JP2009122264A - Active matrix type display device and manufacturing method of the active matrix type display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an active matrix type display device which allows defective display pixels to be efficiently repaired, is improved in manufacture yield, and has superior tone reproduction, and to provide a manufacturing method of the active matrix type display device. <P>SOLUTION: The active matrix type display device has a plurality of video signal lines VL and a plurality of display pixels PX. Each display pixel PX has a plurality of pixel circuits 18a and 18b each of which includes a drive transistor, a display element, an output switch, and a connection portion; and at least one selector switch XT connected between drains of a plurality of transistors DRT1 and DRT2 closer to the drain sides of the plurality of transistors than to the connection portion and electrically connecting or disconnecting the plurality of drains, and a capacitance portion connected to the gates of the plurality of driving transistors. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an active matrix display device and a method for manufacturing an active matrix display device.

  In recent years, organic EL display devices, liquid crystal display devices, and the like have been used as display devices. Since an organic EL display device does not require a backlight used in a liquid crystal display device, it is possible to reduce the thickness, weight, power consumption, cost, and mercury of the product. Since the organic EL display device is a self-luminous display device, it has characteristics such as a high viewing angle and a high-speed response. From the above, the organic EL display device has attracted attention as a product for moving images such as a TV (television) receiver as well as a product for still images such as a notebook PC (personal computer), a monitor, and a viewer. .

  The organic EL display device includes an array substrate. The array substrate has a glass substrate and a plurality of organic EL elements arranged in a matrix on the glass substrate. Each organic EL element forms one pixel. Each organic EL element has an anode, a cathode facing the anode, and an EL layer sandwiched between the anode and the cathode. The EL layer contains an organic compound having a light emitting function and can emit light in any one of red, green, and blue.

  By the way, the distance between the anode and the cathode is as very narrow as about 1 μm. For this reason, a short circuit may occur between the anode and the cathode during the manufacturing process of the organic EL display device. A short circuit between the anode and the cathode occurs when foreign matter adheres between the anode and the cathode. Pixels to which foreign matter has adhered become dark spots and cannot emit light. If there are many dark spots, the image quality and display quality will deteriorate significantly, and the product cannot be shipped. For this reason, it is necessary to repair the dark pixel.

As a repair method, a method of forming a high resistance region between an anode and a cathode by irradiating a laser at a short-circuit portion between the anode and the cathode is disclosed (for example, see Patent Document 1). As a result, the dark spot pixel is improved, and functions as a normal pixel. In addition, it is possible to remove the foreign matter by irradiating the foreign matter with a laser to improve the pixel.
JP 2004-227852 A

  However, since the shape and size of the foreign matter are various, the repair rate of the repair varies depending on the conventional repair method, and there are cases where the dark spot pixel can be improved or not. As described above, since it is difficult to efficiently improve the pixel, it is difficult to produce a stable product. In addition, in order to improve display quality, it is necessary to improve gradation reproducibility for each pixel.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an active matrix display device capable of efficiently repairing defective display pixels, improving the manufacturing yield, and excellent in gradation reproducibility. An object of the present invention is to provide a method for manufacturing an active matrix display device.

In order to solve the above problems, an active matrix display device according to an aspect of the present invention provides:
Multiple video signal lines;
A plurality of display pixels connected to each of the video signal lines,
Each display pixel is
A driving transistor that outputs a driving signal corresponding to an image to be displayed; a display element that receives the driving signal and displays an image corresponding to the driving signal; and a drain and a display element of the driving transistor, and An output switch for switching whether or not to output a drive signal to the display element; and a connection portion formed so as to be electrically disconnected between at least one of the drain and the output switch of the drive transistor and between the output switch and the display element; A plurality of pixel circuits including
At least one changeover switch that is connected between the drains of the plurality of drive transistors on the drain side of the plurality of drive transistors from the plurality of connection portions, and switches between the plurality of drains to a conductive state or a non-conductive state;
And a capacitor connected to the gates of the plurality of driving transistors.

In addition, a method for manufacturing an active matrix display device according to another aspect of the present invention includes:
A plurality of video signal lines; and a plurality of display pixels connected to each video signal line, wherein each display pixel outputs a drive signal corresponding to an image to be displayed, and the drive signal A display element that displays an image corresponding to the drive signal, an output switch that is connected to a drain and a display element of the drive transistor, and switches whether to output the drive signal to the display element, and the drive transistor A plurality of pixel circuits including a connection portion formed so as to be electrically disconnectable between at least one of the drain and the output switch and between the output switch and the display element, and the plurality of drives from the plurality of connection portions. The drain side of the transistor is connected between the drains of the plurality of driving transistors, and the plurality of drains are in a conductive state or are connected. At least one changeover switch switches non-conductive, in the manufacturing method of the active matrix display device having a, a capacitor section connected to a gate of said plurality of driving transistors,
A drive signal is output to the plurality of display elements, and whether or not a defect has occurred in the display elements,
When a defect occurs in the display element, the connection portion of the pixel circuit including the defective display element is disconnected.

  According to the present invention, it is possible to efficiently repair defective display pixels, improve the manufacturing yield, and provide an active matrix display device excellent in gradation reproducibility and a method for manufacturing the active matrix display device. be able to.

  Hereinafter, an active matrix display device, a manufacturing method of an active matrix display device, and a driving method of an active matrix display device according to the present invention will be described with reference to the drawings. Organic EL display device, organic EL display device manufacturing method, and organic Embodiments applied to a method for driving an EL display device will be described in detail.

  FIG. 1 is a plan view schematically showing an organic EL display device. As shown in FIG. 1, the organic EL display device includes an organic EL panel DP and a controller 12 that controls the organic EL panel.

  The organic EL panel DP includes an insulating substrate 8 having optical transparency such as a glass plate, n × m display pixels PX arranged in a matrix on the insulating substrate and constituting a display region 11, and each display pixel row. The scanning lines SL1 (1 to n), the scanning lines SL2 (1 to n), the scanning lines SL3 (1 to n), and the scanning lines SL4 (1 to n) that are connected and provided independently by n are respectively provided. , Scanning line SL5 (1 to n), scanning line SL6 (1 to n), m video signal lines VL (1 to m) connected to each column of display pixels PX, scanning line SL1 (1 to n) , SL2 (1-n), SL3 (1-n), SL4 (1-n), SL5 (1-n), SL6 (1-n) are sequentially driven for each row of the display pixels PX. 14 and a signal line driving circuit 15 for driving the plurality of video signal lines VL (1 to m).

The scanning line driving circuit 14 and the signal line driving circuit 15 are integrally formed on the insulating substrate 8 outside the display area 11. The controller 12, the scanning line driving circuit 14, and the signal line driving circuit 15 form a driving unit 10.
In addition, the organic EL panel DP includes a voltage power supply line SLa and a reference voltage power supply line SLb formed on the insulating substrate 8. A constant voltage is applied to each of the voltage power supply line SLa and the reference voltage power supply line SLb. When the potential of the voltage power supply line SLa and the potential of the reference voltage power supply line SLb are compared, the potential of the voltage power supply line SLa is relatively high level, and the potential of the reference voltage power supply line SLb is relatively low level. Therefore, the node ND1 of the voltage power supply line SLa is a high potential power supply terminal, and the node ND2 of the reference voltage power supply line SLb is a low potential power supply terminal.

  FIG. 2 shows an equivalent circuit of the display pixel PX. Each display pixel PX includes a plurality of pixel circuits 18a and 18b, at least one changeover switch XT, a capacitor, a reset switch RST, and a write switch SST. Here, each display pixel PX includes two pixel circuits and one changeover switch XT.

The pixel circuit 18a is connected to a driving transistor DRT1 that outputs a driving signal corresponding to an image to be displayed, a display element that receives the driving signal and displays an image corresponding to the driving signal, a drain of the driving transistor DRT1, and a display element. The output switch BCT1 for switching whether or not to output a drive signal to the display element, the connection part 21 formed to be cuttable between the drain of the drive transistor DRT1 and the output switch BCT1, and the output switch BCT1 and the display element can be cut off. And a cancel switch TCT1.
The display element of the pixel circuit 18a is, for example, a self-light emitting element, and in this embodiment, the display element is an organic EL element EL1 including at least an organic light emitting layer as a photoactive layer.

  The source and drain of the output switch BCT1 are formed of a polysilicon thin film or a metal thin film to which impurities are added at a high concentration. The source of the output switch BCT 1 has a connection part 21, and the drain of the output switch BCT 1 has a connection part 23. And at least one of the connection part 21 and the connection part 23 should just be formed so that cutting | disconnection is possible.

The pixel circuit 18b is connected to a driving transistor DRT2 that outputs a driving signal corresponding to an image to be displayed, a display element that receives the driving signal and displays an image corresponding to the driving signal, a drain of the driving transistor DRT2, and a display element. The output switch BCT2 for switching whether or not to output a drive signal to the display element, the connection part 22 formed to be cuttable between the drain of the drive transistor DRT2 and the output switch BCT2, and the output switch BCT2 and the display element can be cut off. And a cancel switch TCT2.
The display element of the pixel circuit 18b is, for example, a self-light emitting element, and in this embodiment, the display element is an organic EL element EL2 having at least an organic light emitting layer as a photoactive layer.

  The source and drain of the output switch BCT2 are formed of a polysilicon thin film or a metal thin film to which impurities are added at a high concentration. The source of the output switch BCT2 has a connection part 22, and the drain of the output switch BCT2 has a connection part 24. And at least one of the connection part 22 and the connection part 24 should just be formed so that cutting | disconnection is possible.

  The changeover switch XT is connected between the drains of the drive transistors DRT1 and DRT2 on the drain side of the drive transistors DRT1 and DRT2 from the connection portions 21, 22, 23, and 24, and switches between the drains to a conductive state or a nonconductive state. It is. That is, even when any one of the connection portions 21, 22, 23, and 24 is disconnected, the changeover switch XT can switch between the drains of the drive transistors DRT1 and DRT2 to a conductive state or a non-conductive state.

  The capacitor is connected to the gates of the drive transistors DRT1 and DRT2. The capacitor unit includes a first capacitor unit Ck and a second capacitor unit Cs. Here, the first capacitor unit Ck and the second capacitor unit Cs are capacitors.

  The write switch SST, the changeover switch XT, the reset switch RST, the drive transistor DRT1, the output switch BCT1, the cancel switch TCT1, the drive transistor DRT2, the output switch BCT2, and the cancel switch TCT2 are here made of the same conductivity type, for example, a P-channel type thin film transistor. It is configured.

  The thin film transistors that constitute the write switch SST, changeover switch XT, reset switch RST, drive transistor DRT1, output switch BCT1, cancel switch TCT1, drive transistor DRT2, output switch BCT2, and cancel switch TCT2 are all formed in the same process and the same layer structure. A thin film transistor having a top gate structure using polysilicon as a semiconductor layer.

  The sources of the drive transistors DRT1 and DRT2 are connected to the node ND1 of the voltage power supply line SLa, respectively.

  The cancel switch TCT1 is connected between the gate and drain of the drive transistor DRT1. The cancel switch TCT2 is connected between the gate and drain of the drive transistor DRT2. The gates of the cancel switches TCT1 and TCT2 are each connected to the scanning line SL5. The cancel switches TCT1 and TCT2 are turned on (conductive state) and turned off (non-conductive state) in response to the control signal CG supplied from the scanning line SL5.

  In the output switch BCT1, the source is connected to the drain of the drive transistor DRT1, and the drain is connected to the organic EL element EL1. In the output switch BCT2, the source is connected to the drain of the drive transistor DRT2, and the drain is connected to the organic EL element EL2. The gates of the output switches BCT1 and BCT2 are each connected to the scanning line SL1. The output switches BCT1 and BCT2 are turned on and off in response to a control signal BG supplied from the scanning line SL1.

  The organic EL element EL1 is connected to the drain of the output switch BCT1 and the node ND2 of the reference voltage power supply line SLb. The organic EL element EL2 is connected to the drain of the output switch BCT2 and the reference voltage power line SLb.

  The changeover switch XT is connected between the drains of the drive transistors DRT1 and DRT2, and the gate thereof is connected to the scanning line SL4. The changeover switch XT is turned on / off in response to a control signal XG supplied from the scanning line SL4.

  The write switch SST is connected between the video signal line VL and the first capacitor unit Ck, and its gate is connected to the scanning line SL2. The write switch SST is turned on / off in response to a control signal SG supplied from the scanning line SL2. The write switch SST switches whether to output the reference voltage Vsig0 or the video signal voltage Vsig1 transmitted through the video signal line VL.

  The reset switch RST is connected between the scanning line SL3 and the gates of the driving transistors DRT1 and DRT2. The gate of the reset switch RST is connected to the scanning line SL6. The reset switch RST is turned on / off in response to a control signal RG supplied from the scanning line SL6. The reset switch RST switches whether to output the reset voltage RS transmitted through the scanning line SL3.

  The first capacitor Ck is connected between the gates of the drive transistors DRT1, DRT2 and the write switch SST. More specifically, the upper electrode of the first capacitor Ck is connected to the gates of the drive transistors DRT1 and DRT2. The lower electrode of the first capacitor unit Ck is connected to the write switch SST. The first capacitor Ck holds (stores) the reference voltage Vsig0 and the video signal voltage Vsig1.

  The second capacitor Cs is connected between the gate and source of the drive transistor DRT1 and between the gate and source of the drive transistor DRT2. More specifically, the upper electrode of the second capacitor Cs is connected to the gates of the drive transistors DRT1 and DRT2. The lower electrode of the second capacitor Cs is connected to the sources of the drive transistors DRT1 and DRT2. The second capacitor Cs holds a potential difference between the gates and the sources of the drive transistors DRT1 and DRT2.

Next, the configuration of the drive transistor DRT1 and the organic EL element EL1 will be described in detail with reference to FIG. FIG. 3 shows a cross section of the display pixel PX including the organic EL element EL1.
The P-channel type thin film transistor that constitutes the drive transistor DRT1 includes a channel layer 50 made of polysilicon formed on the insulating substrate 8, and this channel layer is formed between the source region 50a, the drain region 50b, and the source and drain regions. It has a channel region 50c located.

  A gate insulating film 52 is formed over the channel layer 50, and a gate electrode G is provided on the gate insulating film so as to face the channel region 50c. An interlayer insulating film 54 is formed over the gate electrode G, and a source electrode (source) S and a drain electrode (drain) D are provided on the interlayer insulating film.

  The source electrode S and the drain electrode D are connected to the source region 50a and the drain region 50b of the channel layer 50 through contacts formed through the interlayer insulating film 54 and the gate insulating film 52, respectively. The drain electrode D of the drive transistor DRT1 is connected to the output switch BCT1 via a wiring (connection portion 21 and the like) formed on the interlayer insulating film 54.

  The thin film transistors constituting the write switch SST, changeover switch XT, reset switch RST, output switch BCT1, cancel switch TCT1, drive transistor DRT2, output switch BCT2 and cancel switch TCT2 are also formed in the same structure as the drive transistor DRT1. ing.

  A plurality of wirings including the video signal lines VL are provided on the interlayer insulating film 54. A protective film 56 is formed on the interlayer insulating film 54 so as to cover the source electrode S, the drain electrode D, and the wiring. On the protective film 56, a hydrophilic film 58 and a partition film 60 are laminated in this order.

  The organic EL element EL1 has a structure in which an organic light emitting layer 64 containing a luminescent organic compound is sandwiched between an anode 62 and a cathode 66. The anode 62 is made of a transparent electrode material such as ITO (indium tin oxide) and is provided on the protective film 56. Of the hydrophilic film 58 and the partition wall film 60, the part facing the anode 62 is removed by etching. An anode buffer layer 63 and an organic light emitting layer 64 are formed on the anode 62, and a cathode 66 made of silver / aluminum alloy is laminated on the organic light emitting layer 64 and the partition wall film 60.

  In the organic EL element EL1 having such a structure, when the holes injected from the anode 62 and the electrons injected from the cathode 66 are recombined inside the organic light emitting layer 64, organic molecules constituting the organic light emitting layer are formed. Is excited to generate excitons. The excitons emit light in the process of radiation deactivation, and the light is emitted from the organic light emitting layer 64 to the outside through the transparent anode 62 and the insulating substrate 8.

  Here, the cathode 66 may be made light transmissive, and light may be taken out from the surface facing the insulating substrate 8. Further, a reverse lamination type in which the anode 62 is disposed on the insulating substrate 8 side with respect to the cathode 66 may be employed. In either case, it is necessary to form the light emitting surface side with a transparent conductive material. For example, when the cathode 66 is disposed on the light emitting surface side, the alkaline earth metal and the rare earth metal are thin enough to have light transmittance. This can be achieved by forming.

  On the other hand, the controller 12 shown in FIG. 1 is formed on a printed circuit board disposed outside the organic EL panel DP, and controls the scanning line driving circuit 14 and the signal line driving circuit 15. The controller 12 receives a digital video signal and a synchronization signal supplied from the outside, and generates a vertical scanning control signal for controlling the vertical scanning timing and a horizontal scanning control signal for controlling the horizontal scanning timing based on the synchronizing signal. The controller 12 supplies the vertical scanning control signal and the horizontal scanning control signal to the scanning line driving circuit 14 and the signal line driving circuit 15, respectively, and drives the digital video signal in synchronization with the horizontal and vertical scanning timings. Supply to circuit 15.

  The scanning line driving circuit 14 includes a shift register, an output buffer, etc., and sequentially transfers a horizontal scanning start pulse supplied from the outside to the next stage. As shown in FIGS. A reset voltage RS and five types of control signals, that is, control signals BG, SG, XG, CG, and RG are supplied to the display pixel PX. Control signals BG, SG, XG, CG, and RG are supplied to the scanning lines SL1, SL2, SL4, SL5, and SL6. The reset voltage RS is supplied to the scanning line SL3.

The signal line driving circuit 15 supplies the reference voltage Vsig0 and the video signal voltage Vsig1 to the video signal line VL.
As described above, the scanning line driving circuit 14 and the signal line driving circuit 15 are mounted on the insulating substrate 8. The scanning line driving circuit 14 and the signal line driving circuit 15 may be mounted by TCP (tape carrier package) instead of being mounted by COG (chip on glass).

  Next, the manufacturing apparatus 70 of the organic EL panel DP (organic EL display device) configured as described above will be described in detail. The manufacturing apparatus 70 is an apparatus for inspecting the presence or absence of defective display pixels PX to improve (repair).

  As shown in FIG. 4, the manufacturing apparatus 70 includes a main body 71 having an anti-vibration function, a stage 72 movable in a first direction X, a second direction Y, and a third direction Z that are orthogonal to each other by the main body, A laser oscillator main body 73, a control unit 74 that can control the main body 71 and the laser oscillator main body 73, a CCD 75, and a monitor 76 are provided. The laser oscillator body 73 has an objective lens 73a as an optical system. The laser oscillator main body 73 can irradiate a laser. Information on the image of the laser irradiation location acquired by the laser oscillator main body 73 is transmitted to the monitor 76 via the CCD 75. Then, an image of the laser irradiation location is displayed on the monitor 76.

  Next, in order to improve the quality of defective display pixels using the manufacturing apparatus 70 configured as described above, a method for inspecting the presence or absence of a defective display pixel PX and cutting a portion causing a defect Will be described.

  First, an organic EL panel DP as a processing target is prepared. As shown in FIG. 5, in this embodiment, the case where the foreign matter 100 exists in the organic EL element EL2 of one or a plurality of display pixels PX of the organic EL panel DP will be described. The foreign material 100 exists between the anode 62 and the cathode 66. The foreign matter 100 contributes to a short circuit between the anode 62 and the cathode 66, and the organic EL element EL2 in which the foreign matter exists cannot emit light. In this case, the display pixel PX only emits light from the organic EL element EL1, causes a decrease in luminance level (gradation reproducibility), and becomes a defective display pixel.

  The foreign material 100 is a metal or an organic substance attached during the manufacturing process such as when the anode 62, the anode buffer layer 63, the organic light emitting layer 64, and the cathode 66 are formed. Further, in the vicinity of the foreign matter 100 attached, a thin film portion or a missing film occurs. That is, a portion where the organic light emitting layer 64 is formed thin or a portion where it is missing occurs. From the above, the anode 62 and the cathode 66 are short-circuited regardless of whether or not the foreign material 100 has conductivity.

  Next, the organic EL panel DP is transported, and the organic EL panel DP is disposed on the stage 72. At this time, the organic EL panel DP is arranged so that the laser oscillator main body 73 faces the insulating substrate 8. Thereafter, the organic EL panel DP is driven to cause all the organic EL elements EL1 and EL2 to emit light. Therefore, drive signals are output to all the organic EL elements EL1 and EL2. Then, the organic EL element in which the foreign substance 100 exists becomes a display defect (non-light emission), and the organic EL element with a display defect is detected by visual observation, for example.

Next, the stage 72 is moved so that the connection portion 22 of the pixel circuit 18b including the organic EL element EL2 which has caused a display defect and the objective lens 73a are opposed to each other.
As shown in FIG. 6, the connection portion 22 is disconnected from other wirings and electrodes. More specifically, the connection portion 22 is formed by the source of the output switch BCT2, and is disconnected from the output switch BCT2, the cancel switch TCT2, the changeover switch XT, and the drive transistor DRT2 in the first direction X. In the first direction X, the length L of the connecting portion 22 is 2 μm. In addition, if the length L of the connection part 22 is 2 micrometers or more, the cutting | disconnection by a laser beam can be performed favorably. In the second direction Y, the connection portion 22 is disposed with a distance from another wiring and electrode.

As shown in FIG. 7, subsequently, the laser oscillator main body 73 is used to irradiate the foreign material 100 with a predetermined laser beam via the objective lens 73a.
As shown in FIG. 8, the connection part 22 of the location irradiated with the laser beam is thereby cut off. And the cutting part 22a is formed in the connection part 22, and the connection part 22 is electrically insulated. When a plurality of defective display pixels PX are detected, laser irradiation may be performed for each pixel.

  Next, the operation of the display pixel PX when the organic EL elements EL1 and EL2 emit light (display an image) will be described. Here, the description will be made using the display pixel PX including the organic EL element EL2 having a display defect and the disconnected connection portion 22 in particular.

  In the organic EL display device configured as described above, the operation of the display pixel PX is divided into a reset operation, a cancel operation, a write operation, and a light emission operation as a display operation. These series of operations are performed, for example, in one vertical scanning period.

  FIG. 9 is a timing chart showing on / off timings of the control signals BG, RG, CG, SG, and XG, the reference voltage Vsig0, the video signal voltage Vsig1, and the reset voltage RS.

First, the reset operation will be described.
The reset operation is performed during the reset period t1.
FIG. 10 shows the display pixel PX in the reset period t1.

  As shown in FIGS. 1, 2, 9, and 10, in the reset operation, the scanning line driving circuit 14 sets the cancel switch TCT <b> 1 and the cancel switch TCT <b> 2 to an off state (off potential), which is a high level here. In the state where the control signal CG is being output, the control signal BG having an off potential for turning off the output switch BCT1 and the output switch BCT2 is output.

  At the same time, the write switch SST and the reset switch RST are turned on while a level (on potential) at which the changeover switch XT is turned on from the scanning line driving circuit 14, here, a low level control signal XG is output. The on-potential control signals SG and RG are output.

  For this reason, the output switches BCT1 and BCT2 are turned off, and the write switch SST and the reset switch RST are turned on. As a result, the gate potentials of the drive transistors DRT1 and DRT2 are set to the ON potential, and the electrode (lower electrode) on the write switch SST side of the first capacitor unit Ck is supplied from the scanning line drive circuit 14 to the video signal line VL and the write signal. The reference potential (Vsig0) is set by the reference voltage Vsig0 supplied via the switch SST.

Next, the cancel operation will be described.
The cancel operation is performed in a cancel period t2 following the reset period t1.
FIG. 11 shows the display pixel PX in the cancel period t2.

  As shown in FIGS. 1, 2, 9 and 11, in the cancel operation, the output of the off-potential control signal BG is maintained from the scanning line driving circuit 14 to the output switches BCT1 and BCT2, and the write switch SST and switching are performed. The outputs of the on-potential control signals SG and XG are maintained at the switch XT, the off-potential control signal RG is output to the reset switch RST, and the on-potential control signal CG is output to the cancel switches TCT1 and TCT2.

  For this reason, the reset switch RST is turned off and the cancel switches TCT1 and TCT2 are turned on. As a result, the gate and drain potentials of the drive transistors DRT1 and DRT2 are the same, and a cancel current flows through the drive transistors DRT1 and DRT2 while maintaining this state, and the voltage between the gate and source of the drive transistors DRT1 and DRT2 Gradually approaches the threshold voltage.

  In this embodiment, the voltage between the gate and source of the drive transistors DRT1, DRT2 reaches the threshold voltage, and the potential difference corresponding to the threshold voltage is held (stored) in the first capacitor Ck.

Next, the write operation will be described.
The write operation is performed in a write period t3 following the cancel period t2. Here, the total length of the reset period t1, the cancel period t2, and the writing period t3 is one horizontal scanning period (1H).
FIG. 12 shows the display pixel PX in the writing period t3.

  As shown in FIGS. 1, 2, 9, and 12, in the write operation, the output of the off-potential control signals BG and RG is maintained from the scanning line driving circuit 14 to the output switches BCT 1 and BCT 2 and the reset switch RST. Then, the output of the on-potential control signal SG is maintained in the write switch SST, and the off-potential control signal CG is output to the cancel switches TCT1 and TCT2.

  For this reason, the cancel switches TCT1 and TCT2 are switched off. Accordingly, the potential of the electrode (lower electrode) on the write switch SST side of the first capacitor unit Ck is determined by the video signal voltage Vsig1 supplied from the signal line drive circuit 15 via the video signal line VL and the write switch SST. It is displaced from the reference potential (Vsig0) to the video signal potential (Vsig1).

  That is, the video signal voltage Vsig1 corresponding to the gradation of the image displayed on the organic EL element EL1 is applied to the first capacitor Ck via the write switch SST and stored in the first capacitor Ck.

  Therefore, the gate potentials of the drive transistors DRT1 and DRT2 can be displaced by the potential for obtaining the gradation of the image. In other words, the gate potentials of the drive transistors DRT1 and DRT2 are set to a state where a desired light emission current can flow.

  When the display pixel PX is not defective, the video signal voltage Vsig1 corresponding to the gradation of the image displayed on the organic EL elements EL1 and EL2 is applied to the first capacitor Ck and stored in the first capacitor Ck.

Next, the light emission operation will be described.
The light emission operation is performed in a light emission period t4 as a display period following the writing period t3. The length of the light emission period t4 is, for example, from the start of the reset period t1 to the end of one vertical scanning period.
FIG. 13 shows the display pixel PX in the light emission period t4.

  As shown in FIG. 1, FIG. 2, FIG. 9, and FIG. 13, in the light emission operation, the output of the off-potential control signals CG, RG is maintained from the scanning line driving circuit 14 to the cancel switches TCT1, TCT2, and the reset switch RST. The on-potential control signal XG is maintained on the changeover switch XT, the off-potential control signal SG is output on the write switch SST, and the on-potential control signal BG is output on the output switches BCT1 and BCT2.

  For this reason, the write switch SST is turned off, and the output switches BCT1 and BCT2 are turned on. As a result, a drive signal is output from the drive transistor DRT1 to the organic EL element EL1, and a drive signal is output from the drive transistor DRT2 to the organic EL element EL1 via the changeover switch XT. In other words, a drive current corresponding to the gradation of the image displayed on the display pixel PX is given to the organic EL element EL1.

  If the display pixel PX is not defective, the drive signals from the drive transistors DRT1 and DRT2 are output to the organic EL elements EL1 and EL2. In other words, the drive current corresponding to the gradation of the image displayed on the display pixel PX is given to the organic EL elements EL1 and EL2.

  According to the organic EL display device, the organic EL display device manufacturing method, and the organic EL display device driving method configured as described above, the display pixel PX includes two pixel circuits 18a and 18b and one changeover switch XT. I have. When there is a display pixel PX having a defective display due to the defective organic EL element EL2, the connection portion 22 of the pixel circuit 18b including the defective organic EL element EL2 is cut and electrically insulated.

  Therefore, it is possible to prevent the drive signal from flowing from the drive transistors DRT1 and DRT2 to the organic EL element EL2. Thereby, all the drive signals from the drive transistors DRT1 and DRT2 can be output to the organic EL element EL1. That is, the drive current corresponding to the gradation of the image displayed on the display pixel PX is given to the organic EL element EL1. As described above, even in the display pixel PX having the defective organic EL element EL2, the gradation reproducibility of the display pixel PX can be improved.

  The connection portions 21, 22, 23, and 24 are formed of a polysilicon thin film or a metal thin film to which impurities are added at a high concentration. For this reason, a connection part can be easily cut | disconnected by a laser beam.

  The connecting portion 22 is disconnected from other wirings and electrodes. For this reason, the cutting | disconnection by a laser beam can be performed favorably. Note that the connection portions 21, 23, and 24 may also be provided away from other wirings and electrodes, similarly to the connection portion 22.

The output switches BCT1 and BCT2 are each formed of a P-channel transistor and are controlled to be opened and closed by a common control signal BG. Since the number of control signals can be reduced, power consumption can be reduced.
The cancel switches TCT1 and TCT2 are each formed of a P-channel transistor and are controlled to be opened and closed by a common control signal CG. Since the number of control signals can be reduced, power consumption can be reduced.

  From the above, it is possible to efficiently repair defective display pixels, improve the manufacturing yield, and have excellent gradation reproducibility, an organic EL display device manufacturing method, and an organic EL display device A driving method can be obtained.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

  For example, as shown in FIG. 14, a control signal XG at a level (off potential) that turns off the changeover switch XT may be output in the reset period t1, the cancel period t2, and the write period t3.

As shown in FIG. 15, the output switch BCT1 and the output switch BCT2 may be controlled to open and close independently. In this case, the organic EL panel DP includes a scanning line SL7 connected to the scanning line driving circuit 14. The gate of the output switch BCT2 is connected to the scanning line SL7. The output switch BCT1 is turned on / off in response to a control signal BG1 supplied from the scanning line SL1. The output switch BCT2 is turned on / off in response to the control signal BG2 supplied from the scanning line SL7.
By configuring the organic EL panel DP as described above, for example, it is effective in detecting defective organic EL elements.

  The pixel circuit 18 a only needs to have the connection portion 21 or the connection portion 23. The pixel circuit 18 b only needs to have the connection portion 22 or the connection portion 24. When the organic EL element EL1 is defective, at least one of the connection portion 21 and the connection portion 23 of the pixel circuit 18a including the defective organic EL element EL1 may be disconnected. When the organic EL element EL2 is defective, at least one of the connection portion 22 and the connection portion 24 of the pixel circuit 18b including the defective organic EL element EL2 may be disconnected.

  As shown in FIG. 16, the display pixel PX may include three or more pixel circuits and two or more changeover switches XT. For example, when the display pixel PX includes three pixel circuits 18a, 18b, and 18c, the display pixel PX includes two changeover switches XT.

  The pixel circuit 18c is formed in the same manner as the pixel circuits 18a and 18b, and includes a drive transistor DRT3, an output switch BCT3, a cancel switch TCT3, and connection portions 25 and 26.

  The changeover switch XT for connecting the pixel circuit 18b and the pixel circuit 18c is connected between the drains of the drive transistors DRT2 and DRT3 on the drain side of the drive transistors DRT2 and DRT3 from the connection portions 22, 24, 25, and 26, and between the drains. Is switched to a conductive state or a non-conductive state.

  Further, the circuit configuration of the display pixel PX is not limited to the above-described embodiment, and the above-described organic EL display device and the organic EL display device are applied to the display pixel PX having the same voltage signal method as the above-described embodiment. Even if the manufacturing method and the driving method of the organic EL display device are applied, it can be expected to obtain the same effect as the above-described embodiment.

The write switch SST, the changeover switch XT, the reset switch RST, the drive transistor DRT1, the output switch BCT1, the cancel switch TCT1, the drive transistor DRT2, the output switch BCT2, the cancel switch TCT2, and the like are not limited to P-channel transistors but N-channel type You may comprise by the transistor of.
The present invention is not limited to the organic EL display device, the organic EL display device manufacturing method, and the organic EL display device driving method, but the active matrix display device, the active matrix display device manufacturing method, and the active matrix type. Any display device driving method can be applied.

1 is a plan view schematically showing an organic EL display device according to an embodiment of the present invention. The figure which shows the equivalent circuit of the display pixel in the said organic EL display apparatus. Sectional drawing which shows the drive transistor and organic EL element of the said organic EL display apparatus. The schematic block diagram which shows the manufacturing apparatus of the said organic EL display apparatus. The expanded sectional view of the organic electroluminescent display which shows the state in which the foreign material existed in the said organic electroluminescent element. It is an enlarged plan view which shows a part of said organic EL element, and is a figure which shows a connection part especially. Sectional drawing of the organic electroluminescence display which shows the state which irradiates the laser beam to the said connection part. The figure which shows the equivalent circuit of the display pixel which shows the state by which the cutting part is formed in the said connection part. FIG. 4 is a timing chart showing on / off (high, low) timings of control signals in the driving method of the organic EL display device, and also shows a reference voltage, a video signal voltage, and a reset voltage. The figure which shows the equivalent circuit of the display pixel in the reset operation | movement of the said organic EL display apparatus. The figure which shows the equivalent circuit of the display pixel in the cancellation operation | movement of the said organic EL display apparatus. The figure which shows the equivalent circuit of the display pixel in the write-in operation | movement of the said organic EL display apparatus. The figure which shows the equivalent circuit of the display pixel in the light emission operation | movement of the said organic electroluminescence display. FIG. 10 is a timing chart showing a modification example of on / off (high, low) timing of a control signal in the driving method of the organic EL display device, and also shows a reference voltage, a video signal voltage, and a reset voltage. It is a figure which shows the modification of the display pixel of the said organic EL display apparatus, and is a figure which shows a display pixel by an equivalent circuit. It is a figure which shows the other modification of the display pixel of the said organic electroluminescence display, and is a figure which shows a display pixel by an equivalent circuit.

Explanation of symbols

  DP ... Organic EL panel, 10 ... Drive unit, 14 ... Scan line drive circuit, 15 ... Signal line drive circuit, VL ... Video signal line, SL1, SL2, SL3, SL4, SL5, SL6, SL7 ... Scan line, SLa ... Voltage power supply line, SLb ... Reference voltage power supply line SL, PX ... Display pixel, XT ... Changeover switch, RST ... Reset switch, 18a, 18b, 18c ... Pixel circuit, SST ... Write switch, EL1, EL2 ... Organic EL element, Ck ... 1st capacity part, Cs ... 2nd capacity part, DRT1, DRT2, DRT3 ... Drive transistor, BCT1, BCT2, BCT3 ... Output switch, TCT1, TCT2, TCT3 ... Cancel switch, 21, 22, 23, 24, 25, 26 ... Connecting part, 22a ... Cutting part, 62 ... Anode, 64 ... Organic light emitting layer, 66 ... Cathode, 70 ... Manufacturing apparatus, 100 ... Thing, t1 ... reset period, t2 ... cancellation period, t3 ... writing period, t4 ... light emission period, BG, BG1, BG2, RG, CG, SG, XG ... control signal, RS ... reset voltage, Vsig0 ... reference voltage, Vsig1 ... Video signal voltage.

Claims (9)

Multiple video signal lines;
A plurality of display pixels connected to each of the video signal lines,
Each display pixel is
A driving transistor that outputs a driving signal corresponding to an image to be displayed; a display element that receives the driving signal and displays an image corresponding to the driving signal; and a drain and a display element of the driving transistor, and An output switch for switching whether or not to output a drive signal to the display element; and a connection portion formed so as to be electrically disconnected between at least one of the drain and the output switch of the drive transistor and between the output switch and the display element; A plurality of pixel circuits including
At least one changeover switch that is connected between the drains of the plurality of drive transistors on the drain side of the plurality of drive transistors from the plurality of connection portions, and switches between the plurality of drains to a conductive state or a non-conductive state;
An active matrix display device having a capacitor connected to gates of the plurality of drive transistors. Each of the output switches is
A source connected to a drain of the driving transistor;
A drain connected to the display element,
2. The active matrix display device according to claim 1, wherein the source or drain of each output switch is formed of a polysilicon thin film or a metal thin film to which an impurity is added at a high concentration, and has the connection portion.   The active matrix display device according to claim 2, wherein the connection portion is disconnected from other wirings and electrodes.   The active matrix display device according to claim 3, wherein a length of the connection portion is 2 μm or more.   6. The active matrix display device according to claim 5, wherein the plurality of drive transistors of each display pixel are of the same conductivity type. A drive unit for switching the changeover switch to a conductive state or a non-conductive state;
The connection portion has a cut display pixel,
In the display period, the drive unit switches the changeover switch to a conductive state, and causes the display element of the pixel circuit in which the connection unit is not disconnected to output a drive signal from the drive transistor of the same pixel circuit, 2. The active matrix display device according to claim 1, wherein another drive signal is output from the drive transistor of the pixel circuit in which the connection portion is disconnected through the changeover switch. The plurality of output switches of each display pixel are formed identically,
The active matrix display device according to claim 6, wherein the driving unit simultaneously controls opening and closing of the plurality of output switches of the display pixels by a common control signal. A plurality of video signal lines; and a plurality of display pixels connected to each video signal line, wherein each display pixel outputs a drive signal corresponding to an image to be displayed, and the drive signal A display element that displays an image corresponding to the drive signal, an output switch that is connected to a drain and a display element of the drive transistor, and switches whether to output the drive signal to the display element, and the drive transistor A plurality of pixel circuits including a connection portion formed so as to be electrically disconnectable between at least one of the drain and the output switch and between the output switch and the display element, and the plurality of drives from the plurality of connection portions. The drain side of the transistor is connected between the drains of the plurality of driving transistors, and the plurality of drains are in a conductive state or are connected. At least one changeover switch switches non-conductive, in the manufacturing method of the active matrix display device having a, a capacitor section connected to a gate of said plurality of driving transistors,
A drive signal is output to the plurality of display elements, and whether or not a defect has occurred in the display elements,
A method for manufacturing an active matrix display device, wherein when the display element is defective, the connection portion of the pixel circuit including the defective display element is cut.   The method for manufacturing an active matrix display device according to claim 8, wherein when the connection portion is cut, the connection portion is irradiated with a laser beam to cut the connection portion.

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