CA1085443A - Flat panel display and method of operating the same - Google Patents
Flat panel display and method of operating the sameInfo
- Publication number
- CA1085443A CA1085443A CA292,214A CA292214A CA1085443A CA 1085443 A CA1085443 A CA 1085443A CA 292214 A CA292214 A CA 292214A CA 1085443 A CA1085443 A CA 1085443A
- Authority
- CA
- Canada
- Prior art keywords
- phosphor screen
- beams
- along
- channels
- points
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J31/00—Cathode ray tubes; Electron beam tubes
- H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
- H01J31/10—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes
- H01J31/12—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes with luminescent screen
- H01J31/123—Flat display tubes
- H01J31/124—Flat display tubes using electron beam scanning
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
- H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
Landscapes
- Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
Abstract
FLAT PANEL DISPLAY AND METHOD OF OPERATING THE SAME
Abstract An evacuated envelope includes front and back walls and a plurality of spaced,parallel supports between the front and back walls and forming a plurality of parallel channels.
A gun structure at one end of the channels directs one or more beams of electrons along each of the channels. In each of the channels is at least one beam guide which confines the electrons of the beams. The beam guides include a plurality of spaced, parallel deflection electrodes extending transversely across the channels, which electrodes, under application of an appropriate potential, will cause the deflection of the electron beam out of the guides toward a phosphor screen on the front wall. In the operation of the display, a first potential is selectively applied to the electrodes to cause the beams to deflect out of the guides and impinge on the phosphor screen at a first series of spaced points along the channels, and then a second potential different from the first potential is selectively applied to the electrodes to cause the beams to be deflected out of the guides and impinge on the phosphor screen at a second series of spaced points between the points of the first series.
Abstract An evacuated envelope includes front and back walls and a plurality of spaced,parallel supports between the front and back walls and forming a plurality of parallel channels.
A gun structure at one end of the channels directs one or more beams of electrons along each of the channels. In each of the channels is at least one beam guide which confines the electrons of the beams. The beam guides include a plurality of spaced, parallel deflection electrodes extending transversely across the channels, which electrodes, under application of an appropriate potential, will cause the deflection of the electron beam out of the guides toward a phosphor screen on the front wall. In the operation of the display, a first potential is selectively applied to the electrodes to cause the beams to deflect out of the guides and impinge on the phosphor screen at a first series of spaced points along the channels, and then a second potential different from the first potential is selectively applied to the electrodes to cause the beams to be deflected out of the guides and impinge on the phosphor screen at a second series of spaced points between the points of the first series.
Description
I'('A -/ r~
S~4;3 The presellt invent~on relates to a flat panel display and method of operatlng the same, and particularly to a display in which line scanninc3 of the entire display screen is achieved with a minimum number of deflection electrodes.
There is known a flat panel cathodo-luminescent display device which includes an evacuated envelope having a display section which includes a plurality of parallel channels extending along rectangular front and back walls. A gun section extends across one end of the channels and includes gun structure which will direct one or more electron beams along each of the channels. In each of the channels is a beam guide which confines the electrons in each beam and guides each beam along the channel. The beam guides also include electrodes which are used to selectlvely deflect the beams out of the guides toward a phosphor screen on the inner surface of the ront wall.
At each point that the electron beams are deflected out of the beam guides toward the phosphor screen, the beams impinge on the phosphor screen to provide a line scan of the phosphor screen in one direction across the display section, e.g., the horizontal direction. By sequentially switching the deflection of the beams along the deflection electrodes a scanning of the phosphor screen is achieved in a direction orthogonal to the above stated direction, e.g., the vertical direction. The combination of these two scans provides a complete raster scanning of the phosphor screen. In a standard TV display device in the United States there are about 500 vertical scan points. Thus, there would be 3 required in the above display device about 500 deflection
S~4;3 The presellt invent~on relates to a flat panel display and method of operatlng the same, and particularly to a display in which line scanninc3 of the entire display screen is achieved with a minimum number of deflection electrodes.
There is known a flat panel cathodo-luminescent display device which includes an evacuated envelope having a display section which includes a plurality of parallel channels extending along rectangular front and back walls. A gun section extends across one end of the channels and includes gun structure which will direct one or more electron beams along each of the channels. In each of the channels is a beam guide which confines the electrons in each beam and guides each beam along the channel. The beam guides also include electrodes which are used to selectlvely deflect the beams out of the guides toward a phosphor screen on the inner surface of the ront wall.
At each point that the electron beams are deflected out of the beam guides toward the phosphor screen, the beams impinge on the phosphor screen to provide a line scan of the phosphor screen in one direction across the display section, e.g., the horizontal direction. By sequentially switching the deflection of the beams along the deflection electrodes a scanning of the phosphor screen is achieved in a direction orthogonal to the above stated direction, e.g., the vertical direction. The combination of these two scans provides a complete raster scanning of the phosphor screen. In a standard TV display device in the United States there are about 500 vertical scan points. Thus, there would be 3 required in the above display device about 500 deflection
-2-RC~ 7(),')3l ~0~544;~
1 electrodes to achieve the needed number of vertical scan points. In order to se4uentially switch the 500 deflection electrodes they must be connectecl to some type o~ switchin~J
mechanism which is either insicle or outside the envelope of the display device. Th:LS results in either a complex mechanism inside the envelope or a large number of terminals extending through the envelope to be connected to the switching mechanism outside the envelope.
In accordance with the invention, a display device includes an evacuated envelope having a fron-t wall, a phosphor screen extending across the inner surface of the front wall, means for generating at least one beam of electrons and directing the beam along a path substantially parallel to the front wall, and a focusing guide extending along substantially the entire length of the beam path for applying electrostatic forces to the electrons of the beam for confining the electrons to the beam. The display device also includes means for selectively deflecting the beam toward the front wall at spaced points along the beam path so that the beam impinges the phosphor screen at a first series of spaced points, and means for selectively deflecting the beam toward the front wall at each of the spaced points along the beam path so that the beam impinges the phosphor screen at a second series of spaced points with each of said second points being interlaced between two of the first points.
In the drawing:
FIGURE 1 is a perspective view, partially cut away, of one form of a flat display device according to the present invention.
FIGURE 2 is a longi-tudinal sectional view taken .' , . .
1'(`~ 7!), ~
~8544.3 I along a portion of olle o the channcls of the display device of FIGURE 1.
FIGURE 3 is a sectional view similar to FIGUR~ 2 showing another form of a display device according to the present invention.
Referring to FIGURE 1, one form of a flat display device according to the present invention is generally designated as 10. The display device 10 comprises an evacuated envelope 12, typically of glass, having a display section 14 and an electron gun section 16. The display section 14 includes a rectangular front wall 18 which supports the viewing screen, and a rectangular back wall 20 in spaced, parallel relation with the front wall 18. The front wall 15 18 and back wall 20 are connected by side walls 22. The front wall 18 and back wall 20 are dimensioned to provide the size of the viewing screen desired, e.g., 75 by 100 centimeters, and are spaced apart about 2.5 to 7.5 centimeters.
A plurality of spaced, parallel support walls 24 are secured between the front wall 18 and the back wall 20 and extend from the gun section 16 to the opposite side wall 22. The support walls 24 provide the desired internal support for the evacuated envelope 12 against external atmospheric pressure,and divide the display section 14 into a plurality of channels 26. On the inner surface of the front wall 18 is a phosphor screen 28. The phosphor screen 28 may be of any well known type presently being used in cathode ray tubes, e.g., black and white or color television display tubes. A metal film electrode 30 is provided on the phosphor screen 28.
R(A 7(),9`~1 ~()85~;3 1 The gun section 16 is an extention of the display section 14 and extends along one ~et of adjacent ends of the channels 26. The c3un section may be of any shape suitahle to enclose the particular gun structure contained therein. The electron gun structure contained in the gun section 16 may be of any well known construction sui-table for selectively directing beams of electrons along each of the channels 26.
For example, the gun structure may comprise a plurality of individual guns mounted at the end of the channels 26 for directing separate beams of electrons along the channels.
Alternatively, the gun structure may include a line cathode extending along the gun section 16 across the ends of the channels 26 and adapted to selectively direct individual beams of electrons along the channels. A gun structure of the line type is described in U. S. Patent No. 2,858,464, issued October 28, 1958 to W. L. Roberts.
In each of the channels 26 are focusing guides for confining electrons directed into the channel into a beam, which travels a path along the channel. Each guide also includes means for deflecting its beam out of the guide and toward the phosphor screen 28 at various points along the length of the channel 26.
Referring to FIGURE 2, there is shown one form of a focusing guide which can be used in the channels 26.
The focusing guide includes spaced, parallel first and second metal grid plates 32 and 36 which ~ 7(),'~
l~Sf.~
I extend transvers~ly across the channel 26 with the first grld p:late 32 bein(l adjacent to but spaced from the back wall 20. The metal grid p:La'-es 32 and 36 extend longitudinally the full length of the channel 2h. The grid plates 32 and 36 have a plurality of spaced, rectangular openings 34 and 38 therethrough. The openings 34 and 38 are arranged in rows both longitudinally along and transversely across the channel 26 and each of the openings 34 is co-axially aligned with the opening 38. A plurality of spaced, parallel conductors 40 are Oil the inner surface of the back wall 20 and extend transversely across the channel 26. The conductors 40 are strips of an electrically conductive material, such as a metal coated on the back wall 20. Each of the conductors 40 extends directly behind a transverse row of the openings 34 in the first grid plate 32.
A focusing grid plate 42 extends transversely across the channel 26 between the second grid plate 36 of the focusing guide and the front wall 18. An acceleration grid plate 44 extends transversely across the channel 26 between the focusing grid plate 42 and the fro.nt wall 18. The focusing grid plate 42 and the acceleration grld plate 44 are in spaced, parallel relation and extend the full length of the channel 26. The focusing grid plate 42 and the acceleration grid plate 44 each have a plurality of spaced, rectangular openings 46 and 48 respectively therethrough.
The openings 46 and 48 are arranged in rows both longitudinally along and transversely across the channel 26, with each of the openings 48 in the acceleration grid plate 44 being co-axially aligned with one of the openings 46 in the focusing grid plate 42. The longitudinal rows of the ~ 7~),'J3l I openings 46 and 48 are aligned with the longitudinal rows of the openings 34 and 38. However, the transverse rows of the openings 46 and 48 are offset from the transverse rows of the openings 34 and 38 so that each of the openings 46 and 48 overlays two of the openings 34 and 38.
In a typical display device of the construction shown in FIGURE 2, the conductors 40 are each of a width, i.e., dimension longitudinally along the channel 26, of about 2.5 mm. The first grid plate 32 of the focusing guide 10 is spaced from the conductors 40 about 0.50 mm and the second grid plate 36 is spaced from the first grid plate 32 about 0.76 mm. The openings 34 and 38 in the grid plates 32 and 36 respectively are rectangular and each have a dimension , transversely of the channel 26 of about 3.30 mm and a dimension longitudinally of the channel 26 of about 2.0 mm.
The openings in each of the qrid plates are spaced apart transversely of the channel 26 about 1.78 mm and longitudinally of the channel 26 about 1.0 mm. The focusing grid plate 42 is spaced from the second grid plate 36 of the 20 focusing guide about 3.18 mm. The acceleration grid plate 44 is spaced from the focusing grid plate 42 about 2.79 mm and is spaced from the front wall 18 about 6.78 cm. The openings 46 and 48 in the focusing grid plate 42 and acceleration grid plate 44,respectively,are rectangular and ~5 have a dimension longitudinally of the channel 26 of about 2.54 mm and a dimension transversely of the channel 26 approximately equal to that dimension of the openings 34 and 38.
In the operation of the display device 10 having the focusing guide shown in FIGURE 2, a relatively high positive ~C~ 70,931 16)ff5~;3 1 potential, typically about 300 volts, is applied to each of the conductors 40; ~nd a low positive potential, typically about 40 volts, is applied to each of the first and second grid plates 32 and 36. A positive potential of about 1000 volts is applied to the focusing grid plate 42, and a potential of about 8000 volts is applied to each of the acceleration grid plate 44 and the metal film 30 on the phosphor screen 28.
Beams of electrons 50 are directed into the focusing guides between the first grid plate 32 and the second grid plate 36, with each beam 50 extending along a substantially straight line path along a separate longitudinal row of the openings in the grid plates. The potential differences between the first grid plate 32 of the focusing guide and the conductors 40, and between the second grid plate 36 of the focusing guide and the focusing grid 42, create electrostatic force fields which confine the electrons in the beam along the entire length of the path of the beam through the focusing guide.
To extract the electron beam 50 from the focusing guide, the potential applied to a conductor 40 is switched to a negative voltage. When the electron beam reaches this conductor, the beam will bend away from the negative potential conductor 40 and pass through an adjacent opening 38 in the first grid plate 36 to pass out of the beam guide. The electron beam will then pass through an adjacent opening 46 in the focusing grid plate 42 which will result in a focusing of the beam because of the potential applied to the focusing grid plate 42. The electron beam will then be accelerated I'(`A 7 !), ') ~ I
S4~3 1 toward the phos~ or s(reen 28 by the high potential applied to the acceleratio~ rid ~la~e 44. The beam will pass through an adjacent o~enin(J 48 in the acceleration grid plate 44 and will finally im~inge on the phosphor screen 28.
It has been found that the electron beam 50 can be extracted from the focusing beam guide at different angles by applying different negative potentials to the conductor 40.
For example, referring to FIGURE 2, if a negative potential of one magnitude, for example, -100 volts, is applied to the conductor 40, the electron beam 50 will be extracted from the beam guide at one angle, indicated by the beam path 50a, to impinge on the phosphor screen 28 at one point. However, if the potential applied to the conductor 40 is more negative, for example -200 volts, the electron beam 50 will be extracted at a greater angle to follow a path such as indicated as 50b and will impinge on the phosphor screen 28 at a different point. Thus, at each of the conductors 40, the electron beam 50 may be extracted from the focusing beam guide at different angles,to impinge on the phosphor In a preferred manner of operation of the display device 10, the conductor 40 closest to the side wall 22 directly opposite the gun section 16, i.e., the top-most conductor in FIGURE 1 or left-most-conductor in FIGURE 2, is first switched to a negative potential. Thus all of the ~S beams 50 in all of the channels 26 will be deflected at a point close to that side wall 22 to pass out of their respective guides and impinge on the phosphor screen 28 to provide a line scan of the phosphor screen. The alternate conductors 40 are then switched to the negative potential in sequence along the entire length ~ 7 n, ~ ~3l 1 of the channels so that the Deams are extracted from their guides at various points along the length oE the guides to provide a line-by-line scan of the phosphor screen 28. This sequence of switching the potentials applied to the conduc-tors 40 is then repeated but with the conductors 40 beingswitched to a second negative potential different from that of the first negative potential. This deflects the beams out of their guides at each of the same points along the guides as the first set of deflections but at a different angle so that the beams will impinge on the phosphor screen 28 at a second set of points which are between the first set of points of impingement. This provides a second set of line scans of the phosphor screen 28 between the first set of line scans. By carrying out the switching at the proper speed and by modulating the various beams in the gun section 16 during each line scan, a visual display can be provided on the phosphor screen 28 which can be viewed through the front wall 18 of the envelope 12. This manner of operation provides a field interlace which has the advantage that it is compatable with the conventional field interlace system presently used in television display.
Referring to FIGURE 3, another form of a display device according to the present invention is generally designated as 100. The display device 100 is similar in construction to the display device 10 shown in FIGURE 1 in that it includes a display section and an electron gun section with the display section having rectangular front and back walls 118 and 120 in spaced, parallel relation. The front and back walls 118 and 120 are connected by side walls. A plurality of spaced, parallel support walls are secured between the ~ A 7r)~931 i~85~43~
1 front wall 118 and back wall 120 and extend from the gun section to the opposite side wall and divide the display section into a plurality of channels 126. A phosphor screen 128 is on the inner surface of the front wall 118,and a metal film electrode 130 is on the phosphor screen 128. In each of the channels 126 are focusing guides for confining electrons directed into the channel into a beam, which beam travels a path along the channel. The display device 100 differs from the device 10 shown in FIGURES 1 and 2 in that 10 the spacing between the front wall 118 and back wall 120 is less in the display device 100 than in the display device 10, and in the construction of the focusing guides in the channels.
The focusing guide includes a plurality of spaced, parallel wires 52 extending transversely across the channels 126. The wires 52 are in a common plane which is spaced from and parallel to the back wall 120. A metal ground plane plate 54 extends transversely across the channels 126 spaced from and parallel to the wires 52 and between the wires 52 and the front wall 118. The ground plane plate 54 has a plurality of openings 56 therethrough which are arranged in rows longitudinally along and transversely across the channel 126.
The transverse rows of the openings 56 are positioned between adjacent wires 52 with the openings 56 being longitudinally spaced so as to be positioned between alternate pairs of the wires 52. A plurality of spaced, parallel conductors 58 are ~S~43 RCA 70,93l 1 on the inner surface of the back wall 120 and extend transversely across the channels 126. Each of the conductors 58 extends along a separate ~ransverse row of the openings 56 in the ground plane plate 54.
In the operation of the display device 100, a positive potential is applied to each of the wires 52,and zero potential is applied to each of the conductors 58 and the ground plane plate 54. Electron beams 150 are directed into the focusing guides between the ground plane plate 54 1O and the back wall 120,with each beam 150 being along a separate longitudinal row of the opening 56 in the ground plane plate 54. The potential difference between the wires 52 and the conductors 58 and the ground plane plate 54 creates electrostatic fields which will cause the electron beams 150 to follow an undulating path along the array of the wires 52, so as to guide the electron beams along the length of the channels 126.
By switching the potential applied to each of the conductors 58 to a negative potential, the electrostatic forces applied to the beam as it passes between the switch conductor and the adjacent wire 52 will cause the beam to be deflected out of its undulating path away from the negative potential conductor. The deflected beam will then pass through an adjacent opening 56 in the ground plane plate 54 and will impinge on the phosphor screen 128. As previously described with regard to the display device 10, the beam can be deflected out of the focusing guide at different angles by using different negative potentials on the conductors 58.
Thus, if a relatively low negative potential, e.g. -100 volts, 5~3 ~c A 7(), 9 31 I is applied to a conductor 58, the beam 150 wilL be deflected at a relatively low ancJle to follow a first path 150a and impinge on the phosphor screen 128 at a first point. ~lowever, if a higher negative potential, e.g., -200 volts,is applied to the conductor 58, the beam will be deflected at a greater angle to follow a path 150b and impinge on the phosphor screen 128 at a second point. Thus, by switching the conductors 58 in sequence to a first negative potentia~ the beams in the channels 126 can be deflected at various points along the channels to achieve a scanning of the phosphor screen 128 along a first set of lines; and then by switching the conductors 58 in sequence to a second negative potential, the beams can be deflected at the various points along the channel to achieve a scanning of the phosphor screen along a second set of lines interlaced with the first set of lines.
Although the deflection of the electron beam 150 in the display device 100 has been described as being accomplished by applying a negative potential to a conductor 58, the deflection can alternatively be achieved by changing the potential applied to a wire 52 to a negative potential. This will cause the beam 150 to be deflected out of the guide at a point just prior to the wire 52 having the negative potential applied thereto. The angle at which the beam 150 will be deflected will depend on the particular potential applied to the wire 80, so that the beam can be deflected at different angles to impinge on the phosphor screen 128 at different points by applying different negative potential to the wire 52. If the beam 150 is to be deflected out of the focusing guide by means of applying negative potential to the ~ 7(),93l lC)~S~IL4;~
I wires 52, the conductor 58 on the inner section of the back wall 120 can be a single layer of metal over the entire surface of the back wall 120 rather than individual strips.
Although the display device 10 is shown in FIGURE 2 as having a focusing guide of the type which includes two plates between which the electron beams flow, the display device 10 can alternatively use the type of focusing guide shown in FIGURE 3 which includes a set of wires between a ground plane plate and the conductor. Likewise the display device 100 can alternatively use the type of focusing guide shown in FIGURE 2.
Thus, there is provided a display device in which a plurality of individual beams of electrons are individually guided along substantially parallel paths substantially parallel to a phosphor screen. The beams are simultaneously deflected out of these paths toward the phosphor screen at a plurality of points along the paths to achieve a pluraiity of line scans of the phosphor screen.
The deflection of the beams is achieved by a deflection potential in the beam guide, the magnitude of which controls the angle of deflection and thus the point on the phosphor screen that the beams will impinge upon. In accordance with the present invention,the beams are deflected at each point by at least two different deflection potentials so that at least two different line scans ofthephosphorscreenresult at each point of deflection of the electron beams. The scanning of the entire phosphor screen can be achieved by first deflecting the electron beams at each of the points in sequence at one deflection potential to achieve one set of line scans,and then deflecting the electron beams at each of 1~3~443 1 the points in sequence at the second deflection potential to achieve a second set of line scans which are interlaced with the line scans of the first set.
The present invention has the advantage that since two or more line scans of the phosphor screen can be obtained at each deflection point of the electron beams,there is required fewer deflection points, one half or less than was previously required with this type of flat panel display. Also, in the focusing guide shown in FIGURE
2, the openings 34 and 38 in the grid plates 32 and 36 can be made larger with fewer openings per unit length of the focusing guide required. ln the focusing guide shown in FIGURE 3, the openings 56 in the ground plane plate 54 can be larger with fewer openings per unit len~th of the focusing guide, and the wires 52 can be spread further apart with fewer wires per unit length of the focusing guide. This greatly simplifies the structure of the display device in that it greatly reduces the number of deflection electrodes needed, thus reducing the number of terminals which would extend through the envelope and simplifying the switching mechanism for achieving the scanning. Also, the structure of the focusing guide is simplified since there are fewer openings in the grid or ground plane plates and fewer wires. Also, since a factor affecting the focusing action of the focusing guides is the size of the openings in the grid plates in one of the guides and the spacing of the wires in the other guide, reducing the number of these openings or wires reduces the possible inconsistancies in the size or spacing so that the consistancy of the
1 electrodes to achieve the needed number of vertical scan points. In order to se4uentially switch the 500 deflection electrodes they must be connectecl to some type o~ switchin~J
mechanism which is either insicle or outside the envelope of the display device. Th:LS results in either a complex mechanism inside the envelope or a large number of terminals extending through the envelope to be connected to the switching mechanism outside the envelope.
In accordance with the invention, a display device includes an evacuated envelope having a fron-t wall, a phosphor screen extending across the inner surface of the front wall, means for generating at least one beam of electrons and directing the beam along a path substantially parallel to the front wall, and a focusing guide extending along substantially the entire length of the beam path for applying electrostatic forces to the electrons of the beam for confining the electrons to the beam. The display device also includes means for selectively deflecting the beam toward the front wall at spaced points along the beam path so that the beam impinges the phosphor screen at a first series of spaced points, and means for selectively deflecting the beam toward the front wall at each of the spaced points along the beam path so that the beam impinges the phosphor screen at a second series of spaced points with each of said second points being interlaced between two of the first points.
In the drawing:
FIGURE 1 is a perspective view, partially cut away, of one form of a flat display device according to the present invention.
FIGURE 2 is a longi-tudinal sectional view taken .' , . .
1'(`~ 7!), ~
~8544.3 I along a portion of olle o the channcls of the display device of FIGURE 1.
FIGURE 3 is a sectional view similar to FIGUR~ 2 showing another form of a display device according to the present invention.
Referring to FIGURE 1, one form of a flat display device according to the present invention is generally designated as 10. The display device 10 comprises an evacuated envelope 12, typically of glass, having a display section 14 and an electron gun section 16. The display section 14 includes a rectangular front wall 18 which supports the viewing screen, and a rectangular back wall 20 in spaced, parallel relation with the front wall 18. The front wall 15 18 and back wall 20 are connected by side walls 22. The front wall 18 and back wall 20 are dimensioned to provide the size of the viewing screen desired, e.g., 75 by 100 centimeters, and are spaced apart about 2.5 to 7.5 centimeters.
A plurality of spaced, parallel support walls 24 are secured between the front wall 18 and the back wall 20 and extend from the gun section 16 to the opposite side wall 22. The support walls 24 provide the desired internal support for the evacuated envelope 12 against external atmospheric pressure,and divide the display section 14 into a plurality of channels 26. On the inner surface of the front wall 18 is a phosphor screen 28. The phosphor screen 28 may be of any well known type presently being used in cathode ray tubes, e.g., black and white or color television display tubes. A metal film electrode 30 is provided on the phosphor screen 28.
R(A 7(),9`~1 ~()85~;3 1 The gun section 16 is an extention of the display section 14 and extends along one ~et of adjacent ends of the channels 26. The c3un section may be of any shape suitahle to enclose the particular gun structure contained therein. The electron gun structure contained in the gun section 16 may be of any well known construction sui-table for selectively directing beams of electrons along each of the channels 26.
For example, the gun structure may comprise a plurality of individual guns mounted at the end of the channels 26 for directing separate beams of electrons along the channels.
Alternatively, the gun structure may include a line cathode extending along the gun section 16 across the ends of the channels 26 and adapted to selectively direct individual beams of electrons along the channels. A gun structure of the line type is described in U. S. Patent No. 2,858,464, issued October 28, 1958 to W. L. Roberts.
In each of the channels 26 are focusing guides for confining electrons directed into the channel into a beam, which travels a path along the channel. Each guide also includes means for deflecting its beam out of the guide and toward the phosphor screen 28 at various points along the length of the channel 26.
Referring to FIGURE 2, there is shown one form of a focusing guide which can be used in the channels 26.
The focusing guide includes spaced, parallel first and second metal grid plates 32 and 36 which ~ 7(),'~
l~Sf.~
I extend transvers~ly across the channel 26 with the first grld p:late 32 bein(l adjacent to but spaced from the back wall 20. The metal grid p:La'-es 32 and 36 extend longitudinally the full length of the channel 2h. The grid plates 32 and 36 have a plurality of spaced, rectangular openings 34 and 38 therethrough. The openings 34 and 38 are arranged in rows both longitudinally along and transversely across the channel 26 and each of the openings 34 is co-axially aligned with the opening 38. A plurality of spaced, parallel conductors 40 are Oil the inner surface of the back wall 20 and extend transversely across the channel 26. The conductors 40 are strips of an electrically conductive material, such as a metal coated on the back wall 20. Each of the conductors 40 extends directly behind a transverse row of the openings 34 in the first grid plate 32.
A focusing grid plate 42 extends transversely across the channel 26 between the second grid plate 36 of the focusing guide and the front wall 18. An acceleration grid plate 44 extends transversely across the channel 26 between the focusing grid plate 42 and the fro.nt wall 18. The focusing grid plate 42 and the acceleration grld plate 44 are in spaced, parallel relation and extend the full length of the channel 26. The focusing grid plate 42 and the acceleration grid plate 44 each have a plurality of spaced, rectangular openings 46 and 48 respectively therethrough.
The openings 46 and 48 are arranged in rows both longitudinally along and transversely across the channel 26, with each of the openings 48 in the acceleration grid plate 44 being co-axially aligned with one of the openings 46 in the focusing grid plate 42. The longitudinal rows of the ~ 7~),'J3l I openings 46 and 48 are aligned with the longitudinal rows of the openings 34 and 38. However, the transverse rows of the openings 46 and 48 are offset from the transverse rows of the openings 34 and 38 so that each of the openings 46 and 48 overlays two of the openings 34 and 38.
In a typical display device of the construction shown in FIGURE 2, the conductors 40 are each of a width, i.e., dimension longitudinally along the channel 26, of about 2.5 mm. The first grid plate 32 of the focusing guide 10 is spaced from the conductors 40 about 0.50 mm and the second grid plate 36 is spaced from the first grid plate 32 about 0.76 mm. The openings 34 and 38 in the grid plates 32 and 36 respectively are rectangular and each have a dimension , transversely of the channel 26 of about 3.30 mm and a dimension longitudinally of the channel 26 of about 2.0 mm.
The openings in each of the qrid plates are spaced apart transversely of the channel 26 about 1.78 mm and longitudinally of the channel 26 about 1.0 mm. The focusing grid plate 42 is spaced from the second grid plate 36 of the 20 focusing guide about 3.18 mm. The acceleration grid plate 44 is spaced from the focusing grid plate 42 about 2.79 mm and is spaced from the front wall 18 about 6.78 cm. The openings 46 and 48 in the focusing grid plate 42 and acceleration grid plate 44,respectively,are rectangular and ~5 have a dimension longitudinally of the channel 26 of about 2.54 mm and a dimension transversely of the channel 26 approximately equal to that dimension of the openings 34 and 38.
In the operation of the display device 10 having the focusing guide shown in FIGURE 2, a relatively high positive ~C~ 70,931 16)ff5~;3 1 potential, typically about 300 volts, is applied to each of the conductors 40; ~nd a low positive potential, typically about 40 volts, is applied to each of the first and second grid plates 32 and 36. A positive potential of about 1000 volts is applied to the focusing grid plate 42, and a potential of about 8000 volts is applied to each of the acceleration grid plate 44 and the metal film 30 on the phosphor screen 28.
Beams of electrons 50 are directed into the focusing guides between the first grid plate 32 and the second grid plate 36, with each beam 50 extending along a substantially straight line path along a separate longitudinal row of the openings in the grid plates. The potential differences between the first grid plate 32 of the focusing guide and the conductors 40, and between the second grid plate 36 of the focusing guide and the focusing grid 42, create electrostatic force fields which confine the electrons in the beam along the entire length of the path of the beam through the focusing guide.
To extract the electron beam 50 from the focusing guide, the potential applied to a conductor 40 is switched to a negative voltage. When the electron beam reaches this conductor, the beam will bend away from the negative potential conductor 40 and pass through an adjacent opening 38 in the first grid plate 36 to pass out of the beam guide. The electron beam will then pass through an adjacent opening 46 in the focusing grid plate 42 which will result in a focusing of the beam because of the potential applied to the focusing grid plate 42. The electron beam will then be accelerated I'(`A 7 !), ') ~ I
S4~3 1 toward the phos~ or s(reen 28 by the high potential applied to the acceleratio~ rid ~la~e 44. The beam will pass through an adjacent o~enin(J 48 in the acceleration grid plate 44 and will finally im~inge on the phosphor screen 28.
It has been found that the electron beam 50 can be extracted from the focusing beam guide at different angles by applying different negative potentials to the conductor 40.
For example, referring to FIGURE 2, if a negative potential of one magnitude, for example, -100 volts, is applied to the conductor 40, the electron beam 50 will be extracted from the beam guide at one angle, indicated by the beam path 50a, to impinge on the phosphor screen 28 at one point. However, if the potential applied to the conductor 40 is more negative, for example -200 volts, the electron beam 50 will be extracted at a greater angle to follow a path such as indicated as 50b and will impinge on the phosphor screen 28 at a different point. Thus, at each of the conductors 40, the electron beam 50 may be extracted from the focusing beam guide at different angles,to impinge on the phosphor In a preferred manner of operation of the display device 10, the conductor 40 closest to the side wall 22 directly opposite the gun section 16, i.e., the top-most conductor in FIGURE 1 or left-most-conductor in FIGURE 2, is first switched to a negative potential. Thus all of the ~S beams 50 in all of the channels 26 will be deflected at a point close to that side wall 22 to pass out of their respective guides and impinge on the phosphor screen 28 to provide a line scan of the phosphor screen. The alternate conductors 40 are then switched to the negative potential in sequence along the entire length ~ 7 n, ~ ~3l 1 of the channels so that the Deams are extracted from their guides at various points along the length oE the guides to provide a line-by-line scan of the phosphor screen 28. This sequence of switching the potentials applied to the conduc-tors 40 is then repeated but with the conductors 40 beingswitched to a second negative potential different from that of the first negative potential. This deflects the beams out of their guides at each of the same points along the guides as the first set of deflections but at a different angle so that the beams will impinge on the phosphor screen 28 at a second set of points which are between the first set of points of impingement. This provides a second set of line scans of the phosphor screen 28 between the first set of line scans. By carrying out the switching at the proper speed and by modulating the various beams in the gun section 16 during each line scan, a visual display can be provided on the phosphor screen 28 which can be viewed through the front wall 18 of the envelope 12. This manner of operation provides a field interlace which has the advantage that it is compatable with the conventional field interlace system presently used in television display.
Referring to FIGURE 3, another form of a display device according to the present invention is generally designated as 100. The display device 100 is similar in construction to the display device 10 shown in FIGURE 1 in that it includes a display section and an electron gun section with the display section having rectangular front and back walls 118 and 120 in spaced, parallel relation. The front and back walls 118 and 120 are connected by side walls. A plurality of spaced, parallel support walls are secured between the ~ A 7r)~931 i~85~43~
1 front wall 118 and back wall 120 and extend from the gun section to the opposite side wall and divide the display section into a plurality of channels 126. A phosphor screen 128 is on the inner surface of the front wall 118,and a metal film electrode 130 is on the phosphor screen 128. In each of the channels 126 are focusing guides for confining electrons directed into the channel into a beam, which beam travels a path along the channel. The display device 100 differs from the device 10 shown in FIGURES 1 and 2 in that 10 the spacing between the front wall 118 and back wall 120 is less in the display device 100 than in the display device 10, and in the construction of the focusing guides in the channels.
The focusing guide includes a plurality of spaced, parallel wires 52 extending transversely across the channels 126. The wires 52 are in a common plane which is spaced from and parallel to the back wall 120. A metal ground plane plate 54 extends transversely across the channels 126 spaced from and parallel to the wires 52 and between the wires 52 and the front wall 118. The ground plane plate 54 has a plurality of openings 56 therethrough which are arranged in rows longitudinally along and transversely across the channel 126.
The transverse rows of the openings 56 are positioned between adjacent wires 52 with the openings 56 being longitudinally spaced so as to be positioned between alternate pairs of the wires 52. A plurality of spaced, parallel conductors 58 are ~S~43 RCA 70,93l 1 on the inner surface of the back wall 120 and extend transversely across the channels 126. Each of the conductors 58 extends along a separate ~ransverse row of the openings 56 in the ground plane plate 54.
In the operation of the display device 100, a positive potential is applied to each of the wires 52,and zero potential is applied to each of the conductors 58 and the ground plane plate 54. Electron beams 150 are directed into the focusing guides between the ground plane plate 54 1O and the back wall 120,with each beam 150 being along a separate longitudinal row of the opening 56 in the ground plane plate 54. The potential difference between the wires 52 and the conductors 58 and the ground plane plate 54 creates electrostatic fields which will cause the electron beams 150 to follow an undulating path along the array of the wires 52, so as to guide the electron beams along the length of the channels 126.
By switching the potential applied to each of the conductors 58 to a negative potential, the electrostatic forces applied to the beam as it passes between the switch conductor and the adjacent wire 52 will cause the beam to be deflected out of its undulating path away from the negative potential conductor. The deflected beam will then pass through an adjacent opening 56 in the ground plane plate 54 and will impinge on the phosphor screen 128. As previously described with regard to the display device 10, the beam can be deflected out of the focusing guide at different angles by using different negative potentials on the conductors 58.
Thus, if a relatively low negative potential, e.g. -100 volts, 5~3 ~c A 7(), 9 31 I is applied to a conductor 58, the beam 150 wilL be deflected at a relatively low ancJle to follow a first path 150a and impinge on the phosphor screen 128 at a first point. ~lowever, if a higher negative potential, e.g., -200 volts,is applied to the conductor 58, the beam will be deflected at a greater angle to follow a path 150b and impinge on the phosphor screen 128 at a second point. Thus, by switching the conductors 58 in sequence to a first negative potentia~ the beams in the channels 126 can be deflected at various points along the channels to achieve a scanning of the phosphor screen 128 along a first set of lines; and then by switching the conductors 58 in sequence to a second negative potential, the beams can be deflected at the various points along the channel to achieve a scanning of the phosphor screen along a second set of lines interlaced with the first set of lines.
Although the deflection of the electron beam 150 in the display device 100 has been described as being accomplished by applying a negative potential to a conductor 58, the deflection can alternatively be achieved by changing the potential applied to a wire 52 to a negative potential. This will cause the beam 150 to be deflected out of the guide at a point just prior to the wire 52 having the negative potential applied thereto. The angle at which the beam 150 will be deflected will depend on the particular potential applied to the wire 80, so that the beam can be deflected at different angles to impinge on the phosphor screen 128 at different points by applying different negative potential to the wire 52. If the beam 150 is to be deflected out of the focusing guide by means of applying negative potential to the ~ 7(),93l lC)~S~IL4;~
I wires 52, the conductor 58 on the inner section of the back wall 120 can be a single layer of metal over the entire surface of the back wall 120 rather than individual strips.
Although the display device 10 is shown in FIGURE 2 as having a focusing guide of the type which includes two plates between which the electron beams flow, the display device 10 can alternatively use the type of focusing guide shown in FIGURE 3 which includes a set of wires between a ground plane plate and the conductor. Likewise the display device 100 can alternatively use the type of focusing guide shown in FIGURE 2.
Thus, there is provided a display device in which a plurality of individual beams of electrons are individually guided along substantially parallel paths substantially parallel to a phosphor screen. The beams are simultaneously deflected out of these paths toward the phosphor screen at a plurality of points along the paths to achieve a pluraiity of line scans of the phosphor screen.
The deflection of the beams is achieved by a deflection potential in the beam guide, the magnitude of which controls the angle of deflection and thus the point on the phosphor screen that the beams will impinge upon. In accordance with the present invention,the beams are deflected at each point by at least two different deflection potentials so that at least two different line scans ofthephosphorscreenresult at each point of deflection of the electron beams. The scanning of the entire phosphor screen can be achieved by first deflecting the electron beams at each of the points in sequence at one deflection potential to achieve one set of line scans,and then deflecting the electron beams at each of 1~3~443 1 the points in sequence at the second deflection potential to achieve a second set of line scans which are interlaced with the line scans of the first set.
The present invention has the advantage that since two or more line scans of the phosphor screen can be obtained at each deflection point of the electron beams,there is required fewer deflection points, one half or less than was previously required with this type of flat panel display. Also, in the focusing guide shown in FIGURE
2, the openings 34 and 38 in the grid plates 32 and 36 can be made larger with fewer openings per unit length of the focusing guide required. ln the focusing guide shown in FIGURE 3, the openings 56 in the ground plane plate 54 can be larger with fewer openings per unit len~th of the focusing guide, and the wires 52 can be spread further apart with fewer wires per unit length of the focusing guide. This greatly simplifies the structure of the display device in that it greatly reduces the number of deflection electrodes needed, thus reducing the number of terminals which would extend through the envelope and simplifying the switching mechanism for achieving the scanning. Also, the structure of the focusing guide is simplified since there are fewer openings in the grid or ground plane plates and fewer wires. Also, since a factor affecting the focusing action of the focusing guides is the size of the openings in the grid plates in one of the guides and the spacing of the wires in the other guide, reducing the number of these openings or wires reduces the possible inconsistancies in the size or spacing so that the consistancy of the
3 focusing action is improved. Also, the larger the openings ~ 3 l~c~ 7(),93l, l in the grid pl,ates or the greater the spacing between the wires, the less effect minor tolerance errors will having on the focusing action. Hence, using the method of the present invention allows for use of improved focusing guides. ~lso, in the display device which includes a focusing grid plate between the beam guide and the phosphor screen, the openings in the focusing grid plate can be larger so as to reduce lens aberations and achieve improved focusing. Although the display device has been described as having two different potentials applied to each deflection electrode to achieve two different line scans at each deflection point, it is possible to apply three or more different deflection potentials at each deflection point to achieve three or more different line scans on each point.
Claims (3)
1. A display device including an evacuated envelope having a front wall, a phosphor screen extending across the inner surface of said front wall, means for generating at least one beam of electrons and directing said beam along a path substantially parallel to said front wall, and a focusing guide extending along substantially the entire length of said beam path for applying electrostatic forces to the electrons of said beam to confine said electrons in said beam, said guide having a plurality of beam exit apertures through which said beam may be extracted, a plurality of deflection electrodes for deflecting said beam toward said phosphor screen, each of said deflection electrodes being aligned with a respective beam exit aperture;
means for selectively deflecting said beam toward said front wall at spaced points along said beam path so that said beam impinges said phosphor screen at a first series of spaced points, and for selectively deflecting said beam towards said front wall at each of said spaced points along said beam path so that said beam impinges said phosphor screen at a second series of spaced points with each of said second points being interlaced between two of said first points.
means for selectively deflecting said beam toward said front wall at spaced points along said beam path so that said beam impinges said phosphor screen at a first series of spaced points, and for selectively deflecting said beam towards said front wall at each of said spaced points along said beam path so that said beam impinges said phosphor screen at a second series of spaced points with each of said second points being interlaced between two of said first points.
2. A display device in accordance with claim 1 in which said beam deflection means includes means for applying a first potential to each of said electrodes to deflect said beam at an angle with respect to said path so that said beam impinges on said phosphor screen at said first points, and means for applying a second potential to said each of said deflection electrodes to deflect said beam at a different angle with respect to said path so that said beam impinges on said phosphor screen at said second points.
3. A display device in accordance with claim 2 including means for generating a plurality of electron beams and directing said beams along substantially parallel paths which are substantially parallel to said front wall, a focusing guide along each of said beam paths for confining the electrons in each said beam, and deflection electrodes for simultaneously deflecting all of said beams toward said phosphor screen at each of said deflection potentials to achieve a line-by-line raster scan of said phosphor screen.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US74941276A | 1976-12-10 | 1976-12-10 | |
| US749,412 | 1976-12-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1085443A true CA1085443A (en) | 1980-09-09 |
Family
ID=25013660
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA292,214A Expired CA1085443A (en) | 1976-12-10 | 1977-12-01 | Flat panel display and method of operating the same |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS5374354A (en) |
| CA (1) | CA1085443A (en) |
| DE (1) | DE2754986A1 (en) |
| ES (2) | ES464734A1 (en) |
| FI (1) | FI773658A (en) |
| FR (1) | FR2373871A1 (en) |
| PL (1) | PL202826A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4386364A (en) * | 1980-09-12 | 1983-05-31 | Sony Corporation | Image display apparatus |
| US4335332A (en) * | 1981-01-30 | 1982-06-15 | Rca Corporation | Focus mesh structure and biasing technique for flat panel display devices |
| KR850000970B1 (en) * | 1981-02-10 | 1985-07-02 | 야마시다 도시히꼬 | Image display apparatus |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2858464A (en) * | 1955-09-26 | 1958-10-28 | Westinghouse Electric Corp | Cathode ray tube |
| NL212598A (en) * | 1955-12-02 | |||
| US4088920A (en) * | 1976-03-29 | 1978-05-09 | Rca Corporation | Flat display device with beam guide |
-
1977
- 1977-12-01 CA CA292,214A patent/CA1085443A/en not_active Expired
- 1977-12-02 FI FI773658A patent/FI773658A/en not_active Application Discontinuation
- 1977-12-03 ES ES464734A patent/ES464734A1/en not_active Expired
- 1977-12-08 JP JP14771877A patent/JPS5374354A/en active Pending
- 1977-12-09 FR FR7737131A patent/FR2373871A1/en active Pending
- 1977-12-09 DE DE19772754986 patent/DE2754986A1/en not_active Withdrawn
- 1977-12-10 PL PL20282677A patent/PL202826A1/en unknown
-
1978
- 1978-03-17 ES ES467973A patent/ES467973A1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| FR2373871A1 (en) | 1978-07-07 |
| DE2754986A1 (en) | 1978-06-15 |
| FI773658A (en) | 1978-06-11 |
| PL202826A1 (en) | 1978-07-17 |
| ES467973A1 (en) | 1979-09-01 |
| ES464734A1 (en) | 1978-07-01 |
| JPS5374354A (en) | 1978-07-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |