JP2008251515A - Plasma display panel, and its drive method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a discharge characteristic of a plasma display panel. <P>SOLUTION: This plasma display panel is provided with: a front glass substrate 1 and a back glass substrate 4 facing each other through a discharge space; a plurality of row electrode pairs X, Y formed on the front glass substrate 1 side; a plurality of column electrodes D formed on the back glass substrate 4 side to extend in a direction intersecting with the row electrode pairs X, Y, and forming discharge cells C in the discharge space at the respective intersection parts with the row electrode pairs X, Y; and phosphor layers 7 formed at positions facing the discharge cells C between the column electrodes D and the row electrode pairs X, Y. In the phosphor layer 7, MgO crystal 7B containing a magnesium crystalline body having a characteristic of emitting cathode luminescence having a peak in a wavelength range of 200-300 nm by being excited by an electron beam, and a secondary electron emission material containing a low-work-function material 7C are included. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a structure of a plasma display panel and a driving method of the plasma display panel.

  In a conventional surface discharge AC plasma display panel (hereinafter referred to as a PDP), a row electrode pair extending in the row direction and an intersection of the row electrode pair extending in the column direction are interposed between the front glass substrate and the rear glass substrate. A column electrode for forming a discharge cell is provided in a partial discharge space, and the discharge space is partitioned for each discharge cell by a partition wall having a vertical wall and a horizontal wall and formed in a substantially lattice shape, and a dielectric covering the row electrode pair. The surface of the body layer is covered with a protective layer, and when this protective layer is excited by an electron beam, it has a peak in the wavelength range of 200 to 300 nm (especially in the range of 230 to 250 nm, around 235 nm). Some have a structure including a crystalline magnesium oxide layer including a magnesium oxide crystal that emits light (see, for example, Patent Document 1).

  In this conventional PDP, a crystalline magnesium oxide layer constituting a protective layer of a dielectric layer is excited by an electron beam, and a magnesium oxide crystal that emits cathode luminescence having a peak in a wavelength range of 200 to 300 nm is obtained. As a result, the discharge probability of the discharge generated in the discharge cells is deteriorated even when the adjacent discharge cells are closed by providing the grid-shaped partition walls. Therefore, it is possible to achieve the technical effect that it is possible to achieve both the effect of improving the luminance and the number of gradations of the PDP by providing the partition walls and the effect of improving the discharge probability.

  However, for PDPs, it is strongly recommended to further improve the discharge characteristics and brightness and to improve the dark contrast when driving the PDP in accordance with the recent high-definition screen such as Full HD. There has been a demand, and there is an urgent need to develop a PDP that can meet such a demand.

JP 2006-134735 A

  One of the technical problems of the present invention is to meet the demand for the conventional PDP as described above.

  In order to solve the above-described problem, a PDP according to a first invention (the invention described in claim 1) is provided on a pair of substrates facing each other via a discharge space and on one substrate side of the pair of substrates. A plurality of row electrode pairs and a plurality of columns provided on the other substrate side so as to extend in a direction intersecting the row electrode pair and forming unit light-emitting regions in discharge spaces at respective intersections with the row electrode pair In the plasma display panel comprising: an electrode; and a phosphor layer provided at a position facing a unit light emitting region between the column electrode and the row electrode pair, wherein a discharge gas is enclosed in a discharge space. More than magnesium oxide and magnesium oxide containing magnesium oxide crystals having a characteristic that the layer is excited by an electron beam and emits cathode luminescence having a peak in a wavelength range of 200 to 300 nm. Thing function that is characterized in containing the secondary electron emission material comprising a low low work function material.

  In order to achieve the above object, a method for driving a PDP according to a second invention (invention according to claim 7) is provided with a pair of substrates facing each other through a discharge space and one substrate side of the pair of substrates. A plurality of row electrode pairs provided and the other substrate side are provided so as to extend in a direction intersecting the row electrode pairs, and unit light emitting regions are respectively formed in discharge spaces at respective intersections with the row electrode pairs. A plurality of column electrodes and a phosphor layer provided at a position facing the unit light emitting region between the column electrode and the row electrode pair, and the phosphor layer has a lower work function than magnesium oxide and magnesium oxide A secondary electron emission material including a low work function material is included, and a voltage is applied to one row electrode constituting the row electrode pair during a driving process of a plasma display panel in which a discharge gas is sealed in a discharge space. When a pulse is applied In addition, a counter discharge is generated between the column electrode and the one row electrode by setting the potential of the column electrode relatively to the negative electrode side with respect to the one row electrode to which the voltage pulse is applied. It is characterized by including a process.

  A PDP according to the present invention intersects a pair of substrates facing each other through a discharge space, a plurality of row electrode pairs provided on one substrate side of the pair of substrates, and a row electrode pair on the other substrate side. A plurality of column electrodes which are provided so as to extend in a direction to form a unit light emitting region in a discharge space at each intersection with the row electrode pair, and face a unit light emitting region between the column electrode and the row electrode pair And a phosphor layer provided at a position, and the phosphor layer includes a magnesium oxide crystal having a characteristic of performing cathode luminescence emission having a peak in a wavelength range of 200 to 300 nm when excited by an electron beam. A PDP including a secondary electron emission material including a low work function material having a lower work function than magnesium oxide is the best embodiment.

  In the PDP driving method according to the present invention, in the PDP according to the above-described embodiment, a voltage pulse is applied to one of the row electrodes constituting the row electrode pair in the driving process, and one voltage pulse is applied to the other. A driving method that includes a process in which counter discharge is generated between the column electrode and one of the row electrodes by setting the potential of the column electrode relatively to the negative electrode side with respect to the row electrode. In this embodiment.

  In the PDP in the above embodiment, the phosphor layer formed at the position facing the unit light emitting region includes the secondary electron emission material, and the counter discharge is generated between one row electrode and the column electrode of the row electrode pair. When performed, the counter discharge causes cations generated from the discharge gas in the unit emission region to collide with the secondary electron emission material contained in the phosphor layer, and the unit from the secondary electron emission material. Secondary electrons are emitted into the light emitting region.

  At this time, the secondary electron emission material includes magnesium oxide containing a magnesium oxide crystal having a characteristic of performing cathode luminescence emission having a peak in a wavelength range of 200 to 300 nm when excited by an electron beam, and magnesium oxide. By including a low work function material with a low work function, secondary electrons are emitted from the magnesium oxide and the low work function material that collide with cations into the unit emission region, respectively. Since the secondary electron emission function is higher as the γ material has a lower work function, the amount of secondary electron emission into the unit light emitting region is larger than that of magnesium oxide.

  And this secondary electron has the function to reduce the discharge voltage, and compared with the case where only magnesium oxide is mixed with the phosphor layer, the discharge voltage can be further reduced. The discharge that is performed next to the counter discharge performed between the row electrode and the column electrode is easily generated by the secondary electrons existing in the unit light emitting region, and the discharge start voltage of this discharge is lowered.

  When the counter discharge performed between the one row electrode and the column electrode is a reset discharge that initializes all the unit light emitting regions when the PDP is driven, the counter discharge is generated from the pair of substrates. Compared to the case where the reset discharge is performed by surface discharge between the row electrodes at a position close to the panel surface because the unit light emission region is separated from the substrate constituting the panel surface of the PDP. Since the light emission due to the reset discharge recognized on the panel surface is reduced, the dark contrast is prevented from being lowered by the light emission not related to the gradation display of the video due to the reset discharge, and the dark contrast of the PDP is improved. Be able to.

  According to the driving method of the PDP in the above embodiment, the counter discharge performed between one row electrode and the column electrode is caused by applying a voltage pulse to one row electrode and applying this voltage pulse. As a result, the positive electrode generated from the discharge gas by this counter discharge is directed toward the column electrode on the negative electrode side. Since the secondary electron emission material collides with the secondary electron emission material contained in the phosphor layer, secondary electrons are efficiently emitted from the secondary electron emission material into the unit light emitting region.

In the PDP and the driving method thereof according to the embodiment, as the low work function material, Al, Au, Ag, Co, Cu, Ni, Ti which are metals, alkali metal elements, alkaline earth metal elements, boron, earth metallic elements, silicon, titanium, and oxides containing one or more of _{yttrium, LaB 6, La 2 O 3} , Cs 2 SO 4, Cs 2 CO 3, out of the (Sr, Ca) CO ₃ materials Examples include one or more selected materials and one or more materials selected from ZnO and carbon nanotube materials. This low work function material is a high γ material and has a high secondary electron emission function. Therefore, more secondary electrons can be emitted into the unit light emitting region than magnesium oxide by collision with cations generated from the discharge gas.

In the PDP and the driving method thereof according to the above-described embodiment, it is preferable that the secondary electron emission material is positioned at a portion facing the unit light emitting region of the phosphor layer.
As a result, the secondary electron emission material contained in the phosphor layer efficiently collides with the cation, and the secondary electrons can be more efficiently emitted into the unit light emitting region.

  In the PDP and the driving method thereof in the embodiment, as the form in which the secondary electron emission material is included in the phosphor layer, the form in which the secondary electron emission material is mixed with the fluorescent material constituting the phosphor layer, There is a form in which the electron emission material forms a layer and is laminated on the layer formed by the fluorescent material constituting the phosphor layer.

In the PDP and the driving method thereof in the above-described embodiment, it is preferable that the green phosphor layer in the phosphor layer includes only Zn ₂ SiO ₄ : Mn as a green phosphor material. In addition to Zn ₂ SiO ₄ : Mn as a green fluorescent material, the discharge start voltage of the counter discharge in the unit light emitting region where the green phosphor layer is formed is reduced even if (Y, Gd) BO ₃ : Tb is not included. In addition, since the (Y, Gd) BO ₃ : Tb is not included, there is no possibility that the chromaticity is deteriorated in the unit light emitting region where the green phosphor layer is formed.

  In the PDP and the driving method thereof in the above embodiment, it is preferable to use magnesium oxide as a secondary electron emission material, whereby secondary electrons can be efficiently emitted from the phosphor layer into the unit light emitting region.

Furthermore, in the PDP and the driving method thereof according to the above-described embodiment, as the secondary electron emitting material, cathode luminescence emission having a peak in the wavelength range of 200 to 300 nm, and further in the wavelength range of 230 nm to 250 nm is performed by the electron beam. It is preferable to use a magnesium oxide crystal having characteristics, in particular, a magnesium oxide containing a magnesium oxide single crystal produced by a gas phase oxidation method.
As a result, the discharge intensity and discharge delay of the counter discharge performed between the one row electrode and the column electrode can be reduced, and the luminance of the PDP can be improved.

In the PDP driving method of the embodiment, it is preferable to use the counter discharge performed between one row electrode and the column electrode as a reset discharge for initializing the unit light emitting region.
As a result, the reset discharge is performed at substantially the central portion of the unit light emitting region away from the substrate constituting the panel surface of the PDP of the pair of substrates, so that the reset discharge is performed at the position close to the panel surface. Compared to the case where the surface discharge is performed between the two, the light emission due to the reset discharge recognized on the panel surface is reduced, and thus the dark contrast is lowered due to the light emission not related to the gradation display of the image due to the reset discharge. Therefore, the dark contrast of the PDP is improved.

In the PDP driving method of the embodiment, a positive voltage pulse is applied to one row electrode, a negative voltage pulse is applied to the column electrode, or the column electrode is held at the ground potential. It is preferable to make it.
As a result, a so-called negative column electrode discharge is generated between one row electrode and the column electrode, in which the cations generated from the discharge gas by the discharge are directed in the direction of the column electrode serving as the negative electrode.

In the PDP driving method of this embodiment, simultaneously with the application of the voltage pulse to one row electrode, the same polarity as the voltage pulse applied to the one row electrode is applied to the other row electrode constituting the row electrode pair. It is preferable to apply a voltage pulse having a potential that does not generate a potential for generating a discharge with respect to one of the row electrodes.
This prevents a discharge from occurring between the row electrodes of the pair of row electrodes, and ensures that a counter discharge is generated between one of the row electrodes and the column electrode.

Further, in the PDP driving method of the above embodiment, it is preferable that the voltage pulse is applied to one of the row electrodes in such a manner that the voltage increases at a required increase rate from the start of application.
As a result, the counter discharge is generated in a state where the rising voltage of the voltage pulse is not so large, so that the discharge intensity of the counter discharge can be reduced.

  In the PDP and the driving method thereof according to the embodiment, it is preferable that the magnesium oxide crystal has a particle size of 2000 angstroms or more, and is excited by the electron beam of the magnesium oxide crystal to have a wavelength range of 200 to 300 nm. The characteristic of performing cathodoluminescence emission having a peak in the inside is increased.

  1 to 3 show a first example of an embodiment of a PDP according to the present invention, FIG. 1 is a front view schematically showing the PDP in the first example, and FIG. 2 is a VV of FIG. 3 is a cross-sectional view taken along the line WW in FIG.

  The PDP shown in FIGS. 1 to 3 has a plurality of row electrode pairs (X, Y) in the row direction of the front glass substrate 1 (left and right direction in FIG. 1) on the back surface of the front glass substrate 1 as a display surface. They are arranged in parallel so as to extend.

  The row electrode X includes a transparent electrode Xa made of a transparent conductive film such as ITO formed in a T shape, and a metal film that extends in the row direction of the front glass substrate 1 and is connected to a narrow base end portion of the transparent electrode Xa. And the bus electrode Xb.

  Similarly, the row electrode Y is connected to the transparent electrode Ya made of a transparent conductive film such as ITO formed in a T-shape and the narrow base end portion of the transparent electrode Ya extending in the row direction of the front glass substrate 1. The bus electrode Yb is made of a metal film.

  The row electrodes X and Y are alternately arranged in the column direction (vertical direction in FIG. 1) of the front glass substrate 1, and the transparent electrodes Xa and Ya arranged in parallel along the bus electrodes Xb and Yb are respectively Extending to the paired row electrode side, the tops of the wide portions of the transparent electrodes Xa and Ya are opposed to each other via a discharge gap g having a required width.

  A dielectric layer 2 is formed on the back surface of the front glass substrate 1 so as to cover the row electrode pairs (X, Y). On the back surface of the dielectric layer 2, adjacent row electrode pairs (X , Y) protrudes on the back side of the dielectric layer 2 at a position facing the bus electrodes Xb and Yb positioned back to back and a position facing the region between the bus electrodes Xb and Yb positioned back to back. The raised dielectric layer 2A is formed so as to extend in parallel with the bus electrodes Xb and Yb.

  On the back side of the dielectric layer 2 and the raised dielectric layer 2A, cathode luminescence light emission (hereinafter referred to as CL light emission) having a peak in a wavelength range of 200 to 300 nm by being excited by an electron beam as described later. A magnesium oxide layer 3 including a magnesium oxide crystal (hereinafter referred to as a CL emission MgO crystal) is formed.

  On the other hand, on the display side surface of the rear glass substrate 4 arranged in parallel with the front glass substrate 1, the column electrode D is connected to the transparent electrodes Xa and Ya of each pair of row electrodes (X, Y). They are arranged in parallel at predetermined intervals so as to extend in a direction (column direction) orthogonal to the row electrode pair (X, Y) at the opposing positions.

A white column electrode protective layer 5 that covers the column electrode D is further formed on the display side surface of the rear glass substrate 4, and a partition wall 6 is formed on the column electrode protective layer 5.
The partition wall 6 includes a pair of horizontal walls 6A extending in the row direction at positions facing the bus electrodes Xb and Yb of each row electrode pair (X, Y), and a pair of horizontal walls 6A at an intermediate position between adjacent column electrodes D. A vertical wall 6B extending in the column direction is formed in a ladder shape, and each partition wall 6 is interposed through a gap SL extending in the row direction between the side walls 6A facing the back-to-back of other adjacent partition walls 6. Are arranged side by side in the row direction.

  And, by this ladder-shaped partition wall 6, the discharge space S between the front glass substrate 1 and the rear glass substrate 4 is opposed to the transparent electrodes Xa and Ya paired in each row electrode pair (X, Y). Each discharge cell C is formed in a square shape.

A phosphor layer 7 is formed on the side surfaces of the horizontal wall 6A and vertical wall 6B of the partition wall 6 facing the discharge cell C and the surface of the column electrode protection layer 5 so as to cover all five surfaces. The color of the body layer 7 is arranged so that the three primary colors of red, green, and blue are arranged in order in the row direction for each discharge cell C.
The configuration of the phosphor layer 7 will be described in detail later.

The raised dielectric layer 2A is connected to the discharge cell C by contacting the display side surface of the horizontal wall 6A of the partition wall 6 with the magnesium oxide layer 3 covering the raised dielectric layer 2A (see FIG. 2). The gaps SL are closed, but the display side surface of the vertical wall 6B is not in contact with the magnesium oxide layer 3 (see FIG. 3), and a gap r is formed between them in the row direction. Adjacent discharge cells C communicate with each other through the gap r.
A discharge gas containing xenon is enclosed in the discharge space S.

FIG. 4 is an enlarged sectional view showing one discharge cell C in order to show the configuration of the phosphor layer 7.
In FIG. 4, the phosphor layer 7 includes a red, green and blue particulate fluorescent material 7A and an MgO crystal 7B including a CL light emitting MgO crystal as a secondary electron emitting material, and an MgO having a work function lower than that of MgO. A material other than the above (hereinafter referred to as a low work function material) 7C is mixed, and the MgO crystal 7B and the low work function material 7C are respectively formed on the surface of the phosphor layer 7, that is, in the discharge cell C. It is arranged in the position exposed to.

  Examples of the low work function material 7C include the following materials, and at least one of these materials is included.

-Metal materials such as Al, Au, Ag, Co, Cu, Ni, Ti,
Cs ₂ O, CaO, SrO, BaO, Al ₂ O ₃ , B ₂ O ₃ , TiO, SiO ₂ , Y ₂ O _{3 and} other alkali metal elements, alkaline earth metal elements, boron, earth metal elements, silicon , Oxides containing one or more of yttrium, compounds such as LaB ₆ , La ₂ O ₃ , Cs ₂ SO ₄ , Cs ₂ CO ₃ , (Sr, Ca) CO ₃

  As a method for forming the phosphor layer 7, a discharge cell C is prepared by using a paste in which an MgO crystal 7B and a low work function material 7C are mixed in a phosphor 7A by a printing method, a dispenser coating method, an ink jet method, a transfer method, or the like. The method of apply | coating on the column electrode protective layer 5 of the inside is mentioned.

  FIG. 4 shows a state in which the MgO crystal 7B and the low work function material 7C are arranged only on the surface of the phosphor layer 7, but the MgO crystal 7B and the low work function material 7C are in the discharge cell. As long as it is exposed to C, the MgO crystal 7B or the low work function material 7C may be mixed inside the phosphor layer 7.

  In addition, the MgO crystal 7B includes a CL emission MgO crystal having a characteristic of emitting CL light having a peak in a wavelength range of 200 to 300 nm when excited by an electron beam, and other characteristics having a characteristic of emitting secondary electrons. A form of MgO crystal may be included.

  The CL light-emitting MgO crystal includes, for example, a magnesium single crystal obtained by vapor-phase oxidation of magnesium vapor generated by heating magnesium (hereinafter, this magnesium single crystal is vapor-phase-processed magnesium oxide single crystal). The vapor-phase-process magnesium oxide single crystal includes, for example, a magnesium oxide single crystal having a cubic single crystal structure as shown in the SEM photographic image of FIG. 5 and an SEM of FIG. As shown in the photographic image, a magnesium oxide single crystal having a structure in which cubic crystals are fitted into each other (that is, a cubic multiple crystal structure) is included.

As will be described later, this vapor-phase-processed magnesium oxide single crystal contributes to improvement of discharge characteristics such as reduction of discharge delay of PDP.
The vapor-phase-processed magnesium oxide single crystal has characteristics such as high purity, fine particles, and less aggregation of particles as compared with magnesium oxide obtained by other methods.

In this example, a vapor phase magnesium oxide single crystal having an average particle diameter measured by the BET method of 2000 angstroms or more is used.
In addition to the CL emission having a peak at 300 to 400 nm, the vapor phase method magnesium oxide single crystal having a large particle diameter has a CL within a wavelength range of 200 to 300 nm (particularly, around 235 nm and within 230 to 250 nm). It has the property that light emission is excited.

CL emission having a peak in this wavelength range of 200 to 300 nm (especially, around 235 nm and within 230 to 250 nm) is not excited from ordinary vapor deposited MgO and has a peak at 300 to 400 nm as shown in FIG. Only the CL emission it has is excited.
As can be seen from FIGS. 7 and 8, CL emission having a peak in the wavelength range of 200 to 300 nm (particularly 235 nm) increases in peak intensity as the particle size of the vapor-phase-grown magnesium oxide single crystal increases. .

The particle diameter (D _BET ) of the vapor phase magnesium oxide single crystal is calculated by the following equation from the BET specific surface area (s) measured by the nitrogen adsorption method.
D _BET = A / s × ρ A: Shape count (A = 6) ρ: True density of magnesium

FIG. 10 is a graph showing the correlation between the CL emission intensity of the vapor-phase-process magnesium oxide single crystal and the discharge delay of the PDP.
From FIG. 10, since the vapor-phase method magnesium oxide single crystal has CL emission characteristics of 235 nm, a magnesium oxide layer containing the vapor-phase method magnesium oxide single crystal is formed in the discharge cell of the PDP. Thus, it can be seen that the delay of the discharge generated in the discharge cell is shortened, and further, that the discharge delay is shortened as the CL emission intensity at 235 nm is increased.

  From the above, the vapor phase magnesium oxide single crystal having an average particle diameter of 2000 angstroms or more measured by the BET method is used in the part facing the discharge cell of the PDP, so that the discharge probability and discharge delay of the PDP It can be seen that this can contribute to improvement of discharge characteristics such as reduction of discharge delay and improvement of discharge probability.

  FIG. 11 shows a case where a magnesium oxide layer disposed so as to face a PDP discharge cell is formed by applying a paste containing a vapor-phase magnesium oxide single crystal having an average particle diameter of 2000 to 3000 angstroms. FIG. 12 is a graph comparing discharge probabilities of discharge (for example, address discharge) performed between the magnesium oxide layers when formed by a conventional vapor deposition method and when not formed, and FIG. The discharge probabilities when the discharge pause time is 1000 μsec are shown.

  Further, in FIG. 13, similarly, a magnesium oxide layer disposed so as to face a PDP discharge cell is coated with a paste containing a vapor phase magnesium oxide single crystal having an average particle diameter of 2000 to 3000 angstroms. FIG. 14 is a graph comparing the discharge delay times when formed by the conventional vapor deposition method, when formed by the conventional vapor deposition method, and when not formed, and FIG. 14 shows the case where the discharge pause time is 1000 μsec in FIG. Each discharge delay time is shown.

11 to 14 show a case where the magnesium oxide layer includes a vapor-phase magnesium oxide single crystal having a multiple crystal structure.
From FIG. 11 to FIG. 14, the vapor phase magnesium oxide single crystal disposed in the portion facing the PDP discharge cell shows an improvement in the discharge probability of the PDP, the discharge delay, and the decrease in the pause time dependency of the discharge delay. It can be seen that it can greatly contribute to the improvement of the discharge characteristics.

FIG. 15 is a graph showing the relationship between the particle size of the vapor phase magnesium oxide single crystal disposed in the portion facing the discharge cell and the discharge probability in the PDP.
From FIG. 15, the larger the particle size of the vapor-phase-processed magnesium oxide single crystal, the higher the PDP discharge probability, and the particle size at which CL emission having a peak at 235 nm as described above is excited (in the example shown, 2000 angstroms). It can be seen that the discharge probability is greatly improved by the vapor-phase-process magnesium oxide single crystal of 3000 angstroms).

  As described above, the vapor phase magnesium oxide single crystal that performs CL emission having a peak in the wavelength range of 200 to 300 nm (particularly in the vicinity of 235 nm and 230 to 250 nm) contributes to the improvement of the discharge characteristics of the PDP. Is a vapor phase magnesium oxide single crystal having an energy level corresponding to its peak wavelength, and the energy level can trap electrons for a long time (several milliseconds or more). It is presumed that the initial electrons necessary for starting discharge are obtained by taking out.

  And the improvement effect of the discharge characteristic by this vapor phase method magnesium oxide single crystal increases as the intensity of CL emission having a peak in the wavelength range of 200 to 300 nm (especially in the vicinity of 235 nm and within 230 to 250 nm) increases. This is because, as described above, there is a correlation (see FIG. 8) between the CL emission intensity and the particle diameter of the vapor phase magnesium oxide single crystal.

  That is, in order to form a vapor phase magnesium oxide single crystal having a large particle size, it is necessary to increase the heating temperature when generating the magnesium vapor. For this reason, a flame in which magnesium and oxygen react with each other is required. As the length becomes longer and the temperature difference between the flame and the surroundings becomes larger, the vapor phase magnesium oxide single crystal having a larger particle size has a peak wavelength of CL emission as described above (for example, around 235 nm, 230 to This is because many energy levels corresponding to (within 250 nm) are formed.

  Further, compared with a general gas phase oxidation method, the amount of Mg evaporated per unit time is increased to increase the reaction region between Mg and O 2, and the gas phase generated by reacting with more O 2. In the magnesium oxide single crystal, an energy level corresponding to the peak wavelength of CL emission as described above is formed.

  The cubic multi-crystal structure vapor-phase-processed magnesium oxide single crystal has many crystal plane defects, and the existence of this plane defect energy level contributes to the improvement of the discharge probability. Is done.

  Next, a method for driving the PDP shown in FIGS. 1 to 3 will be described.

This PDP is performed by the subfield method, and each subfield obtained by dividing a display period of one field into a plurality is divided into a reset discharge period in which a reset discharge for simultaneously initializing all discharge cells is performed, and a discharge in which light is emitted. An address discharge period in which an address discharge for selecting the cell C is performed, and a sustain discharge period in which a sustain discharge for emitting light for image formation is performed.
In this PDP, the reset discharge performed in the first reset discharge period of each subfield is performed between the row electrode Y and the column electrode D by counter discharge.

FIG. 16 is a pulse waveform diagram showing voltage pulses applied to the row electrode Y and the column electrode D during the reset discharge.
In FIG. 16, not a rectangular pulse but a positive row electrode reset pulse Ry having a slow time constant and a large time constant is applied to the row electrode Y, and a column electrode D is simultaneously applied with the row electrode reset pulse Ry. The negative column electrode reset pulse Rd is applied.

  By applying the negative column electrode reset pulse Rd and the positive row electrode reset pulse Ry, between the column electrode D serving as the cathode and the row electrode Y serving as the anode, the direction from the row electrode Y to the address electrode D ( The electron flow generates a discharge in the direction from the column electrode D to the row electrode Y (hereinafter, the discharge generated when the column electrode D is set to the cathode side and the row electrode Y is set to the anode is the negative column. Collectively referred to as electrode discharge).

  In FIG. 16, SP is a scan pulse applied to the row electrode Y during the address discharge period, and DP is a data pulse selectively applied to the column electrode D during the address discharge period. Address discharge is generated between the row electrode Y to which the scan pulse SP is applied and the column electrode D to which the data pulse DP is applied.

  In the PDP, a reset discharge is generated by a negative electrode discharge between the row electrode Y and the column electrode D facing each other with the discharge cell C interposed therebetween. MgO crystal 7B which is a secondary electron emission material in which the cation in C is mixed in the phosphor layer 7 located on the column electrode D side toward the column electrode D serving as the negative electrode and the low work function material Colliding with 7C, secondary electrons are emitted into the discharge cell C from the MgO crystal 7B and the low work function material 7C, respectively.

At this time, the low work function material 7C is a high γ material, and the lower the work function, the higher the secondary electron emission function. Therefore, cations generated from the discharge gas when the discharge occurs collide with the low work function material 7C. As a result, the amount of secondary electrons emitted into the discharge cell C is larger than that of the MgO crystal 7B having a work function higher than that of the low work function material 7C.
Since the secondary electrons have a function of lowering the discharge voltage, the discharge voltage can be further reduced as compared with the case where only the MgO crystal 7B is mixed in the phosphor layer.

  Further, the CL light-emitting MgO crystal contained in the MgO crystal 7B of the phosphor layer 7 of this PDP has a high initial electron emission function when a voltage is applied to the electrode. This initial electron reduces the discharge delay time and the discharge probability. The improvement effect can be demonstrated.

  As described above, by mixing the phosphor material 7A forming the phosphor layer 7 with the low work function material 7C in addition to the MgO crystal 7B, various discharges generated in the discharge cell C are caused in the discharge cell C. It can be easily generated by secondary electrons present in the battery, and the discharge start voltage of this discharge can be reduced. In addition, the overall discharge characteristics can be improved by shortening the discharge delay and increasing the discharge probability. Will be able to.

  In particular, when the MgO crystal 7B and the low work function material 7C are exposed on the surface of the phosphor layer 7, the counter discharge with the column electrode as the cathode side across the discharge cell C is generated. And the low work function material 7C efficiently collides with cations generated from the discharge gas, and more efficiently releases secondary electrons into the discharge cell C. Therefore, the discharge start voltage of the address discharge performed after the reset discharge is Remarkably reduced.

FIG. 17 is a graph showing the amount of secondary electron emission when MgO crystal and a low work function material are mixed in the phosphor layer.
In FIG. 17, the horizontal axis indicates the energy applied to the material constituting the phosphor layer, that is, the energy when cations collide, and the vertical axis indicates secondary electron emission when cations collide. The relative value of the quantity is shown for each added energy.

In the figure, a shows a case where only the MgO crystal is mixed in the phosphor material of the phosphor layer, and b shows an Mg powder and an Al powder as a low work function material in the phosphor material of the phosphor layer. When mixed, c indicates a case where MgO crystal and LaB ₆ powder, which is a low work function material, are mixed in the fluorescent material of the phosphor layer.

  In any of a, b, and c, the type and weight of the fluorescent material are the same, and the weight of the low work function material is set to be the same as that of the MgO crystal or MgO crystal mixed in the fluorescent material. Has been.

From FIG. 17, when the phosphor material forming the phosphor layer is mixed with Al powder or LaB ₆ which is a low work function material, the phosphor is compared with the case where only MgO crystal 7B is mixed. It can be seen that the amount of secondary electrons emitted from the layer increases, and that the function of lowering the discharge voltage is improved by increasing the amount of secondary electrons emitted.

  In general, in the PDP, the reset discharge also includes light emission. The light emission due to the reset discharge is light emission not related to the gradation display of the image. If it is recognized on the screen, the dark contrast of the image is lowered.

  In the PDP, the reset discharge is performed by a counter discharge between the row electrode Y and the column electrode D, and this counter discharge is performed at the central portion of the discharge cell C away from the panel surface (the surface of the front glass substrate 1). Therefore, compared with the case where the reset discharge is performed by surface discharge between the row electrodes at a position close to the panel surface, the light emission due to the reset discharge recognized on the panel surface is reduced, and thereby the dark contrast of the displayed image. Can be improved.

  In the above description, the example (FIG. 16) in which the negative column electrode reset pulse Rd is applied to the column electrode D has been described. However, in order to generate a reset discharge between the row electrode Y and the column electrode D, When the positive row electrode reset pulse Ry is applied to the row electrode Y, the column electrode D may be set relatively to the negative side with respect to the positive row electrode Y. For example, 18, the column electrode D may be set to the ground (GND) potential, and the potential of the column electrode D is higher than that of the row electrode reset pulse Ry applied to the row electrode Y. A small positive voltage pulse may be applied so that a discharge occurs between the row electrode Y and the column electrode D.

  In the following, the negative column electrode discharge is the positive voltage when the column electrode D is set to the ground (GND) potential during the reset discharge or when the column electrode D has a potential lower than the row electrode reset pulse Ry. This includes all cases where the potential of the column electrode D is set on the negative side relative to the row electrode Y, such as when a pulse is applied.

  Further, during this reset discharge, the row electrode X constituting the row electrode pair with the row electrode Y may hold the ground (GND) potential during the reset discharge period, as shown in FIG. As described above, a voltage pulse Rx having the same polarity as the row electrode reset pulse Ry applied to the Y electrode and not causing a potential difference with the row electrode Y may be applied. .

  This prevents a potential difference that generates a discharge between the row electrodes X and Y constituting the row electrode pair while the reset discharge is generated, so that the reset discharge is reliably performed between the row electrode Y and the column. Only the counter discharge between the electrodes D can be achieved, and the dark contrast of the display image can be further improved.

  In the PDP, a CL light-emitting MgO crystal having a characteristic that the MgO crystal 7B mixed in the phosphor layer 7 emits CL having a peak in a wavelength range of 200 to 300 nm when excited by an electron beam as described above. The CL emission MgO is higher than that of a normal MgO crystal having no CL emission characteristic (hereinafter, this MgO crystal having no CL emission characteristic is referred to as a normal MgO crystal). Due to the characteristics described with reference to FIGS. 7 to 15 of the crystal, the discharge delay time is shortened, and furthermore, a voltage pulse having a large time constant and a gradual rise is applied to the row electrode Y, whereby dark contrast is reduced. The discharge intensity of the reset discharge that causes the decrease is reduced, and the dark contrast of the PDP is greatly improved.

  Further, when the CL light-emitting MgO crystal is included in the phosphor layer 7 and mixed with the MgO crystal 7B, the PDP is discharged from the CL light-emitting MgO crystal in the phosphor layer 7 by the reset discharge. The initial electrons are emitted in the inside, and the discharge delay of the reset discharge is further shortened by the initial electrons, and the priming effect is maintained for a long time, so that the address discharge generated after the reset discharge is further accelerated.

  As shown in FIG. 4, the PDP is disposed at a position where the CL light-emitting MgO crystal mixed with the phosphor layer 7 is exposed in the discharge cell C on the surface of the phosphor layer 7. Since the initial electrons can be efficiently discharged into the discharge cell C without being obstructed by the phosphor particles in the phosphor layer 7, the discharge start voltage of the address discharge can be further reduced.

  20 shows a voltage pulse of the form shown in FIG. 18 in the row electrode Y and the column electrode D in the PDP in which the MgO crystal 7B mixed with the phosphor layer 7 of the PDP in FIGS. FIG. 21 is an oscilloscope waveform diagram showing the discharge intensity when reset discharge is performed by a negative electrode discharge. FIG. 21 is a diagram of a row electrode in a conventional PDP in which a phosphor layer is formed only of a fluorescent material. FIG. 19 is an oscilloscope waveform diagram showing discharge intensity when reset discharge is performed by applying a voltage pulse of the form shown in FIG. 18 to a column electrode.

  20 and 21, the horizontal axis (time) of FIG. 21 shows 1 ms on 10 scales, whereas in FIG. 20, the discharge intensity of reset discharge is very small, so 0.1 ms on 10 scales. The scale of the vertical axis (discharge intensity) in FIG. 20 is also displayed at a scale 10 times that in FIG. 21.

  20 and FIG. 21 are compared, in FIG. 20, the discharge intensity of the reset discharge (negative electrode discharge) is very weak (about 1/40 to 1/50) compared to the case of FIG. In contrast to the discharge time being about 0.04 ms or less, in the case of FIG. 21, it can be seen that the discharge intensity of the reset discharge is strong and the discharge time is over 1 ms or longer.

  Accordingly, in the case of FIG. 21, the discharge intensity and the discharge delay are large, whereas in the case of FIG. 20, the discharge intensity and the discharge delay are greatly reduced. In the PDP of FIGS. It can be seen that mixing the CL light-emitting MgO crystal as the MgO crystal 7B with the body layer 7 further improves the dark contrast by reducing the discharge intensity and the discharge delay time.

  In FIG. 20, the discharge intensity decreases because the CL light-emitting MgO crystal has an effect of improving the discharge delay as described above, and this CL light-emitting MgO crystal is mixed with the phosphor layer 7. As a result, the discharge time of the reset discharge is greatly shortened to within about 0.04 ms, and the time constant as shown in FIGS. This is considered to be because, when a large voltage pulse is applied, the reset discharge ends when the voltage value in the middle of the rise of the voltage pulse applied to the row electrode Y is small.

  FIG. 22 shows a case where a voltage pulse having a large time constant and a slow rise is applied to the row electrode Y in the PDP in which the phosphor layer 7 of the PDP in FIGS. 1 to 3 includes a CL light-emitting MgO crystal as the MgO crystal 7B. The measurement result of the discharge delay time when the negative electrode discharge is generated is shown.

The horizontal axis of FIG. 22 shows the mixing ratio (weight percent) of the MgO crystal containing the CL emission MgO crystal to the fluorescent material, and the vertical axis shows the discharge delay time.
Here, the numerical value indicating the discharge delay on the vertical axis in FIG. 22 is a value normalized by setting the discharge delay to 1.0 when the mixing ratio of this MgO crystal is 5%.

  From FIG. 22, it can be seen that the larger the mixing ratio of the MgO crystal to the fluorescent material in the phosphor layer 7, that is, the larger the mixing ratio of the CL light emitting MgO crystal, is, the smaller the discharge delay of the negative electrode discharge is. It can be seen that the effect of shortening the discharge delay time is large.

  As described above, according to FIG. 20, the phosphor layer 7 of the PDP of FIGS. 1 to 3 is mixed with the CL emission MgO crystal as the MgO crystal 7B, and the row electrode Y has a large time constant and a slowly rising voltage. It can be seen that by applying the pulse, the discharge delay of the reset discharge is reduced, the discharge intensity is further reduced, and the dark contrast of the PDP is greatly improved.

  When the same measurement was performed on the PDP in which only normal MgO crystals that are not CL light-emitting MgO crystals were mixed in the state of FIG. 4 in the phosphor layer, the same results as in FIG. 21 were obtained, as described above. Although the effect of reducing the discharge start voltage and the improvement of the dark contrast by the secondary electron emission can be obtained, the effect of improving the discharge delay and the discharge intensity cannot be obtained.

  The reason is that an ordinary MgO crystal that is not a CL light-emitting MgO crystal has a secondary electron emission function, but an energy level corresponding to a peak wavelength region of 230 to 250 nm like a CL light-emitting MgO crystal. It is presumed that the electrons cannot be trapped for a long period of time and the initial electrons taken out to the discharge space when a voltage pulse is applied cannot be sufficiently obtained.

  The PDP shown in FIGS. 1 to 3 improves the brightness of the PDP in addition to the dark contrast improvement effect as described above by mixing the phosphor layer 7 with the CL emission MgO crystal as the MgO crystal 7B. Has the effect of

  That is, during the sustain discharge period of the subfield, a sustain discharge due to surface discharge is generated between the row electrodes X and Y of the row electrode pair in the discharge cell C selected by the address discharge performed in the previous address discharge period. However, the sustain discharge generates vacuum ultraviolet rays of 146 nm and 172 nm from xenon in the discharge gas, and the vacuum ultraviolet rays excite the CL emission MgO crystal in the phosphor layer 7 to emit PL light (photoluminescence). By emitting light, ultraviolet rays having a peak at 230 to 250 nm (hereinafter referred to as PL ultraviolet rays) are generated.

  The PL ultraviolet light further excites the fluorescent material 7A in the phosphor layer 7, so that the brightness of the PDP is improved as compared with the case where only the normal MgO crystal is mixed in the phosphor layer.

  When the phosphor layer 7 contains and mixes a CL light-emitting MgO crystal as the MgO crystal 7B, the brightness improvement effect of the PDP as described above is exhibited for the following reason.

  That is, in general, MgO crystals have a characteristic of absorbing vacuum ultraviolet rays generated from xenon in the discharge gas without being transmitted by discharge, and are therefore not normally CL light-emitting MgO crystals, for example. When only the MgO crystal is mixed in the phosphor layer, the vacuum ultraviolet ray generated from the discharge gas xenon is absorbed by the MgO crystal, and the amount of the vacuum ultraviolet ray irradiated to the phosphor particles around the MgO crystal As a result, the brightness of the PDP is reduced as compared with the case where the phosphor layer 7 is formed only of the fluorescent material.

  On the other hand, when the phosphor layer 7 contains and mixes a CL light-emitting MgO crystal as the MgO crystal 7B, the CL light-emitting MgO crystal absorbs vacuum ultraviolet rays generated from xenon in the discharge gas. After absorption, PL light is emitted by this vacuum ultraviolet ray, and PL ultraviolet ray having a peak wavelength at 230 to 250 nm is emitted.

  Since this PL ultraviolet light excites the phosphor 7A in the phosphor layer 7 to emit light, there is no possibility that the luminance is reduced by mixing only ordinary MgO crystals in the phosphor layer 7 as described above. The fluorescent material 7A of the phosphor layer 7 is also excited by PL ultraviolet rays generated from the CL emission MgO crystal in addition to the vacuum ultraviolet rays generated from the discharge gas xenon, so that the visible light amount generated from the phosphor layer 7 is increased. Compared with the case where the mixed MgO crystal 7B is only a normal MgO crystal other than the CL light-emitting MgO crystal, the brightness of the PDP is greatly increased.

  Furthermore, since the CL light-emitting MgO crystal is mixed with the fluorescent material 7A in the phosphor layer 7 and is positioned immediately next to the phosphor particles, the PL ultraviolet rays generated from the CL light-emitting MgO crystal are efficiently reflected by the fluorescent material. 7A is irradiated to further increase the brightness of the PDP.

In the above, the voltage of the form in which the row electrode reset pulse applied to the row electrode Y at the time of the reset discharge increases smoothly while changing the rising slope as shown in FIGS. The example of the pulse has been described. In addition to this, the row electrode reset pulse is set as a voltage pulse R1y in a form of increasing linearly with a constant rising slope as shown in FIG. Also good.
Also in this case, it is possible to obtain the dark contrast improvement effect which is almost the same as the case where the row electrode reset pulse is a voltage pulse having a form as shown in FIGS.

Similarly to the case of FIG. 19, when a voltage pulse is also applied to the other row electrode X constituting the row electrode pair simultaneously with the application of the row electrode reset pulse to the row electrode Y, it is shown in FIG. As described above, it is preferable to apply a voltage pulse R1x having the same polarity and the same waveform as the row electrode reset pulse R1y applied to the row electrode Y.
As a result, the reset discharge can be reliably generated only between the row electrode Y and the column electrode D.

  In the above description, the configuration in which reset discharge is performed between the row electrode Y and the column electrode D has been described as an example. However, the PDP is applied with a row electrode reset pulse to the X electrode, A configuration in which reset discharge is performed between the row electrode X and the column electrode D may be employed.

  FIG. 25 is a sectional view showing a second example of the PDP according to the present invention.

  While the phosphor layer of the PDP of the first embodiment described above is formed by mixing a phosphor material with MgO crystal as a secondary electron emission material and a low work function material, the PDP according to the second embodiment. Is a secondary electron emission material layer in which the phosphor layer 17 is formed of a material in which MgO crystal as a secondary electron emission material and a low work function material are mixed on a fluorescent material layer 17A formed of the fluorescent material. 17B has a configuration in which the discharge cells C are stacked so as to be exposed.

  After the formation of the fluorescent material layer 17A, the secondary electron emission material layer 17B is formed by applying a paste material mixed with MgO crystals and a low work function material onto the fluorescent material layer 17A by a printing method, a dispenser coating method, an inkjet method, It is formed by a method such as coating by a transfer method or the like.

The configuration of the other parts of the PDP is substantially the same as in the first embodiment, and the same reference numerals are assigned to the same components as in the first embodiment.
This PDP is driven by the same method as in the first embodiment.

  That is, the reset discharge is performed by the counter discharge by the negative electrode discharge between the column electrode D and the column electrode D when the row electrode reset pulse of the form as shown in FIG.

  As a result, as in the case of the first embodiment, the effect of improving the dark contrast of the PDP by the reset discharge being performed by the counter discharge, and the discharge from the secondary electron emission material layer 17B into the discharge cell C by the reset discharge. The secondary electrons exhibit the effect of reducing the discharge start voltage of the next address discharge.

  Then, the CL emission MgO crystal and the low work function material contained in the secondary electron emission material layer 17B, as in the case of the first example, have a remarkable effect of shortening the discharge delay and reducing the discharge intensity. Can further improve the dark contrast, and the CL light emitting MgO crystal emits PL by the vacuum ultraviolet rays generated from the xenon in the discharge gas to generate PL ultraviolet rays. The PL ultraviolet rays are used as the fluorescent material of the phosphor layer 17. Since the layer 17A is further excited to emit light, the brightness of the PDP can be increased.

The third example of the PDP according to the present invention will be described below.
In the first embodiment described above, as a low work function material in the phosphor layer of the PDP,
-Metal materials such as Al, Au, Ag, Co, Cu, Ni, Ti,
Cs ₂ O, CaO, SrO, BaO, Al ₂ O ₃ , B ₂ O ₃ , TiO, SiO ₂ , Y ₂ O _{3 and} other alkali metal elements, alkaline earth metal elements, boron, earth metal elements, silicon An oxide containing one or more of titanium, yttrium, and at least one of compounds such as LaB ₆ , La ₂ O ₃ , Cs ₂ SO ₄ , Cs ₂ CO ₃ , (Sr, Ca) CO ₃ An example including one or more types is shown.

  On the other hand, in the PDP according to the third embodiment, the phosphor layer includes one or more materials of ZnO or carbon nanotubes as a low work function material.

  FIG. 26 shows a case where, in the PDP in this embodiment, a negative electrode discharge is generated in the discharge cell by applying a voltage so that the column electrode is set on the cathode side and the row electrode Y is set on the anode side. The discharge start voltage is a value compared with the PDP of the first embodiment for each phosphor layer of red, green, and blue.

In FIG. 26, A to C are comparative examples showing the PDP of the first embodiment.
A: When the phosphor layer contains 5 weight percent of MgO crystal including CL light emitting MgO crystal,
B: When the phosphor layer contains 5 wt% of MgO crystal including CL light emitting MgO crystal and Cs ₂ CO ₃ which is a low work function material,
C: When the phosphor layer contains 5 wt% of MgO crystal including CL light emitting MgO crystal and Cs ₂ SO ₄ which is a low work function material,
Is shown.

And in FIG. 26, D and E have shown PDP of this Example, respectively,
D: When the phosphor layer contains 5 wt% of MgO crystal including CL light emitting MgO crystal and ZnO which is a low work function material,
E: When the phosphor layer contains 5 weight percent of MgO crystals including CL light-emitting MgO crystals and 1.5 weight percent of carbon nanotubes (CNT), which is a low work function material,
Is shown.

  Each numerical value in FIG. 26 indicates that the red phosphor layer of the PDP is formed in the case of the comparative example A described above (when the phosphor layer contains 5 weight percent of MgO crystal containing CL light-emitting Mg0 crystal). The difference (V) in the value of the discharge start voltage is shown when the discharge start voltage in the discharged cell is the reference value (0).

  Further, in each numerical value in which the arrows D and E in the example of FIG. 26 are shown, the numerical value on the left side of the arrow indicates that the aging of the phosphor layer after the panel sealing in the manufacturing process of the PDP is A to A in the comparative example. The pressure difference from the reference value when performed at the same time as in the case of C is shown, and the numerical value on the right side of the arrow indicates that this aging is performed for a longer time than in the case of Comparative Examples A to C. The differential pressure from the reference value is shown.

In the case of the same aging time, compared to the case of the red phosphor layer in the example A, the discharge start voltage is lowered in the cases of the phosphor layers in the examples B and C in any of red, green, and blue.
On the other hand, in the case of the same aging time, compared to the case of the red phosphor layer of the example A, the examples of D and E are discharged except for the discharge cell in which the blue phosphor layer of the example E is formed. Although the start voltage is increased, it can be seen that when the aging time is long, the discharge start voltage is decreased as compared with the discharge cell in which the red phosphor layer of the example A is formed.

In the example of A, even when the aging time was increased, the discharge start voltage hardly changed.
In the examples of D and E, when the aging time is increased, the discharge start voltage is decreased because the surface activation of ZnO and CNT which are low work function materials is insufficient when the aging time is short. it is conceivable that.

  In the PDP of this embodiment, the discharge start voltage of the negative electrode discharge can be reduced by setting the aging time of the phosphor layer to an arbitrary time longer than that of the first embodiment.

The fourth example of the PDP according to the present invention will be described below.
In the PDP of the fourth embodiment, the green phosphor layer is formed of a phosphor material containing only Zn ₂ SiO ₄ : Mn, an MgO crystal containing a CL light-emitting MgO crystal, and a low work function material.
The modes of the MgO crystal and the low work function material including the CL light emitting MgO crystal are the same as those in the first to third embodiments described above.

FIG. 27 shows the discharge start voltage when a negative electrode discharge is generated in the discharge cell in which the green phosphor layer of the PDP in this embodiment is formed, and the PDP in which the green phosphor layer is formed in another mode. The value compared with the case of is shown.
In this FIG. 27, F thru | or K has shown the comparative example with PDP in this Example, and in each green fluorescent substance layer,
F: When only Zn ₂ SiO ₄ : Mn is used as the green fluorescent material and MgO crystal including CL light emitting MgO crystal is included in 5 weight percent,
G: When a fluorescent material in which 30 weight percent of YBT is mixed in Zn ₂ SiO ₄ : Mn is used as a green fluorescent material and MgO crystal including CL light emitting MgO crystal is contained in 5 weight percent,
H: When a fluorescent material in which 50 wt% of YBT is mixed with Zn ₂ SiO ₄ : Mn is used as a green fluorescent material, and MgO crystal including CL light emitting MgO crystal is included in 5 wt%,
I: When a fluorescent material in which 70 wt percent of YBT is mixed in Zn ₂ SiO ₄ : Mn is used as a green fluorescent material and MgO crystals including CL light emitting MgO crystals are contained in 5 wt percent,
Is shown.

And in FIG. 27, J and K have shown PDP of this Example, and in green phosphor layer,
J: Only Zn ₂ SiO ₄ : Mn is used as a green fluorescent material, 5 wt% of MgO crystal including CL light emitting MgO crystal is included, and 5 wt% of Cs ₂ SO ₄ is included as a low work function material. If
K: Only Zn ₂ SiO ₄ : Mn is used as the green fluorescent material, 5% by weight of MgO crystal including CL emitting MgO crystal is included, and 10% by weight of Cs ₂ SO ₄ is included as the low work function material. If
Is shown.

In addition, each numerical value of the term of voltage in FIG. 27 is the case of Comparative Example F above (only Zn ₂ SiO ₄ : Mn is used as the green fluorescent material, and 5 wt% of MgO crystal including CL light-emitting MgO crystal is included. The difference (V) in the value of the discharge start voltage when the discharge start voltage in the green discharge cell of the PDP is set to a reference value (0) is shown.
The numerical values of the x-coordinate term and the y-coordinate term in FIG. 27 indicate the x-coordinate value and the y-coordinate value in the xy coordinate system in the case where white lighting for emitting all the discharge cells is performed, respectively. .

  In general, the discharge start voltage of the counter discharge generated in the green discharge cell in which the phosphor layer is formed of the PDP green phosphor material is red in which the phosphor layer is formed of another red or blue phosphor material. It becomes higher than the discharge start voltage of the counter discharge in the discharge cell and the blue discharge cell.

Therefore, in a conventional PDP, by mixing (Y, Gd) BO ₃ : Tb (hereinafter referred to as YBT), which is also a green fluorescent material, with Zn ₂ SiO ₄ : Mn, which is a green fluorescent material, The discharge start voltage of the counter discharge in the green discharge cell is lowered to balance the discharge start voltage of the counter discharge in the other red discharge cells and the blue discharge cells.

  However, if the mixing amount of YBT is increased in order to reduce the discharge start voltage of the counter discharge in the green discharge cell, there arises a problem that the chromaticity in the green discharge cell is deteriorated.

In FIG. 27, in the case of G to I of the comparative examples, a green phosphor material in which YBT is mixed with Zn ₂ SiO ₄ : Mn is used for forming the green phosphor layer. Although it is lower than the case of the example of FIG. 5, it can be seen that the x coordinate value increases and the y coordinate value decreases, and the chromaticity of white deteriorates.
This is probably because YBT was mixed as a green fluorescent material, and the white chromaticity was deteriorated due to the deterioration of the chromaticity of the green phosphor layer.

On the other hand, in the case of the examples of J and K in this example, since only the Zn ₂ SiO ₄ : Mn is used as the green fluorescent material, there is no deterioration of white chromaticity, and further, the green fluorescence By mixing Cs ₂ SO ₄ as a low work function material in the body layer, even if YBT is not mixed in the green phosphor layer, it is equal to or more than that in the examples of F to H of the comparative examples. The effect of reducing the discharge start voltage is exhibited.
Further, the effect of reducing the discharge start voltage is larger in the case of the K example in which the amount of mixing of Cs ₂ SO ₄ , which is a low work function material, is larger than that in the J example.

  The PDP in each of the above embodiments has a pair of substrates opposed via a discharge space, a plurality of row electrode pairs provided on one substrate side of the pair of substrates, and a row electrode pair on the other substrate side. A plurality of column electrodes which are provided so as to extend in the intersecting direction and form unit light-emitting regions in the discharge spaces at the respective intersections with the row electrode pairs, and unit light-emitting regions between the column electrodes and the row electrode pairs. A phosphor layer provided at the facing position, and the phosphor layer includes a magnesium oxide crystal having a characteristic of performing cathode luminescence emission having a peak in a wavelength range of 200 to 300 nm when excited by an electron beam The PDP of the embodiment including the secondary electron emission material including magnesium oxide and a low work function material having a work function lower than that of magnesium oxide is an embodiment of the superordinate concept. In the PDP of this embodiment, in the PDP of this embodiment, a voltage pulse is applied to one row electrode constituting the row electrode pair in the driving process, and the one row electrode to which this voltage pulse is applied is applied to the row electrode. A driving method that includes a process in which a counter discharge is generated between the column electrode and one of the row electrodes by setting the potential of the column electrode relatively to the negative electrode side is implemented in a superordinate concept. It is in form.

  In the PDP in the above embodiment, the phosphor layer formed at the position facing the unit light emitting region includes the secondary electron emission material, and the counter discharge is generated between one row electrode and the column electrode of the row electrode pair. When performed, the counter discharge causes cations generated from the discharge gas in the unit emission region to collide with the secondary electron emission material contained in the phosphor layer, and the unit from the secondary electron emission material. Secondary electrons are emitted into the light emitting region.

  At this time, the secondary electron-emitting material is more active than magnesium oxide and magnesium oxide including a magnesium oxide crystal that has a characteristic of performing cathodoluminescence emission that is excited by an electron beam and has a peak in a wavelength range of 200 to 300 nm. By including a low work function material with a low function, secondary electrons are emitted from the magnesium oxide colliding with the cation and the low work function material into the unit emission region. The lower the work function of the material, the higher the secondary electron emission function, so that the amount of secondary electron emission into the unit light emitting region is larger than that of magnesium oxide.

  This secondary electron has a function of lowering the discharge voltage, and the discharge voltage can be further lowered as compared with the case where only the magnesium oxide is mixed in the phosphor layer. The discharge performed next to the counter discharge performed between the row electrode and the column electrode is easily generated by secondary electrons existing in the unit light emitting region, and the discharge start voltage of this discharge is lowered.

  When the counter discharge performed between the one row electrode and the column electrode is a reset discharge that initializes all the unit light emitting regions when the PDP is driven, the counter discharge is generated between the pair of substrates. Compared to the case where the reset discharge is performed by surface discharge between the row electrodes at a position close to the panel surface because the unit light emission region is separated from the substrate constituting the panel surface of the PDP. Therefore, the light emission due to the reset discharge recognized on the panel surface is reduced, so that the dark contrast is prevented from being lowered by the light emission not related to the gradation display of the video due to the reset discharge, and the dark contrast of the PDP is improved. Become figured.

  Furthermore, according to the driving method of the PDP in the above-described embodiment, the counter discharge performed between one row electrode and the column electrode is caused by applying a voltage pulse to one row electrode and applying the voltage pulse. As a result, the positive electrode generated from the discharge gas by this counter discharge is directed toward the column electrode on the negative electrode side. Since the secondary electron emission material collides with the secondary electron emission material contained in the phosphor layer, secondary electrons are efficiently emitted from the secondary electron emission material into the unit light emitting region.

It is a front view which shows the 1st Example of embodiment of this invention. It is sectional drawing in the VV line of FIG. It is sectional drawing in the WW line of FIG. It is sectional drawing which shows the structure of the fluorescent substance layer of the Example. It is a figure which shows the SEM photograph image of the magnesium oxide single crystal which has a cubic single crystal structure. It is a figure which shows the SEM photograph image of the magnesium oxide single crystal which has a cubic multiple crystal structure. It is a graph which shows the relationship between the particle size of a magnesium oxide single crystal, and the wavelength and intensity | strength of CL light emission. It is a graph which shows the relationship between the particle size of a magnesium oxide single crystal, and the peak intensity of CL light emission of 235 nm. It is a graph which shows the state of the wavelength of CL light emission from the magnesium oxide layer by a vapor deposition method. It is a graph which shows the relationship between the peak intensity of CL light emission of 235 nm from a magnesium oxide single crystal body, and a discharge delay. It is a graph which shows the relationship between the magnesium oxide single crystal body of a multicrystal structure, and a discharge probability. It is a table | surface figure which shows the relationship between the magnesium oxide single crystal of the same multicrystal structure, and a discharge probability. It is a graph which shows the relationship between the magnesium oxide single crystal body of the same multicrystal structure, and discharge delay. It is a table | surface figure which shows the relationship between the magnesium oxide single crystal body of the same multicrystal structure, and discharge delay. It is a graph which shows the relationship between the particle size of a magnesium oxide single crystal, and a discharge probability. In the same example, it is a pulse waveform diagram showing the form of voltage pulses applied to the row electrode and the column electrode. In the example, it is a graph which shows the secondary electron emission amount from the fluorescent substance layer containing a low work function material. It is a pulse waveform diagram showing another example of the same voltage pulse. It is a pulse waveform diagram showing still another example of the same voltage pulse. It is an oscilloscope waveform diagram which shows the discharge intensity in case the CL light emission MgO crystal is contained in the fluorescent substance layer in the example. It is an oscilloscope waveform diagram which shows the discharge intensity in case a fluorescent substance layer is formed only with fluorescent material. It is a graph which shows the relationship between the mixing ratio of CL light emission MgO crystal contained in a fluorescent substance layer, and a discharge delay in the example. In the example, it is a pulse waveform diagram which shows the other form of the voltage pulse applied to a row electrode. It is a pulse waveform diagram showing another example of the same voltage pulse. It is sectional drawing which shows the 2nd Example of embodiment of this invention. It is a table | surface figure which shows 3rd Example of embodiment of this invention. It is a table | surface figure which shows the 4th Example of embodiment of this invention.

Explanation of symbols

1 ... Front glass substrate (one substrate)
4 ... Back glass substrate (the other substrate)
7, 17 ... Phosphor layer 7A ... Fluorescent material 7B ... MgO crystal (secondary electron emission material)
7C: Low work function material (secondary electron emission material)
17A: Fluorescent material layer 17B: Secondary electron emission material layer C: Discharge cell (unit emission region)
Rx, R1x ... Voltage pulse Ry, R1y ... Row electrode reset pulse (voltage pulse)
Rd ... Column electrode reset pulse (voltage pulse)
X: Row electrode (the other row electrode)
Y: Row electrode (one row electrode)
D: Column electrode

Claims (26)

A pair of substrates facing each other through the discharge space, a plurality of row electrode pairs provided on one substrate side of the pair of substrates, and extending in a direction intersecting the row electrode pair on the other substrate side A plurality of column electrodes each forming a unit light emitting region in a discharge space at each intersection with the row electrode pair, and a fluorescence provided at a position facing the unit light emitting region between the column electrode and the row electrode pair In a plasma display panel comprising a body layer and having a discharge gas sealed in a discharge space,
The phosphor layer includes a magnesium oxide crystal having a characteristic of performing cathode luminescence emission having a peak in a wavelength range of 200 to 300 nm when excited by an electron beam, and a low work function lower than that of magnesium oxide and magnesium oxide. A plasma display panel comprising a secondary electron emission material including a functional material. The low work function material is
Metals such as Al, Au, Ag, Co, Cu, Ni, Ti,
An oxide containing one or more of alkali metal elements, alkaline earth metal elements, boron, earth metal elements, silicon, titanium, yttrium,
_{LaB 6, La 2 O 3,} Cs 2 SO 4, Cs 2 CO 3, (Sr, Ca) CO 3,
The plasma display panel according to claim 1, wherein the plasma display panel includes one or more kinds of materials.   The plasma display panel according to claim 1, wherein the low work function material includes one or more of ZnO and carbon nanotube materials.   The plasma display panel according to claim 1, wherein the secondary electron emission material is exposed to a discharge space.   The plasma display panel according to claim 1, wherein the secondary electron emission material is mixed with a fluorescent material constituting the phosphor layer.   The plasma display panel according to claim 1, wherein the layer formed of the secondary electron emission material is laminated on the layer formed of the fluorescent material constituting the phosphor layer. The plasma display panel according to claim 1, wherein the green phosphor layer in the phosphor layer contains only Zn ₂ SiO ₄ : Mn as a green phosphor material.   2. The plasma display panel according to claim 1, wherein the magnesium oxide crystal has a characteristic of performing cathodoluminescence emission having a peak within 230 nm to 250 nm.   The plasma display panel according to claim 1, wherein the magnesium oxide crystal is a magnesium oxide single crystal produced by a gas phase oxidation method.   The plasma display panel according to claim 1, wherein the magnesium oxide crystal has a particle size of 2000 angstroms or more. A pair of substrates facing each other through the discharge space, a plurality of row electrode pairs provided on one substrate side of the pair of substrates, and extending in a direction intersecting the row electrode pair on the other substrate side A plurality of column electrodes each forming a unit light emitting region in a discharge space at each intersection with the row electrode pair, and a fluorescence provided at a position facing the unit light emitting region between the column electrode and the row electrode pair The phosphor layer includes a secondary electron emission material including magnesium oxide and a low work function material whose work function is lower than that of magnesium oxide, and a discharge gas is sealed in the discharge space. In the driving process of the plasma display panel
A voltage pulse is applied to one row electrode constituting the row electrode pair, and the potential of the column electrode is set relatively to the negative side with respect to the one row electrode to which the voltage pulse is applied. A process in which a counter discharge is generated between the column electrode and one of the row electrodes is included.
A method for driving a plasma display panel. The low work function material is
Metals such as Al, Au, Ag, Co, Cu, Ni, Ti,
An oxide containing one or more of alkali metal elements, alkaline earth metal elements, boron, earth metal elements, silicon, titanium, yttrium,
_{LaB 6, La 2 O 3,} Cs 2 SO 4, Cs 2 CO 3, (Sr, Ca) CO 3,
The method for driving a plasma display panel according to claim 11, comprising at least one of the materials.   12. The method of driving a plasma display panel according to claim 11, wherein the low work function material includes at least one of ZnO and carbon nanotube materials.   The method of driving a plasma display panel according to claim 11, wherein the counter discharge is a reset discharge for initializing a unit light emitting region.   12. The method of driving a plasma display panel according to claim 11, wherein a positive voltage pulse is applied to the one row electrode and a negative voltage pulse is applied to the column electrode.   12. The method of driving a plasma display panel according to claim 11, wherein a positive voltage pulse is applied to the one row electrode, and the column electrode is held at a ground potential.   The voltage pulse having the same polarity as the voltage pulse applied to one row electrode is applied to the other row electrode constituting the row electrode pair simultaneously with the application of the voltage pulse to the one row electrode. A driving method of the plasma display panel as described.   12. The method of driving a plasma display panel according to claim 11, wherein the voltage pulse is applied in such a manner that the voltage increases at a required increase rate as time passes from the start of application.   The method of driving a plasma display panel according to claim 11, wherein the secondary electron emission material is exposed to a discharge space.   The method for driving a plasma display panel according to claim 11, wherein the secondary electron emission material is mixed with a fluorescent material constituting the phosphor layer.   The method for driving a plasma display panel according to claim 11, wherein the layer formed of the secondary electron emission material is laminated on the layer formed of the fluorescent material constituting the phosphor layer. The method for driving a plasma display panel according to claim 11, wherein the green phosphor layer in the phosphor layer contains only Zn ₂ SiO ₄ : Mn as a green phosphor material.   12. The method for driving a plasma display panel according to claim 11, wherein the magnesium oxide includes a magnesium oxide crystal having a characteristic of performing cathode luminescence emission having a peak in a wavelength range of 200 to 300 nm when excited by an electron beam. .   24. The method of driving a plasma display panel according to claim 23, wherein the magnesium oxide crystal has a characteristic of performing cathode luminescence emission having a peak in the range of 230 nm to 250 nm.   The method for driving a plasma display panel according to claim 23, wherein the magnesium oxide crystal is a magnesium oxide single crystal produced by a gas phase oxidation method.   The method for driving a plasma display panel according to claim 23, wherein the magnesium oxide crystal has a particle size of 2000 angstroms or more.