EP0485285B1 - Elektrooptische bistabile Vorrichtung, eine solche Vorrichtung enthaltender Bildschirm und Steuerungsverfahren dazu - Google Patents

Elektrooptische bistabile Vorrichtung, eine solche Vorrichtung enthaltender Bildschirm und Steuerungsverfahren dazu Download PDF

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Publication number
EP0485285B1
EP0485285B1 EP91402973A EP91402973A EP0485285B1 EP 0485285 B1 EP0485285 B1 EP 0485285B1 EP 91402973 A EP91402973 A EP 91402973A EP 91402973 A EP91402973 A EP 91402973A EP 0485285 B1 EP0485285 B1 EP 0485285B1
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Prior art keywords
bistable
material layer
layer
conductive material
cathodoluminescent
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French (fr)
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EP0485285A1 (de
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Thierry Leroux
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Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
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Commissariat a lEnergie Atomique CEA
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    • 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
    • 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

Definitions

  • the present invention relates to a bistable electrooptical device, a screen comprising such a device and a method for implementing this screen. It applies in particular to display and visualization but also to optical logic systems such as optical computers.
  • Bistable electrooptical devices are known, such as those described in the document "Electro-optic applications of ferroelectric liquid crystals to optical computing" written by M.A. Handschy et al. and published in the journal Ferroelectrics 1988, vol.85, pp.279-289 published by Gordon and Breach Science publishers SA These include a liquid crystal cell attached to a layer of photoconductive material, the whole being controlled by an external luminous flux.
  • the liquid crystal cell may be transparent or opaque and may or may not transmit the control light beam.
  • the resistivity of the photoconductive material is reduced whereas when the transmission is substantially zero, the resistivity becomes very high.
  • the transition from one to the other of the conductive or insulating states is carried out according to a hysteresis curve: at a given light flux, there may exist two states of transmission of the cell associated with the photoconductor such that the photoconductive material can be in either state (conductive or insulating). Logical information can thus be recorded.
  • Optical computer memories work with such devices although these perform poorly. Indeed, the switching time of such a bistable device is long (a few milliseconds) which prohibits the carrying out of logic operations at high frequencies.
  • the object of the present invention is to provide a bistable electro-optical device with rapid tilting time, of the order of a microsecond.
  • a device according to the invention has the advantage of a simple embodiment using well-controlled manufacturing techniques.
  • the first substrate and the first layer of conductive material are transparent.
  • a bistable element comprises a second layer of conductive material, the first and the second layers of conductive material being separated and deposited on the first substrate, the layer of photoconductive material at least partially covering the first and second layers of conductive material so as to electrically connect these layers of conductive material, the layers of conductive material and of photoconductive material forming a substantially coplanar structure covered by the layer of cathodoluminescent material.
  • the second layer of conductive material may optionally be transparent.
  • an insulating layer is interposed between the substantially coplanar structure and the layer of cathodoluminescent material, this insulating layer being provided with an opening pierced at the level of the second layer of conductive material so that an electrical contact is established between the second layer of conductive material and the layer of cathodoluminescent material.
  • This insulating layer makes it possible to isolate the first layer of conductive material and the layer of cathodoluminescent material, when the photoconductive material does not completely cover the first layer of conductive material.
  • the first layer of conductive material is deposited on the first substrate, the layer of photoconductive material covering at least partially the first layer of conductive material, these layers forming a stacked structure covered by the layer of cathodoluminescent material , and in that said bistable element comprises means for electrically insulating the first layer of conductive material from the layer of cathodoluminescent material.
  • said means for electrically insulating the first layer of conductive material from the layer of cathodoluminescent material may consist of an extension of the layer of photoconductive material completely covering the first layer of conductive material.
  • Said means for electrically insulating the first layer of conductive material from the layer of cathodoluminescent material may consist of an insulating layer covering the stacked structure, when the layer of photoconductive material partially covers the first layer of conductive material, this insulating layer being provided an opening at the layer of photoconductive material so as to ensure electrical contact between the layer of photoconductive material and the layer of cathodoluminescent material.
  • the stacking structure comprises a second layer of conductive material covering at least partially the layer of photoconductive material.
  • This second layer can be partially arranged on the substrate.
  • the bistable device has two operating modes detailed below, one with a constant or zero excitation light flux, the other at a constant excitation voltage.
  • the device comprises a light source arranged for example outside the enclosure.
  • the external light source is advantageously placed on the side of the first substrate, the latter as well as the layer of first conductive material which must then be transparent. Furthermore, when the device of the invention is used in a display screen, the light emitted by the cathodoluminescent material is advantageously transmitted through layers interposed between this material and the first substrate, the assembly having to be transparent.
  • cathodoluminescent material can be used: one can cite in particular a source of electrons with emissive cathodes with microtips, a source of electrons with semiconductor diodes having a metal-insulating metal structure or any other source of electrons.
  • the device comprises several bistable elements
  • a single layer of cathodoluminescent material is common to all the bistable elements.
  • the device comprises several bistable elements
  • these elements can be arranged in a matrix. This arrangement allows a multiplexed operation of the bistable elements, which can facilitate the control of the device.
  • the first layers of conductive material are advantageously connected together in parallel conductive columns and the excitation means is controlled along parallel lines.
  • Another object of the present invention is to take advantage of the bistability of the preceding device and therefore the possibility of memorizing a state to produce a very bright advantageously multiplexed flat display screen.
  • the present invention therefore relates to a flat screen comprising a bistable device comprising several bistable elements arranged in rows and in columns, each bistable element of a line and a column forming a pixel of the screen.
  • the number of lines of such a screen is not limited. Large screens can be produced while retaining simplicity of control.
  • the signals corresponding to the information to be displayed are delivered on the conductive columns produced by the first layers of conductive material connected to each other. These conductive columns are anodes; they have much lower capacities (by a factor of 500 to 1000) than cathodes to which these signals are usually applied.
  • the capacitive power required to control the screen is reduced accordingly. Indeed, the sources of electrons have limited thicknesses and therefore high capacities whereas a bistable element taking into account the thickness of vacuum has a lower capacity.
  • the present invention also relates to a method for the implementation of such a screen.
  • Figure 1 schematically shows a sectional view of a bistable electrooptical device according to the invention.
  • This device comprises a first substrate 10 possibly transparent, for example made of glass, and a second substrate 12, for example made of glass too.
  • a seal 14 for example made of fusible glass, hermetically seals the first and second substrates 10, 12 between them so as to obtain an enclosure in which a high vacuum is produced (for example, 10 ⁇ 6 mm Hg).
  • the device comprises, contained in said enclosure, several bistable elements 16 arranged in a matrix along lines and columns.
  • Each bistable element 16 comprises, supported by the first substrate, a series of layers forming a stacking structure.
  • a first layer 18 of conductive material, possibly transparent, for example of indium tin oxide (ITO) is deposited on the substrate 10; this layer 18 has a thickness of for example 500 ⁇ ; a layer of photoconductive material 20, for example formed of a stack of n+-doped amorphous silicon (a-Si-n+), of amorphous silicon (a-Si) and of nhe-doped amorphous silicon (a-Si-n +), completely covers the first layer of conductive material 18; this layer 20 has for example a thickness of 1 to 2 ⁇ m.
  • ITO indium tin oxide
  • a second layer of transparent conductive material 24 is deposited so as to make a contact between the layer of photoconductive material 20 and the layer of cathodoluminescent material 22. This contact defines the active area of each bistable element.
  • This layer 24 has for example a thickness of 500 to 1000 ⁇ .
  • This layer ensures good ohmic contact between the photoconductive material and the cathodoluminescent material 22.
  • cathodolumiscent material 22 is common to all the bistable elements. In this way, the deposition of this layer is simplified.
  • the first layers of conductive material 18 are connected together to form conductive columns. In this way, it is possible to carry out a multiplexed control of the bistable elements 16 if the excitation means is controllable online.
  • the layer 24 is etched so that the contacts between the layer 20 and the layer 22 thus produced define separate bistable elements.
  • FIG. 2B schematically represents an alternative embodiment of a bistable element in a stacking arrangement.
  • an insulating layer 23 covers the layer of photoconductive material 20.
  • This insulating layer 23 has an opening 25 clearing the base of the layer of photoconductive material 20 so as to ensure electrical contact between the layer 20 and the layer of photoluminescent material 22.
  • FIG. 3 schematically represents an alternative embodiment of a bistable element.
  • the layers are arranged in a substantially coplanar structure.
  • the first layer of conductive material 18 as well as the second layer of conductive material 24 are deposited on the first substrate 10; the layer of photoconductive material 20 completely covers the conductive material 18 and partially the layer 24.
  • the layer of cathodoluminescent material 22 covers the coplanar structure 18, 20, 24, while having no contact with the layer 18 and contact with the layer 24.
  • a bistable element 16 also includes a means 26 for exciting the layer of cathodoluminescent material 22.
  • This means 26 is a source of electrons supported by the second substrate 12.
  • the means 26 allows an excitation of the successive lines of bistable elements.
  • FIG. 4 schematically represents a first embodiment of a means 26 for exciting the cathodoluminescent layer. It is a source of electrons with microtip emissive cathodes. A description of such a source of electrons is found, for example, in French patent application No. 2,623,013.
  • conductive lines 28 are deposited on the substrate 12. These lines support microtips 30 capable of emitting electrons. They are covered with an insulating layer 32 pierced with orifices 34 at the locations of the microtips 30.
  • lines are formed on the grid while the microtips rest on a common conductive layer.
  • FIG. 5 schematically represents a second embodiment of a means for exciting the cathodoluminescent layer. It is a diode electron source with a metal-insulator-metal structure, called MIM (or MDM for metal-dielectric-metal).
  • MIM metal-insulator-metal structure
  • conductive lines 38 of metal rest on the substrate 12.
  • Each conductive line 38 is covered with a thin dielectric layer 40.
  • the dielectric (insulating) layers 40 are covered by a single metallic film 42.
  • the MIM structure forms a diode capable of emitting electrons.
  • FIG. 6 schematically represents a third embodiment of a means for exciting the cathodoluminescent layer. It is a source of electrons with semiconductor diodes. A description of such a source of electrons is found in the aforementioned book.
  • Sources with a semiconductor-metal structure and sources with p-n junctions belong to the category of semiconductor diode sources.
  • FIG 6 there is shown by way of non-limiting example a source of electrons to semiconductor-metal structure.
  • Lines of semiconductor material 44 rest on the substrate 12. These lines 44 are covered by a metallic layer 46.
  • control means 48 which can be seen in FIG. 1.
  • This control means 48 is connected to the electrodes (18, 28, 36 or 18, 38, 42 or 18, 44, 46) which must be via contacts leaving the enclosure.
  • the layers of conductive material 18 act as an anode; the lines drawn in the electron sources are cathodes.
  • FIG. 7 representing an output light flux Fs emitted by the cathodoluminescent material (or what amounts to the same an acceleration voltage Va of the electrons emitted by the source of electrons) as a function of the voltage Vak applied between the anode and the cathode at the intersection of which the considered bistable element is located.
  • the current emitted by the electron source 26 (fig. 1) is kept fixed by application of an adequate control voltage.
  • This voltage is applied between the grid 36 and the cathode 28 considered for a source of electrons with emissive cathodes with microtips (fig. 4), between the metallic film 42 and the metallic layer 38 constituting the cathode considered for a MIM structure (fig. .5), or between the metal layer 46 and the semiconductor layer 44 constituting the cathode considered for a semiconductor structure (fig. 6).
  • the electrons emitted by the electron source are more or less accelerated according to the value of the potential difference Vak applied between the anode and the cathode considered.
  • the voltage Va When decreasing Vak from a value greater than V1 (part B of the curve), the voltage Va substantially retains its maximum value and then drops sharply to its minimum value when Vak becomes below a threshold Vo approximately equal to 90 V .
  • the curve describing the output light flux Fs is identical to that describing the behavior of Va. In fact, when the acceleration voltage is low, the cathodoluminescent material emits little light and the conductivity of the photoconductive material is low.
  • the phenomenon is similar but in reverse, when Vak decreases.
  • the curve describes a hysteresis cycle comprising an operating zone between V0 and V1 with two stable states.
  • the input luminous flux, external luminous flux directed towards the photoconductive material is considered to be constant or zero.
  • this input light flux is delivered by a light source 50 disposed outside the enclosure containing the bistable elements.
  • This light source is controlled by the control means 48.
  • the different bistable elements can be illuminated independently of one another advantageously from the substrate 10.
  • Such a light source 50 can for example be produced by one or more lasers or one or more other bistable elements for example.
  • the conductivity of the photoconductive material is varied by subjecting it to an increasingly intense input light flux Fe.
  • a threshold F1 part C of the curve
  • the conductivity is minimal and therefore as before, the voltage Vak is practically entirely brought back to the terminals of the photoconductive material for a low acceleration voltage.
  • the output light flux Fs is therefore minimal.
  • the conductivity is maximum; the voltage across the photoconductive material is negligible and the acceleration voltage becomes maximum: the output light flux Fs is maximum.
  • the curve therefore describes a hysteresis cycle comprising an operating zone between Fo and F1 with two stable states.
  • the switching from one to the other of the stable states is obtained in a time of the order of a microsecond. It is thus possible to produce fast optoelectronic memories, competitive with electronic systems and simple to produce.
  • a device according to the invention allows the production of a flat display screen.
  • FIG. 9 Such a screen is represented diagrammatically in FIG. 9. It takes up the elements of the bistable electrooptical device described above and the references adopted are identical to those of FIG. 1. In the rest of the description, it will be considered that this screen is observed from the side of substrate 10.
  • the screen is matrix; the bistable elements 16 are arranged in rows and columns: each bistable element corresponds to a pixel on the screen.
  • the first layers of conductive material 18 are interconnected to form conductive columns and the electron sources are controlled online, a bistable element being defined at the intersection of the lines and the columns.
  • FIG. 10 Another coplanar structure than that of FIG. 3 is shown diagrammatically in section in FIG. 10.
  • the first and second layers of conductive material 18, 24 are deposited on the first substrate 10: the first layer 18 as we have seen, in the form of a conductive column, the second 24 defining the dimensions of the pixel, this second layer being transparent.
  • the first and second layers of conductive material 18, 24 are interconnected by a layer of photoconductive material 20 partially covering them.
  • a layer of insulating material 23 covers this coplanar arrangement with the exception of a location corresponding to an opening 25 and situated at the level of the second conductive layer 24.
  • This coplanar arrangement is covered by a deposit of cathodoluminescent material 22 which has electrical contact with the only second layer 24.
  • FIG. 11 schematically represents a section of another structure in stacking than those represented in FIGS. 1, 2A and 2B.
  • the first layer of conductive material 18, deposited on the substrate 10, is covered by a layer of photoconductive material 20.
  • a second layer of conductive material 24 has a part 24A which at least partially covers the layer of photoconductive material 20 and another part resting on the substrate 10 whose geometry defines the dimensions of the pixel.
  • the structure is covered by a layer of cathodoluminescent material 22.
  • the electron source 26 (fig. 9) is able to excite the successive lines of pixels on the screen under the action of the control means 48.
  • control means 48 delivers control signals to the conductive columns to switch the pixels of this line on or off.
  • FIGS. 12A to 12E schematically represent timing diagrams for controlling the state of a pixel on the screen. In these diagrams, the amplitude scales of the potentials are not respected.
  • the control of the screen is carried out with constant light flux and constant electron current.
  • the conductivity of the photoconductive material of the pixel in question is varied by varying the difference in potentials applied between the anode and the cathode (namely the conductive column associated with the pixel and for example the conductive line of an electron source with cathodes microtip transmitters, the pixel considered being placed at the intersection of this line and this column).
  • the electron acceleration voltage is minimum and the pixel is in an extinct state.
  • the electron acceleration voltage is maximum and the pixel is in an on state.
  • FIG. 12A represents the potential Vl applied to a cathode (line) as a function of time.
  • a given line is addressed every frame time Tt.
  • the addressing time of a line T1 is divided into two periods: a first period Te devoted to erasing the state of the pixels of the addressed line (all the pixels are brought to an extinct state), a second period Ta of addressing itself during which the pixels are carried in the state which they must take.
  • Vl takes a value -VlN, with VlN for example equal to 80 V; during Ta, Vl takes a value -VlB with VlB for example equal to 100 V. Vl takes the value -Vr the rest of the time with Vr for example equal to 95 V.
  • FIG. 12B schematically represents the potential VcB applied to a conductive column to obtain a pixel in an on state.
  • the potential VcB takes the value -Vc.
  • the values Vc and VlN are chosen such that VlN ⁇ Vc is less than Vo lower threshold value of the bistable element (fig. 7). As we saw previously, Vo can be equal to 90 V. VlN being chosen equal to 80 V, Vc is for example equal to 4 V.
  • VcB takes the value Vc.
  • FIG. 12C schematically represents the difference in potentials Vak between anode and cathode for carrying a pixel in an on state.
  • Vak takes the value VlN - Vc, that is to say in the example described 76 V which is much lower than Vo, the photoconductive material has a minimum conductivity resulting in an acceleration voltage minimum of excitation electrons; the output luminous flux is negligible: whatever its previous state (represented by dotted lines in FIG. 12C), the pixel is brought to an extinct state.
  • Vak takes the value VlB + Vc, that is to say in the example described 104 V which is much higher than the threshold value V1 (FIG. 7).
  • VlB + Vc the threshold value
  • FIG. 12D schematically represents the potential VcN applied to a conductive column to get a pixel in an off state.
  • the potential VcN takes the value Vc then the value -Vc during the addressing period.
  • FIG. 12E schematically represents the difference in potentials Vak between anode and cathode for carrying a pixel in an extinct state whatever its previous state represented by dotted lines in FIG. 12E.
  • Vak takes the value VlN + Vc, that is to say in the example described 84 V which is much lower than Vo: the pixel is brought into an extinct state.
  • Vak takes the value VlB - Vc, that is to say in the example described 96 V, which is much less than V1: the pixel remains in the previous state, namely extinct .
  • N is the number of lines of a screen, thanks to this memorization, a lit state of a pixel is maintained N times longer than in a usual screen where the lit state is only maintained in the period of addressing of the corresponding line. We therefore obtain a much brighter screen than in the prior art.
  • the invention is in no way limited to the embodiments more specifically described and shown; on the contrary, it admits all variants.
  • other types of electron sources can be used or else, for a screen, other implementation methods are possible.

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  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Electrodes For Cathode-Ray Tubes (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)

Claims (19)

  1. Elektrooptische, bistabile Vorrichtung, dadurch gekennzeichnet, daß sie umfaßt
    ein erstes und ein zweites Substrat (10, 12), Mittel (14) um das erste und das zweite Substrat (10, 12) zwischen ihnen derart hermetisch einzuschließen, daß ein Raum unter Vakuum hergestellt wird,
    wobei in dem genannten Raum mindestens ein bistabiles Element (16) enthalten ist, das umfaßt:
    einerseits von dem ersten Substrat (10) gehalten:
    eine erste Schicht aus einem Leitermaterial (18), eine Schicht aus einem fotoleitenden Material (20),
    eine Schicht aus einem kathodolumineszierenden Material (22),
    andererseits eine Einrichtung (26), um das genannte kathodolumineszierende Material (22) anzuregen.
  2. Elektrooptische, bistabile Vorrichtung, gemäß Anspruch 1, dadurch gekennzeichnet, daß das erste Substrat (10) und die erste Schicht aus Leitermaterial (18) transparent sind.
  3. Elektrooptische, bistabile Vorrichtung, gemäß irgendeinem der Ansprüche 1 und 2, dadurch gekennzeichnet, daß ein bistabiles Element (16) eine zweite Schicht (24) aus Leitermaterial umfaßt, die erste und die zweite Schicht aus Leitermaterial (18, 24) getrennt und auf dem ersten Substrat (10) abgeschieden sind, die Schicht aus fotoleitendem Material (20) mindestens teilweise die erste und die zweite Schicht aus Leitermaterial (18, 24) derart überdeckt, daß diese Schichten aus Leitermaterial (18, 24) elektrisch verbunden werden, die Schichten aus Leitermaterial und fotoleitendem Material (20) eine im wesentlichen koplanare Struktur bilden, die von der Schicht aus kathodolumineszentem Material (22) überdeckt ist.
  4. Elektrooptische, bistabile Vorrichtung, gemäß Anspruch 3, dadurch gekennzeichnet, daß die zweite Schicht aus Leitermaterial (24) transparent ist.
  5. Elektrooptische, bistabile Vorrichtung, gemäß Anspruch 3, dadurch gekennzeichnet, daß eine isolierende Schicht (23) zwischen die im wesentlichen koplanare Struktur (18, 20, 24) und die Schicht aus kathodolumineszentem Material (22) eingefügt ist, diese isolierende Schicht (23) mit einer Öffnung (25) versehen ist, die auf der Höhe der zweiten Schicht aus Leitermaterial (24) derart gebohrt ist, daß ein elektrischer Kontakt zwischen der zweiten Schicht aus Leitermaterial und der Schicht aus kathodolumineszentem Material hergestellt ist.
  6. Elektrooptische, bistabile Vorrichtung, gemäß Anspruch 1 und 2, dadurch gekennzeichnet, daß die erste Schicht aus Leitermaterial (18) auf dem ersten Substrat (10) abgeschieden ist, die Schicht aus fotoleitendem Material (20) die erste Schicht aus Leitermaterial (18) bedeckt, diese Schichten eine Stapelstruktur bilden, die mit der Schicht aus kathodolumineszentem Material (22) bedeckt ist, und daß das genannte bistabile Element eine Einrichtung umfaßt, um die erste Schicht aus Leitermaterial (18) elektrisch von der Schicht aus kathodolumineszentem Material (22) zu isolieren.
  7. Elektrooptische, bistabile Vorrichtung, gemäß Anspruch 6, dadurch gekennzeichnet, daß die genannte Einrichtung zum elektrischen Isolieren der ersten Schicht aus Leitermaterial (18) von der Schicht aus kathodolumineszentem Material (22) von einer Fortsetzung der Schicht aus fotoleitendem Material (20) gebildet ist, die die erste Schicht aus Leitermaterial (18) vollständig überdeckt.
  8. Elektrooptische, bistabile Vorrichtung, gemäß Anspruch 6, dadurch gekennzeichnet, daß die genannte Einrichtung zum elektrischen Isolieren der ersten Schicht aus Leitermaterial (8) von der Schicht aus kathodolumineszentem Material (22) eine isolierende Schicht (23) umfaßt, die die Stapelstruktur überdeckt, wobei diese isolierende Schicht (23) mit einer Öffnung (25) auf der Höhe der Schicht aus fotoleitendem Material (20) derart versehen ist, daß ein elektrischer Kontakt zwischen der Schicht aus fotoleitendem Material (20) und der Schicht aus kathodolumineszentem Material (22) sichergestellt ist.
  9. Elektrooptische, bistabile Vorrichtung, gemäß Anspruch 6 oder 7 oder 8, dadurch gekennzeichnet, daß die Stapelstruktur eine zweite Schicht aus Leitermaterial (24) umfaßt, die die Schicht aus fotoleitendem Material (20) bedeckt.
  10. Elektrooptische, bistabile Vorrichtung, gemäß irgendeinem der Ansprüche 1 bis 9, dadurch gekennzeichnet, daß sie eine Lichtquelle umfaßt.
  11. Elektrooptische, bistabile Vorrichtung, nach irgendeinem der Ansprüche 1 bis 10, dadurch gekennzeichnet, daß die Einrichtung (26) zum Anregen des kathodolumineszenten Materials eine Elektronenquelle mit Emissionskathodo mit Mikrospitzen umfaßt.
  12. Elektrooptische, bistabile Vorrichtung, gemäß irgendeinem der Ansprüche 1 bis 10, dadurch gekennzeichnet, daß die Einrichtung (26), die das kathodolumineszente Material anregen kann, eine Elektronenquelle mit Diodo umfaßt, die eine Metall-Isoliermaterial-Metall Struktur besitzt.
  13. Elektrooptische, bistabile Vorrichtung, gemäß irgendeinem der Ansprüche 1 bis 10, dadurch gekennzeichnet, daß die Einrichtung (26), die das kathodolumineszente Material anregen kann, eine Elektrodoquelle aus halbleitenden Diodo umfaßt.
  14. Elektrooptische, bistabile Vorrichtung, gemäß irgendeinem der Ansprüche 1 bis 13, dadurch gekennzeichnet, daß die Vorrichtung mehrere bistabile Elemente (16) umfaßt, eine einzige Schicht aus kathodolumineszentem Material (22) allen bistabilen Elementen (16) gemeinsam ist.
  15. Elektrooptische, bistabile Vorrichtung, gemäß irgendeinem der Ansprüche 1 bis 14, dadurch gekennzeichnet, daß die Vorrichtung mehrere bistabile Elemente (16) umfaßt, diese bistabilen Elemente (16) in Zeilen und Spalten gemäß einer Matrix angeordnet sind.
  16. Elektrooptische, bistabile Vorrichtung, gemäß Anspruch 15, dadurch gekennzeichnet, daß die ersten Schichten aus Leitermaterial (18) unter einander zu parallelen, leitenden Spalten verbunden sind, die Einrichtung (26) zum Anregen des genannten kathodolumineszenten Material (22), die parallelen Zeilen anregen kann.
  17. Flacher Sichtschirm, dadurch gekennzeichnet, daß er eine Vorrichtung gemäß irgendeinem der Ansprüche 15 und 16 umfaßt, wobei jedes bistabile Element einem Bildelement des Schirms entspricht.
  18. Verfahren zum Herstellen eines Schirms gemäß Anspruch 17, dadurch gekennzeichnet, daß die Bildelemente des Schirms einen "eingeschalteten" oder einen "gelöschten" Zustand annehmen können, wobei das Verfahren darin besteht:
    nacheinander die Bildelementzeilen zu adressieren, bei der Adressierung einer Zeile alle Bildelemente dieser Zeile in einen "gelöschten" Zustand zu bringen, dann die Bildelemente dieser Zeile einzuschalten, die es sein sollen,
    die Bildelemente der nichtadressierten Zeilen in demjenigen der Zustände beizubehalten, die während ihrer vorhergehenden Adressierung angenommen worden waren.
  19. Verfahren gemäß Anspruch 18, dadurch gekennzeichnet, daß
    V0   eine niedrigere Schwellenspannung für die Bistabilität eines bistabilen Elements ist,
    V1   eine höherere Schwellenspannung für die Bistabilität eines bistabilen Elements ist,
    der Zustand eines Bildelements, das sich an der Kreuzung einer Zeile und einer Spalte befindet, gesteuert wird, indem eine Potentialdifferenz zwischen dieser leitenden Spalte (Anode) und einer Kathode der genannten Einrichtung angelegt wird, um das kathodolumineszente Material anzuregen, wobei diese Kathode die betrachtete Zeile erregt,
    A- bei der Adressierung einer Zeile:
    a) während einer Dauer Te bringt man die betrachtete Kathode auf ein Potential -VlN, dann
    b) während einer Dauer Ta bringt man die betrachtete Kathode auf ein Potential -VlB,
    1) zum Einschalten des Bildelements, das sich an dem Kreuzungspunkt der betrachteten Zeile und der betrachteten Spalte befindet,
    i) während der Dauer Te bringt man die Spalte auf ein Potential -Vc mit der Bedingung VlN - Vc < V0,
    ii) während der Dauer Ta bringt man die Spalte auf ein Potential Vc mit der Bedingung VlB + Vc > V1,
    2) zum Löschen des Bildelements, das sich an dem Schnittpunkt der betrachteten Zeile und der betrachteten Spalte befindet,
    i) während der Dauer Te bringt man die Spalte auf ein Potential Vc mit der Bedingung VlN + Vc < V0,
    ii) während der Dauer Ta bringt man die Spalte auf ein Potential -Vc mit der Bedingung VlB - Vc < V1,
    B - außerhalb der Adressierung der betrachteten Zeile bringt man die betrachtete Kathode auf ein Potential -Vr, so daß Vr + Vc < V1 und Vr - Vc > 0 sind, um die Bildelemente der betrachteten Zeile in dem Zustand beizubehalten, der bei der vorhergehenden Adressierung eingenommen worden ist.
EP91402973A 1990-11-08 1991-11-06 Elektrooptische bistabile Vorrichtung, eine solche Vorrichtung enthaltender Bildschirm und Steuerungsverfahren dazu Expired - Lifetime EP0485285B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9013871 1990-11-08
FR9013871A FR2669124B1 (fr) 1990-11-08 1990-11-08 Dispositif electrooptique bistable, ecran comportant un tel dispositif et procede de mise en óoeuvre de cet ecran.

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EP0485285A1 EP0485285A1 (de) 1992-05-13
EP0485285B1 true EP0485285B1 (de) 1996-02-28

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FR2713823B1 (fr) * 1993-12-08 1996-01-12 Commissariat Energie Atomique Collecteur d'électrons comportant des bandes conductrices commandables indépendamment.
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US5278544A (en) 1994-01-11
FR2669124B1 (fr) 1993-01-22
DE69117437D1 (de) 1996-04-04
JPH0688975A (ja) 1994-03-29
JP2803417B2 (ja) 1998-09-24
EP0485285A1 (de) 1992-05-13
FR2669124A1 (fr) 1992-05-15
DE69117437T2 (de) 1996-09-05

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