CA1319390C - Microtip fluorescent screen with a reduced number of addressing circuits and process for addressing said screen - Google Patents
Microtip fluorescent screen with a reduced number of addressing circuits and process for addressing said screenInfo
- Publication number
- CA1319390C CA1319390C CA000604031A CA604031A CA1319390C CA 1319390 C CA1319390 C CA 1319390C CA 000604031 A CA000604031 A CA 000604031A CA 604031 A CA604031 A CA 604031A CA 1319390 C CA1319390 C CA 1319390C
- Authority
- CA
- Canada
- Prior art keywords
- addressing
- rows
- anodes
- potential
- zone
- 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.)
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Classifications
-
- 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
- H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
- H01J29/08—Electrodes intimately associated with a screen on or from which an image or pattern is formed, picked-up, converted or stored, e.g. backing-plates for storage tubes or collecting secondary electrons
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y10/00—Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
-
- 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
- H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
- H01J29/08—Electrodes intimately associated with a screen on or from which an image or pattern is formed, picked-up, converted or stored, e.g. backing-plates for storage tubes or collecting secondary electrons
- H01J29/085—Anode plates, e.g. for screens of flat panel displays
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2310/00—Command of the display device
- G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
- G09G2310/0235—Field-sequential colour display
Abstract
ABSTRACT OF THE DISCLOSURE
Microtip fluorescent screen having a reduced number of addressing circuits. This screen of N rows (16) is divided into k zones Zi, each of the N/k rows (16) belonging to N/k families of rows. The k rows (16) of the same family are electrically interconnected. Each zone Zi also comprises three series of N/k conductive bands (26) each. The bands (26) of a first series are covered by a material (28) luminescing in the red, the bands (26) of a second series are covered by a material (29) luminescing in the green and the bands (26) of a third series are covered by a material (30) luminescing in the blue.
Each triplet formed by three bands (26) covered by material luminescing in the red, green and blue is aligned substantially facing a row (16) (grid). The bands (26) of each series in a zone Zi are electrically interconnected for forming three anodes Al,i, A2,i and A3,i. Application to the display or fixed or moving pictures.
Microtip fluorescent screen having a reduced number of addressing circuits. This screen of N rows (16) is divided into k zones Zi, each of the N/k rows (16) belonging to N/k families of rows. The k rows (16) of the same family are electrically interconnected. Each zone Zi also comprises three series of N/k conductive bands (26) each. The bands (26) of a first series are covered by a material (28) luminescing in the red, the bands (26) of a second series are covered by a material (29) luminescing in the green and the bands (26) of a third series are covered by a material (30) luminescing in the blue.
Each triplet formed by three bands (26) covered by material luminescing in the red, green and blue is aligned substantially facing a row (16) (grid). The bands (26) of each series in a zone Zi are electrically interconnected for forming three anodes Al,i, A2,i and A3,i. Application to the display or fixed or moving pictures.
Description
1319~
The present invention relates to a microtip fluorescent screen having a reduced number of addressing circuits and to its addressing process. It applies more particularly to the display of fixed or moving images or pictures.
The known microtip fluorescent screens are monochromatic. A description thereof is given in the repork of the "Japan Display 86 Congress", p. 152 and in Canadian patent No. 1,261,911 granted on September 26, 1989. The procedure used for monochromatic screens can be extrapolated to trichromatic screens.
The objective of the present invention is to reduce the total number of control circuits of a microtip fluorescent screen, no matter whether it is of a trichromatic or a monochromatic type.
The invention also permits the autofocussing of the electrons emitted to the phosphor emitting in the desired colour, which ensures a good colour purity of the image or picture.
More specifically, the invention relates to the matrix display microtip fluorescent screen having a first insulating substrate on which are arranged in the two directions of the matrix, conductive columns (cathode conductors) supporting metal microtips and above the columns, N perforated conductive rows (grids), the rows and columns being separated by an insulating layer having apertures permitting the passage of the microtips, each intersection of a row and a column corresponding to a pixel, characterized in that it is subdivided into k zones Zi, i ranging from 1 to k, with ~, 131939~
N/k successive rows each, the N rows of the screen being grouped into N/k families of rows, a zone Zi only having a single row of each family, the rows of the different families alternating within a zone Zi, the rows of a same family being electrically interconnecked and in that on a second transparent substrate facing the first, each zone Zi comprises a family of anodes covered by at least one luminescent material, the families of the different zones being electrically independent and identical, each family of one zone Zi facing N/k rows of the zone Zi.
According to a first embodiment, with the screen according to the invention being trichromatic, each family of anodes of a zone Zi comprises three series of N/k conductive bands each, the bands of the different series alternately succeeding one another, the bands of one of the series being covered by a material luminescing in the red, the bands of another of said series being covered by a material luminescing in the green and the bands of the final series being covered by a material luminescing in the blue, each triplet formed by three bands respectively covered by materials luminescing in the red, green and blue being substantially aligned facing a row (grid), the bands of each series in a zone Zi being electrically interconnected for forming three anodes Al,i, A2,i and A3,i.
The system of electrodes and grids forms N/k combs with k teeth along the rows of the screen.
Each comb corresponds to one of the N/k families of rows.
13~90 The anodes are also in the form of combs.
For a trichromatic screen, a zone Zi comprises three combs-anodes, one for each of the primary colours red, green and blue. The teeth of these combs are aligned on the grids of the screen. The width thereo~ is substantially less than one third of the width of a grid and in this way one tooth of each comb can ~ace a grid.
The invention also makes it possible to produce a monochromatic screen. In this case, on the second transparent substrate, each family of anodes of a zone Zi comprises a series of conductive strips covered by a luminescent material, each conductive strip being substantially aligned facing a row (grid), the conductive strips of a zone Zi being electrically interconnected to form an anode Ai.
The invention also relates to a process for addressing said screen.
According to a first process for addressing a screen according to the invention, the display of a trichromatic frame takes place during a frame time T.
The following operations are carried out for the anodes Al,i, i ranging between 1 and k and which are of a successive nature. These operations are then repeated for anodes A2,i and then A3,i, so as to display for a frame time T three monochromatic images in the three primary colours red, green and blue. These operations consist of:
successively raising each of the anodes Al,i (respectively A2,i, A3,i) of the zone Zi, i ranging between 1 and k, to a potential Valmax (respectively VA2max, VA3max) adequate for attracting the electrons possibly emitted by the microtips with an energy higher than the threshold cathodoluminescence threshold of the corresponding luminescent material for an addressing time tl (respectively t2, t3) periodically at a period corresponding to a frame time T, such that T=k(tl+t2+t3), when the anodes Al,i (respectively A2,i, A3,i) are not raised to the potential VAlmax (respectively VA2max, VA3max), the anodes Al,i (respectively A2,i, A3,i~ are raised to a potential VAlmin (respectively VA2min, VA3min), such that the electrons emitted by the microtips are repelled or have an energy below the cathodoluminescence threshold energy of the corresponding luminescent material;
for the addressing time tl (respectively t2, t3) of each anode Al,i (respectively A2,i, A3,i), successively raising the different families of rows to a potential VGmax for a row selection time ~1 (respectively ~2, ~3), such that T=N(~1+~2+a3), when they are not raised to the potential VGmax, the different families of rows are raised to a potential VGmin, such that the microtips emit no electrons; and during the row selection time ~1 (respectively ~2, ~3) of each row of each zone Zi, addressing the cathode conductors in such a way as to "illuminate" the pixels of the row which should be illuminated.
According to a second process for addressing a screen according to the invention ~or the display o~ a trichromatic frame of the image produced during a frame time T, the following operations are performed successively for each of the zones Zi, ranging from 1 to k:
13~93~3 successively raising the families of ro~7s to a potential VGmax for the row selection time t, such that t=T/N, when they are not raised to the potential VGmax, the families of rows are raised to the potential VGmin, such that the microtips do not emit electrons;
during the selection time t of each row of the zone Zi in question, successively raising the anodes Al,i, A2,i and A3,i respectively to potentials VAlmax, VA2max and VA3max, which are adequate for attracting the electrons optionally emitted hy the microtips with an energy higher than the threshold cathodoluminescence energy of the corresponding luminescent materials, during addressing times respectively tl, t2 and t3, such that tl~t2+t3=t, when they are not raised to the potsntials VAlmax, VA2max and VA3max, the anodes Al,i, A2,i and A3,i are raised to the potentials VAlmin, VA2min and VA3min respectively, such that the electrons emitted by the microtips are repelled or have an energy below the threshold cathodoluminescence energy of the corresponding luminescent material; and during the addressing times tl, t2 and t3 of each anode Al,i, A2,i and A3,i, addressing the cathode conductors so as to "illuminate" the pixels of the row which should be illuminated.
For each process and at a given instant, a single family of rows and a single anode of a zone are selected. The emission of the electrons is localized on the overlap surface of the grid and selected anode.
This emission is modulated by the potential applied to the cathode conductors, which function in accordance with the prior art. The electrons are repelled by the unselected anodes and drop onto the grid. They are then eliminated, or ha~e an energy below the threshold .- . , 13~939~
cathodoluminescence energy of the corresponding luminescent materials and are also eliminated.
The screen is addressed sequentially with a reduced number of control circuits. The number of families of rows added to the number of anodes (three per zone and k zones), remains well below the number of rows or lines of the screen.
At each instant, the electrons emitted by the microtips are focused on the anode of the selected colour, thus guaranteeing a colour purity not reduced by the phenomena of the lateral emission of electrons from the microtips.
In these embodiments of the addressing process, the three primary colours of the screen are never displayed at the same time. The colour sensation on a broad spectrum perceived by a screen viewer is due to the reconstitution of the coloured spectrum by the viewer's eye. The eye is a "slow" detector compared with the different characteristic display times of the screen (frame time T, etc.) and the perception of the full colour is due to an averaging effect on several frames of the picture.
For a monochromatic screen, an addressing process consists of carrying out the following operations for displaying one frame of the screen, said display taking place during a frame time T: successively raising each of the anodes Ai, i ranging between 1 and k to a potential VAmax for an addressing time tZ, such that T=ktZ, when they are not raised to an adequate potential VAmax for attracting the electrons possibly ~3~93~
emitted by the microtips, the anodes Ai are raised to a potential VAmin, such that the electrons emitted by the microtips are repelled, or have an energy below the threshold cathodoluminescence energy of the luminescent material; during the addressing time tZ of each anode Ai, successively raising each family of rows to a potential VGmax for a row selection time t, such that t=T/N, when they are not raised to the potential VGmax, the families of rows are raised to a potential VGmin, such that the microtips do not emit electrons; and during the row selection time t of each family of rows, addressing the cathode conductors in such a way as to "illuminate" the pixels of each row which should be illuminated.
The characteristics and advantages of the invention can be better gathered from the following non-limitative description with reference to the attached drawings, wherein show:
Fig. 1 illustrates diagrammatically a microtip fluorescent trichromatic screen such as could be extrapolated.
Fig. 2 illustrates diagrammatically a section of a microtip fluorescQnt trichromatic screen, such as could be extrapolated in accordance with fig. 1.
Fig. 3A diagrammatically a portion of a trichromatic screen according to the invention, fig. 3B
showing a section along axis aa' of said screen.
,, .'~f 1 ~19,790 Fig. 4 on a larger scale than in fig. 3 diagrammatically and partially two successive rows o~ a trichromatic screen according to the invention.
Fig. 5 diagrammatically the timing diagrams relating to the addressing of one o~ the three anode series according to a first process for addressing a trichromatic screen according to the invention.
Fig. 6 diagrammatically the timing diagrams relating to the first process for addressing a pixel o~
a trichromatic screen according to the invention.
Fig. 7 diagrammatically the timing diagrams relating to the addressing of one of the three series of anodes according to a second process for addressing a trichromatic screen according to the invention.
Fig. 8 diagrammatically the timing diagrams relating to the second process for addressing a pixel of a trichromatic screen according to the invention.
Fig. 9 diagrammatically part of a microtip fluorescent monochromatic screen according to the invention.
Fig. 10 diagrammatically the timing diagrams relating to a process for addressing a pixel of a monochromatic screen according to the invention.
- Fig. 1 diagrammatically shows in perspective a matrix-type trichromatic screen, such as could be logically extrapolated from a monochromatic screen.
, . ~, 13193~0 On a first e.g. glass substrate lO are provided conductive columns 12 (cathode conductors of e.g. indium tin oxide) supporting metal, e.g. molybdenum microtips 14. The columns 12 intersect the perforated conductive rows 16 (grids) which are e.g. of niobium.
A11 the microtips 14 positioned at an intersec~ion of a row 16 and a conductive column 12 have their apex substantially facing a perforation of row 16.
The cathode conductors 12 and grids 16 are separated by an e.g. silica insulating layer 18 provided with openings or apertures permitting the passage of the microtips 14.
A conductive material layer 20 (anode) is deposited on a second transparent, e.g. glass substrate 22. Parallel bands alternately in phosphors luminescing in red 24R, in grean 24V and in blue 24B are deposited on the anode 20 facing the cathode conductors 12. The bands can be replaced by a mosaic pattern.
In this configuration, it is necessary to have a triplet of cathode conductors 12 (one facing a red band 24R, another facing a green band 24V and a third facing a blue band 24B), in order to bring about a colour display along a screen column.
Each intersection of a grid 16 and a cathode conductor 12, in this embodiment, corresponds to a monochromatic pixel. A ~'colour" pixel is composed by three monochromatic red, green and blue pixels. The combination of these three primary colours enables the viewer's eye to reconstitute a wide coloured spectrum.
~3~ 9390 A screen of this type having N rows and M
columns requires, in the colour mode, N control circuits for the grids 16, 3M control circuits for the 3M cathode conductors 12, plus a circuit for the anode 20. ~or example a colour display screen with 575 rows or lines and 720 columns (French colour television standard) comprises 575 control circuits for the grids 16 and 2160 control circuits for the cathode conductors 12.
A microtip monochromatic fluorescent display screen 14 has 575 control circuits for grids 16 and 720 control circuits for the cathode conductors 12.
Fig. 2 shows a section of the microtip trichromatic fluorescent screen of fig. 1, as could be extrapolated by the Expert. As there is only one anode 20, the electrons emitted by the microtips 14 of a pixel are directed either to the red 24R, green 2~V or blue 24B phosphor. In particular, the lateral emission o~ a microtip 14 leads electrons intended for a red phosphor 24R, e.g. to a green phosphor 24V. This lateral emission also exists for monochromatic screens and leads to a resolution loss. For a trichromatic screen, said resolution loss is accompanied by a "dilution" of the colours, which is prejudicial to the viewing quality.
Fig. 3A diagrammatically shows a portion of a trichromatic screen according to the invention. The screen is viewed through the diagrammatically represented second transparent substrate 22. The screen is subdivided into k zones Zi, i ranging between 1 and k, three of these Zi-l, Zi and Zi+l being at least partly visible in fig. 3A. 3N parallel conductive bands 26, N being the number of rows or lines of the screen, 131939~
rest on substrate 22. These bands 26 are e.g. of indium tin oxide. These conductive bands 26 are grouped and electrically interconnected in order ~o form three series of N/k bands each per zone Zi, corresponding to three anodes Al,i, A2,i and A3,i. Each of the bands 26 is covered by a luminescent material. Fig. 3B
diagrammatically shows a section of the trichromatic screen according to the invention. This section is along axis aa' shown in fig. 3A. On the first e.g.
glass substrate 10, the elements are the same and are arranged in the same way as in the prior art. The cathode conductors 12 are aligned in accordance with the screen columns. These cathode conductors 12 support microtips 14. The grids 16 along the rows of the screen intersect the cathode conductors 12. The grids 16 (rows) and cathode conductors 12 (columns) are separated by an insulating layer 18 having apertures permitting the passage of the microtips.
The second transparent, insulating and e.g.
glass substrate 22 supports the conductive bands 26 aligned on grids 16 and therefore aligned in accordance with the rows of the screen. These conductive bands 26 are covered with luminescent material. Along the axis aa', the band 26 shown in fig. 3B is covered with a material 28, e.g. luminescing in the red.
As can be seen in fig. 4, a first series of such bands 26 is covered by a material 28 luminescing in the red, e.g. Eu-doped Y2O2S and forms an anode A1,8 e.~.
for zone Zi, a second series of said bands is covered by a material 29 luminescing in the green, e.g. CuA1-doped ZnS and forms an anode A2,i, e.g. for zone Zi; and the third series of bands 26 is covered by a material 30 131~90 luminescing in the blue, e.g. Ag-doped ZnS and forms an anode A3,i e.g. for zone Zi. The bands 26 of the different series alternate and are equidistant.
Each triplet formed by an anode of each series faces a grid 16 (row). The grids 16 rest on a second substrate 10 (not shown in figs 3A and 4). The grids 16 intersect cathode conductors 12 (not shown in figs. 3A and ~). Grids 16 and cathode conductors 12 are separated by an insulating layer 16 (not shown in figs.
3A and 4). Each intersection of a grid 26 and a cathode conductor 12 forms a trichromatic pixel.
The grids 16 (along the rows) of the screen are grouped into N/k families. One zone Zi of the screen has a single grid 16 of each family. The grids 16 of the different families alternate within a zone Zi and the grids 16 of the same family are electrically interconnected.
First exam~le of the process for addressing a microtip fluorescent trichromatic screen according to the invention ffiqs. 5 and 6) This process consists of dividing the display time of a frame T into three:
a subframe time T1 corresponds to the display of a first frame, e.g. red, of the screen, a subframe time T2 corresponds to the display of a second frame, e.g. green, of the screen, a subframe time T3 corresponds to the display of a third frame, e.g. blue, of the screen, Tl, T2, T3 being connected by the relation Tl + T2 + T3 = T.
~ls~a The red, green and blue frames of the picture are successively displayed.
As can be seen in fig. 5 within the subframe time Tl (T2, T3 respectively), during which i~
displayed the red frame (green, blue respectively~ of the screen, the k anodes of the zones Zl, ..., Zk correspond to red (respectively green, blue), designated Al,i (respectively A2,i A3,i) are successively addressed. This addressing consists of raising each anode Al,i (respectively A2,i, A3,i) successively to a potential VAlmax (respectively VA2max, VA3max) during a time tl (respectively t2, t3). This potential VAlmax (respectively VA2max, VA3max) is adequate for attracting the electrons optionally emitted by the microtips with an energy higher than the threshold cathodoluminescence energy of the material 28 (respectively 29, 30) luminescing in the red (or green or blue). Outside the addressing time tl, the anodes Al,i (respectively A2,i and A3,i) are raised to a potential VAlmin (respectively VA2min, VA3min), such that the electrons emitted by the microtips are repelled and eliminated by means of a grid 16, or have an energy below the threshold cathodoluminescence energy of the luminescent material corresponding thereto and are also eliminated.
The subframe time Tl (respectively T2, T3) is iinked with the addressing time tl (respectively t2, t3) of an anode Al,i (respectively A2,i A3,i) by the relation: Tl = ktl (respectively T2=kt2, T3=kt3).
The frame times Tl, T2 and T3 and the values of the addressing potentials of the anodes are experimentally adjusted as a function of the luminescent ,. , 1 319~
materials 28, 29 and 30, so as to obtain a pure white when all the scresn is addressed.
Fig. 6 diagrammatically shows the timing diagrams relating to the first process for addressing a pixel of a trichromatic screen according to the invention.
The display of a trichromatic frame of the screen takes place in a frame time T subdivided into three subframe times Tl, T2 and T3 corresponding to the respective display of a red, green and blue frame.
Fig. 6 only shows the addressing of the anodes Al,i, A2,i and A3,i of zone Zi. These addressing operations take place during respective addressing periods tl, t2 and t3, the first being within the red frame, the second within the green frame and the third within thP blue frame.
The grids 16 are addressed by families.
The pixels involved in each addressing of a family of rows are those corresponding to the superimposing of a row of the addressed family with the selected anode.
The families of rows Gj, j ranging between 1 and N/k, are raised to a potential VGj. VGj assumes a value VGmax for the row selection times ~1, periodically at period tl, for the entire frame time Tl, then VGj assumes the value VGmax for the row selection time ~2, periodically at period t2, throughout the frame time T2 and then VGj assumes the value VGmax for a row selection time ~3, periodically at period t3, for the entire frame time T3. Outside the row selection times, 131~39~
VGj assumes the value VGmin permitting no electron emission by microtips 14.
The addressing times tl, t2 and t3 are linked with the row selection time ~ 2 and ~3 by the relations: tl/~l = t2/~2 = t3/~3 = N/k.
The "illumination" of the pixels positioned on the row of family Gj facing the anodes of zone Zi is controlled by the potential applied to the cathode conductors 12.
The three timing diagrams Cl, C2 and C3 of fig. 6 represent the control signals VCl of the cathode conductor 12 of number 1 in the matrix making it possible to "illuminate" the pixel corresponding to the intersection of the row of family Gj in zon~ Zi with the cathode conductor 12 of number 1, said pixel being ijl.
Timinq diaqram Cl: pixel ijl "illuminated" in red.
To illuminate the pixel ijl in red, the control potential VCl of cathode conductor 12 of number 1 assumes a value VCmin during the selection time ~1 of the row of family Gj in zone Zi. The potential difference VGmax-VCmin permits the emission of electrons by microtips 14. Pixel ijl is extinguished in the two other colours, because the potential VCl then assumes the value VCmax not permitting the emission of electrons by the microtips 14 during selection times ~2 and ~3 of the row of family Gj.
Timina diaaram C2: Pixel ijl "illuminated" in the three primary colours red, green and blue= pixel ijl "white".
"' ., ~3~9~
For each selection of the row corresponding to pixel ijl, the potential VCl assumes the value VCmin.
Pixel ijl successively assumes the colours red, green and blue, the white colour being restored by the psrsistence of vision of a viewer's eye.
T.iminq diagram C3: Pixel ijl "extinguished", pixel ijl "black".
For each selection of the row corresponding to pixel ijl, potential VCl is maintained at the value VCmax, no colour being "illuminated".
Example of numerical data corresponding to the first process for addressing a trichromatic screen according to the invention:
N: number of rows 500 k: number of zones 20 20 T: frame time 20 ms Tl: red frame time 5 ms T2: green frame time 5 ms T3: blue frame time 10 ms tl: addressing time of a red anode in a zone 5 ms/20 = 0.25ms t2: addressing time of a green anode in a zone 5 ms/20 = 0.25 ms t3: addressing time of a blue anode in a zone 10 ms/20 = 0.5 ms 30 ~1: selection time of a family of rows during the addressing of a red anode 0.25 ms/25 = 10 ~s ~2: selection time of a family of rows during the addressing of a green anode 10 ~s 13~3~
~3: selection time of a family of rows during the addressing of a blue anode 20 ~s VAl: addressing potential of anodes Al,i:
VAlmin = 40 V, VAlmax = 100 V
VA2: addressing potential of anodes A2,i:
VA2min = 40 V, VA2max = 100 V
VA3: Addressing potential of anodes A3,i:
VA/min = 40 V, VA3max = 150 V
~Gj: addressing potential of a family of raws:
VGmin = -40 V, VGmax = 40 V
VCl: control potential of column 1:
VCmin = -40 V, VCmax = 0 ~.
Second example of process for addressinq a microtiP
fluorescent trichromatic screen accordinq to the invention (fi~s 7 and 8) This process consists of the row by row addressing of the three primary colours for each pixel.
Fig. 7 shows the addressing sequences of anodes Al,i, ....... Al,k of zones Zl to Zk respectively.
Anodes Al,i, A2,i and A3,i, i ranging between 1 and k, are successively addressed. The display frame time T is subdivided into zone times tZ during which all the rows of one zone are addressed. The frame time T and the zone time tZ are linked by the relation T = k.tZ.
Each anode Al,i (respectively A2,i, A3,i) is addressed for an addressing time tl (respectively t2, t3), for the zone time tZ and at the period of a frame time T.
, . .
l3ls3~a During the zone time tZ, an anode Al,i (respectively A2,i A3,i) is periodically raised during an addressing time tl (respectively t2, t3) to a potential VAlmax (respectively VA2max, VA3max) adequate for attracting the electrons emitted by the microtips 14 with an energy exceeding the threshold cathodoluminescence energy of the material 28 (respectively 29, 30). The period is in this case t the selection time of a row in a zone. Thus the zone time is linked with the row selection time t by the relation tZ = N/k.t.
The addressing times tl, t2 and t3 of the anodes Al,i, A2,i and A3,i respectively are linked with the row selection times t by the relation tl + t2 + t3 = t.
Outside the addressing times, the anodes Al,i (respectively A2,i, A3,i) are raised to a potential VAlmin (respectively VA2min, VA3min) such that the electrons emitted by the microtips 14 are rejected towards the grids 16 and eliminated or have an energy below the threshold cathodoluminescence energy of the luminescent material corresponding thereto and are also eliminated.
Fig. 8 diagrammatically shows the timing diagrams relating to the second process for addressing a pixel of a trichromatic screen according to the invention.
The displaying of a trichromatic frame of the screen takes place in a frame time T, which is 13~3~
subdivided into zone times tZ. In a zone time tZ, all the rows of a zone are successively addressed.
The timing diagrams of fig. 8 represent the addressing of the pixel ijl. The families of rows Gj, j ranging between 1 and N/k, are successively raised to a potential VGmax. VGj assumes a value VGmax during th~
row selection time t at period tZ. During the ro~
selection time t, the three anodes Al,i A2,i A3,i of zone Zi are consequently successively addressed during the re~pective addressing times tl, t2 and t3.
The "illumination" of the pixels positioned on the row of family Gj facing the anodes of zone Zi is controlled by the potential applied to the cathode conductors 12.
The three timing diagrams C4, C5 and C6 of fig. 8 show the control signals VCl of the cathode conductor 12 of number 1 making it possible to "illuminate" the pixel ijl.
Timing diaqram C4: Pixel ijl "illuminated" in red.
In order to "illuminate" the selected pixel ijl in red, the control potential VCl of the cathode conductor 12 of number 1 assumes the value VCmin during the addressing time tl of anode Al,i. VCl is kept at value VCmax for the addressing times t2 and t3 of anodes A2,i and A3,i (corresponding to green and blue~.
Timina dia~ram C5: Pixel ijl "illuminated" in the three primary colours red, green and blue = pixel ijl "white".
1 3 ~
The potential VCl is maintained at the value VCmin for the entire row selection time, which permits the emission of the electrons by the microtips 14 during each addressing time tl, t2 and t3 of anodes Al,i, A2,i and A3,i.
Timinq diaqram C6: Pixel ijl "extinguished", pixel ijl "black".
On this occasion the potential VCl is maintained during the row selection time at value VCmax not permitting the emission of electrons, so that the pixel ijl is "black".
Example of numerical data corresponding to the second process for addressing a trichromatic screen according to the invention:
N number of rows 500 20 k: number of zones 20 T: frame time 20 ms tZ: zone time 1 ms t: row selection time 1 ms/25 = 40 ~s tl: addressing time of an anode Al,i = 10 ~s 25 t2: addressing time of an anode A2,i = 10 ~s t3: addressing time of an anode A3,i = 20 ~s VAl: addressing potential of anodes Al,i:
VAlmin = 40 V, Valmax = 100 V
VA2: addressing potential of anodes A~,i:
VA2min = 40 V, VA2max = 100 V
VA3: addressing potential of anodes A3,i:
VA3min = 40 V, VA3max = 150 V
VGj: addressing potential of a family of rows VGmin = -40 V, VGmax = +40 V
13~39~
VCl: control potential of column 1:
VCmin - -40 V, VCmax = 0 V.
A microtip fluorescent trichromatic screen according to the invention with 575 rows and 720 columns (French television standard) can operate wikh 23 families of rows, 25 red anodes, 25 green anodes, 25 blue anodes and 720 cathode conductors, i.e. 818 outputs to be controlled each by a different electric circuit.
This is to be compared with a screen such as could be extrapolated by the Expert (figs. 1 and 2), i.e~ 575 grids and 3x720 cathode conductors, i.e. 2735 ou~puts to be controlled, each by a different electric circuit.
At a given instant, all the electrons emitted are either repelled to a grid or have an energy below the threshold cathodoluminescence energy of the luminescent material, or are attracted by a luminescent phosphor in a given primary colour. The lateral electron emission of the microtips 14 consequently produces no diaphony phenomenon characterized by a dilution of the colours.
The invention can also apply to microtip monochromatic fluorescent screens. The screen is subdivided into k zones Zi~ i ranging between l and k and the N rows are grouped into N/k families. The rows (grids 16) of the samefamily are electrically interconnected. Each zone Zi only comprises a single row of each family. The rows 16 of each family succeed one another within a zone ~i.
Fig. 9 diagrammatically shows part of a monochromatic screen according to the invention. The -. .
13193~0 screen is seen through the second, diagrammatically shown, transparent substrate 22. on the latter are located N conductive bands 26, which are electrically connected by groups of N/k bands 26 to form k anodes Ai:
one anode Ai per zone Zi. Anodes ~i are covered by a luminescent material 31, e.g. ZnS.
In the same way as for a trichromatic screen, the bands 26 face grids 16 (rows). The grids 16 intersect the cathode conductors 12 (not shown in fig.
9). Grids 16 and cathode conductors 20 are separated by an insulating layer 16 (not shown in fig. 9). Each intersection of a row (grid 16) and a column (cathode conductor 12) forms a pixel.
The section of such a monochromatic screen along an axis of a conductive band 26 is identical to the section of a trichromatic screen shown in fig. 3B, the luminescent material 31 replacing material 28. A
single luminescent material 31 is deposited on each conductive band 26.
Example of a process for addressinq a monochromatic screen accordin~ to the invention (fig. 10) The timin~ diagrams relating to this addressing process are diagrammatically shown in fig.
10. They relate to the "illumination" of pixel ijl located at the intersection of the row of family Gj in zone Zi with the cathode conductor (column) of number l in the matrix.
A frame of a picture is displayed for a frame time T. The anodes Ai,i ranging between 1 and k, 13193~
are successively addressed during an addressing time tZ.
The addressing of an anode Ai consists of ràising the potential VAi supplied to said anode to the value VAmax during the addressing time tZ. The potential VAmax is such that it attracts the electrons optionally emitted by the microtips 14 with an energy exceeding the threshold cathodoluminescence energy of the material 31.
Outside the addressing time tZ, the potential Vhi is maintained at a value V~min such that the electrons emitted by the microtips are repelled towards a grid 16 or have an energy below the threshold cathodoluminescence energy of the luminescent material.
A family of rows Gi is periodically addressed during a row selection time t. The potential VGj supplied to the family of rows Gj then assumes the value VGmax during t at period tZ. The different families of rows are successively addressed during the period tZ. Potential VGmax permits the emission of electrons. Outside the row selection time, VGj assumes the value VGmin not permitting the emission of electrons.
During the addressing time t of the row of the family Gj in zone Zi, potential VC1 applied to the cathode conductor of number 1 assumes a value VCmin for the "illumination" of pixel ijl and a value VCmax if the pixel must remain "extinguished". Thus, VCmin is such that the potential difference VGmax-VCmin is adequate for tearing away electrons at the microtips, whereas VGmax-VCmax is not.
Examples of numerical date relating to this addressing process:
,. ~
~31 93~0 N: number of rows 500 k: number of zones 20 T: frame time 20 ms tZ: addressing time of an anode Ai = 1 ms 5 t: row selection time 40 ~s VAi: addressing potential of anode ~i:
VAmax = 100 V, VAmin = 40 V
VGj: addressing potential of a family of rows Gj:
VGmax = 40 V, VGmin = -40 V
lO VCl: control potential of column 1:
VCmax = 0 V, VCmin = -40 V.
This type of monochromatic screen only requires N/k addressing circuits for families of rows, k addressing circuits for the anodes and obviously M
control circuits for the cathode conductors (for a screen with M columns). However, a microtip monochromatic fluorescent screen according to the prior art requires N addressing circuits for the rows and M
addressing circuits for the column, so that the gains are significant.
For producing a family of rows which are electrically connected to one another and for producing an anode (formed by electrically interconnected conductive bands 26), it is e.g. possible to etch in a conductive material parallel bands of appropriate dimensions. The different bands of each family of rows or each anode are electrically interconnected via an anisotropic conductive film electrically contacted with a metal ribbon or tape. This film is only conductive at certain crushing points located on the bands to be connected. The conductive crushing points are interconnected by the metal ribbon.
The present invention relates to a microtip fluorescent screen having a reduced number of addressing circuits and to its addressing process. It applies more particularly to the display of fixed or moving images or pictures.
The known microtip fluorescent screens are monochromatic. A description thereof is given in the repork of the "Japan Display 86 Congress", p. 152 and in Canadian patent No. 1,261,911 granted on September 26, 1989. The procedure used for monochromatic screens can be extrapolated to trichromatic screens.
The objective of the present invention is to reduce the total number of control circuits of a microtip fluorescent screen, no matter whether it is of a trichromatic or a monochromatic type.
The invention also permits the autofocussing of the electrons emitted to the phosphor emitting in the desired colour, which ensures a good colour purity of the image or picture.
More specifically, the invention relates to the matrix display microtip fluorescent screen having a first insulating substrate on which are arranged in the two directions of the matrix, conductive columns (cathode conductors) supporting metal microtips and above the columns, N perforated conductive rows (grids), the rows and columns being separated by an insulating layer having apertures permitting the passage of the microtips, each intersection of a row and a column corresponding to a pixel, characterized in that it is subdivided into k zones Zi, i ranging from 1 to k, with ~, 131939~
N/k successive rows each, the N rows of the screen being grouped into N/k families of rows, a zone Zi only having a single row of each family, the rows of the different families alternating within a zone Zi, the rows of a same family being electrically interconnecked and in that on a second transparent substrate facing the first, each zone Zi comprises a family of anodes covered by at least one luminescent material, the families of the different zones being electrically independent and identical, each family of one zone Zi facing N/k rows of the zone Zi.
According to a first embodiment, with the screen according to the invention being trichromatic, each family of anodes of a zone Zi comprises three series of N/k conductive bands each, the bands of the different series alternately succeeding one another, the bands of one of the series being covered by a material luminescing in the red, the bands of another of said series being covered by a material luminescing in the green and the bands of the final series being covered by a material luminescing in the blue, each triplet formed by three bands respectively covered by materials luminescing in the red, green and blue being substantially aligned facing a row (grid), the bands of each series in a zone Zi being electrically interconnected for forming three anodes Al,i, A2,i and A3,i.
The system of electrodes and grids forms N/k combs with k teeth along the rows of the screen.
Each comb corresponds to one of the N/k families of rows.
13~90 The anodes are also in the form of combs.
For a trichromatic screen, a zone Zi comprises three combs-anodes, one for each of the primary colours red, green and blue. The teeth of these combs are aligned on the grids of the screen. The width thereo~ is substantially less than one third of the width of a grid and in this way one tooth of each comb can ~ace a grid.
The invention also makes it possible to produce a monochromatic screen. In this case, on the second transparent substrate, each family of anodes of a zone Zi comprises a series of conductive strips covered by a luminescent material, each conductive strip being substantially aligned facing a row (grid), the conductive strips of a zone Zi being electrically interconnected to form an anode Ai.
The invention also relates to a process for addressing said screen.
According to a first process for addressing a screen according to the invention, the display of a trichromatic frame takes place during a frame time T.
The following operations are carried out for the anodes Al,i, i ranging between 1 and k and which are of a successive nature. These operations are then repeated for anodes A2,i and then A3,i, so as to display for a frame time T three monochromatic images in the three primary colours red, green and blue. These operations consist of:
successively raising each of the anodes Al,i (respectively A2,i, A3,i) of the zone Zi, i ranging between 1 and k, to a potential Valmax (respectively VA2max, VA3max) adequate for attracting the electrons possibly emitted by the microtips with an energy higher than the threshold cathodoluminescence threshold of the corresponding luminescent material for an addressing time tl (respectively t2, t3) periodically at a period corresponding to a frame time T, such that T=k(tl+t2+t3), when the anodes Al,i (respectively A2,i, A3,i) are not raised to the potential VAlmax (respectively VA2max, VA3max), the anodes Al,i (respectively A2,i, A3,i~ are raised to a potential VAlmin (respectively VA2min, VA3min), such that the electrons emitted by the microtips are repelled or have an energy below the cathodoluminescence threshold energy of the corresponding luminescent material;
for the addressing time tl (respectively t2, t3) of each anode Al,i (respectively A2,i, A3,i), successively raising the different families of rows to a potential VGmax for a row selection time ~1 (respectively ~2, ~3), such that T=N(~1+~2+a3), when they are not raised to the potential VGmax, the different families of rows are raised to a potential VGmin, such that the microtips emit no electrons; and during the row selection time ~1 (respectively ~2, ~3) of each row of each zone Zi, addressing the cathode conductors in such a way as to "illuminate" the pixels of the row which should be illuminated.
According to a second process for addressing a screen according to the invention ~or the display o~ a trichromatic frame of the image produced during a frame time T, the following operations are performed successively for each of the zones Zi, ranging from 1 to k:
13~93~3 successively raising the families of ro~7s to a potential VGmax for the row selection time t, such that t=T/N, when they are not raised to the potential VGmax, the families of rows are raised to the potential VGmin, such that the microtips do not emit electrons;
during the selection time t of each row of the zone Zi in question, successively raising the anodes Al,i, A2,i and A3,i respectively to potentials VAlmax, VA2max and VA3max, which are adequate for attracting the electrons optionally emitted hy the microtips with an energy higher than the threshold cathodoluminescence energy of the corresponding luminescent materials, during addressing times respectively tl, t2 and t3, such that tl~t2+t3=t, when they are not raised to the potsntials VAlmax, VA2max and VA3max, the anodes Al,i, A2,i and A3,i are raised to the potentials VAlmin, VA2min and VA3min respectively, such that the electrons emitted by the microtips are repelled or have an energy below the threshold cathodoluminescence energy of the corresponding luminescent material; and during the addressing times tl, t2 and t3 of each anode Al,i, A2,i and A3,i, addressing the cathode conductors so as to "illuminate" the pixels of the row which should be illuminated.
For each process and at a given instant, a single family of rows and a single anode of a zone are selected. The emission of the electrons is localized on the overlap surface of the grid and selected anode.
This emission is modulated by the potential applied to the cathode conductors, which function in accordance with the prior art. The electrons are repelled by the unselected anodes and drop onto the grid. They are then eliminated, or ha~e an energy below the threshold .- . , 13~939~
cathodoluminescence energy of the corresponding luminescent materials and are also eliminated.
The screen is addressed sequentially with a reduced number of control circuits. The number of families of rows added to the number of anodes (three per zone and k zones), remains well below the number of rows or lines of the screen.
At each instant, the electrons emitted by the microtips are focused on the anode of the selected colour, thus guaranteeing a colour purity not reduced by the phenomena of the lateral emission of electrons from the microtips.
In these embodiments of the addressing process, the three primary colours of the screen are never displayed at the same time. The colour sensation on a broad spectrum perceived by a screen viewer is due to the reconstitution of the coloured spectrum by the viewer's eye. The eye is a "slow" detector compared with the different characteristic display times of the screen (frame time T, etc.) and the perception of the full colour is due to an averaging effect on several frames of the picture.
For a monochromatic screen, an addressing process consists of carrying out the following operations for displaying one frame of the screen, said display taking place during a frame time T: successively raising each of the anodes Ai, i ranging between 1 and k to a potential VAmax for an addressing time tZ, such that T=ktZ, when they are not raised to an adequate potential VAmax for attracting the electrons possibly ~3~93~
emitted by the microtips, the anodes Ai are raised to a potential VAmin, such that the electrons emitted by the microtips are repelled, or have an energy below the threshold cathodoluminescence energy of the luminescent material; during the addressing time tZ of each anode Ai, successively raising each family of rows to a potential VGmax for a row selection time t, such that t=T/N, when they are not raised to the potential VGmax, the families of rows are raised to a potential VGmin, such that the microtips do not emit electrons; and during the row selection time t of each family of rows, addressing the cathode conductors in such a way as to "illuminate" the pixels of each row which should be illuminated.
The characteristics and advantages of the invention can be better gathered from the following non-limitative description with reference to the attached drawings, wherein show:
Fig. 1 illustrates diagrammatically a microtip fluorescent trichromatic screen such as could be extrapolated.
Fig. 2 illustrates diagrammatically a section of a microtip fluorescQnt trichromatic screen, such as could be extrapolated in accordance with fig. 1.
Fig. 3A diagrammatically a portion of a trichromatic screen according to the invention, fig. 3B
showing a section along axis aa' of said screen.
,, .'~f 1 ~19,790 Fig. 4 on a larger scale than in fig. 3 diagrammatically and partially two successive rows o~ a trichromatic screen according to the invention.
Fig. 5 diagrammatically the timing diagrams relating to the addressing of one o~ the three anode series according to a first process for addressing a trichromatic screen according to the invention.
Fig. 6 diagrammatically the timing diagrams relating to the first process for addressing a pixel o~
a trichromatic screen according to the invention.
Fig. 7 diagrammatically the timing diagrams relating to the addressing of one of the three series of anodes according to a second process for addressing a trichromatic screen according to the invention.
Fig. 8 diagrammatically the timing diagrams relating to the second process for addressing a pixel of a trichromatic screen according to the invention.
Fig. 9 diagrammatically part of a microtip fluorescent monochromatic screen according to the invention.
Fig. 10 diagrammatically the timing diagrams relating to a process for addressing a pixel of a monochromatic screen according to the invention.
- Fig. 1 diagrammatically shows in perspective a matrix-type trichromatic screen, such as could be logically extrapolated from a monochromatic screen.
, . ~, 13193~0 On a first e.g. glass substrate lO are provided conductive columns 12 (cathode conductors of e.g. indium tin oxide) supporting metal, e.g. molybdenum microtips 14. The columns 12 intersect the perforated conductive rows 16 (grids) which are e.g. of niobium.
A11 the microtips 14 positioned at an intersec~ion of a row 16 and a conductive column 12 have their apex substantially facing a perforation of row 16.
The cathode conductors 12 and grids 16 are separated by an e.g. silica insulating layer 18 provided with openings or apertures permitting the passage of the microtips 14.
A conductive material layer 20 (anode) is deposited on a second transparent, e.g. glass substrate 22. Parallel bands alternately in phosphors luminescing in red 24R, in grean 24V and in blue 24B are deposited on the anode 20 facing the cathode conductors 12. The bands can be replaced by a mosaic pattern.
In this configuration, it is necessary to have a triplet of cathode conductors 12 (one facing a red band 24R, another facing a green band 24V and a third facing a blue band 24B), in order to bring about a colour display along a screen column.
Each intersection of a grid 16 and a cathode conductor 12, in this embodiment, corresponds to a monochromatic pixel. A ~'colour" pixel is composed by three monochromatic red, green and blue pixels. The combination of these three primary colours enables the viewer's eye to reconstitute a wide coloured spectrum.
~3~ 9390 A screen of this type having N rows and M
columns requires, in the colour mode, N control circuits for the grids 16, 3M control circuits for the 3M cathode conductors 12, plus a circuit for the anode 20. ~or example a colour display screen with 575 rows or lines and 720 columns (French colour television standard) comprises 575 control circuits for the grids 16 and 2160 control circuits for the cathode conductors 12.
A microtip monochromatic fluorescent display screen 14 has 575 control circuits for grids 16 and 720 control circuits for the cathode conductors 12.
Fig. 2 shows a section of the microtip trichromatic fluorescent screen of fig. 1, as could be extrapolated by the Expert. As there is only one anode 20, the electrons emitted by the microtips 14 of a pixel are directed either to the red 24R, green 2~V or blue 24B phosphor. In particular, the lateral emission o~ a microtip 14 leads electrons intended for a red phosphor 24R, e.g. to a green phosphor 24V. This lateral emission also exists for monochromatic screens and leads to a resolution loss. For a trichromatic screen, said resolution loss is accompanied by a "dilution" of the colours, which is prejudicial to the viewing quality.
Fig. 3A diagrammatically shows a portion of a trichromatic screen according to the invention. The screen is viewed through the diagrammatically represented second transparent substrate 22. The screen is subdivided into k zones Zi, i ranging between 1 and k, three of these Zi-l, Zi and Zi+l being at least partly visible in fig. 3A. 3N parallel conductive bands 26, N being the number of rows or lines of the screen, 131939~
rest on substrate 22. These bands 26 are e.g. of indium tin oxide. These conductive bands 26 are grouped and electrically interconnected in order ~o form three series of N/k bands each per zone Zi, corresponding to three anodes Al,i, A2,i and A3,i. Each of the bands 26 is covered by a luminescent material. Fig. 3B
diagrammatically shows a section of the trichromatic screen according to the invention. This section is along axis aa' shown in fig. 3A. On the first e.g.
glass substrate 10, the elements are the same and are arranged in the same way as in the prior art. The cathode conductors 12 are aligned in accordance with the screen columns. These cathode conductors 12 support microtips 14. The grids 16 along the rows of the screen intersect the cathode conductors 12. The grids 16 (rows) and cathode conductors 12 (columns) are separated by an insulating layer 18 having apertures permitting the passage of the microtips.
The second transparent, insulating and e.g.
glass substrate 22 supports the conductive bands 26 aligned on grids 16 and therefore aligned in accordance with the rows of the screen. These conductive bands 26 are covered with luminescent material. Along the axis aa', the band 26 shown in fig. 3B is covered with a material 28, e.g. luminescing in the red.
As can be seen in fig. 4, a first series of such bands 26 is covered by a material 28 luminescing in the red, e.g. Eu-doped Y2O2S and forms an anode A1,8 e.~.
for zone Zi, a second series of said bands is covered by a material 29 luminescing in the green, e.g. CuA1-doped ZnS and forms an anode A2,i, e.g. for zone Zi; and the third series of bands 26 is covered by a material 30 131~90 luminescing in the blue, e.g. Ag-doped ZnS and forms an anode A3,i e.g. for zone Zi. The bands 26 of the different series alternate and are equidistant.
Each triplet formed by an anode of each series faces a grid 16 (row). The grids 16 rest on a second substrate 10 (not shown in figs 3A and 4). The grids 16 intersect cathode conductors 12 (not shown in figs. 3A and ~). Grids 16 and cathode conductors 12 are separated by an insulating layer 16 (not shown in figs.
3A and 4). Each intersection of a grid 26 and a cathode conductor 12 forms a trichromatic pixel.
The grids 16 (along the rows) of the screen are grouped into N/k families. One zone Zi of the screen has a single grid 16 of each family. The grids 16 of the different families alternate within a zone Zi and the grids 16 of the same family are electrically interconnected.
First exam~le of the process for addressing a microtip fluorescent trichromatic screen according to the invention ffiqs. 5 and 6) This process consists of dividing the display time of a frame T into three:
a subframe time T1 corresponds to the display of a first frame, e.g. red, of the screen, a subframe time T2 corresponds to the display of a second frame, e.g. green, of the screen, a subframe time T3 corresponds to the display of a third frame, e.g. blue, of the screen, Tl, T2, T3 being connected by the relation Tl + T2 + T3 = T.
~ls~a The red, green and blue frames of the picture are successively displayed.
As can be seen in fig. 5 within the subframe time Tl (T2, T3 respectively), during which i~
displayed the red frame (green, blue respectively~ of the screen, the k anodes of the zones Zl, ..., Zk correspond to red (respectively green, blue), designated Al,i (respectively A2,i A3,i) are successively addressed. This addressing consists of raising each anode Al,i (respectively A2,i, A3,i) successively to a potential VAlmax (respectively VA2max, VA3max) during a time tl (respectively t2, t3). This potential VAlmax (respectively VA2max, VA3max) is adequate for attracting the electrons optionally emitted by the microtips with an energy higher than the threshold cathodoluminescence energy of the material 28 (respectively 29, 30) luminescing in the red (or green or blue). Outside the addressing time tl, the anodes Al,i (respectively A2,i and A3,i) are raised to a potential VAlmin (respectively VA2min, VA3min), such that the electrons emitted by the microtips are repelled and eliminated by means of a grid 16, or have an energy below the threshold cathodoluminescence energy of the luminescent material corresponding thereto and are also eliminated.
The subframe time Tl (respectively T2, T3) is iinked with the addressing time tl (respectively t2, t3) of an anode Al,i (respectively A2,i A3,i) by the relation: Tl = ktl (respectively T2=kt2, T3=kt3).
The frame times Tl, T2 and T3 and the values of the addressing potentials of the anodes are experimentally adjusted as a function of the luminescent ,. , 1 319~
materials 28, 29 and 30, so as to obtain a pure white when all the scresn is addressed.
Fig. 6 diagrammatically shows the timing diagrams relating to the first process for addressing a pixel of a trichromatic screen according to the invention.
The display of a trichromatic frame of the screen takes place in a frame time T subdivided into three subframe times Tl, T2 and T3 corresponding to the respective display of a red, green and blue frame.
Fig. 6 only shows the addressing of the anodes Al,i, A2,i and A3,i of zone Zi. These addressing operations take place during respective addressing periods tl, t2 and t3, the first being within the red frame, the second within the green frame and the third within thP blue frame.
The grids 16 are addressed by families.
The pixels involved in each addressing of a family of rows are those corresponding to the superimposing of a row of the addressed family with the selected anode.
The families of rows Gj, j ranging between 1 and N/k, are raised to a potential VGj. VGj assumes a value VGmax for the row selection times ~1, periodically at period tl, for the entire frame time Tl, then VGj assumes the value VGmax for the row selection time ~2, periodically at period t2, throughout the frame time T2 and then VGj assumes the value VGmax for a row selection time ~3, periodically at period t3, for the entire frame time T3. Outside the row selection times, 131~39~
VGj assumes the value VGmin permitting no electron emission by microtips 14.
The addressing times tl, t2 and t3 are linked with the row selection time ~ 2 and ~3 by the relations: tl/~l = t2/~2 = t3/~3 = N/k.
The "illumination" of the pixels positioned on the row of family Gj facing the anodes of zone Zi is controlled by the potential applied to the cathode conductors 12.
The three timing diagrams Cl, C2 and C3 of fig. 6 represent the control signals VCl of the cathode conductor 12 of number 1 in the matrix making it possible to "illuminate" the pixel corresponding to the intersection of the row of family Gj in zon~ Zi with the cathode conductor 12 of number 1, said pixel being ijl.
Timinq diaqram Cl: pixel ijl "illuminated" in red.
To illuminate the pixel ijl in red, the control potential VCl of cathode conductor 12 of number 1 assumes a value VCmin during the selection time ~1 of the row of family Gj in zone Zi. The potential difference VGmax-VCmin permits the emission of electrons by microtips 14. Pixel ijl is extinguished in the two other colours, because the potential VCl then assumes the value VCmax not permitting the emission of electrons by the microtips 14 during selection times ~2 and ~3 of the row of family Gj.
Timina diaaram C2: Pixel ijl "illuminated" in the three primary colours red, green and blue= pixel ijl "white".
"' ., ~3~9~
For each selection of the row corresponding to pixel ijl, the potential VCl assumes the value VCmin.
Pixel ijl successively assumes the colours red, green and blue, the white colour being restored by the psrsistence of vision of a viewer's eye.
T.iminq diagram C3: Pixel ijl "extinguished", pixel ijl "black".
For each selection of the row corresponding to pixel ijl, potential VCl is maintained at the value VCmax, no colour being "illuminated".
Example of numerical data corresponding to the first process for addressing a trichromatic screen according to the invention:
N: number of rows 500 k: number of zones 20 20 T: frame time 20 ms Tl: red frame time 5 ms T2: green frame time 5 ms T3: blue frame time 10 ms tl: addressing time of a red anode in a zone 5 ms/20 = 0.25ms t2: addressing time of a green anode in a zone 5 ms/20 = 0.25 ms t3: addressing time of a blue anode in a zone 10 ms/20 = 0.5 ms 30 ~1: selection time of a family of rows during the addressing of a red anode 0.25 ms/25 = 10 ~s ~2: selection time of a family of rows during the addressing of a green anode 10 ~s 13~3~
~3: selection time of a family of rows during the addressing of a blue anode 20 ~s VAl: addressing potential of anodes Al,i:
VAlmin = 40 V, VAlmax = 100 V
VA2: addressing potential of anodes A2,i:
VA2min = 40 V, VA2max = 100 V
VA3: Addressing potential of anodes A3,i:
VA/min = 40 V, VA3max = 150 V
~Gj: addressing potential of a family of raws:
VGmin = -40 V, VGmax = 40 V
VCl: control potential of column 1:
VCmin = -40 V, VCmax = 0 ~.
Second example of process for addressinq a microtiP
fluorescent trichromatic screen accordinq to the invention (fi~s 7 and 8) This process consists of the row by row addressing of the three primary colours for each pixel.
Fig. 7 shows the addressing sequences of anodes Al,i, ....... Al,k of zones Zl to Zk respectively.
Anodes Al,i, A2,i and A3,i, i ranging between 1 and k, are successively addressed. The display frame time T is subdivided into zone times tZ during which all the rows of one zone are addressed. The frame time T and the zone time tZ are linked by the relation T = k.tZ.
Each anode Al,i (respectively A2,i, A3,i) is addressed for an addressing time tl (respectively t2, t3), for the zone time tZ and at the period of a frame time T.
, . .
l3ls3~a During the zone time tZ, an anode Al,i (respectively A2,i A3,i) is periodically raised during an addressing time tl (respectively t2, t3) to a potential VAlmax (respectively VA2max, VA3max) adequate for attracting the electrons emitted by the microtips 14 with an energy exceeding the threshold cathodoluminescence energy of the material 28 (respectively 29, 30). The period is in this case t the selection time of a row in a zone. Thus the zone time is linked with the row selection time t by the relation tZ = N/k.t.
The addressing times tl, t2 and t3 of the anodes Al,i, A2,i and A3,i respectively are linked with the row selection times t by the relation tl + t2 + t3 = t.
Outside the addressing times, the anodes Al,i (respectively A2,i, A3,i) are raised to a potential VAlmin (respectively VA2min, VA3min) such that the electrons emitted by the microtips 14 are rejected towards the grids 16 and eliminated or have an energy below the threshold cathodoluminescence energy of the luminescent material corresponding thereto and are also eliminated.
Fig. 8 diagrammatically shows the timing diagrams relating to the second process for addressing a pixel of a trichromatic screen according to the invention.
The displaying of a trichromatic frame of the screen takes place in a frame time T, which is 13~3~
subdivided into zone times tZ. In a zone time tZ, all the rows of a zone are successively addressed.
The timing diagrams of fig. 8 represent the addressing of the pixel ijl. The families of rows Gj, j ranging between 1 and N/k, are successively raised to a potential VGmax. VGj assumes a value VGmax during th~
row selection time t at period tZ. During the ro~
selection time t, the three anodes Al,i A2,i A3,i of zone Zi are consequently successively addressed during the re~pective addressing times tl, t2 and t3.
The "illumination" of the pixels positioned on the row of family Gj facing the anodes of zone Zi is controlled by the potential applied to the cathode conductors 12.
The three timing diagrams C4, C5 and C6 of fig. 8 show the control signals VCl of the cathode conductor 12 of number 1 making it possible to "illuminate" the pixel ijl.
Timing diaqram C4: Pixel ijl "illuminated" in red.
In order to "illuminate" the selected pixel ijl in red, the control potential VCl of the cathode conductor 12 of number 1 assumes the value VCmin during the addressing time tl of anode Al,i. VCl is kept at value VCmax for the addressing times t2 and t3 of anodes A2,i and A3,i (corresponding to green and blue~.
Timina dia~ram C5: Pixel ijl "illuminated" in the three primary colours red, green and blue = pixel ijl "white".
1 3 ~
The potential VCl is maintained at the value VCmin for the entire row selection time, which permits the emission of the electrons by the microtips 14 during each addressing time tl, t2 and t3 of anodes Al,i, A2,i and A3,i.
Timinq diaqram C6: Pixel ijl "extinguished", pixel ijl "black".
On this occasion the potential VCl is maintained during the row selection time at value VCmax not permitting the emission of electrons, so that the pixel ijl is "black".
Example of numerical data corresponding to the second process for addressing a trichromatic screen according to the invention:
N number of rows 500 20 k: number of zones 20 T: frame time 20 ms tZ: zone time 1 ms t: row selection time 1 ms/25 = 40 ~s tl: addressing time of an anode Al,i = 10 ~s 25 t2: addressing time of an anode A2,i = 10 ~s t3: addressing time of an anode A3,i = 20 ~s VAl: addressing potential of anodes Al,i:
VAlmin = 40 V, Valmax = 100 V
VA2: addressing potential of anodes A~,i:
VA2min = 40 V, VA2max = 100 V
VA3: addressing potential of anodes A3,i:
VA3min = 40 V, VA3max = 150 V
VGj: addressing potential of a family of rows VGmin = -40 V, VGmax = +40 V
13~39~
VCl: control potential of column 1:
VCmin - -40 V, VCmax = 0 V.
A microtip fluorescent trichromatic screen according to the invention with 575 rows and 720 columns (French television standard) can operate wikh 23 families of rows, 25 red anodes, 25 green anodes, 25 blue anodes and 720 cathode conductors, i.e. 818 outputs to be controlled each by a different electric circuit.
This is to be compared with a screen such as could be extrapolated by the Expert (figs. 1 and 2), i.e~ 575 grids and 3x720 cathode conductors, i.e. 2735 ou~puts to be controlled, each by a different electric circuit.
At a given instant, all the electrons emitted are either repelled to a grid or have an energy below the threshold cathodoluminescence energy of the luminescent material, or are attracted by a luminescent phosphor in a given primary colour. The lateral electron emission of the microtips 14 consequently produces no diaphony phenomenon characterized by a dilution of the colours.
The invention can also apply to microtip monochromatic fluorescent screens. The screen is subdivided into k zones Zi~ i ranging between l and k and the N rows are grouped into N/k families. The rows (grids 16) of the samefamily are electrically interconnected. Each zone Zi only comprises a single row of each family. The rows 16 of each family succeed one another within a zone ~i.
Fig. 9 diagrammatically shows part of a monochromatic screen according to the invention. The -. .
13193~0 screen is seen through the second, diagrammatically shown, transparent substrate 22. on the latter are located N conductive bands 26, which are electrically connected by groups of N/k bands 26 to form k anodes Ai:
one anode Ai per zone Zi. Anodes ~i are covered by a luminescent material 31, e.g. ZnS.
In the same way as for a trichromatic screen, the bands 26 face grids 16 (rows). The grids 16 intersect the cathode conductors 12 (not shown in fig.
9). Grids 16 and cathode conductors 20 are separated by an insulating layer 16 (not shown in fig. 9). Each intersection of a row (grid 16) and a column (cathode conductor 12) forms a pixel.
The section of such a monochromatic screen along an axis of a conductive band 26 is identical to the section of a trichromatic screen shown in fig. 3B, the luminescent material 31 replacing material 28. A
single luminescent material 31 is deposited on each conductive band 26.
Example of a process for addressinq a monochromatic screen accordin~ to the invention (fig. 10) The timin~ diagrams relating to this addressing process are diagrammatically shown in fig.
10. They relate to the "illumination" of pixel ijl located at the intersection of the row of family Gj in zone Zi with the cathode conductor (column) of number l in the matrix.
A frame of a picture is displayed for a frame time T. The anodes Ai,i ranging between 1 and k, 13193~
are successively addressed during an addressing time tZ.
The addressing of an anode Ai consists of ràising the potential VAi supplied to said anode to the value VAmax during the addressing time tZ. The potential VAmax is such that it attracts the electrons optionally emitted by the microtips 14 with an energy exceeding the threshold cathodoluminescence energy of the material 31.
Outside the addressing time tZ, the potential Vhi is maintained at a value V~min such that the electrons emitted by the microtips are repelled towards a grid 16 or have an energy below the threshold cathodoluminescence energy of the luminescent material.
A family of rows Gi is periodically addressed during a row selection time t. The potential VGj supplied to the family of rows Gj then assumes the value VGmax during t at period tZ. The different families of rows are successively addressed during the period tZ. Potential VGmax permits the emission of electrons. Outside the row selection time, VGj assumes the value VGmin not permitting the emission of electrons.
During the addressing time t of the row of the family Gj in zone Zi, potential VC1 applied to the cathode conductor of number 1 assumes a value VCmin for the "illumination" of pixel ijl and a value VCmax if the pixel must remain "extinguished". Thus, VCmin is such that the potential difference VGmax-VCmin is adequate for tearing away electrons at the microtips, whereas VGmax-VCmax is not.
Examples of numerical date relating to this addressing process:
,. ~
~31 93~0 N: number of rows 500 k: number of zones 20 T: frame time 20 ms tZ: addressing time of an anode Ai = 1 ms 5 t: row selection time 40 ~s VAi: addressing potential of anode ~i:
VAmax = 100 V, VAmin = 40 V
VGj: addressing potential of a family of rows Gj:
VGmax = 40 V, VGmin = -40 V
lO VCl: control potential of column 1:
VCmax = 0 V, VCmin = -40 V.
This type of monochromatic screen only requires N/k addressing circuits for families of rows, k addressing circuits for the anodes and obviously M
control circuits for the cathode conductors (for a screen with M columns). However, a microtip monochromatic fluorescent screen according to the prior art requires N addressing circuits for the rows and M
addressing circuits for the column, so that the gains are significant.
For producing a family of rows which are electrically connected to one another and for producing an anode (formed by electrically interconnected conductive bands 26), it is e.g. possible to etch in a conductive material parallel bands of appropriate dimensions. The different bands of each family of rows or each anode are electrically interconnected via an anisotropic conductive film electrically contacted with a metal ribbon or tape. This film is only conductive at certain crushing points located on the bands to be connected. The conductive crushing points are interconnected by the metal ribbon.
Claims (6)
1. Matrix display microtip fluorescent screen having a first insulating substrate on which are arranged in the two directions of the matrix, conductive columns (cathode conductors) supporting metal microtips and above the columns, N perforated conductive rows (grids), the rows and columns being separated by an insulating layer having apertures permitting the passage of the microtips, each intersection of a row and a column corresponding to a pixel, characterized in that it is subdivided into k zones Zi, i ranging from 1 to k, with N/k successive rows each, the N rows of the screen being grouped into N/k families of rows, a zone Zi only having a single row of each family, the rows of the different families alternating within a zone Zi, the rows of a same family being electrically interconnected and in that on a second transparent substrate facing the first, each zone Zi comprises a family of anodes covered by at least one luminescent material, the families of anodes of the different zones being electrically independent and identical, each family of anodes of each zone Zi facing N/k rows of the zone Zi.
2. Matrix display microtip fluorescent screen according to claim 1, characterized in that each family of anodes of a zone Zi comprises three series of N/k conductive bands each, the bands of the different series alternately succeeding one another, the bands of one of the series being covered by a material luminescing in the red, the bands of another of said series being covered by a material luminescing in the green and the bands of the final series being covered by a material luminescing in the blue, each triplet formed by three bands respectively covered by materials luminescing in the red, green and blue being substantially aligned facing a row (grid), the bands of each series in a zone Zi being electrically interconnected for forming three anodes A1,i; A2,i;
A3,i.
A3,i.
3. Matrix display microtip fluorescent screen according to claim 1, characterized in that each family of anodes of a zone Zi comprises a series of conductive bands covered by a luminescent material, each conductive band being substantially aligned facing a row (grid), the conductive bands of a zone Zi being electrically interconnected to form an anode Ai.
4. Process for addressing a microtip fluorescent screen according to claim 2, the display of a trichromatic frame of the picture taking place during a frame time T, characterized in that it consists of performing the following operations for anodes A1,i, i ranging between 1 and k successively and repeating these operations for anodes A2,i and then A3,i, so as to display during a frame time T
three monochromatic images in the three primary colours red, green and blue:
successively raising each of the anodes A1,i (respectively A2,i, A3,i) of the zone Zi, i ranging between 1 and k, to a potential VA1max (respectively VA2max, VA3max) adequate for attracting the electrons possibly emitted by the microtips with an energy higher than the threshold cathodoluminescence threshold of the corresponding luminescent material for an addressing time t1 (respectively t2, t3) periodically at a period corresponding to a frame time T, such that T=k(t1+t2+t3), when the anodes A1,i (respectively A2,i, A3,i) are not raised to the potential VA1max (respectively VA2max, VA3max), the anodes A1,i (respectively A2,i, A3,i) are raised to a potential VA1min (respectively VA2min, VA3min), such that the electrons emitted by the microtips are repelled or have an energy below the cathodoluminescence threshold energy of the corresponding luminescent material;
for the addressing time t1 (respectively t2, t3) of each anode A1,i (respectively A2,i, A3,i), successively raising the different families of rows to a potential VGmax for a row selection time .theta.1 (respectively .theta.2, .theta.3), such that T=N(.theta.1+.theta.2+.theta.3), when they are not raised to the potential VGmax, the different families of rows are raised to a potential VGmin, such that the microtips emit no electrons; and during the row selection time .theta.1 (respectively .theta.2, .theta.3) of each row of each zone Zi, addressing the cathode conductors in such a way as to "illuminate" the pixels of the row which should be illuminated.
three monochromatic images in the three primary colours red, green and blue:
successively raising each of the anodes A1,i (respectively A2,i, A3,i) of the zone Zi, i ranging between 1 and k, to a potential VA1max (respectively VA2max, VA3max) adequate for attracting the electrons possibly emitted by the microtips with an energy higher than the threshold cathodoluminescence threshold of the corresponding luminescent material for an addressing time t1 (respectively t2, t3) periodically at a period corresponding to a frame time T, such that T=k(t1+t2+t3), when the anodes A1,i (respectively A2,i, A3,i) are not raised to the potential VA1max (respectively VA2max, VA3max), the anodes A1,i (respectively A2,i, A3,i) are raised to a potential VA1min (respectively VA2min, VA3min), such that the electrons emitted by the microtips are repelled or have an energy below the cathodoluminescence threshold energy of the corresponding luminescent material;
for the addressing time t1 (respectively t2, t3) of each anode A1,i (respectively A2,i, A3,i), successively raising the different families of rows to a potential VGmax for a row selection time .theta.1 (respectively .theta.2, .theta.3), such that T=N(.theta.1+.theta.2+.theta.3), when they are not raised to the potential VGmax, the different families of rows are raised to a potential VGmin, such that the microtips emit no electrons; and during the row selection time .theta.1 (respectively .theta.2, .theta.3) of each row of each zone Zi, addressing the cathode conductors in such a way as to "illuminate" the pixels of the row which should be illuminated.
5. Process for addressing a microtip fluorescent screen according to claim 2, the display of a trichromatic frame of the image taking place during a frame time T, characterized in that, for the display of a trichromatic frame, it comprises carrying out the following operations for each of the zones Zi, i ranging between l and k in a successive manner:
successively raising the families of rows to a potential VGmax for the row selection time t, such that t=T/N, when they are not raised to the potential VGmax, the families of rows are raised to the potential VGmin, such that the microtips do not emit electrons; during the selection time t of each row of the zone Zi in question, successively raising the anodes A1,i, A2,i and A3,i respectively to potentials VA1max, VA2max and VA3max, which are adequate for attracting the electrons optionally emitted by the microtips with an energy higher than the threshold cathodoluminescence energy of the corresponding luminescent materials, during addressing times respectively t1, t2 and t3, such that t1+t2+t3=t, when they are not raised to the potentials VA1max, VA2max and VA3max, the anodes A1,i, A2,i and A3,i are raised to the potentials VA1min, VA2min and VA3min respectively, such that the electrons emitted by the microtips are repelled or have an energy below the threshold cathodoluminescence energy of the corresponding luminescent material; and during the addressing times t1, t2 and t3 of each anode A1,i, A2,i and A3,i, addressing the cathode conductors so as to "illuminate" the pixels of the row which should be illuminated.
successively raising the families of rows to a potential VGmax for the row selection time t, such that t=T/N, when they are not raised to the potential VGmax, the families of rows are raised to the potential VGmin, such that the microtips do not emit electrons; during the selection time t of each row of the zone Zi in question, successively raising the anodes A1,i, A2,i and A3,i respectively to potentials VA1max, VA2max and VA3max, which are adequate for attracting the electrons optionally emitted by the microtips with an energy higher than the threshold cathodoluminescence energy of the corresponding luminescent materials, during addressing times respectively t1, t2 and t3, such that t1+t2+t3=t, when they are not raised to the potentials VA1max, VA2max and VA3max, the anodes A1,i, A2,i and A3,i are raised to the potentials VA1min, VA2min and VA3min respectively, such that the electrons emitted by the microtips are repelled or have an energy below the threshold cathodoluminescence energy of the corresponding luminescent material; and during the addressing times t1, t2 and t3 of each anode A1,i, A2,i and A3,i, addressing the cathode conductors so as to "illuminate" the pixels of the row which should be illuminated.
6. Process for addressing a microtip fluorescent screen according to claim 3, the display of a frame of the picture taking place during a frame time T, characterized in that it comprises, for displaying a frame of the screen, carrying out the following operations:
successively raising each of the anodes Ai, i ranging between 1 and k, to a potential VAmax for an addressing time tZ, such that T=ktZ, when they are not raised to an adequate potential VAmax for attracting the electrons possibly emitted by the microtips, the anodes Ai are raised to a potential VAmin, such that the electrons emitted by the microtips are repelled, or have an energy below the threshold cathodoluminescence energy of the luminescent material; during the addressing time tZ of each anode Ai, successively raising each family of rows to a potential VGmax for a row selection time t, such that t=T/N, when they are not raised to the potential VGmax, the families of rows are raised to a potential VGmin, such that the microtips do not emit electrons;
and during the row selection time t of each family of rows, addressing the cathode conductors in such a way as to "illuminate" the pixels of each row which should be illuminated.
successively raising each of the anodes Ai, i ranging between 1 and k, to a potential VAmax for an addressing time tZ, such that T=ktZ, when they are not raised to an adequate potential VAmax for attracting the electrons possibly emitted by the microtips, the anodes Ai are raised to a potential VAmin, such that the electrons emitted by the microtips are repelled, or have an energy below the threshold cathodoluminescence energy of the luminescent material; during the addressing time tZ of each anode Ai, successively raising each family of rows to a potential VGmax for a row selection time t, such that t=T/N, when they are not raised to the potential VGmax, the families of rows are raised to a potential VGmin, such that the microtips do not emit electrons;
and during the row selection time t of each family of rows, addressing the cathode conductors in such a way as to "illuminate" the pixels of each row which should be illuminated.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8808757A FR2633765B1 (en) | 1988-06-29 | 1988-06-29 | MICROPOINT FLUORESCENT SCREEN HAVING A REDUCED NUMBER OF ADDRESSING CIRCUITS AND METHOD FOR ADDRESSING THE SAME |
| FR8808757 | 1988-06-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1319390C true CA1319390C (en) | 1993-06-22 |
Family
ID=9367862
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000604031A Expired - Fee Related CA1319390C (en) | 1988-06-29 | 1989-06-27 | Microtip fluorescent screen with a reduced number of addressing circuits and process for addressing said screen |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0349426B1 (en) |
| JP (1) | JP2728740B2 (en) |
| KR (1) | KR0140536B1 (en) |
| CA (1) | CA1319390C (en) |
| DE (1) | DE68915866T2 (en) |
| FR (1) | FR2633765B1 (en) |
Families Citing this family (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5045425A (en) * | 1989-08-25 | 1991-09-03 | Commtech International Management Corporation | Electrophotographic liquid developer composition and novel charge directors for use therein |
| JP2616617B2 (en) * | 1991-10-03 | 1997-06-04 | 双葉電子工業株式会社 | Flat fluorescent display |
| US5449970A (en) * | 1992-03-16 | 1995-09-12 | Microelectronics And Computer Technology Corporation | Diode structure flat panel display |
| US5300862A (en) * | 1992-06-11 | 1994-04-05 | Motorola, Inc. | Row activating method for fed cathodoluminescent display assembly |
| FR2704967B1 (en) * | 1993-05-03 | 1995-07-21 | Pixel Int Sa | FLAT SCREEN WITH MICROPOINTS WITH DOUBLE SWITCHED ANODE. |
| JP2800879B2 (en) * | 1994-06-21 | 1998-09-21 | 富士通株式会社 | Fluorescent display device and driving method thereof |
| FR2723254B1 (en) * | 1994-07-26 | 1996-10-11 | Pixel Int Sa | FLAT DISPLAY ANODE |
| EP0707301A1 (en) * | 1994-09-14 | 1996-04-17 | Texas Instruments Incorporated | Power management for a display device |
| FR2725072A1 (en) * | 1994-09-28 | 1996-03-29 | Pixel Int Sa | ELECTRICAL PROTECTION OF A FLAT DISPLAY ANODE |
| EP0706164A1 (en) * | 1994-10-03 | 1996-04-10 | Texas Instruments Incorporated | Power management for display devices |
| FR2730843B1 (en) * | 1995-02-17 | 1997-05-09 | Pixtech Sa | ADDRESSING DEVICE OF A MICROPOINT FLAT DISPLAY ELECTRODE |
| JP2836528B2 (en) * | 1995-04-19 | 1998-12-14 | 双葉電子工業株式会社 | Driving method and driving device for image display device |
| FR2735265B1 (en) * | 1995-06-08 | 1997-08-22 | Pixtech Sa | SWITCHING A FLAT DISPLAY ANODE |
| US6014121A (en) * | 1995-12-28 | 2000-01-11 | Canon Kabushiki Kaisha | Display panel and apparatus capable of resolution conversion |
| FR2799575B1 (en) * | 1999-10-08 | 2001-12-14 | Pixtech Sa | VISUALIZATION SCREEN ANODE |
| KR20090013913A (en) * | 2007-08-03 | 2009-02-06 | 삼성에스디아이 주식회사 | Light emitting device and display using the light emitting device, the driving method of the light emitting device, and the method of the display |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3036219A1 (en) * | 1980-09-25 | 1982-05-06 | Siemens Ag | Flat TV screen with cold cathode matrix - has bi-metal face column conductors with insulator separation from line conductors |
| JPS593469U (en) * | 1982-06-30 | 1984-01-10 | 株式会社日立製作所 | flat fluorescent display tube |
| DE3243596C2 (en) * | 1982-11-25 | 1985-09-26 | M.A.N. Maschinenfabrik Augsburg-Nürnberg AG, 8000 München | Method and device for transferring images to a screen |
| FR2561019B1 (en) * | 1984-03-09 | 1987-07-17 | Etude Surfaces Lab | PROCESS FOR PRODUCING FLAT VISUALIZATION SCREENS AND FLAT SCREENS OBTAINED BY IMPLEMENTING SAID METHOD |
-
1988
- 1988-06-29 FR FR8808757A patent/FR2633765B1/en not_active Expired - Lifetime
-
1989
- 1989-06-27 CA CA000604031A patent/CA1319390C/en not_active Expired - Fee Related
- 1989-06-28 EP EP89401853A patent/EP0349426B1/en not_active Expired - Lifetime
- 1989-06-28 DE DE68915866T patent/DE68915866T2/en not_active Expired - Lifetime
- 1989-06-29 JP JP1168283A patent/JP2728740B2/en not_active Expired - Lifetime
- 1989-06-29 KR KR1019890009384A patent/KR0140536B1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| EP0349426B1 (en) | 1994-06-08 |
| JP2728740B2 (en) | 1998-03-18 |
| DE68915866D1 (en) | 1994-07-14 |
| KR0140536B1 (en) | 1998-06-01 |
| FR2633765B1 (en) | 1991-09-06 |
| DE68915866T2 (en) | 1995-01-05 |
| FR2633765A1 (en) | 1990-01-05 |
| JPH0261949A (en) | 1990-03-01 |
| EP0349426A1 (en) | 1990-01-03 |
| KR900000957A (en) | 1990-01-30 |
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