Capillary electrode discharge plasma display panel device and method of fabricating the same

The present invention provides a capillary electrode discharge plasma display panel device and method of fabricating the same including first and second substrates a first electrode on the first substrate, a second electrode on the second substrate, a pair of barrier ribs connecting the first and second substrates, a discharge charge chamber between the first and second substrates defined by the barrier ribs, and a dielectric layer on the first substrate including the first electrode, the dielectric layer having a capillary to provide a steady state UV emission in the discharge chamber.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The present invention relates to a plasma display panel device and method
 of fabricating the same, and more particularly, to a plasma display panel
 device having micro-channels or capillaries connecting an electrode.
 Although the present invention is suitable for a wide scope of
 applications, it is particularly suitable for generating a high density
 ultraviolet (UV) emission, thereby significantly reducing driving voltage
 and turn-on time.
 2. Discussion of the Related Art
 Plasma display panel ("PDP") devices use gas discharges to convert electric
 energy into light. Each pixel in a PDP device corresponds to a single
 gas-discharge site and the light emitted by each pixel is controlled
 electronically by the video signal that represents the image.
 Many structures for color plasma displays have been suggested since the
 1980's, but only three are still in contention: the alternating current
 matrix sustain structure; the alternating current coplanar sustain
 structure; and the direct current with pulse-memory drive structure.
 Generally, PDP is the choice in flat panel display technologies for large
 size display devices typically larger than 40" diagonal. Extensive
 research toward the PDP devices has been done to increase brightness,
 lower driving voltage, and reduce response time of the devices since a
 proto-type of PDP has been developed. These goals can be achieved by
 maximizing the efficiency of the UV emission from the glow discharge.
 Most of the PDP devices utilizes a high pressure AC barrier type discharge.
 One example of the conventional high pressure AC barrier type discharge is
 disclosed in U.S. Pat. No. 5,701,056as shown in FIG. 1. A conventional
 plasma display panel device has a transparent front substrate 101 and a
 rear substrate 110 facing each other. A plurality of transparent
 electrodes 102 are formed on each of the front substrate 101, and a bus
 electrode 111 is on each of the transparent electrodes 102. The
 transparent electrode 102 and the bus electrodes 111 are covered with a
 thick insulating layer 103 and a protection layer 104 in this order. The
 transparent insulating layer 103 and the protection layer 104 comprises
 lead glass having a low fusing point and magnesium oxide (MgO).
 A plurality of data electrodes 108 are formed on the rear substrate 110. A
 plurality of chambers 112 are defined by first, second, and third
 partition walls 105a, 105b (not shown), and 106, and the first and third
 partition walls have widths W.sub.H and W.sub.D, respectively. A
 white-color insulating layer 107 is formed on the rear substrate 110
 including the data electrode 108. Further, a fluorescent material 109 is
 formed on the third partition wall 106 and the white-color insulating
 layer 107.
 U.S. Pat. No. 5,414,324 has suggested another structure for generating a
 high pressure glow discharge plasma as shown in FIG. 2. An electrode 10 is
 made of copper plate having a representative square plan dimension of 25
 cm.times.25 cm. The integral metallic units comprising plates 10 and
 tubing 11 are covered with a high dielectric insulating layer 14. In this
 structure, the dielectric insulating layer 14 is to prevent a high current
 arc mode from the discharge. However, the dielectric insulating layer 14
 consumes a large amount of the electric field. Moreover, a significant
 fraction of the electric field is applied across the dielectric insulating
 layer, so that the electric field cannot be applied effectively throughout
 the PDP device.
 SUMMARY OF THE INVENTION
 Accordingly, the present invention is directed to a plasma display panel
 device and method of fabricating the same that substantially obviates one
 or more of the problems due to limitations and disadvantages of the
 related art.
 An object of the present invention is to provide a high density UV emission
 in a PDP operated in an AC or DC mode.
 Another object of the present invention is to provide reduced driving
 voltage and short response time.
 Additional features and advantages of the invention will be set forth in
 the description which follows and in part will be apparent from the
 description, or may be learned by practice of the invention. The
 objectives and other advantages of the invention will be realized and
 attained by the structure particularly pointed out in the written
 description and claims hereof as well as the appended drawings.
 To achieve these and other advantages and in accordance with the purpose of
 the present invention, as embodied and broadly described, a plasma display
 panel device includes first and second substrates, a first electrode on
 the first substrate, a second electrode on the second substrate, a pair of
 barrier ribs connecting the first and second substrates, an electric
 charge chamber between the first and second substrates defined by the
 barrier ribs, and a dielectric layer on the first substrate including the
 first electrode, the dielectric layer having a channel to provide a steady
 state UV emission in the electric charge chamber.
 In another aspect of the present invention, a plasma display panel device
 includes first and second substrates, a first electrode on the first
 substrate, a second electrode on the second substrate, a pair of barrier
 ribs connecting the first and second substrates, an electric charge
 chamber between the first and second substrates, and a UV-visible photon
 conversion layer between the first and second substrate, the UV-visible
 photon conversion layer having at least one channel to provide a steady
 state UV emission in the electric charge chamber.
 In another aspect of the present invention, a plasma display panel device
 includes first and second substrates, a first electrode on the first
 substrate, a first dielectric layer on the first electrode, a second
 electrode on the first dielectric layer, a second dielectric layer on the
 second electrode, a third electrode on the second substrate, a UV-visible
 photon conversion layer on the second substrate including the third
 electrode, a pair of barrier ribs connecting the first and second
 substrates, and first and second electric charge chambers between the
 first and second substrates defined by the barrier ribs.
 In another aspect of the present invention, a plasma display panel device
 includes first and second substrates, first and second electrodes on the
 first substrate, a first dielectric layer on the first substrate including
 the first and second electrodes, a third electrode on the first dielectric
 layer, a fourth electrode on the second substrate layer, a UV-visible
 photon conversion layer on the second substrate including the fourth
 electrode, a pair of barrier ribs connecting the first and second
 substrates, a first electric charge chamber between the first and second
 substrates defined by the barrier ribs, and a second electric charge
 chamber between the first and second electrodes in the first dielectric
 layer.
 In another aspect of the present invention, a method of fabricating a
 plasma display panel device having first and second substrates, comprising
 the steps of forming a first electrode on the first substrate, forming a
 dielectric layer on the first substrate including the first electrode, and
 forming at least one channel in the dielectric layer to expose the first
 electrode.
 In a further aspect of the present invention, a method of fabricating a
 plasma display panel device having first and second substrates, comprising
 the steps of forming a first electrode on the first substrate, forming a
 UV-visible photon conversion layer on the first substrate including the
 first electrode, and forming at least one channel in the UV-visible photon
 conversion layer to expose the first electrode.
 It is to be understood that both the foregoing general description and the
 following detailed description are exemplary and explanatory and are
 intended to provide further explanation of the invention as claimed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
 Reference will now be made in detail to the preferred embodiments of the
 present invention, examples of which are illustrated in the accompanying
 drawings.
 Capillary Plasma Electrode Discharge ("CPED") PDP device of the present
 invention utilizes a new type of electrical discharge in a gas in which
 the electrodes produce a high density plasma. Plasma is generated in
 capillary tubes placed in front of and with the axis perpendicular to
 metal electrodes. A diameter of the plasma electrode is determined by the
 number of capillaries that are combined in parallel, as well as by their
 separation. The density and diameter of the capillaries can be varied for
 optimizing the discharge characteristics.
 FIGS. 3A to 3C illustrate comparison of the intensity of the plasma
 discharge between the conventional AC barrier type and the capillary
 electrode discharge of the present invention. Both AC and unipolar pulses
 are used to power the electrodes. As shown in FIGS. 3B and 3C, a plasma
 jet emanating from the capillaries is clearly visible and much more
 brighter than that in FIG. 3A. Accordingly, the intensity of the discharge
 is significantly larger than that of the conventional AC barrier discharge
 for the same conditions.
 These features of the capillary discharge of the present invention are
 schematically illustrated in FIGS. 4A to 4C. FIG. 4A shows a field inside
 the capillary Ec generating a high field discharge starting from the metal
 electrode and an applied electrode field Ea. A high density plasma in the
 capillary emerges from the end of the capillary into the gap serving as an
 electrode for a main discharge. The field inside the capillary does not
 collapse after forming a streamer discharge. This is due to a high
 electron-ion recombination at the wall requiring a large production rate
 on the axis (and therefore a high field) in order to sustain the current.
 A double layer exists at the interface of the capillary plasma and the
 main discharge. By selecting a ratio of the diameter d of the capillary to
 the length of the capillary tube L, a steady state plasma discharge can be
 sustained, as shown in FIG. 4C. A dielectric layer is not necessary to
 cover an anode if unipolar operation is desired.
 A plasma display panel (PDP) device according to a first embodiment of the
 present invention will be described with reference to FIG. 5A. As shown in
 FIG. 5A, a PDP device includes a front glass panel 501, and a rear glass
 panel 507 disposed facing each other. An electrode 502 is formed on the
 front glass panel 501. A dielectric layer 503 is formed on the front glass
 panel 501 including the electrode 502. If necessary, a magnesium oxide
 (MgO) layer may be formed on the dielectric layer 503. On the rear glass
 panel 507, a counter electrode 506 is formed thereon. The counter
 electrode 506 may be disposed at the center of the rear glass panel 507. A
 pair of barrier ribs 504 connect the front glass panel 501 and the rear
 glass panel 507. A UV-visible photon conversion layer 505, for example, a
 phosphor layer, is formed covering the counter electrode 506 between the
 front glass panel 501 and the rear glass panel 507. A electric charge
 chamber 508 is defined by the barrier ribs 504 between the front glass
 panel 501 and the rear glass panel 507. Typically, the electric charge
 chamber 508 is filled with an inert gas mixture such as Xenon (Xe) to
 generate a UV emission. Further, in this embodiment, the dielectric layer
 503 has a channel 509 to expose the electrode 502 to the electric charge
 chamber 508, so that a steady state UV emission is obtained in the
 electric charge chamber. A horizontal cross-section of the channel 509 may
 have a circular or polygonal shape, and a vertical cross-section may be
 have a straight or crooked shape, as shown in FIG. 5B. A dimension of the
 channel may be defined by the following equation:
EQU 1/100&lt;D/L&lt;1
 wherein D is a largest cross-section width of the channel and L is a length
 of the dielectric layer.
 Alternatively, a dimension of the channel is an order of an electron mean
 free path or larger than an electron mean free path.
 FIG. 6A is a cross-sectional view showing a PDP device according to a
 second embodiment of the present invention. The second embodiment of the
 present invention includes a front glass panel 601, a rear glass panel
 609, and first and second electrodes 602 and 603 on the front glass panel
 601. A transparent dielectric layer 604 is formed on the front glass panel
 601 including the first and second electrodes 602 and 603. Although a
 magnesium oxide (MgO) layer 605 is not required in the present invention,
 a MgO layer 605 may be formed on the transparent dielectric layer 604. A
 pair of barrier ribs 606 connect the first and second glass panels 601 and
 609 and define an electric charge chamber 610. An address electrode 608 is
 positioned on the center of the rear glass panel 609. Further, a
 UV-visible photon conversion layer 607, such as a phosphor layer, is
 formed on the second glass panel 609 including the address electrode 608.
 In this embodiment, first and second channels 611 and 612 through the
 transparent dielectric layer 604 are formed to expose the first and second
 electrodes 602 and 603 to provide a steady state UV emission as described
 in FIGS. 4A to 4C. Dimensions of the first and second electrodes 602 and
 603 may be the same as the dimension disclosed in the first embodiment. A
 horizontal cross-section of the channels 611 may have a circular shape or
 polygonal shape, and a vertical cross-section may have a straight or
 crooked shape, as shown in FIG. 6B. The electric charge chamber 610 is
 filled with an inert gas such as Xenon (Xe).
 FIG. 7 illustrates a cross-sectional view of a PDP device according to a
 third embodiment of the present invention. The present embodiment includes
 front and back glass panels 701 and 702 facing each other, a transparent
 electrode 703 such as an indium tin oxide (ITO) layer on the front glass
 panel 701. The transparent electrode 703 acts as an anode electrode in a
 DC operation. A conductive electrode 704 is formed on the back glass panel
 702 and acts as a cathode electrode in a DC operation. A UV-visible photon
 conversion layer 705, such as a phosphor layer, is formed on the back
 glass panel 702 including the conductive electrode 704. The UV-visible
 photon conversion layer 705 has a thickness in the range of about 10 to 50
 .mu.m. A pair of barrier ribs 707 connect the front and back glass panels
 701 and 702 and define a electric charge chamber 708.
 In the present embodiment, a plurality of channels 706 are formed through
 the UV-visible photon conversion layer 705 to expose the conductive
 electrode 704 to the electric charge chamber 708. A number of channels in
 the UV-visible photon conversion layer 705 is preferably in the range of 1
 to 100. A vertical cross-section of the channels 706 may have a circular
 shape or polygonal shape, and it may be straight or crooked, as shown in
 FIG. 7. A dimension of each channel may be defined by the following
 equation:
EQU 1/100&lt;D/L&lt;1
 wherein D is a largest cross-section width of the channel and L is a length
 of the UV-visible photon conversion layer.
 FIGS. 8A and 8B are a fourth embodiment of the present invention which
 reduces even further the response time of a PDP device. The present
 embodiment includes front and rear glass panels 801 and 802 facing each
 other. A first electrode 803 is formed on the front glass panel 801. A
 first dielectric layer 804 is formed on the front glass panel 801
 including the first electrode 803. A first electric charge chamber 805 is
 defined in the first dielectric layer 804. A second electrode 806 is
 formed on the first dielectric layer including the first electric charge
 chamber 805. Further, a second dielectric layer 807 is formed on the
 second electrode 806. A pair of barrier ribs 809 connect the first and
 second glass panels 801 and 802 and define a second electric charge
 chamber 812. Alternatively, the first electric charge chamber 805 may be
 formed in the second dielectric layer 807 as shown in FIG. 8B. A third
 electrode 810 is disposed at the center of the rear glass panel 802. A
 UV-visible photon conversion layer 811 such as a phosphor layer is formed
 on the rear glass panel 802 including the third electrode 810. Channels
 808 through the second dielectric layer 807 and the second electrode 806
 are formed to connect the first and second electric charge chambers 805
 and 812. In the present embodiment, the first electric charge chamber 805
 provides a pilot discharge so that turn-on time is reduced for a steady
 state UV emission. A cross-section of the channels 808 may have the same
 dimension and shape as explained in the previous embodiments. The first
 and second electric charge chambers connected through the channel 808 are
 filled with an inert gas, such as Xenon (Xe).
 FIG. 9 is a fifth embodiment of the present invention showing another
 structure to reduce the turn-on time for a PDP device. A PDP device
 according to the present embodiment comprises first and second glass
 panels 801 and 802, first and second electrodes 803 and 804 on the first
 glass panel 801, a first dielectric layer 805 on the first glass panel 801
 including the first and second electrodes 803 and 804. A first electric
 charge chamber 806 is formed in the first dielectric layer 805 to provide
 a pilot discharge, so that it shortens turn-on time for a main discharge.
 The PDP device according to the present embodiment further includes a
 third electrode 807 on the first dielectric layer 805 including the first
 electric charge chamber 806 and a second dielectric layer 808 on the third
 electrode 807. A plurality of channels 809 through the second dielectric
 layer 808 and the third electrode 807 are connected to the first electric
 charge chamber 806, so that the channels provide a steady state UV
 emission for the PDP device. A pair of barrier ribs 810 connect the first
 and second glass panels 801 and 802, thereby defining a second electric
 charge chamber 811. A fourth electrode 812 is formed on the second glass
 panel 802. A UV-visible photon conversion layer 813 is formed on the
 second glass panel 802 including the fourth electrode 812.
 A method of fabricating a plasma display panel device according to the
 present invention is now explained as follows:
 For example, one of methods of fabricating a plasma display panel device is
 described with reference to FIG. SA. First, a first electrode 502 is
 formed on the first substrate 501. Subsequently, a dielectric layer is
 formed on the first substrate including the first electrode. At least one
 channel 509 in the dielectric layer is formed to expose the first
 electrode 502 to an electric charge chamber 508. In this process, the
 channel is formed by one of a laser machining, wet etching, or dry
 etching.
 In another method of fabricating a plasma display panel device, a first
 electrode 704 is initially formed on the first substrate 702 as shown in
 FIG. 7. The first electrode 704 may be formed of a metal electrode. Next,
 a UV-visible photon conversion layer, such as a phosphor layer, is formed
 on the first substrate including the first electrode 704. Then, at least
 one channel 706 is formed in the UV-visible photon conversion layer to
 expose the first electrode to an electric charge chamber 708. Similarly,
 the channel 706 in the UV-visible photon conversion layer is formed by one
 of a laser machining, wet etching, or dry etching.
 A plasma display panel device and method of fabricating the same of the
 present invention has the following advantages.
 Since the field in the capillary does not collapse, a discharge having a
 high electric field is maintained in the capillary. As a result, much
 enhanced brightness is obtained with the CPED plasma display panel device
 of the present invention.
 The PDP of the present invention is operated both in an Ac or DC mode and
 has a discharge operation voltage less than 200 V. This is possible
 because a breakdown voltage is lowered by using a large field across the
 dielectric layer in the early phase of a cycle for generating electron
 avalanches in the capillary. Since a dielectric buried electrode is not
 required, the device structure is much simpler than the conventional PDP
 structures.
 A life time of the device is much improved since a MgO layer or a current
 limiting resistor is not necessary for the present invention. Further,
 unlike the conventional AC operated PDP, the response time is very short
 because a time for dielectric charging is eliminated from the response
 time. Accordingly, the fabrication cost is much reduced because the
 present invention has a simpler structure and better efficiency in
 generating a steady state UV emission.
 It will be apparent to those skilled in the art that various modifications
 and variations can be made in a plasma display panel device and method of
 fabricating the same of the present invention without departing from the
 spirit or scope of the invention. Thus, it is intended that the present
 invention cover the modifications and variations of this invention
 provided they come within the scope of the appended claims and their
 equivalents.