EP0185674A1 - Affichage a panneau plat utilisant un reseau lineaire de cathodes d'emission de champ - Google Patents
Affichage a panneau plat utilisant un reseau lineaire de cathodes d'emission de champInfo
- Publication number
- EP0185674A1 EP0185674A1 EP85901849A EP85901849A EP0185674A1 EP 0185674 A1 EP0185674 A1 EP 0185674A1 EP 85901849 A EP85901849 A EP 85901849A EP 85901849 A EP85901849 A EP 85901849A EP 0185674 A1 EP0185674 A1 EP 0185674A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- screen
- flat panel
- electron
- panel display
- beams
- 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.)
- Withdrawn
Links
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
Definitions
- the present invention relates to flat panel displays and, more particularly, to an improved display of this type utilizing field emission cathodes.
- Cathode ray tubes generally are used in monitors for computers, in television sets, etc., to visually display information, such as video images, graphics, or alphanumeric characters.
- Such tubes include one or store thermionic cathodes or the like, to generate one or more beams of electrons.
- Beam forming, modulation, and initial acceleration electrodes typically are combined with the cathode (s) to assure that appropriate, discrete electron beams are formed.
- the combination of such electrodes and the cathodes art referred to in the art as electron guns.
- Deflection coils or electrodes sweep each electron beam across the surface of a phosphor-coated anode screen. (Magnetic coils rather than electrostatic electrodes are often selected for deflection control, because an electromagnetic field provides better beam characteristics.) Phosphor on the screen reacts to beam impingement by emitting visible radiation.
- CMOS complementary metal-oxide-semiconductor
- CRTs While monochromatic (black and white) CRTs often only have one electron gun, most color CRTs have three guns (or three beams issuing from a single gun) which respectively bombard a pattern of red, green and blue phosphor dots or strips on the anode screen with differing intensities, to provide desired color.
- Each small area of the screen displaying a discrete element of the image typically is termed a pixel (picture element).
- the number of pixels per unit area of a screen is a measure of the resolution provided by the tube. For example, a typical cathode ray tube now in a color television receiver provides approximately 150,000 pixels, which pixels are individually bombarded in a raster pattern by three scanning electron beams.
- cathode ray tubes do require, though, significant depth in order to have the distance required between the electron gun assemblies and the screen necessary to obtain adequately controlled scanning. lowever, there are a number of important uses which require coopactness, a ⁇ ch as to provide a display for portable computers.
- Flat panel display arrangements requiring the formation of electron beams generally have one of two main configurations.
- a plurality of electron beams are formed by a matrix of cathodes or other electron beam sources, opposed to the display screen.
- the individual electron beam in this matrix approach is dedicated to one or more selected pixels to energize the same.
- the electrons are actually generated by parallel "strip" cathodes and then formed into a matrix of individual beams by appropriate electrodes or shielding structurss.
- a major difficulty with this approach is that typically a relatively large amount of power is required to energize the cathodes to produce the required matrix of beams.
- the electron beam source i.e., one or more electron gun assemblies
- the beam(s) are then deflected by appropriate techniques, e.g., electromagnetic, electrostatic, or both, to impinge on the surface of the screen at desired pixel locations.
- a design of this nature is referred to herein as an "edge mounted" design.
- a major difficulty with this approach is low brightness, since a minimal number of beams must address the entire screen area sequentially and repetitively to form a desired image.
- Another difficulty is that there are significant electron-optical problems. That is, it is difficult to adequately control the path of the electron beams to assure pixels are properly positioned for a high resolution display. Examples of this approach can be found in U.S. Patent Hos. 2,978,601; 4,205,252; 4,394,599; 4,031,421 ⁇ 4,263,529; and 4,374,343.
- the present invention provides a flat panel display of an edge mounted design having some of the desirable structural characteristics of a matrix approach. This is made possible because of the attributes of field emission cathodes of the type described in, for example, Spindt et al. U.S. Patent Mo. 3,789,471. Field emission cathodes of this type typically have a significant number of electron emission sites in a very small area. For example, field emission cathodes are now available which have about 150 emission sites in an area of only about .005 inches in diameter.
- the flat panel display of the invention includes a linear array of electron guns incorporating field emission cathodes, positioned at one edge of a display screen to emit when energized, an array of electron beams which travel along discrete paths generally parallel to one another, adjacent the surface of the screen. Means are provided to deflect the beams to Impact on areas of the screen defining individual pixels. Most desirably, the beams are deflected simultaneously to excite pixels falling in a linear array (preferably a column) which are to be excited to define a portion of the image to be displayed, and sequential arrays of pixels are excited to cover the entire area of the screen. Thus, beams need only be deflected in one direction in order to address the screen in two directions and form a two-dimensional array of excited pixels.
- the field emission cathode guns eliminate the need for scanning in one direction, and a deflection control arrangement need only be provided to deflect the array in another, angularly related direction.
- the deflection means can be a simple electrostatic arrangement, provided in the best mode by a plurality of generally parallel deflector electrodes which are in a plane that also is generally parallel to the display screen surface. Electrostatic deflection requires significantly less power than electromagetic deflection.
- the invention includes not only the apparatus which is described, but also a unique scanning method. Area scanning is achieved even though a deflection arrangement for only one direction is provided. A major advantage provided by this scanning technique is that it allows a full linear array of pixels to be energized all at one time, i.e., a multiple number of pixels are energized simultaneously rather than individually. In this connection, the intensity of each of the individual beams is individually modulated to include the desired, individual pixel information. This considerably enhances the brightness achievable, since there is a relatively long duty cycle of energization for each pixel.
- the invention also includes a mechanism for enhanced beam alignment and/or calibration. That is, means are provided adjacent a second edge of the screen area for detecting electron beams emitted by the cathodes.
- the detection mechanism enables feedback both of beam position and beam intensity information, for controlling the generation and direction of the individual electron beams.
- FIG. 1 is an isometric view of a preferred embodiment of the display panel of the invention
- FIG. 2 is a diagrammatic illustration of an enlarged, broken away elevational view of the panel of the preferred embodiment
- FIG. 3 is a diagrammatic end view of the panel of FIG. 1;
- FIG. 4 is an enlarged, sectional view of a portion of the construction of the electron gun assemblies incorporated into the preferred embodiment, illustrating the relationship of a linear array of field effect cathodes thereto;
- FIG. 5 is an enlarged and diagrammatic illustration of a portion of the panel of FIG. 1 schematically showing alignment/calibration elements and electronics;
- FIG. 5A is an enlarged diagrammatic illustration of the detection anodes shown in FIG. 5;
- FIG. 6 is a schematic representation of electron beam control electronics for the preferred embodiment of the invention. Detailed Description of A Preferred Embodiment
- Flat panel 11 includes a display screen 12 which, as is conventional, is responsive to electron impact by emitting visible radiation.
- the screen 12 has an anode, cathodoluminescent interior surface, i.e., a surface which is attractive to electrons and responds to electron impact by fluorescing or phosphorescing. That is, the screen is a transparent, conductively coated glass having a thin-film coating of one or more phosphors on its interior surface. It will be recognized by those skilled in the art, though, that other screen arrangements could be used, such as one having a conductive, reflective coating through which electrons must pass to impact on a phosphor-coating providing the desired cathodoluminescence.
- panel 11 also includes a shielding grid 13 adjacent the interior surface of the display screen.
- a shielding grid 13 adjacent the interior surface of the display screen.
- Such grid is shown broken away for simplicity and, as is conventional, can be a conductive open mesh or made up of strip electrodes as shown. Its purpose is to shield the beam array during deflection, prior to accelerating the deflected electron beams toward the phosphorcoated surface of screen 12, to increase their energy and angle of impact. It will be appreciated by those skilled in the art that in some instances it may not be preferred to include such a shielding grid. Also, in some instances it will be desirable to provide such a grid with adjacent elements insulated from one another to provide micro positioning of deflected beams for, for example, color selection.
- an array 16 of individually addressable electron guns incorporating field emission cathodes is provided as a part of the flat panel display, positioned at one edge of the screen 12.
- the array 16 includes a multiple number of field emission cathodes, preferably as many of such cathodes as lines of display are desired in the direction perpendicular to the array.
- Array 16 most simply is a linear array. That is, the guns of such array are arranged in a single line.
- a linear array of electron guns is meant to encompass an array of guns positioned to address a linear array (a single line) of pixels. In this connection, it will be recognized that a multiple number of pixels may share an electron gun at differing times.
- one electron gun may be individually modulated to impact adjacent pixels sequentially for different fields of the frame.
- the line be a straight line and in the preferred embodiment be a column of pixels.
- the edge of the display at which the array is positioned be. one of the opposed edges at which the lesser number of lines of pixel elements to be excited originate. This minimizes the number of individual field emission cathode guns needed. It also simplifies the processing of a standard display signal.
- FIG. 4 symbolically illustrates three adjacent field emission cathode guns 17, 18 and 19.
- the cathodes of such guns are of the type disclosed in U.S. Patent Hos. 3,665,241; 3,755,704; and 3,789,471, naming Charles A. Spindt as one of the inventors, the disclosures of which are incorporated by reference.
- Such cathodes include a common base 20 from which a plurality of electron emitters 21 project for each gun.
- Each gun cathode includes a counter-electrode or gate 22, 23 and 24, respectively, to cooperate with the tips 21 for the production of electrons.
- the counter-electrodes are supported spaced from the emitter tips by a layer 30 of insulating material.
- the counter-electrodes are spaced from one another as shown at 25, to delineate the separate cathodes 17, 18 and 19.
- each field emission cathode includes a plurality of electron emission sites enabling relatively high energy beams, and yet is quite small in size. Moreover, activation of such cathodes does not rely on heat, thus eliminating both heat shielding requirements and the necessity of providing power to generate thermal energy.
- Means are provided to assure that the electrons emitted by each of the cathodes in the array form discrete electron beams.
- Such means is represented by inclusion of an aperturing electrode 26 and a plurality of accelerating and focusing electrodes 27 as part of the electron guns.
- the electrodes 26, 27 as well as the base 20, are common to all of the guns.
- the focusing electrodes provide dynamic focusing for all of the beams, for optimum focusing.
- Means are provided for deflecting the beams for bombardment on selected areas of the screen.
- such means takes the form of a plurality of elongated electrodes 28 (FIG. 2) positioned rearwardly of the space through which the beams are to travel.
- the electrodes 28 provide anelectrostatic deflecting arrangement, i.e., an arrangement for establishing deflecting electrostatic fields. As mentioned previously, electrostatic arrangements generally require less power than electromagnetic arrangements. As illustrated, electrodes 28 generally define a plane parallel to the display screen surface. Most simply. the electrodes 28 are provided by depositing metali zed strips, e.g., of aluminum, on a substrate sheet 29 of an insulating material, e.g., a sheet of glass.
- Each of the cathodes is individually provided with an energization voltage and, hence, produces an electron beam having a desired intensity, depending upon the particular pixel it is intended to form.
- the counter-electrode of each field emission cathode has a separate lead 31 for connection to individual voltage sources 32 as illustrated in FIG. 6.
- the beam intensity and the corresponding voltages will of course be dependent upon the desired image to be displayed, etc., as is conventional.
- Image processing,, timing and the like for the cathode voltages is represented in FIG. 6 by a controller 33 which receives as its input, a display signal as represented at 34.
- FIG. 6 Bach of the deflection electrodes 28 is also individually addressable. This is represented in FIG. 6 by the inclusion of separate Z deflection voltage sources 37, 38 and 39 for the three electrode strips 28 illustrated in FIG. 2. Timing of the application of voltages to the deflection electrodes and to the cathodes, is synchronized. This is represented in FIG. 6 by inclusion of a timing generator 40 receiving input from controller 33 as represented at 41, and having individual output leads 42 connected to the deflection voltage sources 37, 38 and 39. The timing is synchronized so that the deflection system deflects the beam emanating from each of the cathodes to strike the pixel for which the cathode beam intensity is determined at the moment.
- a timing generator 40 receiving input from controller 33 as represented at 41, and having individual output leads 42 connected to the deflection voltage sources 37, 38 and 39. The timing is synchronized so that the deflection system deflects the beam emanating from each of the cathodes to strike the pixel for which the cathode beam intensity is determined
- all of the cathodes are simultaneously energized to produce a plurality of beams which travel together on paths adjacent the screen.
- the beams are then most desirably all deflected together toward the screen to impact simultaneously a column of adjacent pixels. This operation is repeated sequentially. Deflection of the beams together in this manner results in a sequence of pixel columns being energized in one direction, i.e., "scanning" in such direction. As mentioned earlier, this results not only in a simplified scanning system, it enables brightness to be enhanced since the pixel elements can be "scanned" at a field or frame rate, rather than at a line rate.
- the invention includes an arrangement enabling precise beam alignment and calibration. That is, adjacent the edge of the screen opposite the edge having the cathode array 16, there is an array 44 of beam detectors, a corresponding detector for each of the beams to be aligned and/or calibrated.
- FIG. 5 illustrates two detector arrangements 46 and 47 positioned to intercept electron beams represented at 48 and 49 emanating from, for example, cathodes 17 and 18.
- Each of such detectors most simply is a plurality of anodes 51-54.
- there are four anodes in each detector arranged in a square. (It will be appreciated that in FIG. 5 anodes 51 and 52 and their leads are respectively shielded from view by anodes 53 and 54 and their leads.)
- the anodes 51-54 are positioned so that a beam to be detected, if properly directed, will strike equally on all four of such anodes. If a beam is slightly misdirected, there will be an imbalance in the current received by the anodes. Thus, a comparison of the current received by the anodes will indicate a misdirection and also provide information defining the orientation of the misdirection.
- a comparator 56 is connected to the outputs of the anodes of each detector and develops signal information indicative of any misdirection.
- An output lead 57 from each of the comparators is connected to appropriate voltage sources for controlling beam alignment electrodes for the individual beams. This is diagrammatically represented in FIGs.
- the electrodes for each gun 17, 18 and 19 are respectively represented symbolically in FIG. 4 at 61, 62 and 63.
- An adder 64 is Illustrated connected to the outputs of all of the anodes of each of the detectors to develop a signal representative of such intensity.
- the output of each of the adders 64 is fed back as control information to each of the sources of cathode voltage. This is represented by output leads 66 emanating from each of the adders providing an input at 67 to an associated cathode voltage source 32.
- detector plates are available which provide differential outputs on output leads positioned strategically at the edges of an electrically resistive plate, depending upon the location on the plate at which a beam impinges.
- Such a detector arrangement could be used for a plurality of different beams if such beams are sequentially energized and the outputs of the detector arrangement are synchronized and programmed to Identify the particular beam responsible for particular outputs.
Landscapes
- Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
Abstract
Un affichage à panneau plat (11) possède au niveau d'un bord un réseau linéaire de canons à électrons (16) incorporant des cathodes d'émission de champ (17, 18, 19). Chacun des canons à électrons d'émission de champ peut être adressé individuellement et sont tous adressables simultanément. Une structure de déflection (28) est prévue pour dévier les faisceaux d'électrons provenant simultanément des canons et dirigés vers un écran d'affichage (12) à revêtement de phosphore pour adresser simultanément une colonne entière de pixels (éléments d'images) sur l'écran. Toutes les colonnes d'un balayage de trame sont adressées séquentiellement de manière à former le balayage de trame complet. Une structure d'alignement/calibrage de faisceaux est incorporée pour permettre la correction de toute déviation d'un faisceau par rapport à une intensité ou alignement désiré.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US60947884A | 1984-05-11 | 1984-05-11 | |
US609478 | 1984-05-11 |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0185674A1 true EP0185674A1 (fr) | 1986-07-02 |
Family
ID=24440974
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP85901849A Withdrawn EP0185674A1 (fr) | 1984-05-11 | 1985-04-01 | Affichage a panneau plat utilisant un reseau lineaire de cathodes d'emission de champ |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0185674A1 (fr) |
JP (1) | JPS61502151A (fr) |
AU (1) | AU4153385A (fr) |
FI (1) | FI860122A0 (fr) |
NO (1) | NO854830L (fr) |
WO (1) | WO1985005491A1 (fr) |
Families Citing this family (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2213029A (en) * | 1987-11-25 | 1989-08-02 | Philips Electronic Associated | Beam position control in a flat crt display system |
EP0364964B1 (fr) * | 1988-10-17 | 1996-03-27 | Matsushita Electric Industrial Co., Ltd. | Cathodes à émission de champ |
US5117159A (en) * | 1988-11-04 | 1992-05-26 | Matsushita Electric Industrial Co., Ltd. | Flat panel type display and method for driving the display |
US5170092A (en) * | 1989-05-19 | 1992-12-08 | Matsushita Electric Industrial Co., Ltd. | Electron-emitting device and process for making the same |
US5227691A (en) * | 1989-05-24 | 1993-07-13 | Matsushita Electric Industrial Co., Ltd. | Flat tube display apparatus |
KR930002660B1 (ko) * | 1989-05-24 | 1993-04-07 | 마쯔시다덴기산교 가부시기가이샤 | 평판형 화상표시장치 |
US5160871A (en) * | 1989-06-19 | 1992-11-03 | Matsushita Electric Industrial Co., Ltd. | Flat configuration image display apparatus and manufacturing method thereof |
JP2982222B2 (ja) * | 1990-06-14 | 1999-11-22 | ソニー株式会社 | 平面型表示装置 |
US5347292A (en) * | 1992-10-28 | 1994-09-13 | Panocorp Display Systems | Super high resolution cold cathode fluorescent display |
CA2138363C (fr) * | 1993-12-22 | 1999-06-22 | Yasuyuki Todokoro | Dispositif generateur de faisceau electronique, dispositif d'affichage d'images et methode d'attaque de ces dispositifs |
ATE220821T1 (de) * | 1993-12-22 | 2002-08-15 | Canon Kk | Bilderzeugungsgerät |
US6559818B1 (en) | 1995-01-24 | 2003-05-06 | Micron Technology, Inc. | Method of testing addressable emissive cathodes |
US5751262A (en) | 1995-01-24 | 1998-05-12 | Micron Display Technology, Inc. | Method and apparatus for testing emissive cathodes |
JPH09212144A (ja) * | 1995-11-28 | 1997-08-15 | Fuji Photo Film Co Ltd | 画像表示方法および装置 |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3720856A (en) * | 1970-07-29 | 1973-03-13 | Westinghouse Electric Corp | Binary material field emitter structure |
AU501361B2 (en) * | 1975-08-25 | 1979-06-21 | Rca Corporation | Flat electron beam addressed device |
USRE30195E (en) * | 1975-09-22 | 1980-01-15 | Rca Corporation | Guided beam flat display device |
US4158157A (en) * | 1976-10-26 | 1979-06-12 | Zenith Radio Corporation | Electron beam cathodoluminescent panel display |
US4121137A (en) * | 1976-11-12 | 1978-10-17 | Rca Corporation | System for achieving image uniformity in display devices |
US4178531A (en) * | 1977-06-15 | 1979-12-11 | Rca Corporation | CRT with field-emission cathode |
-
1985
- 1985-04-01 EP EP85901849A patent/EP0185674A1/fr not_active Withdrawn
- 1985-04-01 WO PCT/US1985/000533 patent/WO1985005491A1/fr not_active Application Discontinuation
- 1985-04-01 AU AU41533/85A patent/AU4153385A/en not_active Abandoned
- 1985-04-01 JP JP60501447A patent/JPS61502151A/ja active Pending
- 1985-12-02 NO NO854830A patent/NO854830L/no unknown
-
1986
- 1986-01-10 FI FI860122A patent/FI860122A0/fi not_active Application Discontinuation
Non-Patent Citations (1)
Title |
---|
See references of WO8505491A1 * |
Also Published As
Publication number | Publication date |
---|---|
FI860122A (fi) | 1986-01-10 |
NO854830L (no) | 1985-12-05 |
FI860122A0 (fi) | 1986-01-10 |
WO1985005491A1 (fr) | 1985-12-05 |
AU4153385A (en) | 1985-12-13 |
JPS61502151A (ja) | 1986-09-25 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US5229691A (en) | Electronic fluorescent display | |
US4525653A (en) | Modular display apparatus with means for preventing brightness variations | |
US5859508A (en) | Electronic fluorescent display system with simplified multiple electrode structure and its processing | |
US6958576B2 (en) | Method of operating a flat CRT display | |
EP0185674A1 (fr) | Affichage a panneau plat utilisant un reseau lineaire de cathodes d'emission de champ | |
US4769575A (en) | Electron gun of an image display apparatus | |
KR920006174B1 (ko) | 화상표시장치 | |
EP0449284B1 (fr) | Appareil et procédé pour commander les électrodes d'un dispositif d'affichage à panneau plat | |
US5347199A (en) | Thin-type picture display device with means for effecting electron transport by secondard emission | |
US5751109A (en) | Segmented cold cathode display panel | |
US4881005A (en) | Flat type display device | |
US4853585A (en) | Display device with multiplicity of closely spaced electron beams | |
US5949395A (en) | Flat-panel matrix-type light emissive display | |
US4386364A (en) | Image display apparatus | |
US6515639B1 (en) | Cathode ray tube with addressable nanotubes | |
US5995152A (en) | Video monitor which superimposes a high frequency periodic wave over signals to vertical deflection plates to increase display quality in low resolution modes | |
US6188178B1 (en) | Flat-panel picture display device with spacer means adjacent the display screen | |
US5029258A (en) | Image display device and its driving method | |
JP3168869B2 (ja) | 薄型表示装置 | |
JPH01117251A (ja) | 画像表示装置 | |
US20060163994A1 (en) | Vacuum display device with increased resolution | |
JPS60193242A (ja) | 平板形陰極線管 | |
JP2765853B2 (ja) | 平面型ディスプレイ | |
Payne | Segmented cold cathode display panel | |
JPH03210741A (ja) | 平板型陰極線管表示装置 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 19850905 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE CH DE FR GB IT LI LU NL SE |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
18D | Application deemed to be withdrawn |
Effective date: 19871102 |
|
RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: SPINDT, ALVIN, CHARLES Inventor name: CONE, ROY, DONALD |