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
• • 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
  • G09G2300/04—Structural and physical details of display devices
  • G09G2300/0404—Matrix technologies
  • G09G2300/0417—Special arrangements specific to the use of low carrier mobility technology
• • 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
  • G09G2300/04—Structural and physical details of display devices
  • G09G2300/0439—Pixel structures
  • G09G2300/0443—Pixel structures with several sub-pixels for the same colour in a pixel, not specifically used to display gradations
• • 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
• • 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
  • G09G2310/0262—The addressing of the pixel, in a display other than an active matrix LCD, involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependent on signals of two data 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
  • G09G2320/00—Control of display operating conditions
  • G09G2320/02—Improving the quality of display appearance
  • G09G2320/0223—Compensation for problems related to R-C delay and attenuation in electrodes of matrix panels, e.g. in gate electrodes or on-substrate video signal 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
  • G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
  • G09G2330/02—Details of power systems and of start or stop of display operation
  • G09G2330/021—Power management, e.g. power saving
• • 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
  • G09G3/2007—Display of intermediate tones
  • G09G3/2011—Display of intermediate tones by amplitude modulation
• • 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
  • G09G3/2007—Display of intermediate tones
  • G09G3/2074—Display of intermediate tones using sub-pixels

Definitions

• the present invention relates to a microelectronic device making it possible to emit light radiation and which can be used for example to form pixels for displays or screens, in particular pixels of OLED type (OLED for “Organic Light Emission Displays”, in French displays). organic electroluminescent).
• OLED type screens are flat screens using the luminescence property of OLED organic diodes.
• a current addressing device integrated into the pixel is generally provided.
• An example according to the prior art of such an addressing device associated with a light-emitting diode 10, for example of the OLED type (OLED for “Organic Light Emission Diode”) is illustrated in FIG. 1.
• This example of a device addressing comprises first of all a first transistor 11, functioning as a switch, and the opening or closing of which is controlled by a selection signal for example in the form of a voltage denoted vlin.
• the addressing device further comprises a second transistor 12 making it possible to produce a current id at the input of the light-emitting diode 10, as a function of an adjustment voltage vdat, the current id causing the emission of radiation by the diode 10.
• the adjustment voltage vdat is a function of a light intensity or luminance value at which one wishes fix the radiation emitted by the diode 10. For a certain value of the selection signal vlin, the first transistor 11 can be put in a “closed” state.
• the adjustment voltage vdat is then applied to the drain of the first transistor 11, and transmitted to the gate of the second transistor 12, the latter then emitting the current id at the input of the light-emitting diode 10.
• the second transistor 12 is generally biased in saturation mode, by a bias voltage denoted Vdd for example of the order of +16 V.
• a pixel formed from the device described above has a contrast depending on the extent of the range of light intensities that the diode is capable of producing.
• the second transistor 12 must preferably be able to deliver a wide range of currents, and be able to produce both "weak" currents, for example of the order of a few tens of nanoamps, for example of the order of 50 nA, as well as "strong" currents, for example example of the order of a few microamps, for example 5 ⁇ A in saturation regime.
• "weak" currents for example of the order of a few tens of nanoamps, for example of the order of 50 nA
• strong currents for example of the order of a few microamps, for example 5 ⁇ A in saturation regime.
• the extent of said range of currents, as well as the values of intensities of this range are dependent in particular on the manner in which the first 11 and the second transistor 12 are polarized.
• the first transistor 11 and the second transistor 12 can be transistors of the TFT type (TFT for “Thin Film Transistor” in French thin film transistor), made in poly-silicon technology lens.
• TFT Thin Film Transistor
• Such a TFT transistor is generally limited when it comes to the extent of the current range that it is capable of debiting, in particular compared to a MOS transistor in monocrystalline silicon technology. This limitation may adversely affect the performance, in particular in terms of contrast, of the pixels using this technology.
• TFT transistors in poly-crystalline silicon technology also have the disadvantage of having a slow transition between their blocked regime which will be called "OFF” and their saturated regime which will be called "ON".
• the adjustment voltage vdat in order for the diode 10 to be able to emit radiation at sufficiently high light intensities, the adjustment voltage vdat must preferably reach high levels. High values of the control voltage vdat induce a high consumption. Given the slow transition between the “ON” and “OFF” regimes of the TFT polycrystalline silicon transistors, so that the diode 10 can emit radiation according to a wide range of light intensities, the difference between the maximum value denoted Vdatmax of the adjustment voltage vdat and the minimum value Vdatmin of this same adjustment voltage is generally important. So that the diode 10 emits at extreme light intensities, the voltage between the drain and the source of the first transistor 11 is generally high.
• Vdat2min can for example be of the order of 8.3 volts.
• the maximum value of the adjustment voltage denoted Vdat2max may for example be of the order of 16.6 volts.
• the invention relates to a microelectronic device for producing total light radiation comprising: - first light-emitting means capable of producing a first radiation of a first light intensity or of a first luminance, - first control means capable of controlling the first electroluminescent means using a first current of an intensity belonging to a first range of intensities, - second electroluminescent means capable of producing a second radiation of a second light intensity or of a second luminance, - second control means able to control the second electroluminescent means, using a second current of an intensity belonging to a second range of intensities different from the first, the total light radiation produced having a light intensity or total luminance combination of said first light intensity or luminance and said second light intensity or luminance.
• the microelectronic device according to the invention can be used to form an improved display or screen pixel.
• luminance will designate values of emitted light intensities related to the same value of a given surface, for example a value equal to the surface of said microelectronic device or of a pixel of display or of r screen formed from said microelectronic device.
• first luminance is meant the ratio between said first light intensity and a given surface.
• second luminance is meant the ratio between said second light intensity and said given surface. At least several intensities of said first range of intensities to which the first current belongs can be lower than the intensities of said second range of intensities to which the second current belongs.
• said first range of intensities and second range of intensities can overlap.
• said first range intensities and second range of intensities can be distinct and not overlap.
• Said first range of intensities can then for example comprise values of intensities all lower than the values of intensities of said second range of intensities.
• the first light-emitting means and second light-emitting means can for example be formed respectively by a first photodiode and a second photodiode, for example organic diodes of OLED type. These first and second electroluminescent means are capable of operating alternately or simultaneously.
• one of said first or second light-emitting means can operate in a mode called "all or nothing", and be capable of producing radiation of a given light intensity or of a given luminance, or of not emit, while the other of said first or second electroluminescent means can operate in another mode which will be called “analog" and be capable of producing light radiation of luminous intensity or luminance varying between a value of minimum luminous intensity or luminance and a value of non-zero luminous intensity or maximum luminance.
• the first electroluminescent means and the second electroluminescent means can be similar or different.
• the first electroluminescent means and the second electroluminescent means can be produced using similar or different technologies.
• the first and second electroluminescent means can have similar or different sizes.
• the first light-emitting means and the second light-emitting means can be formed, for example, respectively from a first photodiode and from a second photodiode of identical or different sizes or of identical or different emitting surfaces.
• the first light-emitting means and second light-emitting means are formed respectively by a first OLED-type photodiode and a second OLED-type photodiode stressed differently from one another in terms of frequency d 'use or / and average light intensity to provide, it may be useful to provide the first and second photodiode with different sizes.
• said first and second photodiode, the photodiode least stressed in terms frequency of use or / and average light intensity or average luminance to be supplied can be designed so as to have a smaller size or a smaller emitting surface than the other photodiode most stressed in terms of frequency of use or / and average light intensity or average luminance to be provided.
• This particular embodiment can make it possible to increase the lifetime of the microelectronic device according to the invention.
• the first and / or second control means can be provided with switch means, for example in the form of a first and / or a second switch transistor, for example of the TFT type.
• the first control means may include current modulating means, for example in the form of a transistor, such as a TFT type transistor, making it possible to modulate the current at the input of the first electroluminescent means.
• the second control means may include current modulating means, for example in the form of another transistor, such as a TFT type transistor, making it possible to modulate the current at the input of the second electroluminescent means.
• the current modulator transistor included in the first control means can be formed according to a ratio denoted (Wi / Li), of the width of its channel denoted Wi over the length of its channel denoted Li, the ratio (Wi / Li) being lower than another ratio noted ( 2 / L 2 ), of the width noted W 2 over the length noted L 2 of the channel of the other transistor, included in the second control means.
• the switching means of the first control means and of the second control means can be controlled for example by the same signal, for example in the form of a so-called “selection” voltage.
• the current modulating means of the first control means and of the second control means can be controlled by different signals, for example respectively by a first voltage called “adjustment” and a second voltage called “adjustment”.
• the microelectronic device according to the invention may be capable of forming an improved display or screen pixel, first of all in terms of consumption.
• the device according to the invention makes it possible to reduce the bias constraints on the current modulating means and on the electroluminescent means compared to pixel addressing devices according to the prior art.
• the levels of the adjustment voltages making it possible to define the levels of the currents respectively at the input of the first electroluminescent means and of the second electroluminescent means of the device according to the invention can thus be reduced compared to the level of the adjustment voltages used for the devices addressing of pixels according to the prior art.
• the consumption induced by a pixel used can be improved.
• the minimum and maximum levels of the adjustment signals used to define the current levels at the input of the electroluminescent means can be reduced compared to those used with the pixel addressing devices according to the prior art. This has the consequence of facilitating the retention of these adjustment signals at the input of the current modulator means. At the level of a pixel, this can make it possible in particular to reduce the phenomenon of untimely variations in light intensity emitted by it.
• This device firstly comprises first and second light-emitting means respectively in the form, for example, of a first diode light emitting 110, for example organic and OLED type, and a second light emitting diode 120 for example of the same type as the first diode 110.
• the diodes 110 and 120 are controlled by current respectively by first control means 130 and second control means 140 and can operate alternately or simultaneously.
• the first diode 110 is capable of receiving as input a current denoted idl, coming from the first control means 130 and the intensity of which belongs to a first range called “low intensities”, going from a minimum value Idlmin for example of l order of several tens of nanoamps, for example equal to 50 nA, at a maximum value Idlmax for example comprised between several hundred nanoamps and several microamps, for example of the order of 1 ⁇ A.
• a current denoted idl coming from the first control means 130 and the intensity of which belongs to a first range called “low intensities”, going from a minimum value Idlmin for example of l order of several tens of nanoamps, for example equal to 50 nA, at a maximum value Idlmax for example comprised between several hundred nanoamps and several microamps, for example of the order of 1 ⁇ A.
• the diode 110 Depending on the intensity of the current idl at its input, the diode 110 produces light radiation of low intensity and luminance, the luminance being included in a range known as “low luminances” situated between a minimum value denoted Llmin, by example of the order of 1 cd / m 2 , and a maximum value of Llmax, for example of the order of 20 cd / m 2 .
• the first control means 130 producing the current id1 at the input of the first diode 110 firstly comprise switch means.
• These switching means can be in the form for example of a first switching transistor 131, such as a TFT type transistor, the opening and closing of which are directed by a selection signal in the form of a voltage denoted vsel applied on his grid.
• the first control means 130 also comprise means for modulating the current idl at the input of the first diode 110, as a function of an adjustment signal in the form of a voltage denoted vdatl.
• the modulators of the current idl take for example the form of a second modulator transistor 132, such as a TFT type transistor, and polarized, preferably in saturation mode, by a bias voltage denoted Vdd, for example l '+ 16V order.
• the adjustment voltage vdatl can be applied to the drain of the first transistor 131.
• the adjustment voltage vdatl can be transmitted to the gate of the second transistor 132, the latter then emitting the current idl at the input of the first diode 110, as a function of the value of the adjustment voltage vdatl received on its wire rack.
• the intensity and the luminance of a light radiation emitted by the first diode 110 is a function of the intensity of the current idl, itself controlled by the adjustment voltage vdatl.
• the adjustment voltage vdatl is emitted by a circuit external to the device illustrated in FIG. 2 and preferably bounded between a minimum value Vdatl m i n and a maximum value Vdatl max .
• These minimum values Vdatl raln and maximum Vdatl max respectively define the light intensity and the minimum luminance Llmin and the light intensity and the maximum luminance Llmax at which the first diode 110 is capable of producing.
• Vdatlmin can be around 9.05 volts to obtain an Idlmin current of around 50 nA and Vdatlmax around 13.75 volts to obtain an Idlmax current around 1 ⁇ A
• Integrated means to the first control means 130 taking for example the form of a capacitor 133, for example of capacitance of the order of 0.5 pF, connected to the gate of the second transistor 132, are also provided to make it possible to retain the adjustment signal vdatl at the input of the second transistor 132 when the first transistor 131 is in the "open" state.
• the second diode 120 is capable of receiving a current denoted id2 from the second control means 140.
• the current id2 at the input of the second diode 120 has an intensity belonging to another range of intensities higher than those of said first range of intensities to which the current idl belongs to the input of the first diode 110.
• This other range of intensities is between a minimum value denoted Id2min, for example of the order of 1 ⁇ A and a maximum value noted Id2max, for example of the order of several microamps, for example of 4 ⁇ A.
• the range of intensities to which the current id1 belongs to the input of the first diode 110 and the other range of intensities to which the current id2 belongs to the input of the first diode 110 are distinct. According to a variant, it can be provided that the range of intensities to which the current id1 belongs and the other range of intensities to which the current id2 belongs to overlap.
• the second diode 120 can produce light radiation of intensity and luminance included in a second range of intensities and luminances, the second range of luminance ranging from a value minimum luminance noted L2min for example of around 20 cd / m 2 at a maximum luminance value denoted L2max, for example around 80 cd / m 2 .
• the second control means 140 making it possible to control the illumination of the second diode 120, are of the same type as the first control means 130 making it possible to control the lighting of the first diode 110.
• the second control means 140 also include switch means, the opening and closing of which are controlled by the selection voltage vsel.
• the switch means of the second control means take the form, for example, of another first switch transistor 141, for example of the TFT type.
• the second control means 140 also comprise means making it possible to modulate the current id2 at the input of the second diode 120 as a function of the value of another adjustment signal in the form of a voltage denoted vdat2 applied to the drain of the other first transistor 141.
• the means modulating the current id2 at the input of the second diode 120 may take the form of another second transistor 142 whose source is connected to the second diode 120 and which, when receives on its grid the other adjustment voltage vdat2, emits the current id2 at the input of said second diode 120.
• the other second transistor 142 can for example be a transistor of TFT type (TFT for "Thin Film Transistor”) . It is preferably biased in saturation mode, for example by the bias voltage Vdd.
• the other second modulating transistor 142 is capable of receiving the other voltage adjustment vdat2 when the other first transistor 141 is set to the “closed” state by the voltage vsel. This voltage vdat2 is emitted by a circuit external to the device illustrated in FIG. 2 and preferably bounded between a minimum value denoted Vdat2 m i n and a maximum value denoted Vdat2 max .
• the minimum and maximum values of the voltage vdat2 respectively determine the minimum luminance denoted L2min and the maximum luminance denoted L2max that the second diode 120 is capable of producing.
• the minimum value Vdat2min of the other adjustment voltage can be of the order of 12.8 volts to allow a minimum current Id2min to be obtained at the input of the second diode of the order of 1 ⁇ A.
• the maximum value Vdat2max of the other control voltage vdat2 can be of the order of 15.3 volts to allow obtaining a current of maximum value Id2max of the order of 4 ⁇ A at the input of the second diode 120.
• the other adjustment voltage vdat2 at the input of the second control means 140 may belong to a range of voltages different from the range of voltages to which the voltage belongs.
• adjusting vdatl at the input of the first control means 140 Means are also provided to enable the other adjustment voltage vdat2 to be retained at the input of the other second transistor 142, when the other first transistor 141 is in the "open" state.
• the first capacitor 133 and the second capacitor 143 may have different capacitances and the values of which are chosen respectively as a function of the respective ranges to which the adjustment voltages vdatl and vdat2 belong.
• the first capacitor 133 can be provided to have a capacitance value lower than that of the second capacitor 143.
• the armatures of the first capacitor 133 may for example occupy a smaller area than those of the second capacitor 143.
• the control means 130 and 140 of the diodes 110 and 120 differ from one another in particular by their current modulating means.
• the current modulator means of the first control means 130 are provided for emitting a current idl in a range of intensities lower than that of the current id2 which can be emitted by the other current modulator means of the second control means 140.
• the other second transistor 142 current modulator, belonging to the first control means 140 can be produced for example so as to comprise a channel shorter than the channel of the second transistor 132 current modulator belonging to the first control means 130.
• the second transistor 132 can be formed with a noted ratio (i Li) of the width of its channel Wi over the length i of its channel, for example of the order of (10/60), while the other second transistor 142, can be formed with a other noted ( 2 / L 2 ) for example of the order of (10/20) of the width W 2 of its channel over the length L 2 of its channel, higher than the ratio (Wi Li).
• the microelectronic device described above can be used for example to form a pixel of a screen or a display.
• the pixel can produce a light radiation of intensity and luminance belonging to a wide range, respectively of intensity and luminances, the range of luminance being able to be comprised between a minimum value of luminance noted Lmin, for example of 1 'order of 12 cd / m 2 and a maximum luminance value Lmax, for example of the order of 120 cd / m 2 , while keeping consumption reduced.
• Said pixel can be shared between a first sub-pixel, formed for example from the first diode 110 associated with the first control means 130, and a second sub-pixel formed from the second diode 120 associated with the second control means 140.
• the selection of said pixel from a set of screen or display pixels can be carried out by means of the selection signal vsel common to the first sub-pixel and to the second sub-pixel, and coming from a circuit external to the screen or display.
• the value of the total intensity or luminance of a light radiation emitted by said pixel can be controlled by the adjustment signal vdatl and the other adjustment signal vdat2 applied respectively to the first sub-pixel and to the second sub-pixel , coming from a circuit outside the screen or display.
• the first sub-pixel can be developed for example to produce radiations of intensity or so-called "weak" luminances included in a first range of intensities or luminances, the value of which is a function of the adjustment signal vdatl.
• the second sub-pixel can be provided to produce radiation of intensities or so-called “high” luminances included in a second range of intensities or luminances higher than those of the first range of intensities or luminances, and whose the value is a function of the other adjustment signal vdat2.
• the first sub-pixel and the second sub-pixel may operate alternately or simultaneously depending on the value of the adjustment signals vdatl and vdat2 and on the value of total intensity or luminance which it is desired to assign to said pixel.
• An example of an operating diagram of a pixel implemented according to the invention and those of a first sub-pixel and a second sub-pixel forming said pixel are illustrated in FIG. 3, respectively by the curves C 2 , C 3 and C.
• the total luminance emitted by the pixel is between a minimum luminance value noted Lmin for example of the order of 12 cd / m 2 and a maximum luminance value noted Lmax for example of the order of 120 cd / m 2 .
• the first sub-pixel and the second sub-pixel produce distinct and contiguous ranges of intensities or luminances.
• the pixel When the pixel produces “low intensities or luminances” included in a first range, for example situated between Lmin for example of the order of 12 cd / m 2 and Lmax / 5, for example of the order of 24 cd / m 2 (Cil portion of the increasing Cl curve), it may be the first sub-pixel which emits light radiation (C21 portion of the increasing C2 curve) while the second sub-pixel does not emit (C31 portion of the curve C3 constant).
• This first range called “low intensity or low luminance” is produced for radiation coming from the first diode 110 when the latter receives an input current idl belonging to a range of low intensity currents ranging for example from 50 nA to 1 uA.
• the second range of intensities or luminances called “high intensities or luminances” is thus produced for light radiation coming from the second diode 120 when the latter receives an input current id2 belonging to a second range of currents intensities ranging for example from 1 ⁇ A to 4 ⁇ A.
• the highest of intensities or luminances can be included in a third range of luminances, for example situated between (4Lmax / 5) for example of the order of 96 cd / m 2 and (Lmax), by example of the order of 120 cd / m 2 (portion C13 of the curve Cl), can be provided both by an illumination of the first sub-pixel and an illumination of the second sub-pixel.
• the third range known as “highest” intensities or luminances can be obtained by radiation from the first diode 110
• portion C23 of the constant curve C2 triggered by a first current idl at the input of the latter of, for example, between 50 nA and 1 ⁇ A, and by radiation coming from the second diode 120 (portion C33 of the curve C3 increasing) triggered by a second current id2 at the input of the latter, for example between 1 ⁇ A to 4 ⁇ A.
• light radiation emitted by the pixel according to the invention can be constantly formed from a combination of radiation from the first sub-pixel and another light radiation from the second sub-pixel.
• a pixel implemented according to the invention is formed first of all of a first sub-pixel operating according to a mode that l 'we will call “all or nothing” and a second sub-pixel operating in another mode which we will call “analog”.
• the first sub-pixel will be able to emit radiation of a given luminance or not to emit, while the second sub-pixel will constantly emit a value of intensity or luminance likely to vary.
• a screen or display pixel is generally associated with an elementary surface, capable of producing light radiation according to a given wavelength and a given intensity or luminance.
• a pixel P implemented according to the invention of a screen or display is divided into a first zone and a second associated zone respectively to a first sub-pixel denoted Pi and to a second sub-pixel denoted P2.
• the first sub-pixel PI and the second sub-pixel P2 respectively comprise a first surface SI capable of emitting radiation of a certain light intensity, and a second surface S2 capable of emitting radiation of another light intensity .
• the surfaces S1 and S2 are capable of emitting according to near or identical wavelengths.
• the first surface S1 and the second surface S2 can be equal or different.
• the surfaces S1 and S2 correspond respectively to an emitting surface of the first organic photodiode and to an emitting surface of the second organic photodiode.
• emitting surface is meant a surface capable of emitting light radiation.
• the surfaces Si and S2 are each capable of emitting light radiation simultaneously or alternately.
• the pixel emits according to the first range of "low luminances” or low intensities, it is for example the first surface SI which emits a light radiation while the second surface S2 does not emit (FIG. 4A). So that the pixel emits according to the second range of "high luminances” or of high intensities, it is for example the second surface S2 which emits light radiation, while the first surface S1 does not emit (FIG. 4B). So that the pixel emits according to the third range of "highest luminances or intensities" the second surface S2 and the first surface SI emit at the same time (FIG. 4C).

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• 2004
  • 2004-02-27 FR FR0450383A patent/FR2866973B1/fr not_active Expired - Fee Related
• 2005
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  • 2005-02-24 EP EP05717722A patent/EP1719102A1/de not_active Withdrawn
  • 2005-02-24 WO PCT/FR2005/050124 patent/WO2005086130A1/fr active Application Filing
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