JP2003022049A - Circuit, driver circuit, organic electroluminescent display device, electro-optical device, electronic apparatus, method of controlling current supply to organic electroluminescent pixel and method for driving circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an EL pixel driving circuit which operates in stages that comprise a programming stage and a reproduction stage. SOLUTION: The EL pixel driving circuit comprises a plurality of current paths each of which passes through the circuit, a current driven element, a transistor connected so as operatively to control the current supplied to the element, a capacitor connected for storing an operating voltage of the transistor during the programming stage, and switching means which control the current paths, and the arrangement is such that one of the current paths does not include the element. No current is applied to the current driven element by the current controlling transistor during the programming stage and thus the overall power consumption is reduced. Furthermore, the circuit can be operated from a normal supply voltage rather than requiring a high bias voltage. During the programming stage, the circuit uses a current sink rather than a current source.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention particularly relates to a driving circuit. One characteristic application of this drive circuit is a circuit for driving pixels of an organic electroluminescence device.

[0002]

2. Description of the Related Art Organic electroluminescence (OE)
The L) element includes a light emitting material layer sandwiched between an anode layer and a cathode layer. This element electrically operates like a diode. This element optically emits light when forward biased, and its emission intensity increases as the forward bias current increases. It is possible to construct a display panel using a matrix of organic electroluminescent elements built on a transparent substrate while having at least one transparent electrode layer. By using low temperature polysilicon thin film transistor (thin film transistor) technology, a drive circuit can also be integrally provided on this panel.

The basic analog drive scheme for active matrix organic electroluminescent displays, in principle, requires at least two transistors per pixel (FIG. 1). T1 selects the pixel,
T2 converts the data voltage signal into a drive current for causing the organic electroluminescence element (OELD) to emit light with a specified brightness. The data signal is a storage capacitor when a pixel is not selected.
r) Saved in Cstorage. Although a P-channel type thin film transistor is shown in each figure, the same principle can be applied to a circuit using an N-channel type thin film transistor.

There is a problem with thin film transistor analog circuits, and organic electroluminescent devices do not behave exactly like diodes. But,
Luminescent materials have relatively uniform properties. Due to the thin film transistor manufacturing method, there is a spatial variation in the characteristics of the thin film transistor in the entire panel. One of the most important considerations in thin film transistor analog circuits is the variation in threshold voltage ΔVt between devices. Variations in such organic electroluminescent displays due to the lack of complete diode-like behavior result in non-uniform pixel brightness across the display panel. This significantly impairs the image quality. Therefore, a built-in circuit for compensating for variations in transistor characteristics is needed.

The circuit shown in FIG. 2 is one of built-in circuits for compensating for variations in transistor characteristics. In this circuit, T1 is for selecting a pixel. T2 functions as an analog current control,
Supply drive current. T3 connects the drain and gate of T2 and switches T2 to a diode or saturated state. T4 operates as a switch. T1 and T4
Is turned on at any one time. In the initial state, T1 and T3 are off and T4 is on. When T4 is turned off, T1 and T3 are turned on, and a current having a predetermined (known) value can flow into the organic electroluminescence device (OELD) via T2. The threshold voltage of T2 is measured with T2 operating as a diode (T3 on),
At this time, a programming current can flow into the organic electroluminescent device via T1 and T2. This is the programming stag
e). T3 shorts the drain and gate of T2, switching T2 to the diode state. The threshold voltage detected at T2 is stored in the capacitive element C1 connected between the gate and source terminals of T2 when T3 and T1 are off. When T4 turns on, this time VDD
Supplies current. As long as the output characteristic has a flat slope, no matter what the threshold voltage of T2 is detected, the reproduction current (reproduced current)
current) will be equal to the program current. T4
By turning on, the drain-source voltage of T2 is raised, and as a result, the flatness of the output characteristics keeps the reproduction current equal to the program current. Note that ΔVT2 shown in FIG. 2 is virtual and not real.

In the timing chart of FIG. 2, t2 to t5
In the active programming stage shown by the range, theoretically, a constant current is supplied. The reproduction stage starts at t6.

[0007]

Although the circuit of FIG. 2 is effective, there is still a need for reduced power consumption. In particular, to provide a current source in the circuit of FIG.
A bias voltage VBIAS is required in addition to the supply voltage VDD. The supply voltage VDD can be increased to the required bias voltage VBIAS. This has the effect of reducing the number of components, but at any value the data current (I
Even when programming DAT) the overall system power consumption still increases.

The present invention notes the fact that all the current passing through the circuit of FIG. 2 passes through the organic electroluminescent device. How important this is for the present invention will become apparent from the following description.

[0009]

According to a first aspect of the present invention, there is provided a drive circuit operating in a stage having a programming stage and a reproduction stage, said circuit comprising a plurality of circuits each passing through said circuit. A current path, a current drive element, and a transistor connected to operate for controlling the current supplied to the element,
The circuit configuration includes a capacitive element connected to store an operating voltage of the transistor during a programming stage and a switch means for controlling the current path.
e arrangement), a drive circuit is provided in which one of the current paths does not include the element.

According to a second aspect of the present invention, there is provided a drive circuit for driving a pixel of an EL (electroluminescence) device, wherein the pixel has an electroluminescence element, and the circuit has the electroluminescence. A transistor connected to operate for controlling the current supplied to the element, a capacitive element connected to store the operating voltage of the transistor during the programming stage, and an operating element during the programming stage,
First for producing a current path through the transistor
Switch means and second switch means for producing a current path through the transistor and the electroluminescent element during operation during the reproduction stage, the first switch means comprising: A drive circuit is provided in which a current path is connected so as not to pass through the electroluminescence element.

According to a third aspect of the present invention, there is provided a drive circuit for driving a pixel of an electroluminescence device, wherein the pixel has an electroluminescence element, and the circuit supplies the electroluminescence element. A transistor connected to operate for control of a current being supplied, a capacitive element connected to store an operating voltage of the transistor during a programming stage, and a transistor passing through the transistor during operation during the programming stage. And a first switch means for generating a current path to operate, and during operation during the reproduction stage,
A second switch means for producing a current path through the transistor and the electroluminescent element, and a current sink, wherein the first switch means is configured such that the current path in the programming stage is the A drive circuit is provided, which is connected through a transistor to a current sink.

According to a fourth aspect of the present invention, there is provided a method of controlling a current supply to an electroluminescent device, the method comprising: providing a current path that does not pass through the electroluminescent device during a programming stage; Providing a current path through the electroluminescent device during a production stage.

According to a fifth aspect of the present invention, there is provided a method of controlling current supply to an electroluminescent device, the method comprising: providing a current path connected to a current sink during a programming stage; Providing a current path through the electroluminescent device during a production stage.

According to a sixth aspect of the present invention, there is provided an electroluminescent display device comprising one or more drive circuits according to any one of the first to third aspects of the present invention.

According to a seventh aspect of the present invention, there is provided an electronic apparatus using the electroluminescent display device according to the sixth aspect of the present invention.

According to an eighth aspect of the present invention, there is provided a circuit having a current driving element, the circuit including a first current path including the current driving element and a second current path not including the current driving element. And a current path of

According to a ninth aspect of the present invention, there is provided a circuit having a current driving element, wherein the circuit includes a first current path for flowing a current passing through the current driving element and the current driving element. And a second current path that does not carry current therethrough. According to a tenth aspect of the present invention, there is provided a method of driving a circuit including a current driving element and a transistor controlling a current supply to the current driving element, the method comprising: A method is provided that includes determining a gate voltage.

It will be noted that, according to the present invention, there is no current supply to the current driven element by the current control transistor during the programming stage. In the electroluminescent device of the present invention, the pixel drive circuit can be realized without impairing the quality of the image displayed by the electroluminescent device. The present invention also has the effect of reducing the total power consumption as compared with the prior art by causing equal currents to flow in the programming stage and the reproduction stage.
Moreover, while the prior art required a high bias voltage, the circuit of the present invention can be operated with a normal supply voltage. In fact, the present invention allows to separate the programming current path and the reproduction current path. This has many advantages. For example, in the programming stage, if there is no current passing through the organic electroluminescence device, the programming stage can be operated at higher speed. Because, in such a configuration, the parasitic capacitance (parasitic capacitanc) of the organic electroluminescence device is
This is because the slowdown caused by e) can be prevented.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described further by way of examples with reference to the accompanying drawings. These are merely examples.

A pixel driving circuit according to the first embodiment of the present invention is shown in FIG. The transistor T2 operates as an analog current controller that supplies a drive current to the organic electroluminescence element (OELD). The storage capacitor element (storage capacitor) C1 is connected between the gate and the source of the transistor T2. Figure 2
During the programming stage, the current source is connected via the transistor T1 to the source of the transistor T2 during the programming stage, so that a current is supplied to the organic electroluminescent element. In this embodiment according to the invention, the transistor T1 connects the transistor T2 to the current sink during the programming stage. That is, in the present invention, the current flowing through the organic electroluminescent device via T2 during the programming stage is zero. In the circuit of FIG. 3, the drain of the transistor T2 is connected to the source of the transistor T1 via the source-drain path of the transistor T3. The source of the transistor T1 is connected to the gate of the transistor T2, and the gates of the transistors T1 and T3 are connected to each other. A programming voltage Vp is applied to the gates of T1 and T3. Transistor T4, which is turned off during the programming stage, connects the drain of T2 and the source of T3 to an organic electroluminescent device (OELD). During the programming stage, transistor T1 connects transistor T2 to a current sink connected to ground or a reference voltage.

The circuit of FIG. 3 operates with T4 off and T1 and T3 on during the programming stage. The ON state of T3 has the effect of operating T2 as a diode. T1 also connects this diode to the data current sink. As a result, the capacitive element C
1 stores electricity (accumulates electric charge) (or discharges depending on the voltage accumulated in the previous frame). The capacitive element C1 is
Electricity is stored according to the gate-source voltage of the transistor T2, and as a result, a voltage (VGS2, corresponding to the data current IDAT) that controls the current supply to the organic electroluminescent element during the reproduction stage is stored. At the end of the programming stage, T1 and T3
Turns off. The voltage VGS2 is stored on C1 for the remainder of this frame. As will be readily understood from the schematic and this description, according to the present invention, no bias voltage is specifically required to provide the current source. That is, the supply voltage (VDD) in FIG. 3 is determined by T2 and the organic electroluminescence element, and a high voltage for powering the current source is not particularly required. The maximum voltage required for this circuit is clearly less than that required in the circuit of FIG.

At the start of the programming stage when T4 is in the off state, the parasitic capacitance phenomenon discharged through the device is considered to occur in the organic electroluminescence element (OEL).
D) shows. The charge rate of C1 determines the time taken for the programming stage. In the circuit of the embodiment of the present invention, the capacitance of C1 can be made relatively small,
Therefore, the electricity is stored at a very high speed. As a result, T2
The period during which no current is supplied to the organic electroluminescent element from the device is very short compared to the entire frame. Due to these factors and the afterimage effect of the human eye, recognizable deterioration does not occur in the displayed image.

After C1 is charged and T3 is turned off,
The off-resistance of T3 may be important because it may affect the voltage applied to C1 for the rest of this frame. Therefore, it is desirable that the gate-source capacitance of T3 is smaller than that of C1.

The reproduction voltage VR is applied to the gate of the transistor T4. At the beginning of the reproduction stage in the circuit of FIG. 3, T4 is on and T1 and T3 remain off. As a result, T2
Operates as a current source with VGS2 biased by C1 and supplies current to the organic electroluminescent device. At the end of the reproduction stage, T
4 is turned off and T1 and T3 remain off.
This completes one cycle. This drive waveform is shown in FIG.

FIG. 4 shows a second embodiment according to the present invention. The circuit of FIG. 4 differs from the circuit of FIG. 3 in the connection form of the transistor T3. In the circuit of FIG. 4, T1 is connected to C1 via the drain-source path of T3. The circuit of FIG.
3 is preferred over the circuit of FIG. 3 in that it is not located on the current path. In other points of operation and effect, the second embodiment is the same as the first embodiment.

FIG. 5 is a circuit diagram showing a number of pixels in an active matrix display. Each pixel is realized according to the circuit shown in FIG. A monochrome display device is shown for simplicity of illustration. Since this circuit is an active matrix type, pixels in the same row are selected at the same time. The transistor T3 is responsible for pixel selection. Therefore, the source terminal of T3 is connected to the current data line shared by the column of pixels. Therefore, it is necessary to suppress the leakage current of T3 to the minimum. Multi-gate structure in T1
By using, it is possible to reliably minimize the leakage current. LD in addition to multi-gate structure
The leakage current can be further reduced by using the D structure.

FIG. 6 is a schematic cross-sectional view showing a mounted state of a pixel drive circuit in a certain organic electroluminescence element device. In FIG. 6, reference numeral 132 indicates a hole injection layer, reference numeral 133 indicates an organic electroluminescence layer, and reference numeral 151 indicates a resistor or a separator. A switching thin film transistor 121 and an n-channel type current thin film transistor.
or) 122 is typically used for low-temperature polysilicon thin film transistors such as a top-gate structure or a manufacturing method with a maximum temperature of 600 degrees Celsius or less, such as used in a known thin film transistor liquid crystal display device. Adopt the structure and method used. However, other structures and methods can be used.

The forward oriented organic electroluminescent display device 131 comprises a pixel electrode 115 made of aluminum, an opposite electrode 116 made of ITO,
It is composed of a hole injection layer 132 and an organic electroluminescence layer 133. In the stationary organic electroluminescence display element 131, the direction of the current of the organic electroluminescence display device is I
The orientation can be set from the opposing electrodes 116 made of TO to the pixel electrodes 115 made of aluminum.

The hole injection layer 132 and the organic electroluminescence layer can be formed by an ink jet type printing method while using the resistor 151 as a separation structure between pixels. The opposing electrodes 116 made of ITO can be formed by sputtering. However, other methods can be used to form all of these components.

A typical layout of the entire display panel using the present invention is shown schematically in FIG. This panel is an active matrix organic electroluminescent device 20 having analog current programmed pixels.
0, integrated thin film transistor scan driver 210 with level shifter, flexible TAB tape 220, and integrated RAM / controller (integr
External analog driver LS with ated RAM / controller)
It is composed of I230. Of course, this is just one example of a panel configuration that can be realized using the present invention.

The structure of the organic electroluminescent display device is not limited to the above. Other structures are also applicable.

For example, referring to the circuit of FIG. 3, it can be seen that the present invention provides a data current source (in this example an organic electroluminescent device). This circuit
It can be easily extended to provide amplified and / or multiple levels of (current) output. The principle of such a circuit can be understood with reference to FIG. In addition to the circuit of FIG. 3, the circuit of FIG. 8 has an additional drive transistor T5 and an additional switching transistor T5.
Have six. The source of T5 is connected to VDD,
The same drive voltage signal as that of the gate of the transistor T2 is applied to its gate. The drain of the transistor T5 is connected in series with the drain of the transistor T6,
The source of T6 is connected to the common connection point of the transistors T2, T3, and T4. The gate of the transistor T6 is connected to the gate of the transistor T4. The characteristic of the transistor T2 is W / L, and the transistor T5
If it is assumed that the characteristic of is selected to be (N-1) W / L, the following amplification of current is obtained. Iout = Iin × N Iin is the current flowing through the current sink, that is, FIG. 3 and FIG.
IDAT in. Iout is a current flowing through the organic electroluminescence element. Therefore, when the circuit of FIG. 8 is used, compared with the circuits of FIGS. 3 and 4, it is possible to reduce the value of IDAT while keeping the currents passing through the organic electroluminescence element equal. By reducing the value of IDAT, the operation speed of the circuit can be increased. Further, by reducing the value of IDAT, it is possible to reduce the transmission loss that occurs while passing through the pixel matrix. This effect is especially important for large display panels.

Of course, additional transistors T5 and T
It is possible to add an additional stage of the circuit consisting of six. As shown in FIG. 9 (A, B, etc.), various current values passing through the organic electroluminescence element can be selected by the switching transistor T6 which is connected in series and receives the respective gate drive signals.
As a result, the brightness of the output light can be specified variously.

The circuits shown in FIGS. 3-9 are preferably implemented using thin film transistor technology, most preferably polysilicon thin film transistors.

The present invention is applicable to mobile phones, computers and CDs.
It is particularly effective for small portable electronic devices such as players and DVD players. Of course, it is not limited to these.

Some electronic devices using the above-mentioned organic electroluminescence display device will be described below.

<1: Mobile Computer> An example of a mobile personal computer to which the display device according to one of the above embodiments is applied will be described below.

FIG. 10 is an isometric view showing the configuration of this personal computer. In the figure, a personal computer 1100 includes a main body 11 including a keyboard 1102.
04, and a display unit 1106. The display unit 1106 is realized as described above using the display panel manufactured according to the present invention.

<2: Mobile Phone> Next, an example in which the display device of the present invention is applied to the display portion of a mobile phone will be described. FIG. 11 is an isometric view showing the configuration of this mobile phone. In the figure, a mobile phone 1200 includes a plurality of operation keys 1202, a speaker 1204, a microphone 120.
6, and a display panel 100. This display panel 100 is realized as described above using the display panel manufactured according to the present invention.

<3: Digital Still Camera> Next, a digital still camera using an organic electroluminescence display device as a finder will be described. FIG. 12 is an isometric view showing an outline of the configuration of this digital still camera and the connection to an external device.

A normal camera exposes an optical image of an object on a film, but a digital still camera 1300
Generates an image signal from an optical image of a subject by photoelectric conversion using a charge coupled device (CCD), for example. This digital still camera 1300 is provided with an organic electroluminescence element 100 on the rear surface of a case 1302, which displays based on an image signal from a CCD. Therefore, the display panel 100 functions as a finder that displays a subject. Optical lens and CCD
A photo acceptance unit 13 having
04 is provided on the front surface (rear side in the drawing) of the case 1302.

When the photographer determines the subject image displayed on the organic electroluminescence element panel 100 and releases the shutter, the image signal from the CCD is transmitted,
It is stored in the memory in the circuit board 1308. In this digital still camera 1300, a video signal output terminal 1312 and a data communication input / output terminal 1314 are provided on the side surface of the case 1302. As shown in the figure, the TV monitor 1430 and the personal computer 1440 are respectively connected to the video signal terminal 1 as necessary.
312 and the input / output terminal 1314. The image signal stored in the memory of the circuit board 1308 is output to the TV monitor 1430 and the personal computer 1440 by a predetermined operation.

The personal computer shown in FIG.
Examples of electronic devices other than the mobile phone of FIG. 11 and the digital still camera of FIG. 12 include an organic electroluminescence device TV set, a viewfinder-type and monitoring-type video tape recorder, a car navigation system, and a pager (registered trademark). ), Electronic notebooks, calculators, word processors, workstations, TV phones, POS system terminals, devices with touch panels, and the like. Of course, the above-mentioned organic electroluminescent device is applicable to the display portion of these electronic devices.

The driving circuit of the present invention can be arranged not only in the pixels of the display unit but also outside the display unit.

In the above description, the driving circuit of the present invention has been described by taking various display devices as examples. The application of the drive circuit of the present invention is not limited to a display device, and may be, for example, a magnetoresistive RAM or a capacitance sensor.
r), charge sensors, DNA sensors, night vision cameras, and many other devices.

FIG. 13 shows a magnetic RAM of the drive circuit according to the present invention.
Shows the application to. In FIG. 13, the magnetic head is indicated by reference numeral MH.

FIG. 14 shows an application of the drive circuit of the present invention to a magnetoresistive element. In FIG. 14, the magnetic head is indicated by reference sign MH and the magnetic register is indicated by reference sign MR.

FIG. 15 shows an application of the drive circuit of the present invention to a capacitance sensor or a charge sensor. In FIG. 15, the sense capacitor is designated by the symbol Csense.
It shows with. The circuit of FIG. 15 can be applied to other applications such as a fingerprint sensor and DNA.

FIG. 16 shows an application of the drive circuit of the present invention to a night-vision camera. In FIG. 16, the photoconductor is denoted by R.
It shows with.

In the embodiments shown in the above specified description, each transistor was shown as a p-channel transistor. This is not a limiting element of the invention. For example, FIG. 17 shows a simple outline of a modification of the circuit of FIG. In the circuit of FIG. 17, an n-channel type transistor is used, except that the driving transistor remains the p-channel type.

It will be apparent to those skilled in the art that various modifications and improvements can be made to the configurations described with respect to FIGS. 3-16 without departing from the scope of the invention.

[Brief description of drawings]

FIG. 1 shows a conventional organic electroluminescence element pixel drive circuit using two transistors.

FIG. 2 shows a known current-programmed organic electroluminescence element driving circuit having a threshold voltage compensation function.

FIG. 3 shows a pixel drive circuit according to a first embodiment of the present invention.

FIG. 4 shows a pixel driving circuit according to a second embodiment of the present invention.

FIG. 5 shows a plurality of pixels in a matrix display. Each pixel uses the circuit of FIG.

FIG. 6 is a schematic cross-sectional view showing a mounted state of an organic electroluminescence element and a pixel drive circuit according to an embodiment of the present invention.

FIG. 7 is a schematic plan view of an organic electroluminescence display panel according to the present invention.

FIG. 8 shows another embodiment of a pixel driving circuit according to the present invention.

FIG. 9 shows another embodiment of a pixel driving circuit according to the present invention.

FIG. 10 is a schematic diagram of a mobile personal computer using a display device having a pixel driving circuit of the present invention.

FIG. 11 is a schematic view of a mobile phone using a display device having a pixel driving circuit of the present invention.

FIG. 12 is a schematic view of a digital camera using a display device having the pixel drive circuit of the present invention.

FIG. 13 shows an application of the drive circuit of the present invention to a magnetic RAM.

FIG. 14 shows an application of the drive circuit of the present invention to a magnetoresistive element.

FIG. 15 shows an application of the drive circuit of the present invention to a capacitance sensor or a charge sensor.

FIG. 16 shows an application of the drive circuit of the present invention to a night-vision camera.

FIG. 17 briefly shows an outline of a modified example of the circuit of FIG.

[Explanation of symbols]

T1, T2, T3, T4 Transistor C1 Storage capacitance VP Program voltage VDD Supply voltage IDD Data current VR Reproduction voltage 132 Hole injection layer 133 Organic electroluminescent layer 151 Resistor 121 Switching thin film transistor 122 n-channel type current thin film transistor 131 Organic electroluminescent display 115, 116 Pixel electrode 200 Active matrix type organic electroluminescence element 210 Thin film transistor scanning driver 220 Flexible TAB tape 230 External analog driver 1100 Personal computer 1200 Mobile phone 1300 Digital still camera

Claims (38)

[Claims] 1. A programming stage (programming)
stage) and reproduction stage (reproduction
a driving circuit that operates in a stage having a plurality of current paths each passing through the circuit, a current driving element, and an operation for controlling a current supplied to the current driving element. A transistor connected in this way, a capacitive element connected to store the operating voltage of the transistor during a programming stage, and a switch means for controlling the current path, the arrangement comprising: A driving circuit, wherein one of the current paths does not include the current driving element. 2. A drive circuit for driving a pixel of an EL (electroluminescence) device, wherein the pixel has an electroluminescence element, and the circuit is for controlling a current supplied to the electroluminescence element. A transistor connected to operate during the programming stage, a capacitive element connected to store the operating voltage of the transistor during the programming stage, and a current path through the transistor during operation during the programming stage. A first switch means, and a second switch means for generating a current path through the transistor and the electroluminescent element during operation during a reproduction stage, the first switch means comprising the programming stage The current path in Driving circuit, characterized in that connected to not pass through the recto b ELEMENT. 3. A driving circuit for driving a pixel of an electroluminescent device, wherein the pixel has an electroluminescent element, and the circuit operates to control a current supplied to the electroluminescent element. And a capacitive element connected during the programming stage to store the operating voltage of the transistor, and a first current path that passes through the transistor during operation during the programming stage. Switch means, second switch means for generating a current path through the transistor and the electroluminescent element during operation during a reproduction stage, and a current sink, wherein the first switch means includes: The current profile during the programming stage There driving circuit, characterized in that connected so as to communicate with the previous period current sink through the transistor. 4. The drive circuit according to claim 2, wherein the first and second switch means are controlled by control signals which are independent of each other. 5. The drive circuit according to claim 1, further comprising a bias circuit connected to bias the transistor to operate as a diode during the programming stage. A drive circuit having three switch means. 6. The drive circuit according to claim 5, wherein the third switch means connects the first switch means to a source-drain current path of the transistor. 7. The drive circuit according to claim 5, wherein the third switch means connects the first switch means to the gate of the transistor. 8. The drive circuit according to claim 2, wherein an additional transistor is connected in parallel with the transistor, and additional switch means connects between the drains of both the transistor and the additional transistor. The driving circuit, wherein the gate of the additional transistor is connected to the gate of the transistor. 9. The drive circuit according to claim 8, further comprising a plurality of additional transistors each having additional switch means, each additional transistor and additional switch means being connected as aforesaid as described above. A drive circuit, wherein the additional switch means are connected to each other in series. 10. The drive circuit according to claim 1, wherein the circuit is realized by using a polysilicon thin film transistor. 11. A method of controlling current supply to an electroluminescent device, the method comprising: providing a current path that does not pass through the electroluminescent device during a programming stage; and the electroluminescent device during a reproduction stage. Providing a current path through the. 12. A method of controlling current supply to an electroluminescent device, the method comprising: providing a current path connected to a current sink during a programming stage; and the electroluminescent device during a reproduction stage. Providing a current path through the. 13. An electroluminescence display device comprising one or more drive circuits according to any one of claims 1 to 10. 14. An electronic device using the electroluminescent display device according to claim 13. 15. The drive circuit according to claim 5,
The drive circuit, wherein the third switch means is arranged between the capacitive element and the first switch means. 16. The drive circuit according to claim 1, wherein the transistor is a p-channel thin film transistor. 17. The drive circuit according to claim 5, wherein
The first, second, and third switch means are n-channel thin film transistors, respectively. 18. A circuit having a current driving element, the circuit having a first current path including the current driving element and a second current path not including the current driving element. 19. A circuit having a current driving element, wherein the circuit has a first current path through which a current flows through the current driving element and a second current path through which no current flows through the current driving element. Circuit with. 20. The circuit according to claim 18, further comprising a transistor for controlling a current supplied to the current driving element. 21. The circuit according to claim 20, wherein the second current path is arranged so that the second current path can be connected to a power supply. 22. The circuit of claim 20, wherein the second current path further comprises a first switch means. 23. The circuit of claim 20, wherein the second current path comprises at least one of the transistor and another transistor that determines the flow of current through the transistor. Circuit to be. 24. The circuit according to claim 20, further comprising a capacitive element connected to the gate of the transistor. 25. The circuit according to claim 24, further comprising a second switch means disposed between the current drive element and the transistor. 26. The circuit according to claim 25, further comprising a third switch means arranged between the first switch means and the capacitive element. 27. The circuit according to claim 25, wherein the first switch means and the second switch means are controlled by separate control signals. 28. The circuit according to claim 18 or 19, wherein the current driving element is an organic electroluminescence element. 29. The circuit according to claim 20, wherein the transistor is a p-channel thin film transistor. 30. The circuit according to claim 26, wherein the first, second, and third switch means are n-channel thin film transistors. 31. The circuit according to claim 20, wherein the first current path and the second current path include the transistor. 32. An electro-optical device comprising: a plurality of pixels; at least one pixel including a circuit having a current driving element; and current determining means that determines a current according to a data signal, wherein the circuit comprises: An electro-optical device comprising: a first current path including a current driving element; and a second current path including no current driving element. 33. An electronic apparatus including the electro-optical device according to claim 32. 34. The circuit according to claim 18 or claim 19, wherein the second current path is connected to a current sink. 35. The circuit of claim 21, wherein the second current path is connected to a current sink. 36. A method of driving a circuit including a current driving element and a transistor controlling a current supply to the current driving element, the method comprising: determining a gate voltage of the transistor based on a predetermined current. A method comprising: 37. The method of claim 36, further comprising the step of providing a current to the current driven element. 38. The method of claim 36, wherein no current is supplied to the current driver during the step of determining the gate voltage of the transistor based on a predetermined current.