Classifications

• • 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
  • G09G3/30—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 using electroluminescent panels
  • G09G3/32—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 using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
  • G09G3/3208—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 using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
  • G09G3/3225—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 using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix
  • G09G3/3233—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 using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using an active matrix with pixel circuitry controlling the current through the light-emitting element
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
  • H10K59/10—OLED displays
  • H10K59/12—Active-matrix OLED [AMOLED] 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
  • G09G2300/00—Aspects of the constitution of display devices
  • G09G2300/08—Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
  • G09G2300/0809—Several active elements per pixel in active matrix panels
  • G09G2300/0842—Several active elements per pixel in active matrix panels forming a memory circuit, e.g. a dynamic memory with one capacitor
  • G09G2300/0852—Several active elements per pixel in active matrix panels forming a memory circuit, e.g. a dynamic memory with one capacitor being a dynamic memory with more than one capacitor
• • G—PHYSICS
  • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
  • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
  • G09G2300/00—Aspects of the constitution of display devices
  • G09G2300/08—Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
  • G09G2300/0876—Supplementary capacities in pixels having special driving circuits and electrodes instead of being connected to common electrode or ground; Use of additional capacitively coupled compensation electrodes
• • 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
  • G09G2310/0243—Details of the generation of driving signals
  • G09G2310/0254—Control of polarity reversal in general, other than for liquid crystal 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
  • G09G2320/00—Control of display operating conditions
  • G09G2320/04—Maintaining the quality of display appearance
  • G09G2320/043—Preventing or counteracting the effects of ageing
• • 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
  • G09G3/34—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 by control of light from an independent source
  • G09G3/36—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 by control of light from an independent source using liquid crystals
  • G09G3/3611—Control of matrices with row and column drivers
  • G09G3/3614—Control of polarity reversal in general
• • 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
  • G09G3/34—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 by control of light from an independent source
  • G09G3/36—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 by control of light from an independent source using liquid crystals
  • G09G3/3611—Control of matrices with row and column drivers
  • G09G3/3648—Control of matrices with row and column drivers using an active matrix
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L23/00—Details of semiconductor or other solid state devices
  • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
  • H01L23/40—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs
  • H01L23/4006—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs with bolts or screws
  • H01L2023/4075—Mechanical elements
  • H01L2023/4087—Mounting accessories, interposers, clamping or screwing parts

Definitions

• a method of controlling a display panel by capacitive coupling is a method of controlling a display panel by capacitive coupling.
• the invention relates to active matrix panels for displaying images using light emitter networks, for example light-emitting diodes, or optical valve arrays, for example liquid crystal valves. These emitters or valves are generally divided into rows and columns.
• active matrix designates a substrate which integrates networks of electrodes and circuits able to control and feed emitters or optical valves supported by this substrate.
• These electrode arrays generally comprise at least one addressing electrode array, a selection electrode array, at least one reference electrode for addressing and at least one base electrode for feeding these emitters. . Sometimes the reference electrode for addressing and the base electrode for power are merged.
• the panel further comprises at least one upper feed electrode, generally common to all valves or emitters, but which is not integrated with the active matrix.
• Each valve or emitter is generally interposed between a base supply terminal connected to a base electrode for the supply and the upper supply electrode which generally covers the entire panel.
• Each control circuit comprises a control terminal connected to or coupled to an addressing electrode via a selection switch, a selection terminal which corresponds to the control of this switch and which is connected to a selection electrode, and a terminal of reference connected to or coupled to a reference electrode.
• Each control circuit therefore comprises a selection switch adapted to transmit to this circuit the addressing signals from an addressing electrode. Closing the selection switch of a circuit corresponds to the selection of this circuit.
• each addressing electrode is connected to or coupled to the control terminals of the control circuits of all the emitters or valves of the same column; each selection electrode is connected to the selection terminals of the control circuits of all the transmitters or all the valves of the same line.
• the active matrix may also include other row or column electrodes.
• the addressing electrodes are used to address to the control circuits control signals, analog voltage or current, or digital; during the transmission periods, each control signal intended for the control circuit of a valve or transmitter is representative of an image datum of a pixel or sub-pixel associated with this valve or transmitter .
• each control and power supply circuit comprises a memory element, generally a capacitor able to maintain the control voltage of this valve during the duration of an image frame; this capacitor is connected in parallel directly to this valve.
• the control voltage of a valve is the potential difference across this valve.
• the control terminal of the circuit is connected to or coupled to one of the terminals of the valve.
• each control and supply circuit generally comprises a current modulator, generally a TFT transistor, provided with two terminals. current flow, a source terminal and a drain terminal, and a gate terminal for voltage control; this modulator is then connected in series with the transmitter to be controlled, this series being itself connected between an electrode (upper) supply and a base electrode for the power supply; generally, it is the drain terminal which is common to the modulator and the emitter, and the source terminal, connected to the base electrode for the supply, is thus at a constant potential; the modulator control voltage is the potential difference between the gate and the source of the modulator; each control circuit comprises means for generating a control voltage of the modulator as a function of the signal addressed to the control terminal of this circuit; each control circuit also comprises, as previously, a holding capacitor adapted to maintain the control voltage of the modulator during the duration of each image or image frame.
• a current modulator generally a TFT transistor, provided with two terminals. current flow, a source terminal and a drain terminal, and a gate terminal for voltage control;
• each control circuit is adapted in a manner known per se to "program", from a current signal, a control voltage of the modulator of this circuit. circuit, which is therefore applied to the gate terminal.
• the addressing electrodes and the selection electrodes are themselves controlled by means of control ("drivers" in English) arranged at the ends of these electrodes, at the edge of the panel; these means generally comprise controllable switches.
• control in English
• these means generally comprise controllable switches.
• the voltage across the valves is generally alternated to avoid initiating a continuous polarization component of the liquid crystal
• the emitters are light-emitting diodes
• the emission periods and the periods of depolarization may overlap: while the emitters or valves of certain lines emit light, the circuits, emitters or valves of other lines may be in the process of depolarization. Nevertheless, overall, the alternation of these periods is detrimental to the maximum luminance of the panel, since the overall duration available for the emission of the transmitters is reduced by the duration of the periods of depolarization.
• the addressing signals are generally transmitted to the control circuits by direct conduction between the addressing electrodes and the control terminals of the circuits, via the selection switch: in the case of analog voltage control of emitter panels, where the control terminal of the circuit corresponds to the gate terminal of the modulator, this gate voltage of the modulator is then equal to the voltage of the addressing electrode which controls this circuit, at least while this circuit is selected.
• connection by capacitive coupling, and not by conduction, between the addressing electrodes and the control terminals of the circuits makes it possible to compensate for the differences in tripping thresholds of the modulators of these circuits, so as to obtain a better uniformity of luminance. screen and better picture display.
• the other documents US6777888, US6618030 and US6885029 describe a capacitive coupling between the addressing electrodes and the control of the current modulators of the emitters.
• An essential aspect of the invention consists in using such a capacitive coupling for another purpose, namely for the purpose of inverting the voltages at the terminals of the valves or at the terminals of the emitters, or the control voltages of the modulators of the circuit circuits.
• the voltage signal that is transmitted by capacitive coupling is in particular an addressing signal for the transmission, which is representative of an image data item and / or an addressing signal (likewise sign) for depolarization, in particular for the depolarization of the current modulator of an emitter.
• the capacitive coupling makes it possible to modify the voltage of a terminal by a voltage jump.
• an algebraic value voltage step signal ⁇ V transmitted via capacitive coupling by an addressing electrode to a control terminal prior to the potential V cal changes the potential of this terminal from V to V cal + ⁇ V.
• This voltage jump is independent of the value V ini of the initial potential (before the jump) of the addressing electrode.
• the initial value V ini (eg: V ini > 0) of the potential of the addressing electrode coupled to this terminal is sufficiently high for the algebraic sum V ini + ⁇ V ( ⁇ V ⁇ 0) to retain the same sign as V ini , thus to choose
• control of each control circuit of a transmitter comprises, during the display of each image frame, two periods, a period of emission of this transmitter and a period of depolarization of the modulator of the control circuit of this transmitter.
• this circuit is selected by capacitively coupling the control terminal of this circuit to an addressing electrode and "shifts" the potential of this terminal to the potential V cal of a reference terminal which thus becomes a " clamping terminal »of this circuit; during this selection and this "setting", a potential V ini is applied to the addressing electrode, with no effect other than transient, because of the setting, on the potential of the control terminal which remains at the value V cal ;
• the potential of the control terminal is maintained at this value by the holding capacitor, as in the prior art.
• V ini has no effect on the potential of the control terminal.
• the value of V ini is adapted so that
• V p ro g on ' a control terminal does not change sign. It is thus advantageously avoided to resort to expensive means for controlling the addressing electrodes.
• the same principle can be applied for the purpose of reversing the voltages across valves or emitter terminals, without having to reverse the polarity between the supply electrodes.
• control method of the invention can be used either only during depolarization periods - and conventional conduction addressing is then used during the emission periods, both during the emission and depolarization periods.
• An advantage of this control method is that it makes it possible to send each circuit a specific depolarization signal, and to adapt the depolarization operation to the polarization level of the modulator of each circuit, which level depends in particular on the signal of addressed issue in the previous issue period.
• the subject of the invention is therefore a method for controlling a display panel which comprises: a network of light emitters or optical valves,
• an active matrix comprising an array of electrodes for addressing voltage signals, an array of selection electrodes, a clamping electrode array, at least one reference electrode for addressing, a network of electrodes, circuits adapted to control each of said transmitters or valves and each having a voltage control terminal adapted to be coupled to an addressing electrode via a coupling capacitor and a selection switch which are connected in series, a voltage stall terminal adapted to be connected to said control terminal via a stall switch, and a holding capacitor connected between said control terminal and said stub terminal,
• the stall terminal being connected to the at least one reference electrode, the control of said selection switch being connected to a selection electrode and the control of said stall switch being connected to a stalling electrode,
• said method comprising transmission periods during which a predetermined transmission voltage V prog . data , which has a first polarity, is applied and maintained at the control terminal of at least one control circuit of said panel,
• this method also comprises depolarization periods during which a predetermined V prog . pol , which has a second polarity, opposite to the first polarity, is applied and maintained at the control terminal of at least one control circuit of said panel.
• the emitters or valves are capable of being fed between at least two feed electrodes, namely a base electrode for the supply which is generally part of the active matrix, and a so-called “upper” supply electrode, which covers generally all the emitters or valves.
• the holding capacitor is adapted to maintain an approximately constant voltage on said control terminal during the duration of an image when said first selector switch and said stall switch are open.
• Other switches than the stall switch, including the selector switch itself, can be used to connect the voltage stall terminal to the control terminal.
• a predetermined transmission or depolarization voltage is generally applied and maintained at the control terminal of each of said control circuits of said panel.
• said predetermined transmission voltage V prog . data or depolarization V prog . pol at the control terminal of the at least one capacitive coupling control circuit according to the following steps:
• a stalling step in which, said reference electrode of the panel being brought to a stalling potential, a selection signal is applied to the selection electrode which controls the selection switch and a calibration signal to the setting electrode which controls the stall switch of said control circuit, these signals being able to close said switches, and, during the simultaneous application of said selection signal and of said stall signal, an initial voltage signal V is applied ini . E , V ini . P to the addressing electrode to which said control terminal is able to be coupled,
• V pol - V cal on said control terminal which is coupled to said addressing electrode, the values of said initial signal V ini . E , V ini . P and said final signal V data , V pol being adapted to obtain, after said voltage jump on said control terminal, said predetermined voltage V prog . data , V prog . pol .
• Control of the panel is generally intended for displaying a succession (or sequence) of images; each emitter or valve of the panel, then corresponds to a pixel or sub-pixel of the images to be displayed; during each emission period, at each emitter or valve of the panel, is associated a predetermined transmission voltage to control this emitter or valve, this voltage being adapted to obtain the display of said pixel or sub-pixel by this emitter or valve; during each depolarization period, each emitter or valve of the panel, is associated with a predetermined depolarization voltage able to depolarize this emitter, this valve, and / or its control circuit.
• the predetermined voltage to be applied and maintained at the control terminal of the control circuits of said panel is intended: - that the emitter or the valve of the panel which is controlled by this circuit emits a pixel or sub-pixel of the image to be displayed, or / and that the emitter or the valve of the panel, or the control circuit, or, if appropriate, the current modulator of this circuit, are depolarized, at least partially.
• the selection signal is terminated, which has the effect of opening the selection switch of the control circuit.
• the voltage of the control terminal is equal to said predetermined voltage, and is maintained at approximately this value for the remainder of the duration of the period by means of the holding capacitor to which this terminal is connected.
• Obtaining said predetermined voltage from the control terminal in this way results from a voltage jump caused to this terminal by capacitive coupling to the addressing electrode itself subjected to a voltage jump; of this predetermined voltage, it is possible to deduce the voltage jump to be obtained at the control terminal by difference with the potential of the reference electrode to which this terminal has been previously wedged; from this jump in voltage to be obtained at the control terminal, it is possible to deduce the voltage jump to be generated at the addressing electrode, as a function, in particular, of the coupling level with the control terminal.
• said panel comprises an array of light emitters capable of being fed between at least one feed base electrode and at least one feed upper electrode
• each of said emitter control circuits comprises a modulator current generator comprising a voltage control electrode forming the control electrode of said circuit and two current-pass electrodes, which are connected between one of said supply electrodes and a supply electrode of said emitter.
• a modulator is a TFT transistor; the current delivered by the modulator is then a function of the potential difference between the gate terminal and the source terminal of this transistor; this potential difference is generally a function, if not equal to, the potential difference between the control terminal and a reference electrode for the control voltage of the circuit; the reference electrode for the control voltage of the circuit is then formed by the supply base electrode.
• said current modulator is a transistor comprising an amorphous silicon semiconductor layer.
• said emitters are electroluminescent diodes, preferably organic.
• FIG. 3 is a timing diagram of the signals applied during a succession of periods and frames for the control of the circuit of FIG. 1 when driving a panel according to the first embodiment of the invention (logic signals V YS , V YC addressing signals Vx 0 ); this timing diagram also illustrates the evolution of the control potential of the modulator V G of this circuit, and the intensity I ⁇ of the current flowing in the diode that this circuit controls.
• the embodiments presented below relate to image display panels where the emitters are organic electroluminescent diodes deposited on an active matrix incorporating control circuits and power supply of these diodes. These emitters are arranged in line and in column.
• the panel comprises two electrode arrays arranged in line, and where the control circuits of the emitters each comprise only three TFT transistors forming one a current modulator and the other two switches.
• the active matrix of the panel comprises:
• the active matrix also comprises a control and power circuit 1 for each diode 2.
• the panel also comprises an upper supply electrode P A common to all the diodes.
• the circuit 1 for controlling and feeding each diode 2 comprises:
• a current modulator T2 comprising two current terminals, namely a drain terminal D and a source terminal S, and a gate terminal G, which corresponds here to the control terminal C of the circuit.
• a holding capacitor C s connected between said gate G and a clamping terminal R of the circuit.
• the control terminal C of the circuit is coupled to a X address electrode D via a select switch T4 and a coupling capacitor C c, which are connected in series; there is no connection here by electrical conduction between this control terminal C and this address electrode X D.
• this coupling capacitor C c is common to all the control circuits served by this addressing electrode.
• the selection switch T4 is controlled by a selection electrode Y s .
• the circuit 1 also comprises a setting switch T3 adapted to connect, via the switch T4, the control terminal C to the clamping terminal R of the circuit; this setting switch T3 is controlled by a setting electrode Y c .
• the clamping terminal R is connected to the reference electrode P R.
• the current modulator T2 is connected in series with the diode 2: the drain terminal D is thus connected to the cathode of the diode 2. This series is connected between two supply electrodes: the source terminal S is connected to the supply base electrode P B and the anode of the diode 2 is connected to the upper supply electrode P A.
• V cal , Vdd and Vss are respectively applied to the reference electrodes P R , supply P A and P B.
• Other references for the control voltage of the circuit can be envisaged without departing from the invention.
• the difference Vdd - Vss is adapted to obtain the emission of the diode when the control of the modulator is greater than its trigger threshold voltage.
• V cal is generally negative (that is to say less than the level "0" of the addressing signal) for reasons which will be described later.
• each frame of image is broken down into a transmission period of the transmitter, for the display of the pixel or sub- corresponding pixel of this image, and a depolarization period, for the compensation of the modulator threshold drift of this circuit.
• the duration of each image frame is then broken down into six steps.
• Step 1 of setting the modulator control during the transmission period this step marks the beginning of the emission period of the diode during this frame of image.
• the closing of T4 has the effect of selecting the control circuit 1 of the diode 2 (as well as the other circuits of the same line), by coupling, via the capacitor C c , the control terminal C to the electrode of X D addressing;
• the duration of this step is sufficiently high to obtain the stabilization of the potentials, and in particular so that the potential of the gate G remains at the value V cal .
• Step 2 addressing the circuit during the transmission period:
• the T3 blocking switch is then opened while keeping the selection switch T4 closed; during this time, the potential of the addressing electrode is raised to the value V ⁇ 4 (and the potential of the other addressing electrodes to the values V ⁇ . ! , ..., V data, i5 ... .).
• the duration of step 2 is adapted in a manner known per se to obtain the stabilization of the potentials at these values and to charge the holding capacitor C s .
• the diode 2 begins to emit a luminance proportional, with said correction, to the image data of the pixel or subpixel associated with it during this image frame.
• Step 3 of maintaining the circuit during the emission period :
• the selection switch T4 is opened while keeping the blocking switch T3 open; the control circuit 1 is no longer selected and there is no longer any capacitive coupling between the addressing electrode X D and the control terminal C of the circuit 1.
• the capacitor C s is maintained at a constant value the voltage of the control terminal C, and the diode 2 continues to emit a luminance proportional to the image data of the pixel or subpixel associated therewith. It is possible that the voltage of the control terminal C undergoes a slight drop - ⁇ V prog . data .
• step 2 cor between step 2 and step 3 due to the suppression of the capacitive coupling; in order for the luminance of the diode to be well proportional to the image data, it is preferable to provide a correction + ⁇ V prog . data . cor at the value V p ⁇ referred to in step 2.
• control circuits of the other diode lines are selected and addressed by also applying to them steps 1 and 2 above; the panel then displays the entire image.
• Step 4 of calibration of the modulator control during the depolarization period the beginning of this step marks the end of the emission period of the diode and the beginning of the depolarization period of the modulator T2. Simultaneously closes the selection switch T4 and the clamping switch T3 by applying electrodes to respectively Y s and Y c an appropriate logic signal (see the first two timing diagrams of Figure 3); the closing of T4 has the effect of selecting the control circuit 1 of the diode 2 by coupling, via the capacitor C c , the control terminal C to the address electrode X D ; the simultaneous closing of the switches T3 and T4 has the effect, despite the capacitive coupling, of setting the potential of the control terminal C to the setting potential V cal applied to the reference electrode P R ; during the setting of the control terminal C, the potential of the addressing electrode is raised to the value V 1n ⁇ p 4 whose value will be determined later.
• the duration of this step is sufficiently high to obtain the stabilization of the potentials, and in particular so that
• Step 5 for addressing the circuit during the depolarization period The calibration switch T3 is then opened while keeping the selection switch T4 closed; during this time, the potential of the addressing electrode is raised to the value V p014 less than - P ar capacitive coupling via the coupling capacitor C c, the voltage V G of the control terminal C therefore undergoes a jump voltage l ⁇ / wog. vo ⁇ .
• V ini P4 and V p014 are chosen according to a double criterion:
• V ini P4 is sufficiently high for V p014 , defined according to criterion 1, to be positive or zero.
• V ini P4 0, as illustrated in FIG. 3 in the case of the first frame.
• V ini P4 0, as illustrated in FIG. 3 in the case of the first frame.
• step 5 The duration of step 5 is adapted in a manner known per se to obtain the stabilization of the potentials at these values and to charge the holding capacitor C s .
• the modulator T2 begins to be depolarized in proportion to the value of V prog . pol4 .
• Step 6 of maintaining the circuit during the depolarization period During the remainder of the depolarization period of this diode 2 during this image frame, the selection switch T4 is opened while keeping the calibration switch open. T3; the control circuit 1 is no longer selected and there is no longer any capacitive coupling between the addressing electrode X D and the control terminal C of the circuit 1.
• the capacitor C s is maintained at a constant value the control voltage of the modulator T2, and the modulator T2 continues to be depolarized in proportion to the value of V prog . pol4 . It is possible that the control voltage of the modulator T2 undergoes a slight drop - ⁇ V prog . pol .
• step 4 cor between step 4 and step 5 due to the suppression of the capacitive coupling; so that the depolarization of the modulator is in accordance with objectives, it is then preferable to make a correction + ⁇ V prog . pol . cor to the value V prog _ POL4 referred to in step 4.
• steps 4 and 5 are applied to the control circuits of the other diode lines so as to depolarize the modulators of the circuits of the other lines; the depolarization of the modulators of the whole panel is thus obtained.
• FIG. 3 represents the control timing diagrams of a control circuit 1 of a transmitter 2 for two successive image frames.
• V prog _ data-2 V prog _ data _ 2 - V cal
• ⁇ V pol _ 2 V pol _ 2 - V ini _p_ 2
• ⁇ V prog _p ⁇ l _ 2 V prog .p ⁇ l . 2 "V ca i.
• V prog _ pol _ 2 ⁇ V cal .
• V ini _ P _ 2 > - ⁇ V pol _ 2 of so that V ini _ P _ 2 + ⁇ V pol 2 V pol _ 2 remains positive or zero, that is to say the same sign of V data _ 2.
• K (t) Kx (I - e ⁇ ⁇ ),
• the duration of this step be at least equal to 5 ⁇ ⁇ .
• the transistors of the control circuit are amorphous silicon
• V prog _ data _ 2 "V p ⁇ . ⁇ , which means that the modulator T2 is much more strongly polarized in the second frame than in the first frame, resulting in changes in the trigger threshold voltage of this much larger modulator; therefore, we choose
• this embodiment of the invention advantageously makes it possible to adapt the value of each depolarization addressing signal V p01-1 of a depolarization period to the value of each display addressing signal V data .j of the preceding display period so as to best compensate for the tripping threshold voltage drifts of the modulators of each control circuit 1.
• FIG. 2 A variant of the first embodiment is illustrated in FIG. 2: the panel the display is identical to the previous except that the T3 stall switch is able to connect directly, without going through the selection switch T4, the clamping terminal R to the control terminal C of the circuit V.
• the panel according to this variant can be controlled as described above for the main embodiment.
• the embodiments described below relate to display panels with organic electroluminescent diodes active matrix; the invention applies more generally to all kinds of active matrix display panels, including current-controllable emitters or optical valves.

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• 2005
  • 2005-12-20 FR FR0553978A patent/FR2895130A1/fr active Pending
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  • 2006-12-19 JP JP2008546428A patent/JP5666778B2/ja not_active Expired - Fee Related
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  • 2006-12-19 WO PCT/EP2006/069924 patent/WO2007071680A1/fr active Application Filing
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