JP2006184898A - Programming circuit and light emitting device using it, and display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize the programming for the control electrode of a drive transistor even when the data signals are small by suppressing the effects of the characteristic differences even when the transistors in each circuit have different characteristics. <P>SOLUTION: This programming circuit programs the signals for the circuit groups 61, 62 having circuits with the 1st switch elements M21, M22 connected to the control electrodes of the transistors M11, M12, and the 2nd switch elements M31, M32 connected to the main electrodes of the transistor. It has current generator circuits M3 and M4 connected with the 2nd switch elements in common for generating current matching the current in the transistors of the selected circuit, and an operational amplifier OPAMP1 connected with the 1st switch elements in common for supplying programming signals to the control electrodes of the transistor of the selected circuit. Data signals and the signal matching the current generated by the current generator circuit are inputted to the operational amplifier. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light emitting device used for a display device such as a digital still camera, a digital video camera, a television receiver, a personal computer, an exposure device of an electrophotographic printer, and a programming circuit used therefor.

  As the light emitting device, an active matrix display device will be described as an example. FIG. 5 shows a circuit configuration of an active matrix display device described in Patent Document 1.

  The pixel circuit 1 is configured by connecting a driving transistor T1, switching elements T2, T3, and T4, a storage capacitor C, and an organic EL element OLED as a light emitting element as shown in the figure.

  The gate of the drive transistor T1 is connected to the data line drive circuit 3 via the switch element T2. The drain of the drive transistor T1 is connected to the data line Id via the switch element T3.

  The data line driving circuit 3 includes a constant current source I11 and a source follower transistor T9.

  Vdd is a drive power supply line connected to the source of the drive transistor T1. SA is a selection line that supplies a selection signal for exclusively turning on or off one of the switch elements T3 and T4, and SC is another selection line that supplies a selection signal for turning on or off the switch element T2. is there.

  When the switch elements T2 and T3 are turned on, a programming voltage corresponding to the amount of current supplied to the data line Id is output from the source of the transistor T9 and applied to the gate of the drive transistor T1. Next, when the switch element T2 is turned off, the programming voltage is stored in the storage capacitor C. Further, the switch T4 is turned on, a current corresponding to the programming voltage stored in the storage capacitor is supplied from the drive transistor T1 to the organic EL element OLED, and the organic EL element OLED emits light. Here, the video data current is input to the data line driving circuit 3 functioning as a voltage buffer so that the setting operation period can be shortened even if the video data current supplied to the data line Id is a small current.

  FIG. 6 shows a circuit configuration of an active matrix display device described in Patent Document 2.

  Here, the data line driving circuit 2 has an operational amplifier AMP1, and is configured such that the reference voltage Vr is input to the inverting input terminal of the operational amplifier and the video data current is input to the non-inverting input terminal. ing.

  Further, the pixel circuit 1 has a reset switch element T5. When the programming voltage is written, the reset switch element T5 is turned on together with the switch element T2 to reset the organic EL element OLED.

  This display device uses a p-channel field effect transistor having the same conductivity type as the switch element T3 and the switch element T4. Therefore, the two selection lines SA and SB are used to drive and control the switch elements T3 and T4 so that they are exclusively turned on or off.

  FIG. 7 shows a circuit configuration of an active matrix display device described in Patent Document 3.

Here, it is configured such that the same amount of current as that flowing in the driving transistor T1 is caused to flow to the resistor R2 via the switch element T14 by the current mirror circuit including the transistors T12 and T13 provided in the pixel circuit 1. ing. Thus, the current flowing through the driving transistor T1 is detected and input to the inverting input terminal of the operational amplifier AMP1. On the other hand, the voltage Vr converted from the video data current Id by the resistor R1 is input to the non-inverting input terminal of the open amplifier AMP1. When the voltages Vr and Vm have the same voltage value, the current flowing through the drive transistor T1 and the organic EL element OLED becomes a desired value corresponding to the video data current Id. At this time, the output voltage of the operational amplifier AMP1 is written to the gate of the drive transistor T1 as a write voltage via the switch elements T7 and T2. Even when the switch element T2 is turned off, the organic EL element OLED continues to emit light according to the write voltage stored in the storage capacitor C. Here, the switch elements T6 and T8 and the reset power source Vs are used when setting the initial voltage of the anode of the organic EL element OLED.
JP 2004-118181 A JP 2003-043993 A Japanese Patent Laid-Open No. 2003-140613

  However, in the circuit of FIG. 7, a drive current flows through the organic EL element during a write operation using a video data current.

  In addition, since a current mirror circuit is provided in each pixel circuit, the detected monitor current Im varies depending on the pixel circuit even if the same drive current is supplied to the drive transistor T1. As a result, the write voltage to the gate of the drive transistor T1 is different for each pixel circuit.

  An object of the present invention is to provide a programming device that can suppress the influence of transistors even if the characteristics of the transistors differ from circuit to circuit.

  Another object of the present invention is to provide a programming device capable of stabilizing a programming operation to a control electrode of a driving transistor even when a data signal is small.

  Another object of the present invention is to provide a light emitting device that is unlikely to cause a difference in light emission amount for each light emitting element when video data having the same luminance level is input.

The programming circuit of the present invention comprises:
In a circuit group including a plurality of circuits each including a transistor, a first switch element having one terminal connected to the control electrode of the transistor, and a second switch element connected to one main electrode of the transistor, In a programming device for programming
A current generating circuit connected in common to each second switch element of the circuit group for generating a current corresponding to a current flowing through the transistor of the selected circuit;
An operational amplifier connected in common to each first switch element of the circuit group for supplying a programming signal to a control electrode of the transistor of the selected circuit;
Comprising
The operational amplifier is configured such that a data signal is input to one input terminal and a signal corresponding to the current generated by the current generation circuit is input to the other input terminal.

The light emitting device of the present invention is
A plurality of light emitting elements;
A driving transistor composed of a thin film transistor having an active layer of a non-single-crystal semiconductor for driving the corresponding light emitting element, a first switch element having one terminal connected to a control electrode of the driving transistor, A circuit group including a plurality of circuits each having a second switch element connected to one main electrode;
A programming circuit for programming signals in the circuit group;
Comprising
The programming circuit is:
A current generation circuit connected in common to each second switch element of the circuit group for generating a current corresponding to a current flowing through the drive transistor of the selected circuit;
An operational amplifier connected in common to each first switch element of the circuit group for supplying a programming signal to a control electrode of the drive transistor of the selected circuit;
Have
The operational amplifier is configured such that a data signal is input to one input terminal and a signal corresponding to the current generated by the current generation circuit is input to the other input terminal.

The display device of the present invention includes:
A pixel portion having a plurality of light emitting elements;
A driving transistor composed of a thin film transistor having an active layer of a non-single-crystal semiconductor for driving the corresponding light emitting element, a first switch element having one terminal connected to a control electrode of the driving transistor, A drive circuit unit comprising a plurality of drive circuits having a second switch element connected to one main electrode;
A programming circuit for programming signals in the drive circuit unit;
Comprising
The programming circuit is:
A current generation circuit that is connected in common to each second switch element of the drive circuit unit and generates a current corresponding to a current flowing through the drive transistor of the selected drive circuit;
An operational amplifier connected in common to each first switch element of the circuit group for supplying a programming signal to a control electrode of the drive transistor of the selected drive circuit;
Have
The operational amplifier is configured such that a data signal is input to one input terminal and a signal corresponding to the current generated by the current generation circuit is input to the other input terminal.

  According to the present invention, a current generating circuit is provided in a programming circuit common to each circuit. Then, a programming signal is determined for the control electrode of the drive transistor so that the data signal input to one input terminal of the operational amplifier is proportional to the signal based on the current input from the current generation circuit. In this way, even if the characteristics of the drive transistor are different among a plurality of circuits, the influence can be suppressed. Even when the data signal is small, the programming operation to the control electrode of the drive transistor can be stabilized.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
The present embodiment is an active matrix display device that includes a programming circuit according to the present invention, a pixel circuit configured by combining a driving circuit and a light emitting element, and the pixel circuits are two-dimensionally arranged.

  FIG. 1 shows two pixel circuits 61 and 62 and a programming circuit 31. FIG. 2 is a driving timing chart for three rows of pixel circuits. FIG. 3 is a block diagram of the display device.

  In the present embodiment, pMOS transistors M11 and M12, which are a kind of field effect transistor (FET), correspond to the drive transistor, the control electrode is its gate, and the main electrode is its source and drain. Further, nMOS transistors M21 and M22, which are a kind of field effect transistors, correspond to the first switch element, and nMOS transistors M31 and M32 correspond to the second switch element. The current generation circuit corresponds to a current mirror circuit composed of nMOS transistors M3 and M4.

  To explain the basic operation, a data voltage signal is inputted to one input terminal of the operational amplifier OPAMP1. This data voltage signal is a signal obtained by converting the data current by the nMOS transistor M1. The other input terminal receives the current from the current generation circuit after being converted into a voltage by the nMOS transistor M2.

  The operational amplifier generates an output signal corresponding to the input difference. An output signal from the operational amplifier is input to the gate of the pMOS transistor M11 or M12 via the auxiliary data line xxx and the nMOS transistor M21 or M22. In the pMOS transistor M11 or M12, a current flows between the source and the drain in accordance with the gate voltage. Thus, a current corresponding to the gate voltage of the pMOS transistor M11 or M12 flows to the nMOS transistor M4 of the current mirror circuit via the feedback data line yyy.

  A mirror current flows through the nMOS transistor M3. This current is converted into a voltage by the nMOS transistor M2 and input to the input terminal of the operational amplifier.

  Here, the nMOS transistors M3 and M4 constituting the current mirror circuit have the same size and a mirror ratio of 1: 1. Further, the nMOS transistors M1 and M2 have the same size and the same current-voltage conversion ratio. In this way, feedback is applied so that the current flowing through the pMOS transistor M11 or M12 has the same current value as the input data current Idata.

  Thus, even if there is a difference in the source / drain current characteristics with respect to the gate voltage between the pMOS transistors M11 and M12, the same source / drain current as the data current data is obtained.

  This will be described in detail below. As shown in FIG. 1, for the first row pixel circuit to the nth row pixel circuit (n is a positive natural number of 2 or more) (here, only the first row and second row pixel circuits are shown), An auxiliary data line xxx and a feedback data line yyy are provided.

  The configuration of the pixel circuit will be described by taking the pixel circuit 61 in the first row as an example. The pixel circuit 61 in the first row includes a light emitting element EL1 and a pMOS transistor M11 serving as a driving transistor that controls a current flowing through the light emitting element EL1. The source of the pMOS transistor M11 is connected to a voltage source that supplies the voltage Vcc, and a capacitor C11 is provided between the source and gate. Further, an nMOS transistor 21 whose drain is connected to the gate of the pMOS transistor M11 as a switching element, and an nMOS transistor 31 provided between the drain of the pMOS transistor M11 and the feedback data line yyy are provided. Further, a pMOS transistor 41 as a switch element is provided between the drain of the pMOS transistor M11 and the light emitting element EL1. A source / drain current of the pMOS transistor M11 flows through the feedback data line yyy.

  The nMOS transistor M21 is on / off controlled by the scanning signal P21, and the nMOS transistor M31 and the pMOS transistor M41 are on / off controlled by the scanning signal P11. A row (pixel circuit) selected by these scanning signals is determined.

  The programming circuit includes a current-voltage conversion circuit, an operational amplifier, and a current generation circuit. The current-voltage conversion circuit includes nMOS transistors M1 and M2. In the nMOS transistor M1, the gate and the source are short-circuited to be connected to a voltage source that supplies the voltage Vcc, and the drain is connected to the data line and the non-inverting input terminal (+) of the operational amplifier. The nMOS transistor M2 has its gate and source short-circuited and connected to a voltage source that supplies the voltage Vcc, and its drain connected to the source of the nMOS transistor M3 and the inverting input terminal (−) of the operational amplifier. The current generating circuit is formed of a current mirror circuit including an nMOS transistor M3, an nMOS transistor M3, and an nMOS transistor M4 which is connected to the feedback data line with the gates connected to each other and the source and gates short-circuited.

  The data current flowing through the data line is converted into a voltage and input to the non-inverting input terminal (+) of the operational amplifier, and the feedback current flowing through the feedback data line is converted into a voltage and input to the inverting input terminal (−) of the operational amplifier. Is done. Based on the voltage difference, the operational amplifier causes a constant current I1 to flow through the auxiliary data line and sets the gate potential of the pMOS transistor M11 so that the source / drain current of the pMOS transistor M11 is equal to the data current. Thus, a signal is programmed to the gate of the pMOS transistor M11, that is, the capacitor C11.

  Next, the operation of the display device of the present invention will be described with reference to FIGS.

  In FIG. 3, reference numeral 6 denotes a pixel circuit unit composed of a group of pixel circuits arranged in a two-dimensional matrix. Reference numeral 7 denotes a row scanning circuit (m is a positive natural number) which is connected to pixel circuits arranged in the row direction (vertical direction) and sequentially outputs a row scanning signal P1m and a row scanning signal P2m to the pixel circuit for each row. A programming circuit 8 receives the video data current Idata and the feedback current, controls the gate potential of the driving transistor, and controls the feedback current to be equal to the video data current Idata. The programming circuit 8 has a circuit indicated by reference numeral 31 in FIG. 1 for each pixel circuit column. A column current control circuit 9 sequentially supplies the video data current Idata to data lines arranged in the column direction (horizontal direction). A column scanning circuit 91 is connected to the column current control circuit 9 and causes the column current control circuit to sequentially sample video signals input in time series.

  1 and 2, assuming that n = 2, the row scanning signal P11 becomes high level during the first row selection period of the pixel circuit 61 in the first row. Then, the nMOS transistor M31 serving as the first program (row selection) switch connected to the feedback data line yyy is turned on, and the pMOS transistor M41 serving as the light emission selection switch is turned off. Next, the row scanning signal P21 becomes high level. Then, the nMOS transistor M21 serving as the first program switch connected to the auxiliary data line xxx connected to the operational amplifier is turned on, and the output of the operational amplifier is applied to the gate of the pMOS transistor M11. At this time, a data voltage corresponding to the data current is applied to the non-inverting input terminal (+) of the operational amplifier. On the other hand, a voltage corresponding to the current of the feedback data line is applied to the inverting input terminal (−) of the operational amplifier. If the voltage at the inverting input terminal (−) is larger than the data voltage at the non-inverting input terminal (+), the operational amplifier raises the gate potential of the pMOS transistor M11 based on the difference, so that the source / drain current decreases. . Conversely, if the voltage at the inverting input terminal (−) is smaller than the data voltage at the non-inverting input terminal (+), the operational amplifier lowers the gate potential of the pMOS transistor M11 based on the difference, so that the source / drain current is reduced. descend. In this way, the source / drain current of the pMOS transistor M11 is controlled to be equal to the data current. The voltage of the capacitor C1 connected to the gate of the pMOS transistor M11 is set to a gate-source voltage sufficient for the current for driving the light emitting element EL to flow through the pMOS transistor M11 based on the video data current flowing through the data line. The Next, when the row scanning signal P21 becomes low level, the nMOS transistor M21 is turned off and the voltage of the capacitor C1 is held. The period so far is the selection period (drive current programming period) of the first row.

  Thereafter, when the row scanning signal P11 becomes low level, the nMOS transistor M31 is turned off and the pMOS transistor M41 serving as a light emission selection switch is turned on. The supply of drive current to the light emitting element EL1 is controlled by the gate potential of the drive transistor M11, and the current flowing through the light emitting element EL1 is controlled. A period during which current is supplied to the light emitting element EL (no current is supplied in the case of black display) is a light emission period (non-light emission in the case of black display). When the selection period for the first row ends, the selection period for the second row starts, and a drive control signal is sequentially written into the pixel circuit based on the video data signal during the selection period for each row. That is, this pixel circuit can display a still image or a moving image by repeating a programming period and a light emission period in units of rows.

  In the present embodiment, the gate potential of the drive transistor M11 is controlled by the constant current I1 that is not directly related to the data current, and the operation when the data current is small is improved. The gate potential of the driving transistor M11 is controlled through an auxiliary data line. Therefore, although there is a parasitic capacitance Cx in the auxiliary data line xxx, even if the data current is a small current, the current flowing through the auxiliary data line is a constant current. Therefore, the influence of the parasitic capacitance can be reduced as compared with the case where a small current is passed directly from the data line to the gate of the driving transistor M11. The feedback data line yyy also has a parasitic capacitance Cy, but the feedback current is received by the diode-connected MOS transistor M4 of the current generation circuit, so that the influence can be reduced.

  Note that the capacitors C11 and C12 of the pixel circuit may be individually formed as capacitive elements. Alternatively, a parasitic capacitance formed between the gate and the source, for example, an overlapping capacitance between the gate electrode and the source region may be used without being formed as an individual element.

  The programming device of the present invention writes the voltage between the source and gate of the drive transistor according to the data current value by the above-described operation. A source-drain current corresponding to the source-gate voltage can be taken out. The current driven element can be driven by the source / drain current. Specifically, the current-driven element includes an organic electroluminescence element, an inorganic LED, an organic LED, and a surface conduction electron-emitting element. The current driven element may be a heating resistor element such as an electrothermal converter.

  If the pixel circuits are arranged in a one-dimensional or two-dimensional array, a light emitting device or a display device can be configured.

  Such a light emitting device can constitute an active matrix display device. Further, this light emitting device can be combined with a photoconductor to constitute an image recording apparatus such as an electrophotographic printer.

  The active matrix display device can be used for a viewer used in a flat-screen television, a digital camera, a digital video camera, or the like, a display unit of a mobile phone, or the like.

It is also possible to construct a pixel circuit using an electron-emitting device, arrange it two-dimensionally on a substrate, and configure an image display device facing a phosphor in a vacuum container (Japanese Patent Laid-Open No. 2-257551, (See JP-A-4-28137)
The driving transistor, the transistor serving as each switch element, and the transistor constituting the operational amplifier according to the embodiment of the present invention described above are preferably formed of a thin film transistor having a non-single crystal semiconductor active layer. As the non-single crystal semiconductor, amorphous silicon, polycrystalline silicon, or the like is preferably used. When an active layer (channel) of a thin film transistor is formed using these non-single-crystal semiconductors, a large-area device can be manufactured at a lower cost than when a single-crystal semiconductor is used. On the other hand, a thin film transistor of a non-single-crystal semiconductor tends to have characteristics that characteristics such as a threshold value and gain are not uniform for each transistor. Therefore, the present invention is effective when at least a driving transistor is constituted by such a thin film transistor. The gate insulating film of the transistor does not need to be an oxide film, and may be a nitride such as silicon nitride.

  The current mirror circuit constituting the current generating circuit used in the present invention is not limited to the illustrated mirror circuit, and various known mirror circuits can be used. The mirror ratio does not need to be 1: 1, and the mirror ratio can be appropriately selected in relation to the input data current.

  Furthermore, the current-voltage conversion circuit used in the present invention does not need to be configured by a diode-connected transistor, and may be a resistor.

(Embodiment 2)
In this embodiment, an electrophotographic scanner is configured as a light emitting device by arranging pixel circuits in a one-dimensional array.

  As shown in FIG. 4, image data of each color of Ye (yellow), Cy (cyan), Mg (magenta), and BK (black) is input to four OLED (organic EL) scanners 12 via the controller IC 12, and the OLED The scanner 12 emits light, and the photosensitive member 10 such as a photosensitive belt or a photosensitive drum is exposed. The OLED scanner 12 is provided with a pixel circuit row as shown in FIG. 1 and a programming circuit 31 provided for each row on the TFT circuit board 13, and further, a column current control circuit 9 and a column scanning circuit 91 as shown in FIG. Is provided. The light emitting element array 14 is linearly arranged, and the modulated light exposes the photoconductor 10 sequentially for each line. A light guide 15 such as a gradient index lens array is provided between the light emitting element array 14 and the photosensitive member 10 as necessary.

  With the above configuration, the image data of each color is exposed to the moving photoconductor. The photoconductor rotates and is developed with toner of each color applied by a developing device (not shown) for each color, and the toner images are sequentially transferred onto paper in the order of Ye, Cy, Mg, Bk, and then fixed by the fixing device. Let it settle. Such a configuration can be used for an electrophotographic printer (optical printer), a copier combined with an image sensor, and the like.

(Embodiment 3)
In this embodiment, a programming device is used for an analog memory.

  For this purpose, in the pixel circuit of FIG. 1, a third scanning selection line is provided in order to control the on / off of the pMOS transistors M41 and M42 with a signal different from the signals P11 and P12 without the light emitting elements EL1 and EL2. To construct a circuit. The light emitting elements EL1 and EL2 may be omitted, and a load such as a dummy resistor may be provided instead.

  With the circuit configured as described above, a signal corresponding to the data current value can be stored (programmed) as the source-gate voltage of the pMOS transistors M11 and M12, that is, the accumulated voltage of the capacitors C11 and C12.

  The current signal written from the pMOS transistors M11 and M12 is taken out to function as an analog memory.

  By arranging unit circuit portions corresponding to the pixel circuits having such a circuit configuration in a one-dimensional or two-dimensional manner, it can be used as an analog line memory or an analog field memory.

It is a figure which shows the circuit structure of the light-emitting device using the programming circuit by one Embodiment of this invention. 2 is a timing chart for explaining the operation of the light emitting device of FIG. 1. It is a figure which shows the structure of the display apparatus by one Embodiment of this invention. It is a figure which shows the structure of the exposure apparatus for electrophotographic printers in which the light-emitting device of this invention is used. It is a circuit diagram of the conventional display apparatus. It is a circuit diagram of another conventional display device. It is a circuit diagram of the other conventional display apparatus.

Explanation of symbols

31 Programming circuit 61, 62 Pixel circuit M11, M12 Drive transistor M21, M22 First switch element M31, M32 Second switch element OPAMP1 operational amplifier

Claims (11)

In a circuit group including a plurality of circuits each including a transistor, a first switch element having one terminal connected to the control electrode of the transistor, and a second switch element connected to one main electrode of the transistor, In a programming circuit for programming
A current generating circuit connected in common to each second switch element of the circuit group for generating a current corresponding to a current flowing through the transistor of the selected circuit;
An operational amplifier connected in common to each first switch element of the circuit group for supplying a programming signal to a control electrode of the transistor of the selected circuit;
Comprising
The operational amplifier is configured such that a data signal is input to one input terminal and a signal corresponding to the current generated by the current generation circuit is input to the other input terminal. circuit.   The programming circuit according to claim 1, further comprising a current-voltage conversion circuit that converts a current generated by the current generation circuit into a voltage and converts an input data current into a voltage signal as the data signal.   The programming circuit according to claim 2, wherein the current-voltage conversion circuit includes a pair of transistors in which one of the main electrodes and the control electrode are short-circuited.   The programming circuit according to claim 1, wherein the current generation circuit includes a current mirror circuit.   The programming circuit according to claim 1, wherein the transistor is a thin film transistor having an active layer of a non-single crystal semiconductor. In the light emitting device,
A plurality of light emitting elements;
The programming circuit of claim 1;
Have
A light-emitting device, wherein the corresponding light-emitting element is driven by the transistor.   The light emitting device according to claim 6, wherein the light emitting element is an organic electroluminescence element. In the display device,
A plurality of light emitting elements arranged in a two-dimensional matrix;
The programming circuit of claim 1;
Have
A display device, wherein the corresponding light emitting element is driven by the transistor.   The display device according to claim 8, wherein the light emitting element is an organic electroluminescence element. A plurality of light emitting elements;
A driving transistor composed of a thin film transistor having an active layer of a non-single-crystal semiconductor for driving the corresponding light emitting element, a first switch element having one terminal connected to a control electrode of the driving transistor, A circuit group including a plurality of circuits each having a second switch element connected to one main electrode;
A programming circuit for programming signals in the circuit group;
In a light emitting device comprising:
The programming circuit is:
A current generation circuit connected in common to each second switch element of the circuit group for generating a current corresponding to a current flowing through the drive transistor of the selected circuit;
An operational amplifier connected in common to each first switch element of the circuit group for supplying a programming signal to a control electrode of the drive transistor of the selected circuit;
Have
The operational amplifier is configured such that a data signal is input to one input terminal and a signal corresponding to the current generated by the current generation circuit is input to the other input terminal. apparatus. A pixel portion having a plurality of light emitting elements;
A driving transistor composed of a thin film transistor having an active layer of a non-single-crystal semiconductor for driving the corresponding light emitting element, a first switch element having one terminal connected to a control electrode of the driving transistor, A drive circuit unit comprising a plurality of drive circuits having a second switch element connected to one main electrode;
A programming circuit for programming signals in the drive circuit unit;
In a display device comprising:
The programming circuit is:
A current generation circuit that is connected in common to each second switch element of the drive circuit unit and generates a current corresponding to a current flowing through the drive transistor of the selected drive circuit;
An operational amplifier connected in common to each first switch element of the circuit group for supplying a programming signal to a control electrode of the drive transistor of the selected drive circuit;
Have
The operational amplifier is configured such that a data signal is input to one input terminal and a signal corresponding to the current generated by the current generation circuit is input to the other input terminal. apparatus.

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