Full color surface discharge type plasma display device Number:6,787,995 from the United States Patent and Trademark Office (PTO) owispatent

Title: Full color surface discharge type plasma display device

Abstract: A full color three electrode surface discharge type plasma display device that has fine image elements and is large and has a bright display. The three primary color luminescent areas are arranged in the extending direction of the display electrode pairs in a successive manner and an image element is composed by the three unit luminescent areas defined by these three luminescent areas and address electrodes intersecting these three luminescent areas. Further, phosphors are coated not only on a substrate but also on the side walls of the barriers and on address electrodes. The manufacturing processes and operation methods of the above constructions are also disclosed.

Patent Number: 6,787,995 Issued on 09/07/2004 to Shinoda,   et al.

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Inventors:	Shinoda; Tsutae (Kawasaki, JP), Awaji; Noriyuki (Kawasaki, JP), Kanagu; Shinji (Kawasaki, JP), Kanae; Tatsutoshi (Kawasaki, JP), Wakitani; Masayuki (Kawasaki, JP), Nanto; Toshiyuki (Kawasaki, JP), Miyahara; Mamaru (late of Kawasaki, JP)
Assignee:	Fujitsu Limited (Kawasaki, JP)
Appl. No.:	09/654,893
Filed:	September 5, 2000

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Related U.S. Patent Documents

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	Application Number	Filing Date	Patent Number	Issue Date
	800759	Feb., 1997	6195070
	469815	Jun., 1995	5661500
	010169	Jan., 1993

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Foreign Application Priority Data

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Jan 28, 1992 [JP]			4-012976
Apr 16, 1992 [JP]			4-96203
Apr 24, 1992 [JP]			4-106953
Apr 24, 1992 [JP]			4-106955
Apr 30, 1992 [JP]			4-110921

Current U.S. Class:	313/582 ; 313/586; 313/587
Current International Class:	H01J 17/49 (20060101)
Field of Search:	313/582,586,587,585,495,496,497,485,486

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References Cited [Referenced By]

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Other References

Kubo, Akira er al., "Full Color Surface-Discharge ac Plasma Display Panels", ITEJ, Technical Report, vol. 12, No. 49, pp. 49-54, EP '88-57, 10 '88-93 (Nov. 1988). . Shinoda et al., "Low-Voltage Operated AC Plasma-Display Panels," IEEE Transactions on Electron Devices, vol. ED-26, No. 8, Aug. 1979, pp. 1163-1167. . Gay et al., "Color Plasma Display Panels with Simplified Structure and Drive," SID 88 Digest, SID International Symposium--Digest of Technical Papers, May 24-26, 1988, Anaheim, CA, pp. 157-159. . Ruckmongathan, T.N., "A Generalized Addressing Technique for RMS Responding Matrix LCDS," 1988 International Display Research Conference, pp. 80-85. . Uchiike et al., "An 86-Ipi High-Resolution Full-Color Surface-Discharge ac Plasma Display Panels," Proceedings of the SID, vol. 31, No. 4, 1990, New York, NY, pp. 361-365. . Yoshikawa et al., "A Full Color AC Plasma Display with 256 Gray Scale," Japan Display '92, Article S16-2, pp. 605-608. . Holz, G.E., "Pulsed Gas Discharged Display with Memory," Burroughs Corporation, ECD, Plainfield, N.J. (2 pages). . Makino et al., "Improvement of Video Image Quality in AC-Plasma Display Panels by Suppressing the Unfavorable Coloration Effect with Sufficient Gray Shades Capability," Asia Display '95, Proceedings of the Fifteenth International Display Research Conference, Oct. 16-18, 1995, Hamamatsu, Japan, Article S19-3, pp. 381-384. . Osamu, T., "Innovation and Commercial Viability of Large Area Plasma Display through Fujitsu's Continued R&D Activities," IDW '96, Proceedings of the Third International Display Workshops, vol. 2, Nov. 27-29, 1996, Kobe, Japan, pp. 7-10..

Primary Examiner: Patel; Nimeshkumar D.
Assistant Examiner: Santiago; Mariceli
Attorney, Agent or Firm: Staas & Halsey LLP

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Parent Case Text

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This is a continuation of application Ser. No. 08/800,759, filed Feb. 13, 1997, now U.S. Pat. No. 6,195,070, which is a continuation of application Ser. No. 08/469,815, filed Jun. 6, 1995, now U.S. Pat. No. 5,661,500, which is a continuation of application Ser. No. 08/010,169, filed Jan. 28, 1993, abandoned.

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Claims

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What is claimed is:

1. A discharge cell of a surface discharge type plasma display panel, comprising: a cavity bounded by a pair of opposing and spaced sidewalls of respective barriers, formed on a first substrate, extending commonly with the pair of sidewalls in a first direction; an address electrode on the first substrate and extending in the first direction; a pair of display electrodes formed on a surface of a second substrate, covered by an insulating layer and positioned in opposed relationship with the address electrode, the pair of display electrodes extending in a second direction and defining the discharge cell, wherein a width of the cell, in the second direction, is approximately one-third a length thereof, in the first direction; and a phosphor layer disposed within the cavity on one of the first and second substrates, the phosphor layer having a thickness in a range of from 10 .mu.m to 50 .mu.m.

2. A discharge cell as recited in claim 1, wherein the phosphor layer is formed on the first substrate, aligned within the cavity, and covers the entire surface of the cavity including sidewalls of the pair of barriers and thereby to constitute a discharge cell of a reflecting type plasma display panel.

3. A discharge cell as recited in claim 1, wherein the pair of display electrodes has a discharge gap of a first width at a central portion of a unit luminescent area and a gap of a second, greater width, at both end portions of the unit luminescent area.

4. A discharge cell as recited in claim 1, wherein a top portion of each barrier is of a dark color.

5. A discharge cell as recited in claim 2, wherein a top portion of each barrier is of a dark color.

6. A discharge cell as recited in claim 1, wherein each of the pair of display electrodes comprises a metal conductor extending in the second direction, transverse to the first direction and the pair of spaced barriers, the pair of metal conductors having a combined width in the first direction which is limited so as not to block more than 21% of light emitted from the discharge cell.

7. A plasma display panel of a surface discharge type and having an array, of plural columns in the first direction and plural rows in a second direction transverse to the first direction, of plural image elements, each image element comprising a respective set of unit luminescent areas, each set of unit luminescent areas comprising a set of discharge cells, wherein each discharge cell comprises: a cavity bounded by respective opposing and spaced sidewalls of a pair of barriers formed on a first substrate, the cavity extending commonly with the pair of barriers in a first direction; an address electrode on the first substrate, extending in the first direction, a pair of display electrodes formed on a surface of a second substrate covered by an insulating layer and positioned in opposed relationship with the address electrode, the pair of display electrodes extending in a second direction, and defining the discharge cell, and a phosphor layer disposed within the cavity on the first substrate; and each set of discharge cells has respective, first and second combined dimensions in the first and second direction which are substantially the same and comprises a common number of discharge cells in successively spaced adjacent positions in the second direction, the respective phosphor layers of each set of the discharge cells being in a common sequence of respective, different colors, and the plural rows of the array having respective, common numbers of sets of discharge cells, aligned in the columns of the array.

8. A plasma display panel as recited in claim 7 wherein in each discharge cell, the phosphor layer covers the respective, opposing sidewalls of the pair of barriers.

9. A plasma display panel as recited in claim 7 wherein, in each discharge cell, the phosphor layer is formed on the first substrate, aligned within the cavity, and covers the address electrode and extends to the respective, opposing sidewalls of the pair of barriers, said phosphor layer having a thickness in a range of from 10 .mu.m to 50 .mu.m.

10. A plasma display panel recited in claim 7, wherein each of the pair of display electrodes of each discharge cell comprises a transparent conductor and a respective metal conductor extending therewith in the second direction, and the pair thereof provides a predetermined discharge gap at a central portion of the cell.

11. A plasma display panel as recited in claim 7 wherein, in each discharge cell, the phosphor layer is formed within the cavity and extends to the respective, opposing sidewalls of the barriers and a top portion of each of the barriers has a dark color.

12. A plasma display panel as recited in claim 7, wherein each of the pair of display electrodes comprises a metal conductor extending in the second direction, transverse to the first direction and the pair of spaced barriers, the pair of metal conductors having a combined width in the first direction which is limited so as not to block more than 21% of light emitted from the discharge cell.

13. A discharge cell of a surface discharge type plasma display panel, comprising: a cavity bounded by respective opposing and spaced sidewalls of a pair of barriers superposed on a first substrate, the cavity extending commonly with the pair of barriers in a first direction; an address electrode superposed on the first substrate, adjacent a bottom of the cavity and extending in the first direction; a pair of display electrodes superposed on a surface of a second substrate, covered by an insulating layer and positioned in opposed relationship with respect to the address electrode, the pair of display electrodes extending in a second direction and defining the discharge cell, wherein a width of each cell, in the second direction, is approximately one-third a length thereof, in the first direction; and a phosphor layer disposed within the cavity and superposed on one of the first and second substrates, the phosphor layer having a thickness in a range of from 10 .mu.m to 50 .mu.m.

14. A discharge cell as recited in claim 13, wherein the phosphor layer is superposed on and covers the address electrode and exposed portions of the first substrate between the spaced and opposing sidewalls and substantially the entire respective surfaces of the spaced and opposing sidewalls of the pair of barriers.

15. A discharge cell as recited in claim 13, wherein the pair of display electrodes has a discharge gap of a first width at a central portion of a discharge cell and a gap of a second, greater width, at both end portions of the discharge cell.

16. A discharge cell as recited in claim 13, wherein a top portion of each barrier is of a dark color.

17. A discharge cell as recited in claim 14, wherein a top portion of each barrier is of a dark color.

18. A discharge cell as recited in claim 13, wherein each of the pair of display electrodes comprises a metal conductor extending in the second direction, transverse to the first direction and the pair of spaced barriers, the pair of metal conductors having a combined width in the first direction which is limited so as not to block more than 21% of light emitted from the discharge cell.

19. A plasma display panel of a surface discharge type and having an array, of plural columns in the first direction and plural rows in a second direction transverse to the first direction, of plural image elements, each image element comprising a respective set of unit luminescent areas, each set of unit luminescent areas comprising a set of discharge cells, wherein each discharge cell comprises: a cavity bounded by respective opposing and spaced sidewalls of a pair of parallel barriers superposed on a first substrate, the cavity extending commonly with the pair of barriers in a first direction; an address electrode superposed on the first substrate, adjacent a bottom of the cavity and extending in the first direction, a pair of display electrodes superposed on a second substrate covered by an insulating layer and positioned in opposed relationship with respect to the address electrode, the pair of display electrodes extending in a second direction, transversely to and crossing the pair of barriers and the cavity therebetween, and defining the discharge cell, and a phosphor layer disposed within the cavity and superposed on and covering the address electrode; and each set of discharge cells has respective, first and second combined dimensions in the first and second directions which are substantially the same and comprises a common number of discharge cells in successively spaced adjacent positions in the second direction, the respective phosphor layers of each set of the discharge cells being in a common sequence of respective, different colors, and the plural rows of the array having respective, common numbers of sets of discharge cells, aligned in the columns of the array.

20. A plasma display panel as recited in claim 19, wherein: each set of discharge cells comprises plural cells having plural, respective and different color phosphor layers, each of which layers having a thickness in a range of from 10 .mu.m to 50 .mu.m.

21. A plasma display panel as recited in claim 19, wherein: the plural cells of each set are of a common width in the second direction.

22. A plasma display panel as recited in claim 19 wherein, in each discharge cell, the phosphor layer, further, covers the respective, opposing sidewalls of the pair of barriers.

23. A plasma display panel as recited in claim 19, wherein said phosphor layer has a thickness in a range of from 10 .mu.m to 50 .mu.m.

24. A plasma display panel recited in claim 19, wherein each of the pair of display electrodes of each discharge cell comprises a transparent conductor and a respective metal conductor extending therewith in the second direction, and the pair thereof provides a predetermined discharge gap at a central portion of the cell.

25. A plasma display panel as recited in claim 19 wherein, in each discharge cell, the phosphor layer is formed within the cavity and extends to the respective, opposing sidewalls of the barriers and a top portion of each of the barriers has a dark color.

26. A plasma display panel as recited in claim 19, wherein each of the pair of display electrodes comprises a metal conductor extending in the second direction, transverse to the first direction and the pair of spaced barriers, the pair of metal conductors having a combined width in the first direction which is limited so as not to block more than 21% of light emitted from the discharge cell.

27. A discharge cell of a surface discharge type plasma display panel, comprising: a cavity bounded at least in part by a respective cavity sidewall supported by a back substrate; an address electrode supported by the back substrate, aligned with the cavity and extending in a first direction; a pair of display electrodes supported by a front substrate, covered by an insulating layer and positioned in opposed, spaced relationship with respect to a portion of the aligned address electrode and defining the discharge cell therebetween, said pair of display electrodes extending in a second direction; and a phosphor layer disposed within the cavity and supported on the cavity sidewall and the portion of the aligned address electrode, wherein a width of each discharge cell, in the second direction, is approximately one-third a length thereof, in the first direction.

28. A discharge cell as recited in claim 27, wherein the phosphor layer has a thickness in a range of from 10 .mu.m to 50 .mu.m.

29. A discharge cell as recited in claim 28, wherein a top portion of each cavity sidewall is of a dark color.

30. A discharge cell as recited in claim 27, wherein the pair of display electrodes has a discharge gap of a first width at a central portion of a discharge cell and a gap of a second, greater width, at both end portions of the discharge cell.

31. A discharge cell as recited in claim 27, wherein the address electrode is disposed adjacent a bottom of the cavity.

32. A discharge cell as recited in claim 27, wherein each of the pair of display electrodes comprises a metal conductor extending in the second direction, transverse to the first direction, the pair of metal conductors having a combined width in the first direction which is limited so as not to block more than 21% of light emitted from the discharge cell.

33. A plasma display panel of a surface discharge type and having an array, of plural columns in the first direction and plural rows in a second direction transverse to the first direction, of plural image elements, each image element comprising a respective set of unit luminescent areas, each set of unit luminescent areas comprising a set of discharge cells, wherein each discharge cell comprises: a cavity bounded at least in part by a respective cavity sidewall supported by a back substrate; an address electrode supported by the back substrate, aligned with the cavity and extending in a first direction; a pair of display electrodes supported by a front substrate, covered by an insulating layer and positioned in opposed, spaced relationship with respect to, and extending in a second direction and crossing, a portion of the aligned address electrode and defining the discharge cell therebetween; a phosphor layer disposed within the cavity and supported on the cavity sidewall and the portion of the aligned address electrode; and each set of discharge cells has respective, first and second combined dimensions in the first and second directions which are substantially the same comprises a common number of discharge cells in successively spaced adjacent positions in the second direction, the respective phosphor layers of each set of the discharge cells being in a common sequence of respective, different colors, and the plural rows of the array having respective, common numbers of sets of discharge cells, aligned in the columns of the array.

34. A plasma display panel as recited in claim 33, wherein: each set of discharge cells comprises plural cells having plural, respective and different color phosphor layers, each of which layers having a thickness in a range of from 10 .mu.m to 50 .mu.m.

35. A plasma display panel as recited in claim 33, wherein: the plural cells of each set are of a common width in the second direction.

36. A plasma display panel as recited in claim 33 wherein, in each discharge cell, the phosphor layer covers the respective, opposing sidewalls of the pair of barriers.

37. A plasma display panel as recited in claim 33 wherein, in each discharge cell, the phosphor layer covers the address electrode and has a thickness in a range of from 10 .mu.m to 50 .mu.m.

38. A plasma display panel as recited in claim 33 wherein, in each discharge cell, a top portion of each cavity sidewall has a dark color.

39. A plasma display panel recited in claim 33, wherein each of the pair of display electrodes of each discharge cell comprises a transparent conductor and a respective metal conductor extending therewith in the second direction, and the pair thereof provides a predetermined discharge gap at a central portion of the discharge cell.

40. A plasma display panel as recited in claim 33, wherein each of the pair of display electrodes comprises a metal conductor extending in the second direction, transverse to the first direction, the pair of metal conductors having a combined width in the first direction which is limited so as not to block more than 21% of light emitted from the discharge cell.

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Description

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BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a surface discharge type full color surface discharge type plasma display panel and a process for manufacturing the same. More specifically, the present invention relates to a full color ac plasma display device high in resolution and brightness of display such that it is adaptable to a high quality display, such as a high definition TV, and can be used in daylight.

2. Description of the Related Art

A plasma display panel (PDP) has been considered the most suitable flat display device for a large size, exceeding over 20 inches, because a high speed display is possible and a large size panel can easily be made. It is also considered to be adaptable to a high definition TV. Accordingly, an improvement in full color display capability in plasma display panels is desired.

In the past, two electrode type dc and ac plasma display panels have been proposed and developed. Also, a surface discharge type ac plasma display panel, among other plasma display panels, has been known to be suitable for a full color display.

For example, a surface discharge type ac plasma display panel having a three electrode structure comprises a plurality of parallel display electrode pairs formed on a substrate and a plurality of address electrodes perpendicular to the display electrode pairs for selectively illuminating unit luminescent areas. Phosphors are arranged, in order to avoid damage by ion bombardment, on the other substrate facing the display electrode pairs with a discharge space between the phosphor and the display electrode pairs and are excited by ultra-violet rays generated from a surface discharge between the display electrodes, thereby causing luminescence. See for example, U.S. Pat. No. 4,638,218 issued on Jan. 20, 1987 and U.S. Pat. No. 4,737,687 issued on Apr. 12, 1988.

The full color display is obtained using an adequate combination of three different colors, such as red (R), green (G) and blue (B), and an image element is defined by at least three luminescent areas corresponding to the above three colors.

Conventionally, an image element is composed of four subpixels arranged in two rows and two columns, including a first color luminescent area, for example, R, a second color luminescent area, for example, G, a third color luminescent area, for example, G, and a fourth color luminescent area, for example, B. Namely, this image element comprises four luminescent areas of a combination of three primary colors for additive mixture of colors and an additional green having a high relative luminous factor. By controlling the additional green area independent from the other three luminescent areas, an apparent image element number can be increased and thus an apparent higher resolution or finer image can be obtained.

In this arrangement of four subpixels, two pairs of display electrodes cross an image element, i.e., each pair of display electrodes crosses each row or column of subpixels, which is apparently disadvantageous in making image elements finer.

If the image elements are to be finer, formation of finer display electrodes becomes difficult and the drive voltage margin for avoiding interference of discharge between different electrode lines becomes narrow. Moreover, the display electrodes become narrower, which may cause damage to the electrodes. Further, a display of one image element requires time for scanning two lines, which may make a high speed display operation difficult because of the frequency limitation of a drive circuit.

The present invention is directed to solve the above problem and provide a flat panel full color surface discharge type plasma display device having fine image elements.

JP-A-01-304638, published on Dec. 8, 1989, discloses a plasma display panel in which a plurality of parallel barriers are arranged on a substrate and luminescent areas, in the form of strips defined by the parallel barriers, are formed. This disclosure is, however, directed only to two electrode type plasma display panels, not to a three electrode type plasma display panel in which parallel display electrode pairs and address electrodes intersecting the display electrode pairs are arranged and three luminescent areas are arranged in the direction of the extending lines of the display electrode pairs as in the present invention.

The present invention is also directed to a plasma display panel exhibiting a high image brightness at a wide view angle range. In this connection, U.S. Pat. No. 5,086,297 issued on Feb. 4, 1992, corresponding to JP-A-01-313837 published on Dec. 19, 1989, discloses a plasma display panel in which phosphors are coated on side walls of barriers. Nevertheless, in this plasma display panel, the phosphors are coated selectively on the side walls of barriers and do not cover the flat surface of the substrate on which electrodes are disposed.

SUMMARY OF THE INVENTION

To attain the above and other objects of the present invention, there is provided a full color surface discharge type plasma display device comprising pairs of lines of display electrodes (X and Y), each pair of lines of display electrodes being parallel to each other and constituting an electrode pair for surface discharge; lines of address electrodes (22 or A) insulated from the display electrodes and running in a direction intersecting the lines of display electrodes; three phosphor layers (28R, 28G and 28B), different from each other in respective luminescent colors, facing the display electrodes and arranged in a successive order of the three phosphor layers along the extending lines of the display electrodes, and a discharge gas in a space (30) between said display electrodes and said phosphor layers, wherein the adjacent three phosphor layers (28R, 28G and 28B) (EU) of said three different luminescent colors and a pair of lines of display electrodes define one image element (EG) of a full color display.

In accordance with the present invention, there is also provided a full color surface discharge plasma display device comprising first and second substrates facing and parallel to each other for defining a space in which a discharge gas is filled; pairs of lines of display electrodes formed on the first substrate facing the second substrate, each pair of lines of display electrodes being parallel to each other and constituting an electrode pair for surface discharge; a dielectric layer over the display electrodes and the first substrate; lines of address electrodes formed on the second substrate facing the first substrate and running in a direction intersecting the lines of display electrodes; three phosphor layers, different from each other in respective luminescent colors, formed on the second substrate in a successive order of said three luminescent colors along the extending lines of the display electrodes, the phosphor layers entirely covering the address electrodes; and barriers standing on the second substrate to divide and separate said discharge space into cells corresponding to respective phosphor layers, the barriers having side walls; wherein the adjacent three phosphor layers of said three different luminescent colors and a pair of lines of display electrodes define one image element of a full color display and said phosphor layers extend to the side walls of said barriers to cover almost the entire surfaces of the side walls of said barriers.

In accordance with a preferred embodiment of the present invention, there is provided a full color surface discharge plasma display device comprising first and second substrates facing and parallel to each other for defining a space in which a discharge gas is filled, the first substrate being disposed on a side of a viewer; pairs of to lines of display electrodes formed on the first substrate facing the second substrate, each pair of lines of display electrodes being parallel to each other and constituting an electrode pair for surface discharge, each of the display electrodes comprising a combination of a transparent conductor line and a metal line in contact with said transparent conductor line and having a width narrower than that of the transparent conductor line; a dielectric layer over the display electrodes and the first substrate; lines of address electrodes formed on the second substrate facing the first substrate and running in a direction intersecting the lines of display electrodes; barriers standing on the second substrate, in parallel to said address electrodes, for dividing said discharge gas space into cells, the barriers having side walls; and three phosphor layers, different from each other in respective luminescent colors formed on the second substrate in a successive order of said three luminescent colors along the extending lines of the display electrodes, the phosphor layers entirely covering the address electrodes and extending to the side walls of said barriers to cover almost the entire surfaces of the side walls of said barriers; wherein the adjacent three phosphor layers of said three different luminescent colors and a pair of lines of display electrodes define one image element of a full color display.

To protect the phosphor provided over the address electrode from ion bombardment, the following drive can be adopted. First, an erase address type drive control system in which once all image elements corresponding the pair of to the display electrodes are written, an erase pulse is applied to one of the pair of the display electrodes and simultaneously an electric field control pulse for neutralizing or cancelling the applied erase pulse is selectively applied to the address electrodes.

Second, a write address type drive control system is provided in which in displaying a line corresponding to a pair of the display electrodes, a discharge display pulse is applied to one of the pair of the display electrodes and simultaneously an electric field control pulse for writing is selectively applied to the address electrodes. This write address type drive control system is preferably constituted such that in displaying a line corresponding to a pair of the display electrodes, once all image elements corresponding to the display electrodes are subject to writing and erasing discharges, to store positive electric charges above said phosphor layers and negative electric charges above said insulating layer, an electric discharge display pulse is applied to one of the pair of the display electrodes to make said one of the pair of the display electrodes negative in electric potential to the other of the pair of the display electrodes, and an electric discharge pulse is selectively applied to the address electrodes to make the address electrodes positive in electric potential relatively to said one of the pair of the display electrodes.

It is preferred in the above full color surface discharge plasma display device that the image element has an almost square area and each of the three phosphor layers has a rectangular shape that is obtained by dividing the square of the image element and is long in a direction perpendicular to the lines of display electrodes. Additionally, it is preferred that each of the lines of the display electrodes comprises a combination of a transparent conductor line and a metal line in contact with the transparent conductor line and having a width narrower than that of the transparent conductor line and is disposed on the side of a viewer compared with the phosphor layers; the transparent conductor lines have partial cutouts in such a shape that the surface discharge is localized to a portion between the display electrodes without the cutout in each unit luminescent area; the total width of a pair of the display electrodes and a gap for discharge formed between the pair of the display electrodes is less than 70% of a pitch of the pairs of display electrodes; the device further comprises barriers standing on a substrate and dividing and separating the space between the display electrodes and the phosphor layers into cells corresponding to respective phosphor layers; the barriers have side walls and the phosphor layers extend to and almost entirely cover the side walls of the barriers; the address electrodes exist on a side of the substrate opposite to the display electrodes and the address electrodes are entirely covered with the phosphor layers; the device further comprises a substrate and a underlying layer of a low melting point glass containing a light color colorant formed on the substrate and the address electrodes are formed on the underlying layer; at least part of the barriers comprises a low melting point glass containing a light color colorant; and the barriers comprise a low melting point glass containing a dark color colorant in a top portion thereof and a low melting point glass admixed with a light color colorant in the other portion.

In accordance with the present invention, there is also provided a process for manufacturing a full color surface discharge plasma display device as above, in which the address electrodes and the barriers are parallel to each other and the address electrodes comprise a main portion for display parallel to the barriers and a portion at an end of said main portion for connecting to outer leads, the process comprising the steps of printing a material for forming the main portions of the address electrodes using a printing mask, printing a material for forming the outer lead-connecting portions, and printing a material for forming the barriers using the printing mask used for printing the material for forming the main portions of the address electrodes.

Further, there is also provided a process for manufacturing a full color surface discharge type plasma display device as above. This process comprises the steps of forming the barriers on the second substrate, almost filling gaps between the barriers above the second substrate with a phosphor paste, firing the phosphor paste to reduce the volume of the phosphor paste and form recesses between the barriers and to form a phosphor layer covering almost the entire surfaces of side walls of the barriers and covering surfaces of the second substrate between the barriers.

It is preferred that the phosphor paste comprise 10 to 50% by weight of a phosphor and the filling of the phosphor paste be performed by screen printing the phosphor paste into the spaces with a square squeezer at a set angle of 70 to 85 degrees.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows the basic construction of a full color surface discharge type plasma display device of the present invention;

FIG. 2 is a perspective view of a full color flat panel ac plasma display device of the present invention;

FIG. 3A shows a first structure of plasma display devices of the prior art;

FIG. 3B shows a second structure of plasma display devices of the prior art;

FIG. 4 shows a third structure of plasma display devices of the prior art;

FIG. 5 shows a first operation of plasma display devices of the prior art;

FIG. 6 shows a fourth structure of plasma display devices of the prior art;

FIG. 7 is one perspective view of another full color flat panel ac plasma display device of the present invention;

FIG. 8 is a second perspective view of another full color flat panel ac plasma display device of the present invention;

FIG. 9 is a first graph illustrating the brightness of display versus the view angle;

FIG. 10 is a second graph illustrating the brightness of display versus the view angle;

FIG. 11 is a first graph to illustrate how the stability of the discharge varies based on the structures of the barriers;

FIG. 12 is a second graph to illustrate how the stability of the discharge varies based on the structures of the barriers;

FIG. 13 is a third graph to illustrate how the stability of the discharge varies based on the structures of the barriers;

FIG. 14 is a block diagram of a full color flat panel ac plasma display device of an embodiment of the present invention;

FIG. 15 schematically shows the arrangement of the electrodes of the plasma display panel, as in FIG. 14;

FIG. 16 shows the waveform of the addressing voltage of a full color flat panel ac plasma display device in an embodiment of the present invention;

FIG. 17 is a block diagram of a full color flat panel ac plasma display device of another embodiment of the present invention;

FIG. 18 shows the waveform of the addressing voltage of a full color flat panel ac plasma display device in another embodiment of the present invention;

FIGS. 19A to 19H show the state of the electric charges at main stages in the operation in accordance with the waveform of the addressing voltage of FIG. 18;

FIG. 20 shows an ideal coverage of a phosphor layer on barriers and a substrate;

FIG. 21 shows the relationship between the thickness of the phosphor layer and the content of phosphor in a phosphor paste;

FIGS. 22A to 22C are cross-sectional views, used as an aid for understanding the main steps of forming a phosphor layer in a preferred embodiment of the present invention;

FIG. 23 is a perspective view of a flat panel ac plasma display device;

FIGS. 24A and 24B are planar views, used as an aid for understanding the steps of forming address electrodes and barriers on a glass substrate in the prior art; and

FIGS. 25A to 25E are planar and segmented views, used as an aid for understanding the steps of forming address electrodes and barriers on a glass substrate in a preferred embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Before describing the present invention in more detail, the prior art is described with reference to drawings so as to understand the present invention more clearly.

FIGS. 3A and 3B show the basic respective constructions of dc and ac two electrode plasma display panels. These constructions of two electrode plasma display panels appear in FIGS. 5 and 6 of JP-A-01-304638. In FIG. 3A of the present application, i.e., an opposite discharge type dc plasma display panel, two substrates 51 and 52 are faced parallel to each other. Gas discharge cells 53 are defined by straight cell barriers 54 and the two substrates 51 and 52. A discharge gas exists in the discharge cells 53. An anode 55 is formed on a substrate 51 on the side of the viewer. A cathode 56 is formed on the other substrate 52. A phosphor layer 57, in the form of strip, is formed on the substrate 51, such that the anode 55 and the phosphor layer 57 do not overlap each other. When a dc voltage is applied between the anode 55 and the cathode 56, an electric discharge emitting ultra-violet rays occurs in the discharge cell 53, which illuminates the phosphor layer 57. Separating the phosphor layer 57 from the anode 55 is to prevent damages of the phosphor layer by ion bombardment due to the discharge, since if the phosphor layer overlaps the anode 55, ion bombardment of the anode damages the phosphor layer on the anode 55.

This conventional panel is an opposite discharge type and different from the surface discharge type of the present invention. Although the phosphors and barriers are straight or in the form of strips, the opposite electrodes are arranged to intersect with each other and the phosphors extend in the direction of one of the extending lines of the opposite electrodes. In the opposite discharge type plasma display panel, ions generated during the discharge bombard and deteriorate the phosphors, thereby shortening the life of the panel. In contrast, in a three electrode surface discharge type panel, discharge occurs between the parallel display electrode pairs formed on one substrate, which prevents deterioration of the phosphor disposed on the other side substrate.

FIG. 3B, i.e., a surface discharge type ac plasma display device, two substrates 61 and 62 are faced parallel to each other. Gas discharge cells 63 are defined by straight cell barriers 64 and the two substrates 61 and 62. A discharge gas exists in the discharge cells 63. Two electrodes 65 and 66, arranged normal to each other in plane view, are formed on the substrate 62 with a dielectric layer. 67 therebetween. A second dielectric layer 68 and a protecting layer 69 are stacked on the dielectric layer 67. A phosphor layer 70 is formed as a strip on the substrate 61. When an electric field is applied between the two electrodes 65 and 66, a discharge generating ultraviolet rays occurs, which illuminates the phosphor layer 70.

In this conventional surface discharge type panel, the straight barriers and the strip phosphors are parallel to each other, but the pair of display electrodes are arranged to intersect with each other and the phosphors extend in the direction of one of the display electrode pair. In contrast the three different luminescent color phosphors are arranged in the extending direction of the parallel display electrode pairs.

This conventional surface discharge type panel has several disadvantages. Selection of the materials of the X and Y display electrodes is difficult since the two electrode layers X and Y are stacked upon each other (as a dielectric layer disposed between the two display electrodes is made of a low melting point glass, failure of the upper electrode on the low melting point glass or a short circuit may occur when the low melting point glass is fired). Additionally, a protecting layer at the cross section (i.e., intersection) of the X and Y display electrodes is damaged by discharge due to the electric field concentration there, which causes variation of the discharge voltage. Further, a large capacitance caused by the stack of the two electrodes on one substrate results in disadvantageous drive. As a result of these disadvantages, this type of panel has never been put into practical use.

Also known is a three electrode type surface gas discharge ac plasma display panel as shown in FIG. 4. A display electrode pair Xj and Yj, each comprising a transparent conductor strip 72 and a metal layer 73, are formed on a glass substrate 71 on the display surface side H. A dielectric layer 74 for an ac drive is formed on the substrate 71 to cover the display electrodes Xj and Yj. A first barrier 75 in the form of a cross lattice, defining a unit luminescent area EUj, is formed on the glass substrate 71. Parallel second barriers 76, corresponding to the vertical lines of the barrier 75, are formed on a glass substrate 79 so that discharge cells 77 are defined between the substrates 71 and 79 by the first and second barriers 75 and 76. An address electrode Aj and a phosphor layer 78 are formed on the substrate 79. The address electrode Aj, which selectively illuminates the unit luminescent area EU, and the phosphor layer 78 intersects the display electrode pair Xj and Yj. The address electrode Aj is formed adjacent to the one side barrier 76 and the phosphor layer 78 is adjacent to the other side barrier 76. The address electrode Aj may be formed on the side of the substrate 71, for example, below the display electrode pairs Xj and Yj with a dielectric layer therebetween.

In this ac plasma discharge panel, erase addressing, in which writing (formation of a stack of wall charges) of a line L is followed by selective erasing, and a self-erase discharge is utilized for selective erasing, is typically used.

More specifically, referring to FIGS. 4 and 5, in an initial address cycle CA of a line display period T corresponding to one line display, a positive writing pulse PW having a wave height Vw is applied to display electrodes Xj, which corresponds to a line to be displayed. Simultaneously, a negative discharge sustain pulse having a wave height Vs is simultaneously applied to a display electrode Y corresponding to the line to be displayed. In FIG. 5, the inclined line added to the discharge sustain voltage PS indicates that it is selectively applied to respective lines.

At this time, a relative electrical potential between the display electrodes Xj and Yj, i.e., a cell voltage applied to the surface discharge cell, is above the firing voltage; therefore, surface discharge occurs in all surface discharge cells C corresponding to one line. By the surface discharge, wall charges, having polarities opposite to those of the applied voltage, are stacked on the protecting layer 18 and, accordingly, the cell voltage is lowered to a predetermined voltage at which the surface discharge stops. The surface discharge cells are then in the written state.

Next, a discharge sustain pulse PS is alternately applied to the display electrodes Xj and Yj, and by superimposing the voltage Vs of the discharge sustain pulse PS onto the wall charges, the cell voltages then become the above firing voltage and surface discharge occurs every time one of the discharge sustain pulses PS is applied.

After the written state is made stable by a plurality of surface discharges, at an end stage of the address cycle CA, a positive selective discharge pulse PA having a wave height Va is applied to address electrodes corresponding to unit luminescent areas EU to be made into a non-display state in one line. Simultaneously, the discharge sustain pulse PS is applied to the display electrode Yj, to erase the wall charges unnecessary for display (selective erase). In FIG. 5, the inclined line added to the selective discharge pulse PA indicates that it is selectively applied to each of the unit luminescent areas EU in one line.

At a rising edge of the selective discharge pulse PA, an opposite discharge occurs at an intersection between the address electrode Aj and the display electrode Yj in the direction of the gap of the discharge space 30 between the substrates 11 and 21. By this discharge, excess wall charges are stacked in surface discharge cells and when the selective discharge pulse PA is lowered and the discharge sustain pulse PS is raised, a discharge due to the wall charges only occurs (self erase discharge). The self-erase discharge has a short discharge sustain time since no discharge current is supplied from the electrodes. Accordingly, the wall charges disappear in the form of neutralization.

In the following display cycle CH, the discharge sustain voltage PS is alternately applied to the display electrodes Xj and Yj. At every rising edge of the discharge sustain voltage PS, only the surface discharge cells C in which the wall charges are not lost are subject to discharge, by which ultra-violet rays are irradiated to excite and illuminate the phosphor layers 28. In the display cycle CH, the period of the discharge sustain voltage PS is selected so as to control the display brightness.

The above operation is repeated for every line display period T and the display is performed for respective lines.

It is noted that it is possible for the writing to be performed simultaneously for all lines followed by line-by-line selective erasing of wall discharges, so that the writing time in an image display period (field) is shortened and the operation of display is sped up.

In this three electrode type ac plasma discharge panel, the selection of the discharge cell for electric discharge is memorized and the power consumption for display or sustainment of discharge can be lowered. Second, the electric discharge occurs near the surface of the protecting layer on the display electrode pair Xj and Yj so that damage of the phosphor layer by ion bombardment can be prevented, particularly when the phosphor layer and the address electrode are separated.

FIG. 6 shows a typical arrangement of three different color phosphor layers for a full color display in a three electrode type ac plasma discharge panel. In FIG. 6, EG denotes an image element, EUj denotes a unit luminescent area, R denotes a unit luminescent area of red, G denotes a unit luminescent area of green, B denotes a unit luminescent area of blue, and Xj and Yj denote a pair of display electrodes, respectively.

As seen in FIG. 6, one display line L is defined by the pair of display electrodes Xj and Yj, and each image element EG is composed of four unit luminescent areas EUj of two rows and two columns, to which two lines L, i.e., four display electrodes Xj and Yj correspond. In an image element EG, the left upper unit luminescent area EUj is a first color, e.g. R, the right upper and left lower unit luminescent areas EUj are a second color, e.g. G, and the right lower unit luminescent area EUj is a third color, e.g. B. More specifically, the image element EG includes a combination of unit luminescent areas EUj of the three primary colors for mixture of additive colors. EG also includes an additional unit lumi