 526 meV to 778 meV. Since the energy width 3k _B T of the window function is about 75 meV, the energy region is 451 meV to 853 meV. Therefore, as the search range of the average activation energy ΔE _{a, j} , the minimum value of E _m (t _i , T) determined by the measurement condition from −3 k _B T to the maximum value of E _m (t _i , T) +3 k _It was set to 400 meV to 900 meV including BT. The energy interval of E _m (t _i , T) determined by the measurement conditions is 10.1 meV for the minimum interval, 52.2 meV for the maximum interval, and 31.5 meV for the average interval, so that the experimental accuracy is about 30 meV at most. . Therefore, the energy search width of the activation energy average value ΔE _{a, j} and the activation energy dispersion value σ _{E, j} is set to 10 meV which is equal to or less than the average value of the energy intervals of E _m (t _i , T). Further, since the effective number N _{ee, j} has a time order width of the measurement condition t _i of about two digits, the effective number search range is set to two digits that are the time order width of 1 × 10 ⁵ pieces / cell to 1 ×. 10 ⁷ cells / cell. Therefore, search points for the effective number N _{ee, j} are 1 × 10 ⁵ cells / cell, 1.1 × 10 ⁵ cells / cell, 2 × 10 ⁵ cells / cell, 2.1 × 10 ⁵ cells / cell, 1 × 10 ⁶ pieces / cell, 1.1 × 10 ⁶ pieces / cell, 2 × 10 ⁶ pieces / cell, 2.1 × 10 ⁶ pieces / cell, and 1 × 10 ⁷ pieces / cell were set to 201 pieces. From the above, the search range for the average activation energy value ΔE _{a, j} is 51 search points obtained by discretizing 400 meV to 900 meV with a width of 10 meV, and the search range for the activation energy variance σ _{E, j} is 5 to 100 meV. The search range for the effective number N _{ee, j} is composed of 201 search points discretized from 1 × 10 ⁵ cells / cell to 1 × 10 ⁷ cells / cell. The search range and the search width, and about 1 × 10 ⁵ parameter values as all combinations are input.

In step S102-5, equation (6) in which each parameter value of activation energy average value ΔE _{a, j} , activation energy variance σ _{E, j,} and effective number N _{ee, j} is set is expressed by equation (4). And the overlap integral for the energy of the electron emission source energy state density D _j (E) and the window function W _j (E, t _i , T) is calculated, and t _s ^th (t _i , T) is calculated from the reciprocal thereof. Can be requested. Here, the phonon frequency f _{ph, j} of one electron emission source type _j was set to 1.19 × 10 ¹³ Hz.

In step S102-6, t _s ^exp (t _i , T) obtained from the measurement data represented by Expression (7) for the total number N = 12 of the measurement conditions of the rest period t _i and the temperature T of MgO. The average value ΔE _{a, j of} the activation energy that minimizes the mean square error RMSD of t _s ^th (t _i , T) obtained from the calculation, the dispersion value σ _{E, j of} the activation energy, the effective number N _{ee, Find j} .

Σ _{N = 12} {t _s ^exp (t _i , T) −t _s ^th (t _i , T)} ² (7)
16, measurement data _t was determined from _s ^exp _(t i, _T) plot 301, shown was determined from the calculated ^{_{t s th (t i, T}} ) and a solid line 501. Both are in very good agreement. As a result, the mean square error RMSD has a minimum value of 165 ns, the average value of activation energy ΔE _{a, j} = 760 meV, the dispersion value of activation energy σ _{E, j} = 55 meV, and the effective number N _{ee, j} = 1. It was determined to be 3 × 10 ⁶ cells / cell.

In this way, as shown in FIG. 17, as the energy state density D _j (E) 601 of the unknown electron emission source, the activation energy average value ΔE _{a, j} = 760 meV, the activation energy dispersion value σ _{E , J} = 55 meV, effective number N _{ee, j} = 1.3 × 10 ⁶ cells / cell are output and displayed from the output device 103.

  Next, with reference to FIGS. 9 and 10, an analysis system and an analysis method when a plurality of electron emission sources are considered to exist in the protective layer will be described. FIG. 18 is a block diagram showing an example of the configuration and procedure in the electron emission characteristic analysis system and analysis method at this time. However, the hardware configuration of the electron emission characteristic analysis system and the operation example thereof are the same as those of the single electron emission source analysis system shown in FIG.

  As shown in FIG. 18, the calculation process in the calculation apparatus 102 by the analysis system of a plurality of electron emission sources is executed in the following procedure.

Steps S102-1 to S102-3 are the same as those in the first embodiment. In step S102-1, measured against the PDP, and inputs from the input device 101 the measured data of the address discharge delay time _{t d} with respect to the temperature T of the rest period _{t i} and MgO to the computing device 102. In step S102-2, based on the measurement data for each idle period _{t i} and MgO temperature T, it calculates the cumulative number of each address discharge delay time, discharge probability frequency P (t) and the previously discharge probability G (t) Is calculated. In step S102-3,

The electron emission time constant t _s ^exp of priming electrons is calculated using t _a , t _b satisfying the long-time region, the already discharged probabilities G (t _a ) and G (t _b ), and equation (3). To do.

FIG. 19 shows priming electrons obtained from measurement data for 18 measurement conditions at measurement conditions t _i = 1 ms, 10 ms, 50 ms, T = −10 ° C., 0 ° C., 10 ° C., 25 ° C., 40 ° C., 60 ° C. The electron emission time constant t _s ^exp is shown by a plot 801.

In step S102-4, when the Gaussian function of Equation (7) is set as the energy state density D ₁ (E) of the first type electron emission source, the effective number N _{ee, 1 is} activated according to FIG. An average value ΔE _{a, 1} of energy and a dispersion value σ _{E, 1} of activation energy are obtained. At this time, the search range, the search width, and the number to be input in order to search for these parameter values will be described.

For the measurement conditions t _i = 1 ms, 10 ms, 50 ms, T = −10 ° C., 0 ° C., 10 ° C., 25 ° C., 40 ° C., 60 ° C., the energy range of the window function is in the range of 451 meV to 853 meV. Similar to the single electron emission source _, the search range of the average activation energy ΔE _{a, 1} was set to 400 meV to 900 meV. The energy interval of E _m (t _i , T) determined by the measurement conditions is 0.5 meV for the minimum interval, 46.2 meV for the maximum interval, and 14.8 meV for the average interval, so the experimental accuracy is about 10 meV at most. . Therefore, the search range of the energy of the activation energy average value ΔE _{a, j} and the activation energy dispersion value σ _{E, j} is set to 5 meV which is equal to or less than the average value of the energy interval of E _m (t _i , T).

Next, since the effective number N _{ee, 1} has a time order width of the measurement condition of about two digits, the effective number search range is set to two digits that are the time order width of 1 × 10 ⁵ pieces / cell to 1 × 10. ⁷ pieces / cell was discretized to 201 pieces. From the above, the search range for the average activation energy ΔE _{a, 1} is 101 search points obtained by discretizing 400 meV to 900 meV with a width of 5 meV, and the search range for the activation energy variance σ _{E, 1} is 5 to 100 meV. The search range for effective number N _{ee, 1} is composed of 201 search points discretized from 1 × 10 ⁵ cells / cell to 1 × 10 ⁷ cells / cell. The search range and the search width, and about 4.1 × 10 ⁵ parameter values are inputted as all combinations.

In step S102-5, equation (8) in which each parameter value of activation energy average value ΔE _{a, 1} , activation energy variance σ _{E, 1} and effective number N _{ee, 1} is set is expressed by equation (4). And the overlap integral for the energy of the energy state density D ₁ (E) and the window function W ₁ (E, t _i , T) of the electron emission source is calculated, and t _{1, s} ^th (t _i , T) can be determined. Here, the phonon frequency of the first type electron emission source was set to 1.19 × 10 ¹³ Hz.

In step S102-6, based on the total number N = 18 of the measurement conditions of the rest period _{t i} and the temperature T of ^{_{MgO, t s exp (t i}} , T) obtained from the measurement data represented by the formula (9) and The average value ΔE _{a, 1} of activation energy that minimizes the mean square error RMSD of t _{1, s} ^th (t _i , T) obtained from the calculation, the dispersion value σ _{E, 1 of} the activation energy _, and the effective number N _{ee , 1} .

^{_{Σ N = 18 {t s exp}} (t i, T) -t 1, s th (t i, T)} 2 (9)
In FIG. 20, t _s ^exo (t _i , T) obtained from the measurement data is indicated by a plot 801, and t _{1, s} ^th (t _i , T) obtained from the calculation is indicated by a solid line 901. Both show a relatively good agreement. As a result, the mean square error RMSD is the minimum value 115 ns, the activation energy average value ΔE _{a, 1} = 780 meV, the activation energy dispersion value σ _{E, 1} = 95 meV, and the effective number N _{ee, 1} = 1. It was determined to be 0 × 10 ⁶ cells / cell.

In this way, as shown in FIG. 21, with respect to the solid line 1001 of the energy state density D ₁ (E) of the first type electron emission source, the activation energy average value ΔE _{a, 1} = 780 meV, activation The energy dispersion value σ _{E, 1} = 95 meV, effective number N _{ee, 1} = 1.0 × 10 ⁶ cells / cell is output and displayed from the output device 103.

Next, when it is considered that a new electron emission source exists, the process returns to step S102-4 according to step S102-7 shown in FIG. 18, and the energy state density D ₂ (E) of the second type electron emission source is obtained. When the Gaussian function of Equation (10) is set, the effective number N _{ee, 2} , the activation energy average value ΔE _{a, 2} , and the activation energy variance σ _{E, 2} are obtained according to FIG. At this time, the search range, search width, and number to be input to search for these parameter values will be described.

For the measurement conditions t _i = 1 ms, 10 ms, 50 ms, T = −10 ° C., 0 ° C., 10 ° C., 25 ° C., 40 ° C., 60 ° C., as described for the first type electron emission source, The search range for the average activation energy ΔE _{a, 2} is 101 search points obtained by discretizing 400 meV to 900 meV with a width of 5 meV, and the search range for the activation energy variance σ _{E, 2} is 5 to 100 meV with a width of 5 meV. The search range for the 20 search points discretized by 1 and the effective number N _{ee, 2} is composed of 201 search points discretized from 1 × 10 ⁵ cells / cell to 1 × 10 ⁷ cells / cell. The search width and about 4.1 × 10 ⁵ parameter values are inputted as all combinations.

In step S102-5, equation (10) in which each parameter value of activation energy average value ΔE _{a, 2} , activation energy dispersion value σ _{E, 2} and effective number N _{ee, 2} is set is expressed by equation (4). And the overlap integral for the energy of the energy state density D ₂ (E) and the window function W ₂ (E, t _i , T) of the electron emission source is calculated, and t _{2 s} ^th (t _i , T) can be determined. Here, the phonon frequency of the second type electron emission source was set to 3.1 × 10 ¹³ Hz.

In step S102-6, t _s ^exp (t _i , T) obtained from the measurement data represented by the expression (11) for the total number N = 18 of the measurement conditions of the pause period t _i and the temperature T of MgO. And the average value ΔE _{a, 2} , of activation energy that minimizes the mean square error RMSD for the sum of t _{1, s} ^th (t _i , T) and t _{2, s} ^th (t _i , T) obtained from The dispersion value σ _{E, 2 of} the activation energy and the effective number N _{ee, 2} are obtained.

^{_{Σ N = 18 {t s exp}} (t i, T) -t 1, s th (t i, T) -t 2, s th (t i, T)} 2 (11)
In FIG. 22, t _s ^exp (t _i , T) obtained from the measurement data is plotted 801, and t _s ^th (t _i , T) obtained from calculation = t _{2, s} ^th (t _i , T) + t _{2, s} ^th (t _i , T) is indicated by a solid line 1001. Both are in very good agreement. As a result, the mean square error RMSD is reduced to the minimum value 95 ns, the activation energy average value ΔE _{a, 2} = 500 meV, the activation energy variance σ _{E, 2} = 20 meV, and the effective number N _{ee, 2.} = 2.0 × 10 ⁵ cells / cell.

In this way, as shown in FIG. 23, activation is performed for the solid line 1001 of the energy state density D ₁ (E) and the solid line 1201 of D ₂ (E) of the first type and second type electron emission sources. Energy average value ΔE _{a, 1} = 780 meV, activation energy variance σ _{E, 1} = 95 meV, effective number N _{ee, 1} = 1.0 × 10 ⁶ cells / cell, and activation energy average value ΔE _The output device 103 outputs and displays _{a, 2} = 500 meV, activation energy variance σ _{E, 2} = 20 meV, effective number N _{ee, 2} = 2.0 × 10 ⁵ cells / cell.

Further, when there is an electron emission source, similarly to the second type electron emission source, the process returns to step S102-4 according to step S102-7 shown in FIG. 18, and the energy state of the nth type electron emission source. When the Gaussian function of Expression (8) is set as the density D _n (E), the effective number N _{ee, n} , the average value of activation energy ΔE _{a, n} , and the dispersion value σ of activation energy are obtained according to FIG. _{E and n} are obtained.

  Each embodiment will be specifically described below based on the basic embodiment.

<Embodiment 1>
The PDP according to the first embodiment of the present invention will be described. In the first embodiment, an HD PDP having a panel size of 50 inches and a display pixel number of 1280 × 1080 is considered. The discharge gas filled in the PDP according to the first embodiment is a gas having a total pressure of 450 Torr and containing Xe in an amount that provides a composition ratio of 18%. The PDP driving method of the first embodiment corresponds to the ADS in FIG. 5, and the address period determined by the address pulse width and the number of scan lines is also within 1 ms.

In the PDP of the first embodiment, the number of reset discharges is reduced to improve contrast, and when the discharge cells display black, the number of reset discharges is once every 2 TV fields (1/60 s). That is, rest period _{t i} in the first embodiment is within 33.3ms at most.

  The main component of the protective layer 3 of the first embodiment is MgO, and contains a predetermined amount of Sc. In the first embodiment, the protective layer 3 is formed by a normal electron beam evaporation method. At this time, vapor deposition is performed in an oxygen atmosphere in order to control film quality such as crystallinity. By these film forming methods, the protective layer 3 is formed to a thickness of 300 nm to 1000 nm at a film forming speed of 5 to 6 Å / s.

  For the vapor deposition source, use is made of powdered MgO mixed with a Sc compound and formed into a pellet, or mixed with pelletized MgO and a pelleted Sc compound, or formed into these pellets. The sintered body is used. The Sc concentration in this vapor deposition source is 5 mass ppm or more and 5000 mass ppm or less with respect to MgO.

  The thickness of the protective layer 3 is 700 nm, and the Sc concentration in the protective layer is 60 ppm by mass. However, the film thickness is not limited to this, and any film having a function as a protective layer may be used. The thickness of the protective layer is not limited to that described in the first embodiment, and the protective layer may be 500 nm or more and 2000 nm or less. In the case of the above-described film thickness range, the influence of the underlayer such as the dielectric layer 4 and the influence of the film stress generated in the protective layer 5 are small. If the thickness is less than 500 nm, the sputtering resistance is insufficient, so that a good discharge response cannot be obtained when driven for a long time. On the other hand, when the thickness exceeds 2000 nm, a columnar crystal structure of MgO grows and a gap is formed between the structures, which may cause problems such as generation of cracks and adsorption of impurity gases.

FIG. 24 shows the measurement data of the statistical delay of the PDP of the first embodiment that satisfies the equation (2), that is, the electron emission time constant t _s ^exp (t _i , T) satisfying the equation (2) from the address discharge delay time measurement method. .

Figure 25 is the measurement data of t _s ^exp of the first embodiment, the protective layer 3 of the first embodiment with two types of electron-emitting source, phonon frequency f _ph, for _j first electron emission sources ( j = 1) a 1.26 × ¹⁰ 13 Hz, the second electron emission sources (j = 2) were analyzed as 1.2 × ¹⁰ 13 Hz and the obtained ^{_{t s th (t i, T}} ) and the solid line Is shown. From FIG. 25, both show a very good match.

In this way, as shown in FIG. 26, the first and second types of electron emission sources have an energy state density D ₁ (E) of solid line 501 and D ₂ (E) of solid line 502. The activation energy average value ΔE _{a, 1} = 645 meV, activation energy dispersion value σ _{E, 1} = 20 meV, effective number of priming electron emission sources N _{ee, 1} = 6.0 × 10 ⁴ / Cell, the second electron emission source is the average activation energy ΔE _{a, 2} = 875 meV, the activation energy dispersion σ _{E, 2} = 95 meV, the effective number of priming electron emission sources N _{ee, 2} = 4. 5 × 10 ⁵ cells / cell.

  As shown in FIG. 26, Sc forms a priming electron emission source in MgO as a protective layer at a depth that can be thermally excited in an energy range 503 corresponding to a practical operating condition of 500 to 900 meV from the bottom of the conduction band.

_{N ee} of the total number of the effective number of priming electron emission source present from the conduction band bottom in the protective layer to a depth of 400~1200meV is 5.1 × 10 ⁵ cells / cell. In the first embodiment, a 50-inch HD PDP having a display pixel number of 1280 × 1080 is studied, and the area of the discharge layer in contact with the discharge space of the protective layer excluding the intersection with the barrier rib is 1.3 ×. 10 ⁻⁷ m ² , and the total effective number N _ee per unit area is 4.0 × 10 ¹² / m ² . Furthermore, since the thickness of the protective layer is 700 nm, the total effective number N _ee per unit volume is 5.7 × 10 ¹⁸ pieces / m ³ .

As shown in FIG. 27, the Sc concentration with respect to MgO which is the main component of the protective layer and the effective number N _{ee, j} of the priming electron emission source are concentration dependent. This relationship is such that the effective number _{Nee, j of the} priming electron emission source increases as the Sc concentration increases, including the origin. Therefore, the effective number N _{ee, j} of the priming electron emission source and the total effective number N _ee can be adjusted by controlling the film quality such as the Sc concentration in the protective layer, for example.

FIG. 28 shows the priming electron emission source in the protective layer capable of performing good address discharge when the PDP device using the PDP of the first embodiment is in the operation guaranteed temperature range of −20 to 60 ° C. The range of the total effective number _Nee is shown. Incidentally, the effective number of the total number N _ee of priming electron emission source at this time is a value determined according to the experimental methods and analysis method shown in the basic form of the embodiment. At this time, the upper limit value of the total effective number N _ee is a condition in which black noise and non-lighting lines that appear to be caused by the voltage fluctuation ΔV _AY do not appear.

The total number N _ee of effective numbers of priming electron emission sources existing at a depth of 400 to 1200 meV from the bottom of the conduction band in the protective layer is 5.4 × 10 ⁵ or more and 1.5 × 10 ⁶ or less. Good address discharge can be performed.

  Therefore, if the Sc concentration with respect to MgO is adjusted to an energy state density of a predetermined amount or more, stable address discharge can be performed even if black display is performed over 1 TV field in a wide temperature range of -20 to 60 ° C. .

<Embodiment 2>
A PDP according to a second embodiment of the present invention will be described. In the second embodiment, a full HD PDP having a panel size of 50 inches and a display pixel number of 1980 × 1080 is considered. The PDP driving method of the second embodiment also corresponds to the ADS of FIG. 5, and the address period determined by the address pulse width and the number of scan lines is also within 1 ms.

In the PDP of the second embodiment, the number of reset discharges is reduced to improve the contrast, and when the discharge cells display black, the number of reset discharges is once every 3 TV fields (1/60 s). That is, rest period t _i in the second embodiment is within 50ms at maximum.

The main component of the protective layer 3 of Embodiment 2 is MgO, and contains a predetermined amount of Sc. In the second embodiment, the protective layer 3 is formed by a plasma gun. Deposition, in order to control the film quality such as crystallinity, performed under an _{O 2} atmosphere by flowing _{O 2} into the deposition apparatus in 350sccm from 250 sccm. By these film formation methods, the protective layer 3 is formed to a thickness of 300 nm to 1000 nm at a film formation rate of 20 Å / s to 140 Å / s.

  For the vapor deposition source, use is made of powdered MgO mixed with a Sc compound and formed into a pellet, or mixed with pelletized MgO and a pelleted Sc compound, or formed into these pellets. The sintered body is used. The Sc concentration in this vapor deposition source is 5 mass ppm or more and 5000 mass ppm or less with respect to MgO.

  The thickness of the protective layer 3 is 700 nm, and the Sc concentration in the protective layer is 40 ppm by mass. However, the film thickness is not limited to this, and any film having a function as a protective layer may be used.

FIG. 29 shows measurement data satisfying the equation (2) for the statistical delay of the PDP of the second embodiment, ie, the electron emission time constant t _s ^exp (t _i , T) of the address discharge delay time measurement method. is there. As shown in FIG. 29, the electron emission time constant t _s ^exp of the limbing electrons of the PDP of the second embodiment tends to decrease when the tube surface temperature T is near room temperature.

FIG. 30 shows the measurement data of t _s ^exp of the second embodiment, using the protective layer 3 as two types of electron emission sources as in the first embodiment, and the first electron emission with respect to the phonon frequency f _{ph, j} . T _s ^th (t _i , T) obtained by analyzing the source (j = 1) as 1.26 × 10 ¹³ Hz and the second electron emission source (j = 2) as 1.2 × 10 ¹³ Hz Is shown by a solid line. From FIG. 30, both show very good agreement.

In this way, as shown in FIG. 31, the first and second types of electron emission sources have an energy state density D ₁ (E) of solid line 504 and D ₂ (E) of solid line 505. The electron emission source has an activation energy average value ΔE _{a, 1} = 650 meV, activation energy dispersion value σ _{E, 1} = 30 meV, effective number of priming electron emission sources N _{ee, 1} = 7.4 × 10 ⁵ / Cell, second electron emission source is average activation energy ΔE _{a, 2} = 785 meV, dispersion of activation energy σ _{E, 2} = 45 meV, effective number of priming electron emission sources N _{ee, 2} = 2. 1 × 10 ⁵ cells / cell.

  As shown in FIG. 31, the protective layer of the second embodiment is Sc at a depth that can be thermally excited to an energy range 503 corresponding to a practical operating condition of 500 to 900 meV from the bottom of the conduction band as in the first embodiment. Priming electron emission sources resulting from the above are formed.

_{N ee} of the total number of the effective number of priming electron emission source present from the conduction band bottom in the protective layer to a depth of 400~1200meV is 9.5 × 10 ⁵ cells / cell. The total effective number N _ee is examined in a 50-inch full HD PDP in which the number of display pixels is 1980 × 1080 in the second embodiment, and the discharge of the protective layer excluding the intersection with the barrier rib in the discharge cell. The area in contact with the space is 7.7 × 10 ⁻⁸ m ² , and the total effective number N _ee per unit area is 1.2 × 10 ¹³ / m ² . Furthermore, since the thickness of the protective layer is 700 nm, the total effective number N _ee per unit volume is 1.7 × 10 ¹⁹ / m ³ .

However, in the second embodiment, the Sc concentration in the protective layer is 40 ppm by mass, and the effective number of priming electron emission sources is higher than that in the first embodiment, although it is as low as 60 ppm by mass in the first embodiment. N _{ee, j} is extremely large. From this, it can be seen that the protective layer according to the second embodiment has an extremely high formation efficiency of the Sc priming electron emission source in the protective layer.

FIG. 32 shows the priming electron emission source in the protective layer capable of performing good address discharge when the PDP device using the PDP according to the second embodiment is in the above-mentioned guaranteed operating temperature range of −20 to 60 ° C. The range of the total effective number _Nee is shown. Incidentally, the effective number of the total number N _ee of priming electron emission source at this time is a value determined according to the experimental methods and analysis method shown in the basic form of the embodiment. At this time, the upper limit value of the total effective number N _ee is a condition in which black noise and non-lighting lines that appear to be caused by the voltage fluctuation ΔV _AY do not appear.

The total effective number N _ee of the priming electron emission sources existing at a depth of 400 to 1200 meV from the bottom of the conduction band in the protective layer is 1.1 × 10 ⁶ / cell or more and 5.4 × 10 ⁶ / cell or less. Good address discharge can be performed.

Therefore, if the Sc concentration with respect to MgO is adjusted to an energy state density of a predetermined amount or more, a wide temperature range of −20 to 60 ° C. and a rest period t _i = 50 ms or more, that is, even if black display is performed for 3 TV fields or more. Stable address discharge can be performed, and a high-definition and high-contrast PDP can be obtained.

  At this time, the Sc concentration in the protective layer with respect to MgO as the main component is 45 mass ppm or more and 520 mass ppm or less.

<Embodiment 3>
A PDP according to Embodiment 3 of the present invention will be described. In the third embodiment, a full HD PDP having a panel size of 50 inches and a display pixel number of 1980 × 1080 is considered. The PDP driving method of the third embodiment also corresponds to the ADS of FIG. 5, and the address period determined by the address pulse width and the number of scan lines is also within 1 ms.

In the PDP of the third embodiment, the number of reset discharges is reduced to improve contrast, and when the discharge cells display black, the number of reset discharges is once every 3 TV fields (1/60 s). That is, rest period t _i in the third embodiment is within 50ms at maximum.

The main component of the protective layer 3 of Embodiment 32 is MgO and contains a predetermined amount of Sc. In the third embodiment, the protective layer 3 is formed by a plasma gun. Vapor deposition is performed in an H ₂ O atmosphere by flowing H ₂ O from 250 sccm to 350 sccm in order to control film quality such as crystallinity. By these film formation methods, the protective layer 3 is formed to a thickness of 300 nm to 1000 nm at a film formation rate of 20 Å / s to 140 Å / s.

  For the vapor deposition source, use is made of powdered MgO mixed with a Sc compound and formed into a pellet, or mixed with pelletized MgO and a pelleted Sc compound, or formed into these pellets. The sintered body is used. The Sc concentration in this vapor deposition source is 5 mass ppm or more and 5000 mass ppm or less with respect to MgO.

  The thickness of the protective layer 3 is 700 nm, and the Sc concentration in the protective layer is 50 ppm by mass. However, the film thickness is not limited to this, and any film having a function as a protective layer may be used.

FIG. 33 shows measurement data satisfying the expression (2) for the statistical delay of the PDP of the third embodiment, that is, the electron emission time constant t _s ^exp (t _i , T) of the third embodiment, from the address discharge delay time measurement method. is there. As shown in FIG. 33, the electron emission time constant t _s ^exp of the limbing electrons of the PDP according to the third embodiment tends to decrease near the room temperature T.

FIG. 34 shows the measurement data of t _s ^exp of the third embodiment, using the protective layer 3 as two types of electron emission sources as in the first embodiment, and the first electron emission with respect to the phonon frequency f _{ph, j} . T _s ^th (t _i , T) obtained by analyzing the source (j = 1) as 1.26 × 10 ¹³ Hz and the second electron emission source (j = 2) as 1.2 × 10 ¹³ Hz Is shown by a solid line. From FIG. 34, both show very good agreement.

In this way, as shown in FIG. 35, the first and second types of electron emission sources have an energy state density D ₁ (E) of solid line 506 and D ₂ (E) of solid line 507. The activation energy average value ΔE _{a, 1} = 650 meV, activation energy dispersion value σ _{E, 1} = 20 meV, effective number N _{ee, 1} = 7.3 × 10 ⁵ priming electron emission sources / Cell, the second electron emission source is the average activation energy ΔE _{a, 2} = 845 meV, the activation energy dispersion σ _{E, 2} = 110 meV, the effective number of priming electron emission sources N _{ee, 2} = 5. 2 × 10 ⁵ cells / cell.

  As shown in FIG. 35, the protective layer according to the third embodiment has a depth Sc that can be thermally excited to an energy range 503 corresponding to a practical operating condition of 500 to 900 meV from the bottom of the conduction band as in the first embodiment. Priming electron emission sources resulting from the above are formed.

_{N ee} of the total number of the effective number of priming electron emission source present from the conduction band bottom in the protective layer to a depth of 400~1200meV is 1.3 × 10 ⁶ cells / cell. The total effective number N _ee is examined in a 50-inch full HD PDP in which the number of display pixels is 1980 × 1080 in the third embodiment, and the discharge of the protective layer excluding the intersection with the barrier rib in the discharge cell. The area in contact with the space is 7.7 × 10 ⁻⁸ m ² , and the total effective number N _ee per unit area is 1.6 × 10 ¹³ / m ² . Furthermore, since the thickness of the protective layer is 700 nm, the total effective number N _ee per unit volume is 2.3 × 10 ¹⁹ / m ³ .

However, in the third embodiment, the Sc concentration in the protective layer is 50 ppm by mass, and the effective number of priming electron emission sources is higher than that in the first embodiment, although it is as low as 60 ppm by mass in the first embodiment. N _{ee, j} is extremely large. From this, it can be seen that the protective layer of the third embodiment has a very high formation efficiency of the Sc priming electron emission source in the protective layer.

FIG. 36 shows a PDP device using the PDP according to the third embodiment, in which the priming electron emission source in the protective layer capable of performing good address discharge when the operation guaranteed temperature range is −20 to 60 ° C. The range of the total effective number _Nee is shown. Incidentally, the effective number of the total number N _ee of priming electron emission source at this time is a value determined according to the experimental methods and analysis method shown in the basic form of the embodiment. At this time, the upper limit value of the total effective number N _ee is a condition in which black noise and non-lighting lines that appear to be caused by the voltage fluctuation ΔV _AY do not appear.

In the following the effective number of the total number _{N ee} is 1.4 × 10 ⁶ cells / cell or more 8.1 × 10 ⁶ cells / cell priming electron emission source present at a depth of 400~1200meV from the conduction band bottom in the protective layer Good address discharge can be performed.

Therefore, if the Sc concentration with respect to MgO is adjusted to an energy state density of a predetermined amount or more, a wide temperature range of −20 to 60 ° C. and a rest period t _i = 50 ms or more, that is, even if black display is performed for 3 TV fields or more. Stable address discharge can be performed, and a high-definition and high-contrast PDP can be obtained.

Further, in the third embodiment, the maximum value of the effective total number _Nee of the priming electron emission sources capable of performing a stable address discharge is larger than that in the second embodiment, and the wall charge holding power and wall charge formation of the protective layer are increased. The condition seems to be excellent.

  At this time, the Sc concentration in the protective layer with respect to MgO as the main component is 55 mass ppm or more and 735 mass ppm or less.

<Embodiment 4>
A PDP according to Embodiment 4 of the present invention will be described. In the fourth embodiment, the main component of the protective layer 3 is MgO, but contains a predetermined amount of impurity elements.

  As described in the first to third embodiments, in order to improve the discharge delay, a depth of 400 to 1200 meV from the bottom of the conduction band in the protective layer, particularly 500 to 900 meV in practical operating conditions for improvement. The priming electron emission source must be formed at a depth that allows thermal excitation.

As such an impurity element that forms a priming electron emission source in the vicinity of 500 to 900 meV from the bottom of the conduction band, in addition to Sc shown in the first to third embodiments, Si, Al, Y, Ce, Ca, La, sm, Sn, H, and the like, by controlling the concentration of these protective layers, the effective number N _ee priming electron emission _source, it is possible to adjust the _j and the total number N _ee. As a selection method, there is a method of measuring a discharge delay time and analyzing a priming electron emission source in the same manner as in the first to third embodiments.

  The PDP containing MgO as the main component of the protective layer 3 and containing 50 mass ppm of Si at maximum is analyzed. The protective layer 3 containing Si is formed to a thickness of 300 nm to 1000 nm by an electron beam evaporation method.

  A sintered compact molded in a pellet shape is used as the vapor deposition source, and the Si concentration in the vapor deposition source is 5 mass ppm or more and 1000 mass ppm or less with respect to MgO.

FIG. 37 shows measurement data satisfying the equation (2) for the statistical delay of the PDP of the fourth embodiment, that is, the electron emission time constant t _s ^exp (t _i , T) of the address discharge delay time measurement method. is there. As shown in FIG. 37, in the PDP of the fourth embodiment, the electron emission time constant t _s ^exp of the priming electrons for the entire rest period decreases as the tube surface temperature T increases.

FIG. 38 shows the measurement data of t _s ^exp of the fourth embodiment, in which the protective layer 3 is an electron emission source of H and Si, and the electron emission source caused by H with respect to the phonon frequency f _{ph, j} (j = 1). the indicated 3.1 × ¹⁰ 13 Hz, an electron emission source due to Si to (j = 2) the _t ^s th obtained by analyzing as _{^{1.19 × 10 13 Hz (t i}} , T) by a solid line ing. The reason why H is one of the electron emission sources is that H forms a shallow level and is included in the protective layer in the PDP manufacturing process such as vapor deposition. From FIG. 38, both show very good agreement.

As shown in FIG. 39, the level structure of the two types of electron emission sources determined by the analysis in this way is that the electron emission source caused by H has an activation energy average value ΔE _{a, 1} = 570 meV, Energy dispersion value σ _{E, 1} = 5 meV, effective number of priming electron emission sources N _{ee, 1} = 2.0 × 10 ³ cells / cell, electron emission source due to Si has an average activation energy ΔE _{a, 2} = 845 meV, activation energy variance σ _{E, 2} = 90 meV, effective number of priming electron emission sources N _{ee, 2} = 5.2 × 10 ⁵ / cell.

From this analysis result, Si and H are primed to a depth that allows the protective layer of the fourth embodiment to be thermally excited under practical operating conditions of 500 to 900 meV from the bottom of the conduction band as in the first to third embodiments. In order to form the emission source, the effective number N _{ee, j} of the priming electron emission source and the total effective number N _ee are the film quality such as the concentration of Si and H in the protective layer, the defect concentration such as vacancies, and the crystallinity. It can be adjusted by controlling. As a result, various characteristics such as discharge delay can be improved.

  Such impurity elements that form the priming electron emission source at a depth that can be thermally excited under practical operating conditions of 500 to 900 meV from the bottom of the conduction band include Al, Y, Ce, Ca, La, Sm in addition to MgO. , Sn. Therefore, Al, Y, Ce, Ca, La, Sm, and Sn are also primed by controlling the film quality such as Sc, Si and Si and H concentration in the protective layer, defect concentration such as vacancies, and crystallinity. The electron emission source can be adjusted, and the discharge delay can be improved.

  As mentioned above, although the invention made by the present inventor has been specifically described based on the basic embodiment and the first to fourth embodiments, the present invention is not limited to the basic embodiment and the first to fourth embodiments. Needless to say, the invention is not limited, and various modifications can be made without departing from the scope of the invention.

  INDUSTRIAL APPLICABILITY The present invention is effective for plasma display devices, particularly high-definition AC surface discharge PDPs, and is widely used in industries such as video equipment industry, advertising equipment industry, medical equipment industry, and plasma display device manufacturing industry. .

1 Front substrate 2 Dielectric layer 3 Protective layer 4 Sustain electrode (X)
4a Transparent electrode 4b Bus electrode 5 Scan electrode (Y)
5a Transparent electrode 5b Bus electrode 6 Display electrode 7 Partition wall 8 Phosphor layer 9 Dielectric layer 10 Address electrode (A)
11 Back substrate 12 Front plate 13 Back plate 14 Discharge space 15 PDP
20 plasma display device 21 address drive circuit 22 scan pulse output circuit 23 sustain pulse output circuit 24 drive control circuit 25 signal processing circuit 26 drive power supply 27 video source 101 input device 102 computer 103 output device 2200 personal computer 2201 CPU device 2202 storage device 2204 Data transfer coupling bus 2205 Data transfer coupling bus CL Discharge cell

Claims (9)

A pair of substrates are arranged to face each other to form a discharge space, a plurality of electrodes are formed on one substrate, a dielectric layer and a protective layer covering the dielectric layer are formed on the electrodes, and a discharge layer is formed in the discharge space. A plasma display panel filled with gas,
The plasma display panel, wherein the protective layer includes a total effective number of priming electron emission sources of 1.1 × 10 ⁶ cells / cell or more and 8.1 × 10 ⁶ cells / cell or less. The plasma display panel according to claim 1, wherein
The plasma display panel, wherein the protective layer contains MgO as a main component and at least Sc as an impurity element. The plasma display panel according to claim 1, wherein
The protective layer includes MgO as a main component and Sc as an impurity element.
The plasma display panel according to claim 1, wherein a concentration of the Sc relative to the MgO is 45 mass ppm or more and 735 mass ppm or less. The plasma display panel according to claim 1, wherein
The protective layer includes MgO as a main component and includes at least one selected from Si, Al, Y, Ce, Ca, La, Sm, Sn, and H as an impurity element. . In the plasma display panel according to any one of claims 1 to 4,
The plasma display panel according to claim 1, wherein the discharge gas includes Xe in an amount of a composition ratio of 8% or more. A plasma display panel manufacturing method for manufacturing the plasma display panel according to any one of claims 1 to 5,
A plasma display panel manufacturing method using a plasma gun in the step of forming the protective layer. In the manufacturing method of the plasma display panel of Claim 6,
In the step of forming the protective layer, vapor deposition is performed while O ₂ is circulated in the vapor deposition chamber. In the manufacturing method of the plasma display panel of Claim 6,
In the step of forming the protective layer, vapor deposition is performed while H ₂ O is circulated in the vapor deposition chamber.   6. A plasma display device comprising: the plasma display panel according to claim 1; and a driving device that drives the plasma display panel.

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