CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of application Ser. No. 551,359, filed Feb. 20, 1975, abandoned.
BACKGROUND OF THE INVENTION
The principles of the invention relate to display panels of the type known as SELF-SCAN panels which are manufactured and sold by Burroughs Corporation. These panels are dot matrix devices which display characters by energizing and generating light in selected cells in a matrix of cells, usually a 5 × 7 matrix, with the total number of energized cells displaying a character. SELF-SCAN panels include separate arrays of scanning cells and display cells which are electrically connected to form a plurality of such 5 × 7 or other matrices, with the scanning cells being adapted to assist in the energization of selected display cells in accordance with input signal information. One form of SELF-SCAN panel is shown and described in U.S. Pat. No. 3,821,586. Panels of this type have achieved commercial success; however, there is a constant need for simplification in the component parts and structure of such devices for mass production manufacture. The present invention provides such simplification.
SUMMARY OF THE INVENTION
Briefly, a display panel embodying the invention includes a plurality of parallel column cathode strips including means dividing the surfaces of the strips into a plurality of separate operating areas, with similar areas being disposed in alignment in rows. The columns of areas thus formed include scanning or priming cathodes areas and display cathode areas, and separate anodes are provided for separately energizing each row of display cathodes and each row of priming cathodes. The panel is operated by separately energizing each column of priming cathodes and selectively transferring cathode glow to the associated display cathodes in accordance with input signal information applied to selected display anodes, the total number of display cathodes thus energized displaying a character or message.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded plan view of the parts of a display panel embodying the invention;
FIG. 2 is an enlarged view of a portion of the panel of FIG. 1;
FIG. 3 is a sectional view of a portion of the panel of FIG. 1 assembled;
FIG. 4 is a sectional view, along the
lines 4--4, in FIG. 1 showing the panel assembled;
FIG. 5 is a sectional view, along the
lines 5--5, in FIG. 1 showing the panel assembled;
FIG. 6 is a schematic representation of the panel of FIG. 1 and a circuit in which it can be operated;
FIG. 7 is a plan view of a modification of a portion of the panel of FIG. 1;
FIG. 8 is a perspective view, partly in section, of a panel modification of the invention;
FIG. 9 is an exploded perspective view of the panel of FIG. 8;
FIG. 10 is an exploded plan view of the panel of FIG. 8;
FIG. 11 is a sectional view of the panel of FIG. 8;
FIG. 12 is an enlarged view of a portion of the panel of FIG. 8 shown to illustrate current flow therein;
FIG. 13 is a plan view of a modification of a portion of the invention;
FIG. 14 is a plan view of still another modification of a portion of the invention; and
FIG. 15 is a plan view of another modification of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A
display panel 10 embodying the invention, referring to FIGS. 1, 2, and 3, includes a
base plate 20 of insulating material such as glass, ceramic, or the like, and having a top surface 30 on which are provided a plurality of
rectangular strips 40 of conductive material arrayed parallel to each other. The conductive strips or
electrodes 40 are formed prferably by a screen printing process using any suitable material such as a mixture of nickel and glass frit in a suitable binder.
An auxiliary
conductive strip 41, used as a reset cathode in a scanning operation to be described, is disposed adjacent to the
first strip 40 at the left-hand end of
panel 10. This is arbitrarily considered to be the end at which the scanning cycle will begin. In addition, at least one keep-alive cell is provided near the reset cathode and comprising two electrodes, a
cathode 43 and an
anode 45, both of which are preferably formed on the base plate.
The
conductive strips 40 are subdivided into rows of
rectangular areas 42 by means of thin parallel
longitudinal lines 60 of insulating material formed on the top surface of the plate and on the
strips 40. The
lines 60 extend along the length of the base plate. In addition, each of the
rectangular areas 42 of the
strips 40 is subdivided by means of
insulating strips 62 formed on each rectangular area to subdivide each such portion into a first, relatively large-
area portion 44, to be operated as a display cathode, and a second generally rectangular but
smaller portion 46, to be operated as a scanning or priming cathode. The
display cathode portion 44 is connected to the
scanning cathode portion 46 by a
narrow portion 48 which lies between the
insulating portions 62. If a 5 × 7 dot matrix is to be used to form characters in
panel 10, then five
subdivisions 42 are provided in each
strip 40.
The inulating
strips 60 and 62 may be formed by a screen printing process.
It is noted that each
portion 42 of a
strip 40, referring to FIG. 2, thus comprises an electrode
pair including electrode 44 and
electrode 46, and the electrode pairs and their component electrodes are all arrayed in rows and columns.
The
panel 10 includes an
insulating plate 70 seated on the
base plate 20 and resting on the
insulating lines 60 and
portions 62 which have a thickness or height of about 2 mils so that they can support the
insulating plate 70 above the
conductive strips 40. With
plate 70 resting on
insulating portions 62, gas communication paths are provided between each
display cathode 44 and its associated
scan cathode 46 through a
path 74 extending along the narrow,
constricted space 48 between
strips 62, as shown in FIGS. 2 and 3.
The
insulating plate 70 includes a plurality of
horizontal slots 76 and 78, each
slot 76 overlaying a row of
display cathodes 44, and each
slot 78 overlying a row of
scan cathodes 46. The lands or
ribs 79 between each
slot 76 and the
adjacent slot 78
overlay insulating portions 62 or
insulating lines 60.
The
panel 10 also includes a
transparent face plate 80 of glass or the like, hermetically sealed to the center plate and the base plate by a
seal 95, and carrying on its inner surface 82 a plurality of transparent
conductive anode electrodes 90 of tin oxide or the like, each anode overlaying a
slot 76 in the center plate and a row of display cathodes. The face plate also carries on its inner surface a plurality of
opaque scan anodes 94, each overlaying a
slot 78 and a row of scan cathodes.
The
panel 10 is filled with a suitable ionizable gas such as neon, xenon, or the like, singly or in combination, at a suitable pressure. The gas atmosphere also includes mercury vapor to minimize cathode sputtering.
In
panel 10, various parameters are selected to insure that one column of cathodes glows at a time even though they are connected in groups. These parameters include the spacing of the columns of cathodes from each other, which, in one panel, was about six mils; the spacing of the face plate from the base plate, which was about 25 mils, and the pressure of the gas filling, which in such one panel was about 400 Torr.
Those skilled in the art will be readily able to modify these parameters to achieve the desired operation of modifications of
panel 10.
In one mode of operation of
panel 10, the
strips 40 are electrically connected in groups by means of
leds 50A, 50B, 50C, with every fourth electrode being in the same group so that there are three such groups of electrodes. The interconnections 50 can be formed on
base plate 20 at the same time as the strips are formed, or they may be provided in any other suitable manner. It will be clear to those skilled in the art, from the following description of the invention and from information already known about SELF-SCAN panels, that other electrode groupings can be used or even that each electrode can be separately connected to an external cicuit However, the electrode groupings provide economies in circuit operation.
A system for
operating panel 10 is shown in FIG. 6. In the system, the keep-
alive electrodes 43 and 45 are connected to a source of potential V, by means of which the keep-alive cell is maintained continually energized and generating exicted particles. The
reset cathode 41 is connected to a
reset driver 96, and the groups of
cathodes 40 are connected by their conductors 50 to separate cathode drivers 100 for connecting each cathode group in an operating circuit. All of the
scan anodes 94 are connected together through a suitable resistive path, if required, to a source of generally
positive operating potential 110. Each of the
display anodes 90 is connected through a separate, suitably resistive path to a
source 116 of information signals which themselves are connected to a
data sopurce 120 which may include a computer, encoders, decoders, character generator, and the like circuit modules. Suitably synchronizing
control circuits 130 are provided for interrelating the various circuit elements to operate as described below.
With the keep-alive cell ON, and all of the
scan anodes 94 energized, a pulse or other signal is applied by source 50R to the reset cathode 40R which turns on, exhibits cathode glow, and generates excited particles.
The excited particles thus generated are present near the first column of
scan cathodes 46, and, when the
first cathode driver 50A is operated to connect the first column of scan cathodes in circuit with the scan anodes, these scan cathodes turn on, exhibit cathode glow, and generate excited particles. Although other columns of scan cathodes in the same group are energized at the same time, they do not glow. This is because the first column of
scan cathodes 46 turns on preferentially because it is close to the reset cathode 100R and to the excited particles generated thereby. These particles do not diffuse to the other columns of scan cathodes in the group. In addition, when the first column of scan cathode turns on, it quickly assumes sustaining potential which is lower than the required firing potential for the other columns of scan cathodes in its group.
As each of the cathode drivers 100 is operated in turn, each of the columns of scan cathodes is energized and exhibits cathode glow, in turn, with each column providing excited particles for the next adjacent column. The scan cathode glow is not visible to a viewer since the
scan anodes 94 are opaque.
As each of the columns of scan cathodes is energized and the scan cathodes glow, information signals applied to selected
display anodes 90 cause cathode glow to transfer from the scan cathode beneath and adjacent to the selected display anodes through the
constricted path 48 to the adjacent display cathode, beneath the selected display anode. The display cathode now glows, and this glow is visible to a viewer through the transparent display anodes. This operation is repeated for each column of electrode pairs, and the total scanning operation is repeated cyclically throughout the panel at such a rate that the display cathodes which are energized present an apparently stationary but changeable message. This mode of operation described above is generally similar to that employed in SELF-SCAN panels of the type described in the above-mentioned patent.
The
panel 10 may also use modified cathode strips 40 (FIG. 7) in which the
rectangular areas 42 are subdivided by rectangular insulating strips 62' formed on each such subdivided
portion 42 and positioned close to
strips 60 to form a relatively large-area display cathode portion 44' and a relatively small-area scan cathode portion 46'. The strips 62' are spaced from the left and right edges of the cathode strips 40 to provide a narrow constricted path 48' on each side of the strip. In operation of a panel with cathode strips of the type shown in FIG. 7, glow transfer takes place from a scan cathode 46' to a display cathode 44' through the two gas communication paths 48'.
A
panel 200 embodying a modification of the invention and shown in FIGS. 8-12 includes a
base plate 210 of glass or other suitable insulating material having a
top surface 220 on which is formed a plurality of parallel
conductive strips 230 disposed generally transverse to the longitudinal axis of the base plate. The
conductive strips 230 are operated as cathode electrodes in the completed panel, and they may be formed by a screen printing process as above. If desired, the conductive strips may also comprise individual metallic elements suitably secured to the base plate.
A slotted insulating
plate 240 is seated on the
cathodes 230 to divide them into generally rectangular
elemental areas 230D and 230S. The
slots 244 and 246 in the plate are alternately wide and narrow so that the
cathodes 230 are divided into alternately large and small areas which, as can be seen, are arrayed in rows and columns. In operation of the panel, the relatively
small cathode areas 230S are operated as scanning pr priming cathodes, and the relatively
large areas 230D are operated as display cathodes.
The panel is completed by a
glass face plate 250 which carries, on it
inner surface 260, a plurality of alternate wide and
narrow anode strips 270D and 270S, respectively, insulated from each other and disposed parallel to the longitudinal axis of the face plate and the panel. The relatively
wide anode strips 270D may be made of material such as tin oxide, and each of these overlays a row of
display cathodes 230D. Adjacent to each transparent anode is an opaque anode film or strip 270S of any suitable material, each of which overlays a row of scanning or
priming cathodes 230S. Thus, when display cathodes are energized and exhibit cathode glow, the glow is visible through their
anodes 270D, and when scanning cathodes are energized and exhibit cathode glow, the glow is not visible through their
anodes 270S.
Although they are not shown,
panel 200 would include a reset cathode and a suitable keep-alive arrangement as required and as described above
The operation of
panel 200 is essentially the same as the operation of the other panels described above except that, as columns of scanning cells are energized by the application of operating potential to the cathode strips and the scan anodes, the information signals are applied to the display anodes, it is believed that glow is transferred from a scan cathode to the selected adjacent display cathode along the left and right hand edges of the cathode strip through the space between insulating
plate 240 and the top surface of
base plate 210 as illustrated by the dash lines in FIG. 12.
Although, in the panel described above, a scanning or priming cathode or cell is associated with each display cathode or display cell, it is clear that other arrangements could be used as taught in U.S. Pat. No. 3,683,364. For example, as illustrated schematically in FIG. 13, each two display area D may have a priming area P between them; or, as illustrated in FIG. 14, priming areas may be provided at the upper and lower ends of a column of display areas D; or, as illustrated in FIG. 15, a column of cathode areas may include a relatively random insertion of priming areas, and a column may include two or three display areas in series, a priming area, then two or three display areas, then a priming area, etc. In each case, any of the means described above may be used to divide the cathode surfaces, as desired.
The panel of the invention utilizes principles of operation and some structural features of SELF-SCAN display panels which are made and sold by Burroughs Corporation. Panels of this type are described and claimed in the following copending applications and U.S. patents which are incorporated herein by reference:
Ser. No. 487,955 filed July 12, 1974
Ser. No. 551,539 filed Feb. 20, 1975
Ser. No. 624,531 filed Oct. 22, 1975
Ser. No. 624,532 filed Oct. 22, 1975
U.s. pat. No. 3,619,698
U.s. pat. No. 3,683,364
U.s. pat. No. 3,699,376
U.s. pat. No. 3,766,420
U.s. pat. No. 3,767,968
U.s. pat. No. 3,863,088