US3573531A - Plasma panel display device - Google Patents

Abstract

A high contrast plasma display device includes transparent and opaque insulator layers spaced and bonded by a plurality of spaced opaque insulator segments forming a plurality of cavities. An insulator substrate having a plurality of spaced conductors on the surface thereof in registry with the cavities and electrical connectors embedded therein is bonded to the opaque insulator layer while a transparent electrode layer is affixed to the transparent insulator layer. An ionizable gas is disposed within the cavities whereby energization of certain conductors alters the device from an opaque to a visual display. Also, the high contrast plasma display device is fabricated by a process which includes affixing the spaced conductor to a substrate, bonding an opaque insulator layer to the substrate and spaced conductors, attaching spaced opaque insulator segments to a transparent insulator layer, bonding the segments to the opaque insulator layer forming cavities in registry with the spaced conductors, affixing a transparent electrode to the transparent insulator layer, and disposing an ionizable gas within the cavities whereby the device appears opaque until energized to provide a visual display.

Description

United States Patent [72] Inventors Donald R. Kerstetter Emporium; Everett C. Smith, Butler, Pa. [2]] Appl. No. 808,271 [22] Filed Mar. 18, 1968 [45] Patented Apr. 6, 1971 [73] Assignee Sylvania Electric Products Inc.

[54] PLASMA PANEL DISPLAY DEVICE Primary ExaminerRobert Segal Attorneys-Norman J. OMalley, Donald R. Castle and Thomas H. Buffton ABSTRACT: A high contrast plasma display device includes transparent and opaque insulator layers spaced and bonded by a plurality of spaced opaque insulator segments forming a plurality of cavities. An insulator substrate having a plurality of spaced conductors on the surface thereof in registry with the cavities and electrical connectors embedded therein is bonded to the opaque insulator layer while a transparent electrode layer is affixed to the transparent insulator layer. An ionizable gas is disposed within the cavities whereby energization of certain conductors alters the device from an opaque to a visual display.

Also, the high contrast plasma display device is fabricated by a process which includes affixing the spaced conductor to a substrate, bonding an opaque insulator layer to the substrate and spaced conductors, attaching spaced opaque insulator segments to a transparent insulator layer, bonding the segments to the opaque insulator layer forming cavities in registry with the spaced conductors, affixing a transparent electrode to the transparent insulator layer, and disposing an ionizable gas within the cavities whereby the device appears opaque until energized to provide a visual display.

Patented April 6, 1971 AFFIX SPACED CONDUCTORSTO SUBSTRATE HAVING ELECTRICAL CONNECTORS EXTENDING THERETHROLLGH BOND OPAGLIE INSULATOR. LAYER TO 'CONDLICTORS AND lNSLlLATOR SI-LBSTRATE ATTACH OPAGLIE INSLLLATOR SEGMENTS TO TRANSPARENT INSULATOR LAYER BOND OPPGLLE SEGMENTS AND OPAGLIE INSLLLATOR LAYER FORMING CAVITIES ALIGNED WITH CONDUCTORS AFFIX TRANSPARENT ELECTRODE LAYER TO TRANSPARENT INSUL- ATOR LAYER DISPOSE IONIZABLE G-AS IN CAVITIES SEAL PERIPHERY OF TRANSPARENT AND OPAGUE INSULATOR LAYERS INVENTORS DONALD R. KERSTETTER 8 EVERETT C. SMITH ATTORNEY IPLASMA PANEL DISPLAY DEVICE BACKGROUND OF THE INVENTION The prior art suggests numerous types of devices for providing a visual display. For instance, there are vacuum-type display devices such as the cathode ray tube; phosphor type devices such as the well-known electroluminescent devices; discharge tubes of the glow discharge variety, and ordinary light sources disposed in the vicinity of the configuration to be displayed. Also, a relatively new type of display device .is the so-called plasma display device which is not only of the solidstate type but also includes a memory capability.

Although each of the above-mentioned types of display device has provided excellent service in numerous applications, it has been found each is limited by one or more features such as relative size, energizing potentials, resolution, and memory. Moreover, all of such display devices are continuously plagued with the problem of lack of contrast between an energized and deenergized state under prevailing ambient lighting conditions.

OBJECTS AND SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to enhance the contrast of a visual display device. Another object of the present invention is to provide an improved plasma display device. Still another object of the invention is to provide a high contrast plasma display device of relatively simple design which is economical of materials and fabrication apparatus and time. A still further object of the invention is to provide an improved process for fabricating a high contrast plasma display device.

These and other objects and advantages are achieved in one aspect of the invention by a plasma display device having transparent and opaque insulator layers separated by spaced opaque insulator segments affixed thereto and forming cavities wherein an ionizable gas is disposed. An insulator support member bonded to the opaque insulator layer has a plurality of electrical connectors embedded therein and extending therethrough and a plurality of spaced conductors affixed to a surface in registry with the cavities A transparent electrode layer is affixed to the transparent insulator layer.

The plasma display device is fabricated in accordance with a process which includes the steps of affixing a plurality of spaced conductors to an insulator substrate having a plurality of electrical connectors therein, bonding an opaque insulator layer to the substrate, attaching a plurality of spaced opaque insulator segments to a transparent insulator layer, bonding the spaced opaque insulator segments to the opaque insulator layer forming cavities in registry with the spaced conductors, affixing a transparent electrode layer to the transparent insulator layer, and disposing an ionizable gas within the cavities.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I illustrates a preferred embodiment of the plasma display device of theinvention; and

FIG. 2 is a flow chart illustrating a preferred process for fabricating a plasma display device of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT For a better understanding of the present invention, together with other and further objects, advantages and capabilities thereof, reference is made to the following disclosure and appended claims in connection with the accompanying drawings.

Referring to the drawings, FIG. I illustrates a preferred embodiment of a high contrast plasma display device which includes a transparent insulator layer 3, such as glass for instance. Also, an opaque insulator layer 5, which is preferably in the form of a black glass frit, is spaced from the transparent insulator layer by a plurality of spaced opaque insulator segments 7. Thus, the transparent and opaque insulator layers 3 and 5 respectively, and the spaced opaque insulator segments 7, form a plurality of cavities 9, intermediate thereto.

An insulator substrate II, such as glass for example, has a plurality of electrical connectors I3 embedded therein and extending therethrough. The connectors 13 are at least flush with one surface I5 of the substrate II, which is bonded to the opaque insulator layer 5, and a plurality of spaced electrical conductors I7 are affixed to the surface I3 in electrical contact with the connectors I3 and in registry with the cavities 9. Also, a transparent electrode layer I9 is affixed to the trans parent insulator layer 3 and an ionizable gas is disposed within the cavities 9. Thereafter, a seal 21 is affixed intermediate the periphery of the transparent and opaque insulator layers 3 and 5 respectively. Moreover, a phosphor Iayer 23, covered by a second transparent insulator layer 25 may be but not neces sarily need be affixed to the transparent electrode layer I9.

As to a preferred process for fabricating the abovedescribed high contrast plasma display device, reference is made to the flow chart of FIG. 2, in conjunction with the structure of FIG. I. As clearly set forth therein, a plurality of spaced electrical conductors I7 of a material such as Nichrome (pcrcent nickel; 20 percent chrome) which will tolerate a reasonably high firing temperature, are affixed to one surface I5 of an insulator substrate II, such as glass. The insulator substrate II has a plurality of electrical connectors I3 embedded therein and each of the conductors 17 contacts and is electrically connected to at least: one of the connectors I3.

Then, an opaque insulator layer 5, of a material such as the well-known and readily available black glass frit, is bonded to and covers the insulator substrate 11 and spaced conductor I7 affixed to the substrate II. Normally, the opaque insulator layer 5 may be applied to the substrate II and conductors I7 by any one of a number of well-known techniques such as silk screening or spraying, and a preferred technique is to employ a cast film. This opaque insulator layer 5 has a thickness dimension, as measured normal to the longitudinal axis of the layer, in the range of about 0.004 to 0.008 inch and a preferred thickness dimension of about 0.006 inch.

Following, a plurality of spaced opaque insulator segments 7 are affixed to a transparent insulator layer 3, such as glass for instance. Again, the segments 7 and. the transparent insulator layer 3 each have a thickness dimension of about 0.004 to 0.008 inch and preferably of about 0.006 inch.

Thereafter, the spaced opaque insulator segments 7 having the transparent insulator layer 3 affixed thereto, are bonded to the opaque insulator layer 5 to provide a plurality of cavities 9 which are aligned with or in registry with the above-mentioned spaced conductors I7 affixed to the insulator substrate II. Then an ionizable gas, such as a neon-nitrogen mixture is disposed within the above-mentioned cavities 9 and the periphery of the transparent and opaque insulator layers 3 and 5 respectively, is sealed by any of the well-known epoxy or metallizing techniques.

A transparent electrode layer I9, such as tin or indium oxide, is applied to the transparent insulator layer 3 by any one of a number of well-known methods. Moreover, the transparent electrode layer I9 may be in segmented form with transparent connectors extending outwardly to the edges of the transparent insulator layer 3.

Additionally, a fluorescent powder Iayer 23 may be affixed to the transparent electrode layer I9 should a variation in display color be desired. Also, a second transparent insulator layer 25, of glass or plastic, may readily be affixed to the fluorescent powder layer 23 to provide a protective coating in a manner well known in the art.

As to the appearance of the high contrast plasma display device, it is obvious that the opaque insulator segments 7 and opaque insulator layer 5 combine to provide a device having an opaque appearance when viewed through the transparent insulator layer 3. It is also obvious that energization of certain ones of the conductors I7, causing ionization of the gas within the cavity 9 aligned therewith, will provide a visual display of relative high contrast as compared with the opaque appearance of the nonenergized portions.

As to the operation of the high contrast plasma display device, application of an alternating voltage to the transparent electrode layer 19 and certain ones of he conductors 17 in an amount sufficient to fire or ionize the gas within the cavities 9 intermediate thereto, will establish a discharge which develops rapidly into a glow. During this period of glow development, charges flow to the insulator walls of the cavity 9 to provide a so-called wall charge. The development of this wall charge" reduces thepotential. applied across the electrodes and diminishes the glow development such that the discharge is quenched.

However, upon application of a potential of reduced magnitude to the transparent electrode layer 19 and certain ones of the conductors l7 mentioned above, the wall charge in conjunction with the applied reduced magnitude of potential causes a discharge to occur and establishment of a glow. Thus, the plasma display device has what might be termed a "memory in that each cavity is either in an off" state wherein no socalled wall charge is present and application of a full alternating potential is necessary to establish a glow discharge, or an on state wherein a wall charge is present and a glow discharge is readily established by application of an alternating voltage of reduced magnitude.

Thus, once a cavity has been shifted from an off to an on" state by application of a potential having a magnitude sufficient to cause development of a discharge, the particular cavity can be maintained in the on" state by an applied slowly varying alternating potential. Also, the particular cavity is readily shifted to a glow discharge display by application of a potential less than firing potential. However, application of a potential less than the firing potential to a cavity in the off state has little or no effect thereon.

ln review of the above description, it is obvious that the device will present an opaque appearance when viewed through the transparent insulator layer so long as none of the electrical conductors are energized. However, energization of certain ones of the conductors will cause ionization of the gas within the cavity aligned therewith. In turn, a visual display will be provided wherein the energized cavity areas and nonenergized portions have a relatively high level of contrast therebetween.

Additionally, it can readily be seen that a white or colored display may readily be provided by the addition of a fluorescent powder layer 23. In this instance, the energy radiated from a particular energized cavity is utilized to activate that portion of the fluorescent powder layer 23 in alignment therewith.

Thus, there has been provided a unique high contrast plasma display device having advantages believed to be unattainable in other known devices. The device is not only of the solid-state type having enhanced reliability, compactness, and resolution, but also is economical of materials, apparatus and time insofar as fabrication is concerned. Moreover, the added relatively high contrast capability is believed to be unattainable in any similar type of device.

While there has been shown and described what is at present considered the preferred embodiments of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention as defined by the appended claims.

We claim:

1. A high contrast plasma display device comprising in combination:

spaced transparent and opaque insulator layers;

spaced opaque insulator segments bonded to and separating said layers and forming a plurality of independent cavities intermediate thereto and said layers;

an insulator substrate affixed to said opaque layer and having plurality of connectors embedded therein and passing therethrough to contact a like plurality of spaced conductors affixed to said substrate in registry with said cavities and embedded in said opaque layer; a transparent electrode layer affixed to said transparent insulator layer on the surface remote from said spaced connectors and a phosphor layer affixed to the opposite surface of said transparent electrode layer;

an ionizable gas disposed within said cavities whereby energization of said spaced conductors causes ionization of said gas within said cavities aligned therewith and alteration in the appearance of said device from opaque to a visual display when viewed through said transparent insulator layer; and

a seal intermediate the periphery of the spaced transparent and opaque insulator layers.

2. The high contrast plasma display device of claim 1 wherein said ionizable gas is in the fonn of a nitrogen neon mixture.

3. The high contrast plasma display device of claim 1 wherein said opaque insulator layer and opaque insulator segments are in the form of a black glass frit.

Claims (3)

1. A high contrast plasma display device comprising in combination: spaced transparent and opaque insulator layers; spaced opaque insulator segments bonded to and separating said layers and forming a plurality of independent cavities intermediate thereto and said layers; an insulator substrate affixed to said opaque layer and having plurality of connectors embedded therein and passing therethrough to contact a like plurality of spaced conductors affixed to said substrate in registry with said cavities and embedded in said opaque layer; a transparent electrode layer affixed to said transparent insulator layer on the surface remote from said spaced connectors and a phosphor layer affixed to the opposite surface of said transparent electrode layer; an ionizable gas disposed within said cavities whereby energization of said spaced conductors causes ionization of said gas within said cavities aligned therewith and alteration in the appearance of said device from opaque to a visual display when viewed through said transparent insulator layer; and a seal intermediate the periphery of the spaced transparent and opaque insulator layers.

2. The high contrast plasma display device of claim 1 wherein said ionizable gas is in the form of a nitrogen neon mixture.

3. The high contrast plasma display device of claim 1 wherein said opaque insulator layer and opaque insulator segments are in the form of a black glass frit.

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