JP2001356734A - Electronic device and drive method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optoelectronic device having a pixel part of a new structure for improving display defects such as crosstalk, caused by a voltage drop due to wiring resistance of a current supply line in the optoelectronic device. SOLUTION: Attention is paid to the fact that no signal is inputted to a source signal line 106 and a gate signal line 105 for a period that signal writing is not performed from the signal line to a pixel. A current supply line 107 is connected with the source signal line 106 or the gate signal line 105 through a connecting transistor 111 or 112, and the connecting transistor 111 or 112 is brought into conduction by inputting a signal to a connection control line 114 for a sustained period, and the source signal line 106 and the gate signal line 105 are used as a current supply path to an EL element 103.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a configuration of an electronic device. The present invention particularly relates to an active matrix electronic device having a thin film transistor (TFT) formed on an insulator.

[0002]

2. Description of the Related Art In recent years, an EL display has attracted attention as a flat panel display replacing an LCD (liquid crystal display), and active research has been conducted.

There are roughly two types of LCD drive systems. One is a passive matrix type used for STN-LCDs and the like, and the other is an active matrix type used for TFT-LCDs and the like. Similarly, in the EL display, there are roughly two types of driving methods. One is a passive matrix type and the other is an active matrix type.

[0004] In the case of the passive matrix type, wirings serving as electrodes are arranged above and below the EL element.
Then, a voltage is sequentially applied to the wiring, and a current is caused to flow through the EL element, thereby lighting the element. On the other hand, in the case of the active matrix type, each pixel has a TFT so that a signal can be held in each pixel.

FIG. 19 shows a configuration example of an active matrix type electronic device used for an EL display. FIG. 19A is an overall circuit configuration diagram.
53. On the left and right sides of the pixel portion, gate signal line side driving circuits 1852 for controlling gate signal lines are arranged. This may be arranged on either one of the right and left sides. However, considering the operation efficiency and reliability, FIG.
It is desirable to arrange on both sides as in (A). A source signal line side driver circuit 1851 for controlling a source signal line is provided above the pixel portion. A circuit for one pixel in the pixel portion 1853 in FIG.
It is shown in (B). In FIG. 19B, reference numeral 1801 denotes a TFT that functions as a switching element when writing a signal to a pixel (hereinafter, referred to as a switching TFT). Reference numeral 1802 denotes a TFT functioning as an element (current control element) for controlling a current supplied to the EL element 1803
(Hereinafter referred to as EL driving TFT). Where T
As for the FT operation, the fact that the source ground is good, the EL element 18
03, the EL driving TFT has P
A method of using a channel type and disposing an EL driving TFT between an anode of an EL element 1803 and a current supply line 1807 is generally used, and is often used. Reference numeral 1804 denotes a storage capacitor for holding a signal (voltage) input from the source signal line 1805. Storage capacity 1 in FIG. 19 (B)
One terminal of 804 is connected to the current supply line 1807, but a dedicated wiring may be used in some cases. The gate terminal of the switching TFT 1801 is connected to the gate signal line 18.
At 06, the source terminal is connected to the source signal line 1805. A drain terminal of the EL driving TFT 1802 is connected to an anode or a cathode of the EL element 1803, and a source terminal is connected to a current supply line 1807.

[0006] An EL element has a layer containing an organic compound capable of obtaining electroluminescence (electroluminescence generated by applying an electric field) (hereinafter, referred to as an EL layer), an anode, and a cathode. Luminescence of an organic compound includes light emission when returning from a singlet excited state to a ground state (fluorescence) and light emission when returning from a triplet excited state to a ground state (phosphorescence). The present invention can also be applied to a light emitting device using.

In this specification, all layers provided between the anode and the cathode are defined as EL layers. Specifically, the EL layer includes a light emitting layer, a hole injection layer, an electron injection layer, a hole transport layer,
An electron transport layer and the like are included. Basically, the EL element has an anode /
It has a structure in which a light emitting layer / cathode is laminated in order. In addition to this structure, an anode / hole injection layer / light emitting layer / cathode or anode / hole injection layer / light emitting layer / electron transport layer / cathode Etc. in some cases.

In this specification, an element formed by an anode, an EL layer, and a cathode is called an EL element.

Next, the operation of the circuit of the active matrix type electronic device will be described with reference to FIG. First, when the gate signal line 1806 is selected, a voltage is applied to the gate electrode of the switching TFT 1801, and the switching TFT 1801 is turned on. Then, the signal (voltage) of the source signal line 1805 changes to the storage capacitor 1
804. The voltage of the storage capacitor 1804 is EL
Since the voltage between the gate and the source of the driving TFT 1802 becomes V _GS , a current corresponding to the voltage of the storage capacitor 1804 flows through the EL driving TFT 1802 and the EL element 1803. As a result, the EL element 1803 is turned on.

[0010] luminance of the EL element 1803, i.e. the amount of current flowing through the EL element 1803 can be controlled by V _GS.
V _GS is a voltage of the storage capacitor 1804, which is a signal (voltage) input to the source signal line 1805. That is, the luminance of the EL element 1803 is controlled by controlling a signal (voltage) input to the source signal line 1805. Finally, the gate signal line 1806 is set to a non-selected state, the gate of the switching TFT 1801 is closed, and the switching TFT 1801 is set to a non-conductive state. At that time, the electric charge accumulated in the storage capacitor 1804 is held.
Therefore, V _GS is held as it is, and a current corresponding to V _GS continues to flow to the EL element 1803 through the EL driving TFT 1802.

Regarding the above contents, SID99 Digest: P
372: “Current Status and futureof Light-Emitting
Polymer Display Driven by Poly-Si TFT ”, ASIA DISP
LAY98: P217: “High Resolution Light Emitting Pol
ymer Display Driven by Low Temperature Polysilicon
Thin Film Transistor with Integrated Driver ”, Eu
ro Display99 Late News: P27: “3.8 Green OLED wit
h Low Temperature Poly-Si TFT ”etc.

[0012]

In an active matrix EL display, a large screen is required at the same time as high definition. However, the increase in the wiring length due to the enlargement of the screen causes problems such as insufficient writing time and variation in supply current. In particular, variations in the supply current to the EL elements due to the resistance of the current supply line directly lead to display failures such as uneven brightness and crosstalk in the screen, which is a hindrance to the enlargement of the screen.

In order to solve the above problem, there is a method of increasing the number of current supply lines to reduce the resistance of the current supply lines per pixel. However, simply increasing the number of wires or making the wires thicker in the pixel portion is not a desirable method because the aperture ratio is reduced.

As described above, in order to reduce the resistance of the wiring while maintaining a high aperture ratio, a novel pixel configuration which has not been used in the past is required.

The present invention meets such a demand and provides an electronic device capable of increasing a current supply path and reducing wiring resistance by using a pixel having a novel configuration. As an issue.

[0016]

In order to solve the above-mentioned problems of the prior art, the present invention takes the following measures.

In the electronic device of the present invention, in the configuration of the pixel portion, the gate signal line and the source signal line existing as wirings in addition to the current supply lines are used during periods other than when signals are written to the pixels. We paid attention to the fact that a certain potential was taken. A feature of the electronic device of the present invention is that a potential of a gate signal line or a source signal line in a sustain (lighting) period which does not overlap with an address (writing) period is made equal to a potential of a current supply line, and a current is supplied through a TFT. It is used as a current supply line by being electrically connected to the line.

In order to increase the current supply path, the method of adding a new current supply line can be said to be the simplest method. However, according to the present invention, by adding a control line of the connection TFT, the source signal line can be added. Since the gate signal line can be used as a current supply path, the number of current supply paths can be increased more efficiently than simply adding a current supply line as described above. As a result, the wiring resistance can be reduced, and unevenness in brightness, crosstalk, and the like can be eliminated, which can greatly contribute to improvement in image quality.

Hereinafter, the configuration of the electronic device of the present invention will be described.

According to the first aspect of the present invention, there is provided an electronic device comprising: a source signal line side driving circuit; a gate signal line side driving circuit;
An electronic device having a pixel portion, wherein the pixel portion has a plurality of source signal lines, a plurality of gate signal lines, a plurality of current supply lines, a connection control line, and a plurality of pixels, Each of the plurality of pixels, a switching transistor,
An EL driving transistor, an EL element, a first connection transistor or a second connection transistor,
A gate electrode of the switching transistor is electrically connected to a gate signal line, and one of a source region and a drain region is electrically connected to a source signal line, and the other is EL. Electrically connected to a gate electrode of a driving transistor;
One of a source region and a drain region of the driving transistor is electrically connected to a current supply line, and the other is electrically connected to one electrode of an EL element. A gate electrode of the connection transistor is electrically connected to the connection control line, and one of a source region and a drain region of the first connection transistor is electrically connected to any one of the plurality of source signal lines. And the other is electrically connected to any one of the plurality of current supply lines, and the second
A gate electrode of the connection transistor is electrically connected to the connection control line, and one of a source region and a drain region of the second connection transistor is connected to one of the plurality of gate signal lines. It is electrically connected, and the other is electrically connected to any one of the plurality of current supply lines.

According to a second aspect of the present invention, there is provided an electronic device comprising: a source signal line side driving circuit; a gate signal line side driving circuit;
An electronic device having a pixel portion, wherein the pixel portion has a plurality of source signal lines, a plurality of gate signal lines, a plurality of current supply lines, a connection control line, and a plurality of pixels, Each of the plurality of pixels, a switching transistor,
An EL driving transistor, an EL element, and a connection transistor, wherein a gate electrode of the switching transistor is electrically connected to a gate signal line;
One of the source region and the drain region is electrically connected to a source signal line, and the other is connected to the E signal line.
The transistor is electrically connected to a gate electrode of the L driving transistor, and one of a source region and a drain region of the EL driving transistor is electrically connected to a current supply line, and the other is EL. Electrically connected to one electrode of the element, a gate electrode of the connection transistor is electrically connected to the connection control line, and one of a source region and a drain region of the connection transistor is It is characterized in that it is electrically connected to any one of the plurality of source signal lines, and the other is electrically connected to any one of the plurality of current control lines.

According to a third aspect of the present invention, there is provided an electronic device comprising: a source signal line side driving circuit; a gate signal line side driving circuit;
An electronic device having a pixel portion, wherein the pixel portion has a plurality of source signal lines, a plurality of gate signal lines, a plurality of current supply lines, a connection control line, and a plurality of pixels, Each of the plurality of pixels, a switching transistor,
An EL driving transistor, an EL element, and a connection transistor, wherein a gate electrode of the switching transistor is electrically connected to a gate signal line;
One of the source region and the drain region is electrically connected to a source signal line, and the other is connected to the E signal line.
The transistor is electrically connected to a gate electrode of the L driving transistor, and one of a source region and a drain region of the EL driving transistor is electrically connected to a current supply line, and the other is EL. Electrically connected to one electrode of the element, a gate electrode of the connection transistor is electrically connected to the connection control line, and one of a source region and a drain region of the connection transistor is It is characterized in that it is electrically connected to any one of the plurality of gate signal lines, and the other is electrically connected to any one of the plurality of current control lines.

According to a fourth aspect of the present invention, there is provided an electronic device comprising: a source signal line side driving circuit; a gate signal line side driving circuit;
An electronic device having a pixel portion, wherein the pixel portion has a plurality of source signal lines, a plurality of gate signal lines, a plurality of current supply lines, a connection control line, and a plurality of pixels, Each of the plurality of pixels, a switching transistor,
An EL driving transistor, an EL element, a first connection transistor, and a second connection transistor;
A gate electrode of the switching transistor is electrically connected to a gate signal line, and one of a source region and a drain region is electrically connected to a source signal line, and the other is EL. Electrically connected to a gate electrode of a driving transistor;
One of a source region and a drain region of the driving transistor is electrically connected to a current supply line, and the other is electrically connected to one electrode of an EL element. A gate electrode of the connection transistor is electrically connected to the connection control line, and one of a source region and a drain region of the first connection transistor is electrically connected to any one of the plurality of source signal lines. And the other is electrically connected to any one of the plurality of current supply lines, and the second
A gate electrode of the connection transistor is electrically connected to the connection control line, and one of a source region and a drain region of the second connection transistor is connected to one of the plurality of gate signal lines. It is electrically connected, and the other is electrically connected to any one of the plurality of current supply lines.

According to a fifth aspect of the present invention, there is provided an electronic device comprising: a source signal line side driving circuit; a gate signal line side driving circuit;
An electronic device having a pixel portion, wherein the pixel portion has a plurality of source signal lines, a plurality of gate signal lines, a plurality of current supply lines, a connection control line, and a plurality of pixels, Each of the plurality of pixels, a switching transistor,
An EL driving transistor, an EL element, a first connection transistor, and a second connection transistor;
A gate electrode of the switching transistor is electrically connected to a gate signal line, and one of a source region and a drain region is electrically connected to a source signal line, and the other is EL. Electrically connected to a gate electrode of a driving transistor;
One of a source region and a drain region of the driving transistor is electrically connected to a current supply line, and the other is electrically connected to one electrode of an EL element. A gate electrode of the connection transistor is electrically connected to the connection control line, and one of a source region and a drain region of the first connection transistor is electrically connected to any one of the plurality of source signal lines. And the other is electrically connected to any one of the plurality of current supply lines, and the second
The gate electrode of the connection transistor is electrically connected to the connection control line, and one of the source region and the drain region of the second connection transistor is connected to one of the plurality of source signal lines. The plurality of gate signal lines are electrically connected, and the other is electrically connected to any one of the plurality of gate signal lines.

According to a sixth aspect of the present invention, there is provided an electronic device comprising: a source signal line side driving circuit; a gate signal line side driving circuit;
An electronic device having a pixel portion, wherein the pixel portion has a plurality of source signal lines, a plurality of gate signal lines, a plurality of current supply lines, a connection control line, and a plurality of pixels, Each of the plurality of pixels, a switching transistor,
An EL driving transistor, an EL element, a first connection transistor, and a second connection transistor;
A gate electrode of the switching transistor is electrically connected to a gate signal line, and one of a source region and a drain region is electrically connected to a source signal line, and the other is EL. Electrically connected to a gate electrode of a driving transistor;
One of a source region and a drain region of the driving transistor is electrically connected to a current supply line, and the other is electrically connected to one electrode of an EL element. A gate electrode of the connection transistor is electrically connected to the connection control line, and one of a source region and a drain region of the first connection transistor is electrically connected to any one of the plurality of gate signal lines. And the other is electrically connected to any one of the plurality of current supply lines, and the second
The gate electrode of the connection transistor is electrically connected to the connection control line, and one of the source region and the drain region of the second connection transistor is connected to one of the plurality of source signal lines. The plurality of gate signal lines are electrically connected, and the other is electrically connected to any one of the plurality of gate signal lines.

According to a seventh aspect of the present invention, there is provided an electronic device comprising: a source signal line side driving circuit; a gate signal line side driving circuit;
An electronic device having a pixel portion, wherein the pixel portion has a plurality of source signal lines, a plurality of gate signal lines, a plurality of current supply lines, a connection control line, and a plurality of pixels, Each of the plurality of pixels, a switching transistor,
An EL driving transistor, an EL element, a first connection transistor, a second connection transistor, and a third connection transistor, wherein a gate electrode of the switching transistor has a gate signal line; Electrically connected, one of a source region and a drain region is electrically connected to a source signal line, and the other is electrically connected to a gate electrode of the EL driving transistor. One of a source region and a drain region of the EL driving transistor is electrically connected to a current supply line, and the other is electrically connected to one electrode of the EL element; A gate electrode of the first connection transistor is electrically connected to the connection control line, and a source region of the first connection transistor or One of the rain regions is electrically connected to any one of the plurality of source signal lines, and the other is electrically connected to any one of the plurality of current supply lines. A gate electrode of the second connection transistor is electrically connected to the connection control line, and one of a source region and a drain region of the second connection transistor is connected to one of the plurality of gate signal lines. The other is electrically connected to any one of the plurality of current supply lines, and the gate electrode of the third connection transistor is electrically connected to the connection control line. One of the source region or the drain region of the third connection transistor is electrically connected to any one of the plurality of source signal lines, and the other is connected to the plurality of source signal lines. It is characterized by being either one electrically connected over preparative signal line.

According to an eighth aspect of the present invention, there is provided the electronic device according to any one of the first to seventh aspects.
When one of the source region and the drain region of the driving transistor is electrically connected to the anode of the EL element, the polarity of the EL driving transistor is a P-channel type, and the polarity of the EL driving transistor is When one of the source region and the drain region is electrically connected to the cathode of the EL element, the polarity of the EL driving transistor is an N-channel type.

According to a ninth aspect of the present invention, in the electronic device according to any one of the first to eighth aspects, the polarity of the switching transistor is the same as the polarity of the EL driving transistor. It is characterized in that it is used.

The electronic device of the present invention according to claim 10 is
The semiconductor device according to any one of claims 1 to 9, wherein the gate signal line is formed using aluminum or a material containing aluminum as a main component.

The electronic device of the present invention according to claim 11 is
In the driving method of an electronic device that controls the length of the lighting time of an EL element to perform n-bit gradation control, the sustain (lighting) that does not overlap with the address (writing) period
In the period, the first connection transistor or the second connection transistor
Is turned on, the current supply line and the source signal line electrically connected to the source region and the drain region of the first connection transistor, or the source region of the second connection transistor. A current supply line electrically connected to the drain region and a gate signal line are electrically connected.

The electronic device according to the twelfth aspect of the present invention provides
In the driving method of an electronic device that controls the length of the lighting time of an EL element to perform n-bit gradation control, the sustain (lighting) that does not overlap with the address (writing) period
In the period, the supply of current to the EL element includes a current supply line and a source signal line electrically connected to the current supply line via a first connection transistor, or
The operation is performed via a gate signal line electrically connected to the current supply line via a second connection transistor.

The electronic device of the present invention according to claim 13 is
In a method for driving an electronic device in which the length of a lighting time of an EL element is controlled to perform n-bit gradation control, a source region of a connection transistor is connected to a source region of a connection transistor during a period in which an i-th gate signal line is in a non-selected state. A current supply line electrically connected to the drain region and the gate signal line in the i-th row are in a conductive state.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described. In the case of the conventional pixel configuration, the current supply line is
For example, it was not connected to a source signal line or a gate signal line. In the present invention, the current supply line is connected to another wiring, for example, a source signal line, a gate signal line, or both of them through a TFT. The TFT used here is called a connection TFT. And when necessary (when using source signal lines and gate signal lines as current supply lines)
Only in this case, the connection TFT is made conductive, and the current supply line is electrically connected to another wiring. When the connection TFT is in a non-conductive state, the current supply line is electrically disconnected from other wiring. Therefore, at this time, even if the potentials of the current supply line, the source signal line, the gate signal line, and the like change, they do not affect each other.

FIG. 1 shows a pixel configuration according to the present invention. FIG.
FIG. 1 is an enlarged view of one pixel shown in a range 100 surrounded by a dotted line frame among 3 × 3 pixels shown in FIG.
It is shown in (B). Gate signal line 105 and current supply line 107
Are connected via a connection TFT 111. Between the source signal line 106 and the current supply line 107,
The connection is made via the connection TFT 112. A connection TFT is provided between the gate signal line 105 and the source signal line 106.
113 are connected. Connection TFT 111,
The gate electrodes of 112 and 113 are connected to a connection control line 114. Then, when necessary, the connection control line 11
4 to the connection TFTs 111, 112, 1
13 is made conductive. At that time, the source signal line 106
Is preferably set to the same potential as the current supply line 107. The potential of the gate signal line 105 is also
It is desirable to keep the same potential as 07.

At this time, since the switching TFT 101 needs to be in a non-conductive state, it is desirable to use a P-channel type for the switching TFT 101.

As a result of the above configuration, the EL element 103
Flows through not only the current supply line 107 but also the source signal line 106 and the gate signal line 105. Therefore, the substantial resistance of the wiring can be reduced, and the voltage drop in the wiring portion is also reduced, which can greatly contribute to the reduction of luminance unevenness and crosstalk in the screen.

According to the present invention, the source signal line 106 and the gate signal line 105
Although it is used not only for controlling the FT but also for supplying a current flowing to the EL element 103, writing a signal to a pixel and supplying a current to the EL element 103 cannot be performed at the same time. Accordingly, during a period in which a signal is written to a pixel (address (write) period) and a period in which a current is supplied to the EL element 103 (sustain (lighting) period) and during an address (write) period, The connection TFTs 111, 112, and 113 must be kept in a non-conductive state.

[0038]

EXAMPLES Examples of the present invention will be described below.

[Embodiment 1] FIGS. 2 to 7 show an example of the configuration of a circuit in a pixel portion for implementing the configuration of the present invention. In the following description, 1 surrounded by a dotted frame
The following description is based on one pixel.

In the case of FIG. 2, the source signal line 2
06 and the current supply line 207 are connected via the connection TFT 211. In the case of FIG. 3, the current supply line 308 is
A source signal line 307 connected to an adjacent pixel is connected via a connection TFT 312. In this case, FIG.
Since the connection TFT can be arranged between the pixels as compared with the above, it is possible to avoid a large decrease in the aperture ratio. In the case of FIG. 4, the current supply line 408
And the source signal line 406 are connected via a connection TFT 412, and further connected to a source signal line 407 connected to an adjacent pixel via a connection TFT 413. In the circuit configuration examples shown in FIGS. 2 to 4, the current supply lines are not connected to the gate signal lines. Therefore, the switching TFTs 201, 301, and 401 may be of an N-channel type. Of course, a P-channel type may be used.

FIG. 5 shows a circuit diagram when the current supply line 508 is connected to both the source signal line 506 and the gate signal line 516. Here, it is connected to the gate signal line 516 connected to the lower pixel, but it is needless to say that the gate signal line 505 of the own pixel and the gate signal line 517 of the upper pixel are connected.
May be connected.

FIG. 6 is a circuit diagram in the case where the source signal line 606 and the gate signal line 617 are connected by further adding a connection TFT 615. Considering that the wiring resistance is reduced and the path of the current flowing through the EL element 603 is increased, the circuit configuration example shown in FIG. 6 is optimal. On the other hand, since the number of connecting TFTs increases, there is a disadvantage that the aperture ratio decreases. It is necessary to consider the optimal configuration in consideration of the balance of each element. When it is desired to prioritize the aperture ratio of the pixel portion in design, a configuration having a small number of connection TFTs as shown in FIGS. 2 and 3 may be used. 5, a configuration in which the signal lines are connected to each other via the connection TFT as shown in FIG. 6 may be used.

FIG. 7 shows the current supply line 707 and the connection control line 7.
12 is shared by the upper, lower, left and right pixels,
And a source signal line 706, and a circuit diagram in the case where the source signal line 706 and the gate signal line 705 are connected.

Incidentally, in the case of the example shown in FIGS. 5 to 7, the wiring connected to the current supply line includes the gate signal line.
Therefore, it is desirable to use a P-channel type for the switching TFT.

In the circuit configuration examples shown in FIGS.
Has used a P-channel type, but may use an N-channel type. Note that when the connection TFT is turned on, the potentials of the current supply line, the source signal line, the gate signal line, and the like are high. When an N-channel connection TFT is used in this state, it is necessary to apply an even higher potential to the gate voltage when the connection TFT is turned on, so that there is concern about reliability such as TFT breakdown voltage. Therefore, in such a case, it is desirable to use a P-channel type for the connection TFT.

Next, a signal timing chart is shown.
FIG. 8 is based on a driving method when an address (writing) period and a sustain (lighting) period are separated in each subframe period. Since the circuit shown in FIG. 1 may be used, the numbers shown in FIG. 1 are used for the description.

The connection control line 114 is sustained (lit).
During the period, the connection TFTs 111, 1
12 and 113 are made conductive. FIG. 8 shows a voltage signal of the connection control line 114 when the connection TFT is a P-channel type. Below that, a voltage signal of the source signal line 106 in a certain column is shown. During the address (write) period, the source signal line 106
The potential takes various values depending on the video (image) signal (801). Then, in the sustain (lighting) period, the potential is fixed to the same potential as the current supply line 107 (802),
Functions as a part of the current supply line. Below that, the voltage signal of the gate signal line 105 in a certain row is shown. During the address (write) period, the potential is low only during one gate signal line selection period in which the row is selected (80).
3). Then, in the sustain (lighting) period, the potential is fixed to the same potential as the current supply line 107 (804).

FIG. 9 shows a timing chart based on a driving method when an address (writing) period and a sustain (lighting) period are not separated in each subframe period. Since the circuit shown in FIG. 1 may be used, the numbers shown in FIG. 1 are used for the description.

The connection control line 114 enters the period of only the sustain (lighting) period after the end of the address (writing) period, and at the same time, the connection TFTs 111 and 11 of all the pixels.
2, 113 are made conductive. In FIG. 9, the connection control line 1 when the connection TFT is a P-channel type is shown.
14 shows voltage signals. Below that, a voltage signal of the source signal line 106 in a certain column is shown. During the address (write) period, the potential of the source signal line 106 takes various values depending on the video (image) signal (9).
01). Then, when the address (write) period ends and only the sustain (lighting) period starts, the potential is fixed to the same potential as the current supply line 107 (902) and functions as a part of the current supply line. Below that, the voltage signal of the gate signal line 105 in a certain row is shown. During the address (write) period, the potential is low only during one gate signal line selection period in which the row is selected (903). Then, when the address (write) period ends and a period of only the sustain (lighting) period starts, the potential is fixed to the same potential as the current supply line 107 (904).

The timing charts shown in FIGS. 8 and 9 are examples in which the switching TFT is a P-channel type, the EL driving TFT is a P-channel type, and the connection TFT is a P-channel type. When the TFTs have different polarities, it is necessary to invert the potential and the like in accordance with the polarity.

In this embodiment, the case where the potentials of the current supply lines 107 of all the pixels are the same has been described. But,
When used in a three-color separation type color EL display of RGB or the like, the voltage applied to the EL element 103 may be changed for each color in order to make the luminance of the three colors RGB the same.

FIG. 10 shows a color EL of RGB three-color separation type.
This is an example in which the configuration of the present invention is implemented in a pixel portion of a display. Emission colors (R, G,
B) is indicated.

Since different voltages need to be applied to the three colors, it is necessary to prepare current supply lines having three types of potentials. When arranging pixels, considering the case where pixels of the same emission color are connected to one current supply line, the arrangement as shown in FIG. 10 is the easiest and requires less wiring. desirable. Pixels 1001 and 100 that display R are provided on a current supply line 1011 having an R potential.
4 and 1007 are connected, and a current supply line 1012 having a G potential is connected to pixels 1002 and 100 for displaying G.
5 and 1008 are connected, and a current supply line 1013 having an R potential is connected to pixels 1003 and 100 for displaying R.
6, 1009 are connected.

The source signal lines 1021, 1022,
Regarding 1023, if the potential of the current supply line is adjusted to the display color of the connected pixel,
Connection TFTs 1051 to 1059 within the same pixel
And can be connected to a current supply line.

With this configuration, the gate signal lines 1031, 10
As an example of a case where the current supply lines 32 and 1033 are used as shown in FIG. 10, only the pixel corresponding to the voltage may be connected to another wiring via the connection TFT. In the case of FIG. 10, the potential when the gate signal line 1031 functions as the current supply line is the potential of the R current supply line 1.
011 so that the current supply line 10 for R
11 and a source signal line 1021 for controlling the R pixel are connected via connection TFTs 1061 and 1071. Since the potential when the gate signal line 1032 functions as a current supply line is the same as the potential of the G current supply line 1012, the G current supply line 1012 and the source signal line 1022 for controlling the G pixel are connected to each other. The connection TFT 10
62, 1072. Gate signal line 10
Since the potential at which the pixel 33 functions as a current supply line is the same as the potential of the B current supply line 1013, the potential is connected to the B current supply line 1013 and the source signal line 1023 that controls the B pixel. Are connected via the TFTs 1063 and 1073.

Further, in the example of FIG. 10, the connection example is shown only within the range of 3 × 3 pixels. However, if the signal lines have the same potential, wiring is drawn from outside the illustrated range. Each signal line may be connected.

Here, conditions for implementing the present invention in an electronic device for color display as shown in FIG. 10 will be described.

Now, in FIG. 10, the EL elements 1001,
Consider the state of three pixels having 1002 and 1003. It is assumed that the connection TFTs 1051 to 1053 and 1071 conduct, and each signal line functions as a current supply line during a sustain (lighting) period.

The potential of the R current supply line is V _{CUL (R)} , the potential of the G current supply line is V _{CUL (G)} , and the potential of the B current supply line is V _{CUL (R)} .
_{When CUL (B)} , the potentials of the source signal lines 1021 to 1023 become the same as the current supply lines due to conduction of the connection TFTs 1051 to 1053.

At this time, the switching TFT 1091
Gate-source voltage of V_{GS (R)}, T for switching
When the gate-source voltage of FT1092 is V_{GS (G)}, Sui
The gate-source voltage of the switching TFT 1093 is V
_{GS (B)}Then, the gate signal line 1031 is connected to the R
Since it has the same potential as the feed line, | V_{GS (R)}| = 0, | V
_{GS (G)}| = | V_{CUL (R)}-V_{CUL (G)}|, | V_{GS (B)}| = | V_{CUL (R)}
-V_{CUL (B)}|

Since the period during which the connection TFT is conductive is within the sustain (lighting) period, the switching TFT is turned on.
Must be non-conductive. That is, | V _{GS (G)} |, |
V _{GS (B)} | must both be lower than the absolute value | V _th | of the threshold value of the switching TFT. In other words, the variation in the potential of the current supply line determined so that the EL elements of each emission color have the same brightness must be smaller than the threshold value of the switching TFT. Otherwise, the switching TFT 1092 or 1093 conducts and malfunctions, even within the sustain (lighting) period.

Therefore, in the electronic device for color display, the gate signal line can be used as the current supply line only when the above condition is satisfied.

When only the current supply line and the gate signal line are electrically connected via the connection TFT, the gate signal line is connected even during the sustain (lighting) period overlapping the address (writing) period. It can be used as a current supply path.

A description will be given with reference to FIGS. The current supply line 1907 and the gate signal line 1905 are electrically connected via the connection TFT 1911. This gate signal line 1905 is assumed to be the i-th gate signal line. Only during the period in which the gate signal line 1905 of the i-th row is in the non-selected state, it can be made conductive with the current supply line to form a current supply path. In the timing charts shown in FIGS. 8 and 9, the same signal is input to all the connection control lines, and the connection TFTs are turned on and off at the same timing.
, But in this case, as shown in FIG.
The connection control line in each column has the same timing as the gate signal line electrically connected to either the source region or the drain region of the connection TFT to which the connection control line and the gate electrode are electrically connected. To input the signal. That is, in FIG. 20, at the same time that the gate signal line 1905 is selected, the potential of the connection control line 1912 changes,
The connection TFT 1911 is turned off. After that, at the same time when the gate signal line 1905 returns to the non-selected state, the potential of the connection control line 1912 changes, and the connection TFT 1911
Becomes conductive. In this manner, the gate signal line can be used as a current supply path even in a sustain (lighting) period overlapping with an address (writing) period. When this method is used, application to a driving method based on an analog gray scale method is also possible.

In the examples shown in FIGS. 20 and 21, the case where the gate signal line and the current supply line are made conductive in one pixel is shown, but the gate signal line and the current supply line in another row are connected. It does not matter. In that case, it is necessary to input a signal to the connection control line so as not to conduct with the current supply line while the gate signal line is selected.

The timing chart shown in FIG. 21 is an example in which the switching TFT is a P-channel type, the EL driving TFT is a P-channel type, and the connection TFT is an N-channel type. When the TFTs have different polarities, it is necessary to invert the potential and the like in accordance with the polarity.

[Embodiment 2] In this embodiment, Embodiment 1
As an example of a method for manufacturing the electronic device described in the above section, a TFT of a driver circuit (a source signal line side driver circuit, a gate signal line side driver circuit, and the like) provided around a pixel portion, a switching TFT of a pixel portion, and an EL driving TFT The method for manufacturing the same on the same substrate will be described in detail according to the steps. However, for the sake of simplicity, the driving circuit section includes a CMOS circuit, which is a basic configuration circuit thereof, and an EL driving TFT.
As an example, a switching TFT and an EL driving TFT will be illustrated.

First, as shown in FIG. 11A, a substrate 5001 made of glass such as barium borosilicate glass represented by Corning # 7059 glass or # 1737 glass or aluminoborosilicate glass is oxidized. A base film 5002 made of an insulating film such as a silicon film, a silicon nitride film, or a silicon oxynitride film is formed.
For example, a plasma CVD method SiH _4, NH _3, N ₂ silicon oxynitride film 5002a made from O 10 to 2
00 [nm] (preferably 50 to 100 [nm]) is formed, similarly SiH _4, N ₂ O hydrogenated silicon oxynitride film 5002b made from 50 to 200 [nm] (preferably 100
１５０150 [nm]). Although the base film 5002 has a two-layer structure in this embodiment, the base film 5002 may have a single-layer structure or a structure in which two or more insulating films are stacked.

The island-shaped semiconductor layers 5003 to 5006 are formed of a crystalline semiconductor film formed by using a semiconductor film having an amorphous structure by a laser crystallization method or a known thermal crystallization method.
The thickness of the island-shaped semiconductor layers 5003 to 5006 is 25 to 8
It is formed with a thickness of 0 [nm] (preferably 30 to 60 [nm]). The material of the crystalline semiconductor film is not limited, but is preferably formed of silicon or a silicon germanium (SiGe) alloy.

In order to form a crystalline semiconductor film by a laser crystallization method, a pulse oscillation type or continuous emission type excimer laser, a YAG laser, or a YVO ₄ laser is used.
In the case of using these lasers, it is preferable to use a method in which laser light emitted from a laser oscillator is linearly condensed by an optical system and irradiated on a semiconductor film. The crystallization conditions are appropriately selected by the practitioner. When an excimer laser is used, the pulse oscillation frequency is 30 [Hz], and the laser energy density is 100 to 400 [mJ / cm ² ] (typically, 2
00 to 300 [mJ / cm ² ]). When a YAG laser is used, the second harmonic is used, the pulse oscillation frequency is set to 1 to 10 [kHz], and the laser energy density is set to 30.
0 to 600 [mJ / cm ² ] (typically 350 to 500 [mJ / cm ² ]
² ]) Then, a laser beam condensed linearly with a width of 100 to 1000 [um], for example, 400 [um] is irradiated over the entire surface of the substrate, and the superposition rate (overlap rate) of the linear laser light at this time is 80. Perform as ~ 98 [%].

Next, island-shaped semiconductor layers 5003 to 5006
Is formed to cover the gate insulating film 5007. The gate insulating film 5007 is formed by a plasma CVD method or a sputtering method.
It is formed of an insulating film containing silicon with a thickness of 40 to 150 [nm]. In this embodiment, a silicon oxynitride film is formed with a thickness of 120 [nm]. Needless to say, the gate insulating film is not limited to such a silicon oxynitride film, and another insulating film containing silicon may be used as a single layer or a stacked structure. For example, when a silicon oxide film is used, TEOS (Tetraethyl Orthosilicat
e) and O ₂ were mixed, the reaction pressure was 40 [Pa], and the substrate temperature was 30.
It can be formed by discharging at a high frequency (13.56 [MHz]) power density of 0.5 to 0.8 [W / cm ² ] at 0 to 400 [° C.]. The silicon oxide film thus manufactured can obtain favorable characteristics as a gate insulating film by subsequent thermal annealing at 400 to 500 [° C.].

Then, a first conductive film 5008 and a second conductive film 5009 for forming a gate electrode are formed over the gate insulating film 5007. In this embodiment, the first conductive film 5008 is formed of Ta to a thickness of 50 to 100 [nm],
A second conductive film 5009 is formed with W to a thickness of 100 to 300 [nm].

The Ta film is formed by a sputtering method, and a Ta target is sputtered with Ar. In this case, when an appropriate amount of Xe or Kr is added to Ar, the internal stress of the Ta film can be relaxed and the film can be prevented from peeling. The resistivity of the α-phase Ta film is about 20 [μΩcm] and can be used for the gate electrode. However, the resistivity of the β-phase Ta film is 180 [μΩc].
m], which is not suitable for use as a gate electrode. In order to form an α-phase Ta film, tantalum nitride having a crystal structure close to the α phase of Ta is formed with a thickness of about 10 to 50 [nm].
If it is formed on an underlayer, an α-phase Ta film can be easily obtained.

When a W film is formed, it is formed by a sputtering method using W as a target. Alternatively, it can be formed by a thermal CVD method using tungsten hexafluoride (WF ₆ ). In any case, it is necessary to lower the resistance in order to use it as a gate electrode.
[μΩcm] or less is desirable. The resistivity of the W film can be reduced by enlarging the crystal grains. However, when there are many impurity elements such as oxygen in W, the crystallization is inhibited and the resistance is increased. From this, in the case of using the sputtering method, a W target having a purity of 99.9999 [%] is used, and a W film is formed by giving sufficient consideration so as not to mix impurities from the gas phase during film formation. Resistivity 9-20
[μΩcm] can be realized.

In this embodiment, the first conductive film 500
8 was Ta, and the second conductive film 5009 was W. However, there is no particular limitation, and any of Ta, W, Ti, Mo, Al, and Cu was used.
Or an alloy material or a compound material containing the element as a main component. Alternatively, a semiconductor film typified by a polycrystalline silicon film doped with an impurity element such as phosphorus may be used. An example of another combination other than this embodiment is a combination in which the first conductive film 5008 is formed of tantalum nitride (TaN), the second conductive film 5009 is formed of W, and the first conductive film 5008 is formed of tantalum nitride (TaN). TaN), the second conductive film 5009 is made of Al, the first conductive film 5008 is made of tantalum nitride (TaN), and the second conductive film 5009 is made of Cu. In particular, the first conductive film 50
08 and the second conductive film 5009 are preferably formed using a combination which can obtain a selectivity by etching. (FIG. 11A)

Next, a mask 5010 made of a resist is formed, and a first etching process for forming electrodes and wirings is performed. In this embodiment, ICP (Inductively Coup
ledPlasma: Inductively coupled plasma) Using an etching method, CF ₄ and Cl ₂ are mixed in an etching gas, and 1 [Pa]
500 [W] RF (13.5)
6 [MHz]) Power is supplied to generate plasma. 100 [W] RF (13.5) is also provided on the substrate side (sample stage).
6 [MHz]) Power is applied and a substantially negative self-bias voltage is applied. When CF ₄ and Cl ₂ are mixed, the W film and the Ta film are etched to the same extent.

Under the above-mentioned etching conditions, the shape of the resist mask is made appropriate, and the end portions of the first and second conductive layers are tapered due to the effect of the bias voltage applied to the substrate side. Becomes The angle of the tapered portion is 15 to 45 °. In order to perform etching without leaving a residue on the gate insulating film, 10 to 20
It is preferable to increase the etching time at a rate of about [%].
Since the selectivity of the silicon oxynitride film to the W film is 2 to 4 (typically 3), the surface where the silicon oxynitride film is exposed by the over-etching process is 20 to 50 [nm].
It will be etched to some extent. Thus, the first-shaped conductive layers 5011 to 5016 (the first conductive layers 5011a to 5016a and the second conductive layers 5011b to 5011b) each including the first conductive layer and the second conductive layer are formed by the first etching process.
5016b) is formed. In the gate insulating film 5007, a region which is not covered with the first shape conductive layers 5011 to 5016 is etched by about 20 to 50 [nm] to form a thinned region.

Then, a first doping process is performed to add an impurity element imparting N-type. The doping may be performed by an ion doping method or an ion implantation method. The condition of the ion doping method is that the dose is 1 × 10 ^{13 to} 5 × 10
¹⁴ [atoms / cm ² ] and an acceleration voltage of 60 to 100 [keV]. An element belonging to Group 15 of the periodic table, typically phosphorus (P) or arsenic (As) is used as the impurity element imparting the N-type. Here, phosphorus (P) is used. In this case, the conductive layers 5011 to 5015 serve as a mask for the impurity element imparting N-type, and the first impurity region 50 is self-aligned.
18 to 5026 are formed. First impurity region 501
For 7 to 5025, 1 × 10 ²⁰ to 1 × 10 ²¹ [atoms / cm ³ ]
Is added within the concentration range of.
(FIG. 11B)

Next, a second etching process is performed. Similarly, using an ICP etching method, CF ₄ is used as an etching gas.
And Cl ₂ and O ₂ are mixed, and RF power (13.56 [MHz]) of 500 [W] is supplied to the coil-type electrode at a pressure of 1 [Pa] to generate plasma. Substrate side (sample stage)
Input 50 [W] RF (13.56 [MHz]) power,
A self-bias voltage lower than that in the first etching process is applied. Under such conditions, the W film is anisotropically etched, and Ta, which is the first conductive layer, is anisotropically etched at a lower etching rate to form the second shape conductive layers 5026 to 5031 (first Conductive layers 5026a to 503
1a and second conductive layers 5026b to 5031b) are formed. The gate insulating film 5007 is formed of the second shape conductive layer 50.
The area not covered by 26 to 5031 is further 20 to 50 [n
m] to form a thinned region.
(FIG. 11 (C))

The etching reaction of the W film or the Ta film by the mixed gas of CF ₄ and Cl ₂ can be inferred from the generated radical or ion species and the vapor pressure of the reaction product.
Comparing the vapor pressures of fluorides and chlorides of W and Ta, W
WF ₆ is extremely high and other WC
l ₅ , TaF ₅ and TaCl ₅ are comparable. Therefore, C
With a mixed gas of F ₄ and Cl ₂ , both the W film and the Ta film are etched. However, when an appropriate amount of O ₂ is added to this mixed gas, CF ₄ and O ₂ react to form CO and F, and a large amount of F radicals or F ions are generated. As a result, the etching rate of the W film having a high fluoride vapor pressure increases. On the other hand, in Ta, the increase in the etching rate is relatively small even if F increases. Further, since Ta is more easily oxidized than W, the surface of Ta is oxidized by adding O ₂ .
Since the oxide of Ta does not react with fluorine or chlorine,
The etching rate of the a film decreases. Therefore, the W film and Ta
It is possible to make a difference in the etching rate with the film, and it is possible to make the etching rate of the W film larger than that of the Ta film.

Then, as shown in FIG.
Perform doping processing. In this case, the first doping process
Lowering the dose than the
Doping with an impurity element for giving a mold. For example,
Speed voltage is set to 70 to 120 [keV] and 1 × 10¹³[atoms / cm
^Two], And an island-shaped semiconductor layer is formed in FIG.
A new impurity region is formed inside the formed first impurity region.
Form. Doping is performed in the second shape conductive layer 5026.
To 5030 as a mask for the impurity element,
The region under one of the conductive layers 5026a to 5030a is also
Doping is performed so that a pure element is added. Like this
The third conductive layer 5026a to 5030a.
Impurity regions 5032 to 5041 and a first impurity region
Second impurity region 5042 between the second impurity region and the third impurity region
To 5051. N-type impurity element
Is 1 × 10 in the second impurity region.¹⁷~ 1 × 10¹⁹[atoms
/cm^Three] In the third impurity region.
10¹⁶~ 1 × 10¹⁸[atoms / cm ^Three]
You.

Then, as shown in FIG. 12B, island-shaped semiconductor layers 5004 and 50 forming a P-channel TFT are formed.
At 05 and 5006, fourth impurity regions 5052 to 5074 having a conductivity type opposite to the one conductivity type are formed. Second conductive layer 5
012 to 5015 are used as a mask for the impurity element, and the impurity region is formed in a self-aligned manner. At this time, N
The island-shaped semiconductor layer 5003 forming the channel type TFT and the second conductive layer 5031 forming the wiring are formed by a resist mask 5
The entire surface is covered with 200. Impurity regions 5052-5
054, 5055-5057, 5058-5060, 5
061 to 5065, 5066 to 5068, 5069 to 5
Phosphorus is added to each of 071 and 5072 to 5074 at different concentrations, but they are formed by ion doping using diborane (B ₂ H ₆ ), and the impurity concentration is 2 × 10 ²⁰ to 10 It should be 2 × 10 ²¹ [atoms / cm ³ ].

Through the above steps, impurity regions are formed in the respective island-shaped semiconductor layers. Second overlapping with the island-shaped semiconductor layer
Of conductive layers 5026 to 5030 function as gate electrodes. 5031 functions as a signal line.

FIG. 12 is a view for controlling the conductivity type.
As shown in (C), a step of activating the impurity element added to each of the island-shaped semiconductor layers is performed. This step is performed by a thermal annealing method using a furnace annealing furnace. In addition, a laser annealing method or a rapid thermal annealing method (RTA method) can be applied. In the thermal annealing method, the oxygen concentration is 1 ppm or less, preferably 0.1 ppm.
The heat treatment is performed in a nitrogen atmosphere of not more than [ppm] at 400 to 700 [° C.], typically 500 to 600 [° C.] In this embodiment, the heat treatment is performed at 500 [° C.] for 4 hours. However, 50
When the wiring material used for 26 to 5031 is weak to heat,
Activation is preferably performed after an interlayer insulating film (mainly composed of silicon) is formed in order to protect wirings and the like.

Further, a heat treatment is performed at 300 to 450 ° C. for 1 to 12 hours in an atmosphere containing 3 to 100% of hydrogen to hydrogenate the island-like semiconductor layer. In this step, dangling bonds in the semiconductor layer are terminated by thermally excited hydrogen. As another means of hydrogenation, plasma hydrogenation (using hydrogen excited by plasma) may be performed.

Next, as shown in FIG. 13A, a first interlayer insulating film 5075 is formed. First interlayer insulating film 5075
For example, a single-layer insulating film containing silicon may be used, or a stacked film in which two or more insulating films containing silicon are combined may be used. Further, the film thickness may be 400 [nm] to 1.5 [μm]. In this embodiment, a silicon nitride oxide film having a thickness of 200 [nm] is formed. As the activation means, a furnace annealing method, a laser annealing method, or a lamp annealing method can be used. In this embodiment, heat treatment is performed in an electric furnace at 550 ° C. for 4 hours in a nitrogen atmosphere.

At this time, the first interlayer insulating film has a function of preventing oxidation of the gate electrode.

Further, a hydrogenation treatment is performed by performing a heat treatment at 300 to 450 ° C. for 1 to 12 hours in an atmosphere containing 3 to 100% hydrogen. This step is a step of terminating dangling bonds of the semiconductor film with thermally excited hydrogen.
As another means of hydrogenation, plasma hydrogenation (using hydrogen excited by plasma) may be performed.

When a stacked film is used for the first interlayer insulating film 5075, hydrogenation treatment may be performed between the step of forming one layer and the step of forming another layer.

Next, when the activation step is completed, FIG.
As shown in (B), after forming a second interlayer insulating film 5076, a first interlayer insulating film 5075 and a second interlayer insulating film 507 are formed.
6, and a contact hole is formed with respect to the gate insulating film 5007, and each wiring (including the connection electrode) 5077-5
082, the gate signal line 5084 is formed by patterning, and then the pixel electrode 5083 in contact with the connection electrode 5082 is formed by patterning.

As the second interlayer insulating film 5076, a film made of an organic resin is used. As the organic resin, polyimide, polyamide, acrylic, BCB (benzocyclobutene) or the like can be used. In particular, since the second interlayer insulating film 5076 has a strong meaning of flattening, acrylic having excellent flatness is preferable. In this embodiment, an acrylic film is formed with a thickness that can sufficiently flatten a step formed by a TFT. Preferably, it is 1 to 5 [μm] (more preferably, 2 to 4 [μm]).

The contact holes are formed by dry etching or wet etching to form N-type impurity regions 5018 to 5026 or P-type impurity regions 5054.
5065, a contact hole reaching the wiring 5032, a contact hole reaching the current supply line 5033, and gate electrodes 5029 and 503.
Contact holes (not shown) reaching 0 are respectively formed.

Further, wiring (including connection electrodes and signal lines) 5
077 to 5082 and 5084, the Ti film is 100 [n
m], an aluminum film containing Ti is 300 [nm], and a Ti film 1
A laminate film having a three-layer structure in which 50 nm is continuously formed by a sputtering method and patterned into a desired shape is used. Of course,
Other conductive films may be used.

When an electronic device having a pixel according to the present invention is manufactured, a gate signal line is formed by utilizing a part of the three-layered laminated film, and the gate signal line is temporarily supplied with a current. Since there is a purpose for use as a supply line, it is desirable to use a low-resistance material (for example, a material mainly containing aluminum, copper, or the like).

In this embodiment, an ITO film having a thickness of 110 [nm] was formed as the pixel electrode 5083, and was patterned. Contact is established by arranging the pixel electrode 5083 so as to be in contact with and overlap with the connection electrode 5082. Alternatively, a transparent conductive film in which 2 to 20% of zinc oxide (ZnO) is mixed with indium oxide may be used. This pixel electrode 5083 becomes an anode of the EL element.

Next, as shown in FIG. 13B, an insulating film containing silicon (a silicon oxide film in this embodiment) is formed to a thickness of 500 [nm], and is formed at a position corresponding to the pixel electrode 5083. An opening is formed, and a third interlayer insulating film 5085 is formed. When the opening is formed, a tapered side wall can be easily formed by using a wet etching method. If the side wall of the opening is not sufficiently gentle, the deterioration of the EL layer due to the step becomes a significant problem.

Next, the EL layer 5086 and the cathode (MgA
g electrode) 5087 is continuously formed using a vacuum deposition method without opening to the atmosphere. Note that the thickness of the EL layer 5086 is 80
The cathode 5087 has a thickness of 180 to 300 [nm] (typically 100 to 120 [nm]) (typically 100 to 120 [nm]).
00 to 250 [nm]).

In this step, an EL layer and a cathode are sequentially formed for a pixel corresponding to red, a pixel corresponding to green, and a pixel corresponding to blue. However, since the EL layer has poor resistance to a solution, it must be formed individually for each color without using a photolithography technique. Therefore, it is preferable that a metal mask is used to hide portions other than the desired pixels, and that the EL layer and the cathode are selectively formed only in necessary portions.

That is, first, a mask for hiding all pixels other than pixels corresponding to red is set, and the EL layer and the cathode for emitting red light are selectively formed using the mask. Next, a mask for hiding all pixels other than pixels corresponding to green is set, and the EL layer and the cathode for emitting green light are selectively formed using the mask. Next, a mask for covering all pixels other than the pixel corresponding to blue is similarly set, and a blue light emitting EL layer and a cathode are selectively formed using the mask. Note that all the masks are described herein as being different, but the same mask may be used again. EL is applied to all pixels.
Processing is preferably performed without breaking vacuum until a layer and a cathode are formed.

Here, a method of forming three types of EL elements corresponding to RGB was used, but a method of combining a white light emitting EL element and a color filter, a blue or blue-green light emitting EL element and a phosphor (fluorescent And a method in which an EL element corresponding to RGB is stacked on a cathode (a counter electrode) using a transparent electrode.

Note that a known material can be used for the EL layer 5086. As a known material, it is preferable to use an organic material in consideration of a driving voltage. For example, a four-layer structure including a hole injection layer, a hole transport layer, a light emitting layer, and an electron injection layer may be used. In this embodiment, an example is shown in which an MgAg electrode is used as the cathode of the EL element, but other known materials may be used.

Next, a protective electrode 5088 is formed to cover the EL layer and the cathode. As the protective electrode 5088, a conductive film mainly containing aluminum may be used. The protective electrode 5088 may be formed by a vacuum evaporation method using a mask different from that used when the EL layer and the cathode are formed. After the EL layer and the cathode are formed, they are preferably formed continuously without being released to the atmosphere.

Finally, a passivation film 5089 made of a silicon nitride film is formed to a thickness of 300 [nm]. Actually, the protection electrode 5088 plays a role of protecting the EL layer 5086 from moisture and the like.
Is formed, the reliability of the EL element can be further improved.

Thus, an active matrix electronic device having a structure as shown in FIG. 13B is completed. In the manufacturing process of the active matrix type electronic device in this embodiment, a source signal line is formed by Ta and W which are materials forming a gate electrode, and a source and a drain are formed due to a circuit configuration and a process. Although the gate signal line is formed of Al which is a wiring material forming the electrode, a different material may be used.

By the way, the active matrix substrate of this embodiment exhibits extremely high reliability by arranging the TFT having the optimum structure not only in the pixel portion but also in the driving circuit portion, and the operating characteristics can be improved. In the crystallization step, N
It is also possible to increase the crystallinity by adding a metal catalyst such as i. Thus, the driving frequency of the source signal line driving circuit can be increased to 10 MHz or more.

First, a TFT having a structure in which hot carrier injection is reduced so as not to reduce the operation speed as much as possible,
N-channel type TF of CMOS circuit forming drive circuit section
Used as T. In addition, as the drive circuit here,
It includes a shift register, a buffer, a level shifter, a latch in line-sequential driving, a transmission gate in point-sequential driving, and the like.

In the case of the present embodiment, the active layer of the N-channel TFT includes a source region, a drain region, a GOLD region,
The GOLD region includes a DD region and a channel formation region, and overlaps with the gate electrode via a gate insulating film.

Also, a P-channel type TFT of a CMOS circuit
Since there is almost no concern about deterioration due to hot carrier injection, it is not necessary to provide an LDD region. Needless to say, it is also possible to provide an LDD region similarly to the N-channel type TFT and take measures against hot carriers.

In addition, in the case where a CMOS circuit in which a current flows bidirectionally in the channel formation region, that is, a CMOS circuit in which the roles of the source region and the drain region are switched is used in the driver circuit, N In the channel type TFT, it is preferable to form an LDD region on both sides of the channel formation region so as to sandwich the channel formation region. An example of such a transmission gate is a transmission gate used for dot-sequential driving. In the case where a CMOS circuit that requires an off-current value to be kept as low as possible is used in a driving circuit, a CMOS
The N-channel TFT forming a circuit preferably has a structure in which a part of an LDD region overlaps with a gate electrode through a gate insulating film. As such an example, a transmission gate used for dot-sequential driving is also mentioned.

When the structure shown in FIG. 13 (B) is actually completed, the protective film (laminate film, ultraviolet curable resin film, etc.) having high airtightness and low degassing is used to prevent further exposure to the outside air. It is preferable to package (enclose) with an optical sealing material. At this time, the reliability of the EL element is improved by setting the inside of the sealing material to an inert atmosphere or disposing a hygroscopic material (for example, barium oxide) inside.

When the airtightness is improved by processing such as packaging, a connector (flexible printed circuit: FPC) for connecting terminals routed from elements or circuits formed on the substrate to external signal terminals. To complete the product. Such a state in which the product can be shipped is referred to as an electronic device in this specification.

[Embodiment 3] In this embodiment, an example in which an electronic device of the present invention is manufactured will be described.

FIG. 14A is a top view of an electronic device using the present invention, and FIG. 14B is a cross-sectional view of FIG. 14A taken along the line XX ′. In FIG. 14A, 4
001 is a substrate, 4002 is a pixel portion, 4003 is a source signal line side driving circuit, 4004 is a gate signal line side driving circuit, and each driving circuit has wirings 4005, 4006,
Via the FPC 4007, the FPC 4008 is connected to an external device.

At this time, the cover member 4009, the sealing member 4010, and the sealing member (also referred to as a housing member) 40 surround the pixel portion, preferably the drive circuit and the pixel portion.
11 (shown in FIG. 14B).

FIG. 14B shows a cross-sectional structure of the electronic device of this embodiment, in which a TFT for a driving circuit (here, an N-channel type TF) is formed on a substrate 4001 and a base film 4012.
A CMOS circuit combining T and P-channel TFTs is shown) 4013 and a TFT 4014 for a pixel portion
(However, here, only the EL driving TFT for controlling the current to the EL element is shown). These TFTs may use a known structure (top gate structure or bottom gate structure).

A TFT for a driving circuit is manufactured by using a known manufacturing method.
4013, when the pixel portion TFT 4014 is completed, a pixel electrode 4016 made of a transparent conductive film electrically connected to the drain of the pixel portion TFT 4014 is formed on an interlayer insulating film (flattening film) 4015 made of a resin material. As the transparent conductive film, a compound of indium oxide and tin oxide (IT
O) or a compound of indium oxide and zinc oxide. Then, the pixel electrode 4016
Is formed, an insulating film 4017 is formed, and the pixel electrode 40 is formed.
An opening is formed on 16.

Next, an EL layer 4018 is formed. A known technique may be used to determine the structure. Also,
EL materials include low molecular weight materials and high molecular weight (polymer) materials. When a low molecular material is used, an evaporation method is used, but when a high molecular material is used, a spin coating method,
A simple method such as a printing method or an inkjet method can be used.

In this embodiment, an EL layer is formed by an evaporation method using a shadow mask. By forming light-emitting layers (red light-emitting layer, green light-emitting layer, and blue light-emitting layer) capable of emitting light of different wavelengths for each pixel using a shadow mask,
Color display becomes possible. In addition, the color conversion layer (CC
There is a method combining M) and a color filter, and a method combining a white light emitting layer and a color filter, and any method may be used. Needless to say, the electronic device can emit light of a single color.

After forming the EL layer 4018, the cathode 4019 is formed thereon. Cathode 4019 and EL layer 4018
It is desirable to remove as much as possible moisture and oxygen existing at the interface. Therefore, the EL layer 4018 and the cathode 40
It is necessary to devise a method of continuously forming the film 19 or forming the EL layer 4018 in an inert atmosphere and forming the cathode 4019 without opening to the atmosphere. In this embodiment, the above-described film formation is made possible by using a multi-chamber type (cluster tool type) film formation apparatus.

In this embodiment, as the cathode 4019,
A laminated structure of a LiF (lithium fluoride) film and an Al (aluminum) film is used. Specifically, a 1-nm-thick LiF (lithium fluoride) film is formed on the EL layer 4018 by a vapor deposition method, and a 300-nm-thick aluminum film is formed thereon. Of course, a MgAg electrode which is a known cathode material may be used. The cathode 4019 is connected to the wiring 4007 in a region indicated by 4020. A wiring 4007 is a power supply line for applying a predetermined voltage to the cathode 4019,
It is connected to the FPC 4008 through the conductive paste material 4021.

In the area indicated by reference numeral 4020, the cathode 40
In order to electrically connect the wiring 19 and the wiring 4007, it is necessary to form a contact hole in the interlayer insulating film 4015 and the insulating film 4017. These are interlayer insulating films 4015
May be formed at the time of etching (at the time of forming a contact hole for a pixel electrode) or at the time of etching of an insulating film 4017 (at the time of forming an opening before forming an EL layer). When the insulating film 4017 is etched, etching may be performed all at once up to the interlayer insulating film 4015. In this case, if the interlayer insulating film 4015 and the insulating film 4017 are the same resin material, the shape of the contact hole can be made good.

The passivation film 4022 and the filler 402 cover the surface of the EL element thus formed.
3. A cover material 4009 is formed.

Further, a sealing material 4 is provided inside the cover 4009 and the substrate 4001 so as to surround the EL element portion.
011 is provided, and a sealing material (second sealing material) 4010 is formed outside the sealing material 4011.

At this time, the filler 4023 also functions as an adhesive for bonding the cover member 4009.
As the filler 4023, PVC (polyvinyl chloride), epoxy resin, silicone resin, PVB (polyvinyl butyral), or EVA (ethylene vinyl acetate) can be used. It is preferable to provide a desiccant inside the filler 4023 because a moisture absorbing effect can be maintained. Further, by disposing an antioxidant or the like having an effect of capturing oxygen inside the filler 4023, deterioration of the EL layer may be suppressed.

Further, a spacer may be contained in the filler 4023. At this time, the spacer may be a granular substance made of BaO or the like, and the spacer itself may have hygroscopicity.

When a spacer is provided, the passivation film 4022 can reduce the spacer pressure.
Further, a resin film or the like for relaxing the spacer pressure may be provided separately from the passivation film.

As the cover material 4009, a glass plate, an aluminum plate, a stainless steel plate, FRP (Fiberga
ss-Reinforced Plastics) plate, PVF (polyvinyl fluoride) film, mylar film, polyester film or acrylic film can be used. When PVB or EVA is used as the filler 4023, it is preferable to use a sheet having a structure in which aluminum foil of several tens [μm] is sandwiched between PVF films or mylar films.

However, depending on the direction of light emission (the direction of light emission) from the EL element, the cover material 4009 needs to have a light transmitting property.

The wiring 4007 is made of a sealing material 401.
1 and the sealant 4010 and the substrate 4001, and electrically connected to the FPC 4008. Although the wiring 4007 has been described here, the other wiring 4007
5 and 4006 are also electrically connected to the FPC 4008 under the sealant 4011 and the sealant 4010 in the same manner.

In this embodiment, the cover member 4009 is adhered after the filler member 4023 is provided, and the sealing member 4011 is attached so as to cover the side surface (exposed surface) of the filler member 4023. Lumber 4
After attaching 011, the filler 4023 may be provided. In this case, an inlet for a filler is provided to communicate with a space formed by the substrate 4001, the cover material 4009, and the sealing material 4011. Then, the gap is vacuumed (1
0 ^-2 [Torr] or less), fill the filling material into the water tank by immersing the injection port in the filling tank, and then make the pressure outside the gap higher than the pressure inside the gap. I do.

[Embodiment 4] In this embodiment, an example in which an electronic device different from that of Embodiment 3 is manufactured using the present invention will be described with reference to FIGS. FIG.
Elements having the same numbers as (A) and (B) indicate the same parts, and thus description thereof will be omitted.

FIG. 15A is a top view of the electronic device of this embodiment, and FIG. 15B is a cross-sectional view of FIG. 15A cut along the YY ′ plane.

According to the third embodiment, up to the passivation film 4022 is formed to cover the surface of the EL element.

Further, a filler 4023 is provided so as to cover the EL element. The filler 4023 is used for the cover material 4
It also functions as an adhesive for bonding 009. As the filler 4023, PVC (polyvinyl chloride), epoxy resin, silicone resin, PVB (polyvinyl butyral), or EVA (ethylene vinyl acetate) can be used. It is preferable to provide a desiccant inside the filler 4023 because a moisture absorbing effect can be maintained. Further, by disposing an antioxidant or the like having an effect of capturing oxygen inside the filler 4023, deterioration of the EL layer may be suppressed.

Further, a spacer may be contained in the filler 4023. At this time, the spacer may be a granular substance made of BaO or the like, and the spacer itself may have hygroscopicity.

When a spacer is provided, the pressure of the passivation film 4022 can be reduced.
Further, a resin film or the like for relaxing the spacer pressure may be provided separately from the passivation film.

As the cover material 4009, a glass plate, an aluminum plate, a stainless steel plate, FRP (Fibergla
ss-Reinforced Plastics) plate, PVF (polyvinyl fluoride) film, mylar film, polyester film or acrylic film can be used. When PVB or EVA is used as the filler 4023, it is preferable to use a sheet having a structure in which aluminum foil of several tens [μm] is sandwiched between PVF films or mylar films.

However, depending on the direction of light emission (the direction of light emission) from the EL element, the cover material 6000 needs to have a light transmitting property.

Next, using the filler 4023, the cover 4
After bonding 009, the side surface (exposure surface) of the filler 4023
The frame member 4024 is attached so as to cover the. The frame material 4024 is a sealing material (functioning as an adhesive)
Adhered by 4025. At this time, a photocurable resin is preferably used as the sealing material 4025, but a thermosetting resin may be used as long as the heat resistance of the EL layer is allowed. Note that it is preferable that the sealing material 4025 be a material that does not transmit moisture or oxygen as much as possible. Further, a desiccant may be added to the inside of the sealing material 4025.

The wiring 4007 is made of a sealing material 402.
5 is electrically connected to the FPC 4008 through a gap between the substrate 5 and the substrate 4001. Note that although the wiring 4007 is described here, the other wirings 4005 and 4006 similarly pass under the sealing material 4025 and are electrically connected to the FPC 4008.

In this embodiment, the frame material 4024 is attached so as to cover the side surface (exposed surface) of the filler material 4023 after the filler material 4023 is provided and then the cover material 4009 is bonded. Lumber 4025
After attaching the frame material 4024 and the filling material 4
023 may be provided. In this case, an injection port for a filler is provided to communicate with a gap formed by the substrate 4001, the cover member 4009, the sealing member 4025, and the frame member 4024. Then, the space is evacuated to a vacuum (10 ^-2 [Torr]).
After filling the filler in the water tank containing the filler, the pressure outside the gap is made higher than the pressure inside the gap, and the filler is filled into the gap.

[Embodiment 5] FIG. 16 shows a more detailed sectional structure of a pixel portion in an electronic device of the present invention.

In FIG. 16, an N-channel TFT is used as a switching TFT 4502 provided on a substrate 4501 in this embodiment. In this embodiment, a double gate structure is used. However, since there is no significant difference between the structure and the manufacturing process, the description is omitted. However, there is an advantage that the double gate structure has a structure in which two TFTs are substantially connected in series, and the off-current value can be reduced. Although the double gate structure is used in this embodiment, a single gate structure, a triple gate structure, or a multi-gate structure having more gates may be used. Further, a P-channel TFT may be used.

The EL driving TFT 4503 uses an N-channel TFT. Switching TFT4502
The drain wiring 4504 of FIG.
It is electrically connected to the gate electrode 4506 of the L driving TFT 4503.

By the way, the drive voltage of the electronic device is high (1
0 [V] or more), the TFT constituting the driving circuit is
In particular, since there is a high risk of deterioration due to hot carriers or the like in the N-channel type, as shown in FIG. 13B of the second embodiment, the N-channel type TFT has a drain side or both a source side and a drain side. A structure in which an LDD region (GOLD region) is provided at a position overlapping a gate electrode with a gate insulating film interposed therebetween is extremely effective. On the other hand, when the drive voltage is low (10 [V] or less), there is almost no fear of deterioration due to hot carriers, and therefore, there is no need to particularly provide a GOLD region as shown in FIG. 16 of this embodiment. However, the switching TFT 4502 in the pixel portion has an N-channel type TF in order to keep the OFF current low.
A structure in which an LDD region is provided on the drain side of T or on both the source side and the drain side so as not to overlap the gate electrode via the gate insulating film is extremely effective. At this time, regarding the EL driving TFT 4503, especially the LD
There is no need to provide a D region, but a switching TFT
When forming the LDD region in 4502, the EL driving TF
In order to cover the portion of T4503 with a resist, a dedicated mask is required. Therefore, in this embodiment, in order to avoid an increase in the number of masks, the EL driving TFT 4503 is used.
With the same structure as the switching TFT 4502 (LDD
(Structure having a region).

Here, the T having the structure shown in this embodiment is used.
The FT manufacturing process will be described. FIG. 17 is referred to for the description.

FIG. 17A shows a state in which the processing is completed up to the state shown in FIG. 11B according to the second embodiment. Through the steps so far, first impurity regions 4701 to 4705 are formed. Subsequently, the first conductive film made of a Ta film and the second conductive film made of a W film were etched as shown in FIG. 17B to form an island-shaped semiconductor layer in FIG. First
The second impurity regions 4706 to 4711 having a lower concentration than the first impurity region are formed inside the impurity region. Second impurity regions 4706 to 47 formed here
Reference numeral 11 denotes the above-mentioned LDD region.

Thereafter, according to the second embodiment, FIG.
The TFT substrate may be completed through the steps shown after 2 (B).

In this embodiment, the EL driving TFT 45 is used.
03 is shown with a single gate structure.
A multi-gate structure in which FTs are connected in series may be used.
Further, a structure in which a plurality of TFTs are connected in parallel to substantially divide the channel formation region into a plurality of regions so that heat can be radiated with high efficiency may be employed. Such a structure is effective as a measure against deterioration due to heat.

The wiring (not shown) including the gate electrode 4506 of the EL driving TFT 4503 is
The drain wiring 4512 of the FT 4503 partially overlaps with an insulating film interposed therebetween, and a storage capacitor is formed in that region. This storage capacitor is connected to the gate electrode 4 of the EL driving TFT 4503.
A function of holding a voltage applied to the 506.

Switching TFT 4502 and EL
A first interlayer insulating film 451 is formed on the driving TFT 4503.
4 is provided thereon, and a second interlayer insulating film 4515 made of a resin insulating film is formed thereon.

Reference numeral 4517 denotes a pixel electrode (cathode of an EL element) made of a conductive film having high reflectivity.
03 is formed so as to partially cover the drain region, and is electrically connected. As the pixel electrode 4517, a low-resistance conductive film such as an aluminum alloy film, a copper alloy film, or a silver alloy film, or a stacked film thereof is preferably used. Of course, a stacked structure with another conductive film may be employed.

Next, an organic resin film 4516 is formed on the pixel electrode 451.
7 and patterning a portion facing the pixel electrode 4517, an EL layer 4519 is formed. Although not shown here, R (red), G (green), B (blue)
The light-emitting layers corresponding to the respective colors may be separately formed. As the organic EL material for the light emitting layer, a π-conjugated polymer material is used. Typical polymer materials include polyparaphenylene vinylene (PPV), polyvinyl carbazole (PVK), and polyfluorene.

There are various types of PPV-based organic EL materials, for example, H. Shenk, H. Becker, OG
elsen, E. Kluge, W. Kreuder and H. Spreitzer: “Polym
ersfor Light Emitting Diodes ”, Euro Display, Procee
dings, 1999, pp. 33-37 ”and JP-A-10-92576.

As a specific light emitting layer, cyanopolyphenylene vinylene is used for a red light emitting layer, polyphenylene vinylene is used for a green light emitting layer, and polyphenylene vinylene or polyalkylphenylene is used for a blue light emitting layer. Good. The film thickness is 30 to 150
[Nm] (preferably 40 to 100 [nm]).

However, the above example is an example of the organic EL material that can be used as the light emitting layer, and it is not necessary to limit the invention to this. An EL layer (a layer for performing light emission and carrier movement therefor) may be formed by freely combining a light emitting layer, a charge transport layer, or a charge injection layer.

For example, in this embodiment, an example in which a polymer material is used as the light emitting layer has been described, but a low molecular organic EL material may be used. It is also possible to use an inorganic material such as silicon carbide for the charge transport layer and the charge injection layer. Known materials can be used for these organic EL materials and inorganic materials.

At the point when the anode 4523 is formed, the EL element 4510 is completed. Note that the EL element 45 here is used.
Reference numeral 10 denotes a pixel electrode (cathode) 4517 and a light emitting layer 451
9 and the storage capacitor formed by the hole injection layer 4522 and the anode 4523.

In this embodiment, a passivation film 4524 is further provided on the anode 4523.
As the passivation film 4524, a silicon nitride film or a silicon nitride oxide film is preferable. The purpose of this is to shut off the EL element from the outside, and has both the meaning of preventing the organic EL material from being deteriorated due to oxidation and the effect of suppressing outgassing from the organic EL material. This increases the reliability of the electronic device.

As described above, the electronic device described in this embodiment has a pixel portion composed of pixels having a structure as shown in FIG. 16, and a switching TFT having a sufficiently low off-state current value.
And an EL driving TFT resistant to hot carrier injection. Therefore, an electronic device having high reliability and capable of displaying an excellent image can be obtained.

E having the structure described in this embodiment
In the case of the L element, light generated in the light emitting layer 4519 is radiated in a direction opposite to the substrate on which the TFT is formed as indicated by an arrow.

[Embodiment 6] In this embodiment, FIG.
In the pixel portion shown in FIG. 6, a structure in which the structure of the EL element 4510 is inverted will be described. FIG. 18 is used for the description. Note that only the EL element portion and the TFT portion are different from the structure of FIG. 16, and the other description will be omitted.

In FIG. 16, the switching TFT 4
Reference numeral 502 denotes a P-channel TFT formed by a known method. As the EL driving TFT 4503, a P-channel TFT formed by a known method is used. Here, it is desirable that the switching TFT and the EL driving TFT have the same polarity.

In this embodiment, the pixel electrode (anode) 4525
Is used as a transparent conductive film. Specifically, a conductive film formed using a compound of indium oxide and zinc oxide is used. Needless to say, a conductive film made of a compound of indium oxide and tin oxide may be used.

Then, the third interlayer insulating film 4 made of a resin film
After 526 is formed, a light emitting layer 4528 is formed.
On top of this, potassium acetylacetonate (acacK
) And a cathode 4530 made of an aluminum alloy.

Thereafter, as in the fifth embodiment, a passivation film 4532 for preventing oxidation of the organic EL material is formed, and thus an EL element 4531 is formed.

E having the structure described in the present embodiment
In the case of the L element, light generated in the light emitting layer 4528 is emitted toward the substrate on which the TFT is formed, as indicated by an arrow. [Embodiment 7] In the present invention, by using an EL material capable of utilizing phosphorescence from a triplet exciton for light emission, external light emission quantum efficiency can be drastically improved. Thus, low power consumption, long life, and light weight of the EL element can be achieved.

Here, a report is shown in which the triplet exciton is used to improve the external light emission quantum efficiency. (T.Tsutsui, C.Adachi, S.Saito, Photochemical Proc
esses in Organized Molecular Systems, ed.K. Honda,
(Elsevier Sci. Pub., Tokyo, 1991) p.437.) EL material (coumarin dye) reported in the above paper
Is shown below.

[0169]

Embedded image

(MABaldo, DFO'Brien, Y.You, A.Sho
ustikov, S. Sibley, METhompson, SRForrest, Natu
re 395 (1998) p.151.) The molecular formula of the EL material (Pt complex) reported by the above paper is shown below.

[0171]

Embedded image

(MABaldo, S. Lamansky, PEBurrrows,
METhompson, SRForrest, Appl.Phys.Lett., 75 (19
99) p.4.) (T.Tsutsui, M.-J.Yang, M.Yahiro, K.Nakamura, T.Wa
tanabe, T.tsuji, Y.Fukuda, T.Wakimoto, S.Mayaguch
i, Jpn. Appl. Phys., 38 (12B) (1999) L1502.) The molecular formula of the EL material (Ir complex) reported by the above-mentioned paper is shown below.

[0173]

Embedded image

As described above, if the phosphorescence emission from the triplet exciton can be used, it is possible in principle to realize an external emission quantum efficiency three to four times higher than the case where the fluorescence emission from the singlet exciton is used. . Note that the configuration of this embodiment is the same as that of Embodiments 1 to
It is possible to freely combine and implement any of the configurations of the sixth embodiment.

[Embodiment 8] EL using electronic device of the present invention
Since the display is a self-luminous type, it has excellent visibility in a bright place compared to a liquid crystal display, and has a wide viewing angle. Therefore, it can be used as a display portion of various electronic devices. For example, to watch a TV broadcast or the like on a large screen, the electronic device of the present invention may be used as a display unit of an EL display having a diagonal of 30 inches or more (typically, 40 inches or more).

The EL display includes all information display devices such as a personal computer display device, a TV broadcast reception display device, and an advertisement display device. In addition, the EL display of the present invention can be used as a display portion of various electronic devices.

[0177] Such electronic devices of the present invention include a video camera, a digital camera, a goggle type display device (head mounted display), a navigation system,
Sound playback devices (car audio, audio components, etc.), notebook personal computers, game machines,
A portable information terminal (a mobile computer, a mobile phone, a portable game machine, an electronic book, or the like), and an image reproducing apparatus provided with a recording medium (specifically, a digital video disc (DV
D) and the like, a device having a display capable of reproducing a recording medium and displaying its image). In particular, for a portable information terminal that is often viewed from an oblique direction, a wide viewing angle is regarded as important, and it is desirable to use an EL display. FIGS. 22 and 23 show specific examples of these electronic devices.
Shown in

FIG. 22A shows an EL display.
A housing 3301, a support 3302, a display portion 3303, and the like are included. The electronic device of the invention can be used for the display portion 3303. Since the EL display is a self-luminous type, it does not require a backlight and can be a display portion thinner than a liquid crystal display.

FIG. 22B shows a video camera, which includes a main body 3311, a display portion 3312, a voice input portion 3313, an operation switch 3314, a battery 3315, and an image receiving portion 331.
6 and so on. The electronic device of the invention can be used for the display portion 3312.

FIG. 22C shows a part (right side) of a head mounted EL display, which includes a main body 3321, a signal cable 3322, a head fixing band 3323, and a display section 33.
24, an optical system 3325, a display device 3326, and the like. The electronic device of the invention can be used for the display device 3326.

FIG. 22D shows an image reproducing apparatus (specifically, a DVD reproducing apparatus) provided with a recording medium.
1, recording medium (DVD, etc.) 3332, operation switch 33
33, a display unit (a) 3334, a display unit (b) 3335, and the like. The display unit (a) 3334 mainly displays image information, and the display unit (b) 3335 mainly displays character information.
4. Can be used for the display portion (b) 3335. Note that the image reproducing device provided with the recording medium includes a home game machine and the like.

FIG. 22E shows a goggle type display device (head mounted display), which includes a main body 3341, a display portion 3342, and an arm portion 3343. The electronic device of the invention can be used for the display portion 3342.

FIG. 22F shows a personal computer, which includes a main body 3351, a housing 3352, a display portion 3353,
A keyboard 3354 and the like. The electronic device of the invention can be used for the display portion 3353.

If the emission luminance of the EL material is increased in the future, the light including the output image information can be enlarged and projected by a lens or the like and used for a front-type or rear-type projector.

[0185] The electronic device may be the Internet or C.
Information distributed through an electronic communication line such as an ATV (cable television) is frequently displayed, and in particular, opportunities to display moving image information are increasing. Since the response speed of the EL material is very high, the EL display is preferable for displaying moving images.

In the EL display, the light emitting portion consumes power. Therefore, in order to save power, it is desirable to display information so that the light emitting portion is reduced as much as possible. Therefore, when an EL display is used for a portable information terminal, particularly a display unit mainly for character information such as a mobile phone or a sound reproducing device, the display is driven so that character information is formed by a light emitting portion with a non-light emitting portion as a background. It is desirable to do.

FIG. 23A shows a mobile phone, and the main body 34 is provided.
01, audio output unit 3402, audio input unit 3403, display unit 3404, operation switch 3405, antenna 3406
including. The electronic device of the present invention can be used for the display portion 3404. Note that the display portion 3404 can reduce power consumption of the mobile phone by displaying white characters on a black background.

FIG. 23B shows a sound reproducing device, specifically, a car audio.
2. Including operation switches 3413 and 3414. The electronic device of the invention can be used for the display portion 3412. In this embodiment, the in-vehicle audio is shown, but the present invention may be applied to a portable or home-use audio reproducing apparatus. The display unit 3
The power consumption 414 can be suppressed by displaying white characters on a black background. This is particularly effective in a portable sound reproducing device.

As described above, the applicable range of the present invention is extremely wide, and the present invention can be used for electronic devices in various fields. Further, the electronic apparatus of the present embodiment may use the electronic device having any configuration shown in the first to seventh embodiments.

By using an electronic device having pixels according to the structure of the present invention, a source signal line and a gate signal line can also be used for supplying a current flowing through an EL element. Wiring resistance can be reduced. As a result, the luminance of the EL element is reduced and the brightness is reduced.
The degree of unevenness can be improved.

Further, since the path of the current flowing through the EL element increases, crosstalk can be improved. In addition, since the wiring resistance is reduced and the load is reduced, when changing the voltage of the current supply line in a pulse shape,
The waveform can be hardly rounded. Therefore, even if the size of the panel is increased, display defects such as a decrease in luminance and crosstalk are less likely to occur, which can greatly contribute to improvement in image quality.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a pixel portion of an electronic device of the present invention.

FIG. 2 is a circuit configuration example illustrating application to the EL display shown in the first embodiment.

FIG. 3 is a circuit configuration example illustrating application to the EL display shown in the first embodiment.

FIG. 4 is a circuit configuration example illustrating application to the EL display shown in the first embodiment.

FIG. 5 is a circuit configuration example illustrating application to the EL display shown in the first embodiment.

FIG. 6 is a circuit configuration example for explaining application to the EL display shown in the first embodiment.

FIG. 7 is a circuit configuration example illustrating application to the EL display shown in the first embodiment.

FIG. 8 is a timing chart illustrating a method for driving the circuit described in Embodiment 1.

FIG. 9 is a timing chart illustrating a method for driving the circuit described in Embodiment 1.

FIG. 10 is a circuit configuration example illustrating application to the color EL display shown in the first embodiment.

FIGS. 11A to 11C illustrate an example of a manufacturing process of the electronic device described in Embodiment 2. FIGS.

FIG. 12 is a diagram illustrating an example of a manufacturing process of the electronic device described in Embodiment 2.

13 illustrates an example of a manufacturing process of the electronic device described in Embodiment 2.

14A and 14B are a top view and a cross-sectional view of the electronic device described in Embodiment 3.

FIGS. 15A and 15B are a top view and a cross-sectional view of the electronic device shown in Embodiment 4. FIGS.

FIG. 16 is a cross-sectional view of a pixel portion of the electronic device described in Embodiment 5.

FIG. 17 is a diagram showing a positive example of manufacturing the electronic device shown in Embodiment 5.

FIG. 18 is a cross-sectional view of a pixel portion of the electronic device described in Embodiment 6.

FIG. 19 is a circuit diagram of a conventional electronic device.

FIG. 20 is a circuit configuration example illustrating application to the EL display shown in the first embodiment.

FIG. 21 is a timing chart illustrating a method for driving the circuit described in Embodiment 1.

FIG. 22 is a diagram illustrating an example of an electronic apparatus in which the electronic device of the present invention is incorporated.

FIG. 23 illustrates an example of an electronic device in which the electronic device of the present invention is incorporated.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) G09G 3/20 624 G09G 3/20 624B 641 641E H05B 33/14 H05B 33/14 A F-term (Reference) 3K007 AB02 AB04 AB13 BA06 BB01 BB05 BB06 CA01 CB01 DA00 DB03 EB00 FA01 GA04 5C080 AA06 BB05 DD05 DD10 FF11 JJ03 JJ04 JJ06 5C094 AA04 AA07 AA08 AA22 AA53 AA55 AA56 BA03 BA12 BA27 CA19 CA24 CA25 DA09 EA01 FB01 FB01

Claims (20)

[Claims] An electronic device comprising a source signal line side driving circuit, a gate signal line side driving circuit, and a pixel portion, wherein the pixel portion includes a plurality of source signal lines, a plurality of gate signal lines, , A plurality of current supply lines, a connection control line, and a plurality of pixels, wherein each of the plurality of pixels includes a switching transistor, an EL driving transistor, an EL element, and a first connection transistor. Or a second connection transistor, wherein a gate electrode of the switching transistor is electrically connected to a gate signal line, and one of a source region and a drain region is electrically connected to the source signal line. And the other is electrically connected to the gate electrode of the EL driving transistor, and of the source region and the drain region of the EL driving transistor One is electrically connected to the current supply line, the other is electrically connected to one electrode of the EL element, and the gate electrode of the first connection transistor is connected to the connection control line. One of the source region and the drain region of the first connection transistor is electrically connected to any one of the plurality of source signal lines, and the other is connected to the first connection transistor. The second connection transistor is electrically connected to any one of the plurality of current supply lines, and the gate electrode of the second connection transistor is electrically connected to the connection control line, and the second connection transistor is electrically connected to the second connection transistor. One of a source region and a drain region of the transistor is electrically connected to any one of the plurality of gate signal lines, and the other is electrically connected to any one of the plurality of current supply lines. Electronic device characterized by there. 2. An electronic device comprising: a source signal line side driving circuit; a gate signal line side driving circuit; and a pixel portion, wherein the pixel portion includes a plurality of source signal lines, a plurality of gate signal lines, , A plurality of current supply lines, a connection control line, and a plurality of pixels. Each of the plurality of pixels includes a switching transistor, an EL driving transistor, an EL element, and a connection transistor. A gate electrode of the switching transistor is electrically connected to a gate signal line, one of a source region and a drain region is electrically connected to a source signal line, and the other is One of a source region and a drain region of the EL driving transistor is electrically connected to a current supply line. The other is electrically connected to one electrode of the EL element, and the gate electrode of the connection transistor is electrically connected to the connection control line; One of the source region or the drain region is electrically connected to any one of the plurality of source signal lines, and the other is electrically connected to any one of the plurality of current control lines. An electronic device, comprising: 3. An electronic device comprising a source signal line side driving circuit, a gate signal line side driving circuit, and a pixel portion, wherein the pixel portion includes a plurality of source signal lines, a plurality of gate signal lines, , A plurality of current supply lines, a connection control line, and a plurality of pixels. Each of the plurality of pixels includes a switching transistor, an EL driving transistor, an EL element, and a connection transistor. A gate electrode of the switching transistor is electrically connected to a gate signal line, one of a source region and a drain region is electrically connected to a source signal line, and the other is One of a source region and a drain region of the EL driving transistor is electrically connected to a current supply line. The other is electrically connected to one electrode of the EL element, and the gate electrode of the connection transistor is electrically connected to the connection control line; One of the source region or the drain region is electrically connected to any one of the plurality of gate signal lines, and the other is electrically connected to any one of the plurality of current control lines. An electronic device, comprising: 4. An electronic device comprising a source signal line side driving circuit, a gate signal line side driving circuit, and a pixel portion, wherein the pixel portion includes a plurality of source signal lines, a plurality of gate signal lines, , A plurality of current supply lines, a connection control line, and a plurality of pixels, wherein each of the plurality of pixels includes a switching transistor, an EL driving transistor, an EL element, and a first connection transistor. And a second connection transistor, wherein a gate electrode of the switching transistor is electrically connected to a gate signal line, and one of a source region and a drain region is connected to the source signal line. The other is electrically connected to the gate electrode of the EL driving transistor, and the other of the source region and the drain region of the EL driving transistor. One is electrically connected to the current supply line, the other is electrically connected to one electrode of the EL element, and the gate electrode of the first connection transistor is connected to the connection control line. One of the source region and the drain region of the first connection transistor is electrically connected to any one of the plurality of source signal lines, and the other is connected to the first connection transistor. The second connection transistor is electrically connected to any one of the plurality of current supply lines, and the gate electrode of the second connection transistor is electrically connected to the connection control line, and the second connection transistor is electrically connected to the second connection transistor. One of a source region and a drain region of the transistor is electrically connected to any one of the plurality of gate signal lines, and the other is electrically connected to any one of the plurality of current supply lines. Electronic device characterized by there. 5. An electronic device comprising a source signal line side driving circuit, a gate signal line side driving circuit, and a pixel portion, wherein the pixel portion includes a plurality of source signal lines, a plurality of gate signal lines, , A plurality of current supply lines, a connection control line, and a plurality of pixels, wherein each of the plurality of pixels includes a switching transistor, an EL driving transistor, an EL element, and a first connection transistor. And a second connection transistor, wherein a gate electrode of the switching transistor is electrically connected to a gate signal line, and one of a source region and a drain region is connected to the source signal line. The other is electrically connected to the gate electrode of the EL driving transistor, and the other of the source region and the drain region of the EL driving transistor. One is electrically connected to the current supply line, the other is electrically connected to one electrode of the EL element, and the gate electrode of the first connection transistor is connected to the connection control line. One of the source region and the drain region of the first connection transistor is electrically connected to any one of the plurality of source signal lines, and the other is connected to the first connection transistor. The second connection transistor is electrically connected to any one of the plurality of current supply lines, and the gate electrode of the second connection transistor is electrically connected to the connection control line, and the second connection transistor is electrically connected to the second connection transistor. One of a source region and a drain region of the transistor is electrically connected to any one of the plurality of source signal lines, and the other is electrically connected to any one of the plurality of gate signal lines. Electronic device characterized in that is. 6. An electronic device comprising a source signal line side driving circuit, a gate signal line side driving circuit, and a pixel portion, wherein the pixel portion includes a plurality of source signal lines, a plurality of gate signal lines, , A plurality of current supply lines, a connection control line, and a plurality of pixels, wherein each of the plurality of pixels includes a switching transistor, an EL driving transistor, an EL element, and a first connection transistor. And a second connection transistor, wherein a gate electrode of the switching transistor is electrically connected to a gate signal line, and one of a source region and a drain region is connected to the source signal line. The other is electrically connected to the gate electrode of the EL driving transistor, and the other of the source region and the drain region of the EL driving transistor. One is electrically connected to the current supply line, the other is electrically connected to one electrode of the EL element, and the gate electrode of the first connection transistor is connected to the connection control line. One of the source region and the drain region of the first connection transistor is electrically connected to any one of the plurality of gate signal lines, and the other is connected to the first connection transistor. The second connection transistor is electrically connected to any one of the plurality of current supply lines, and the gate electrode of the second connection transistor is electrically connected to the connection control line, and the second connection transistor is electrically connected to the second connection transistor. One of a source region and a drain region of the transistor is electrically connected to any one of the plurality of source signal lines, and the other is electrically connected to any one of the plurality of gate signal lines. Electronic device characterized in that is. 7. An electronic device comprising a source signal line side drive circuit, a gate signal line side drive circuit, and a pixel portion, wherein the pixel portion includes a plurality of source signal lines, a plurality of gate signal lines, , A plurality of current supply lines, a connection control line, and a plurality of pixels, wherein each of the plurality of pixels includes a switching transistor, an EL driving transistor, an EL element, and a first connection transistor. And a second connection transistor; and a third connection transistor. The gate electrode of the switching transistor is electrically connected to a gate signal line, and includes a source region and a drain region. One of them is electrically connected to the source signal line, and the other is electrically connected to the gate electrode of the EL driving transistor. One of the source region and the drain region is electrically connected to the current supply line, and the other is electrically connected to one electrode of the EL element; Is electrically connected to the connection control line, and one of a source region and a drain region of the first connection transistor is electrically connected to any one of the plurality of source signal lines. The other is electrically connected to any one of the plurality of current supply lines, and the gate electrode of the second connection transistor is electrically connected to the connection control line. One of the source region and the drain region of the second connection transistor is electrically connected to any one of the plurality of gate signal lines, and the other is connected to the plurality of current supply lines. A gate electrode of the third connection transistor is electrically connected to the connection control line, and a source region or a drain of the third connection transistor. One of the regions is electrically connected to any one of the plurality of source signal lines, and the other is electrically connected to any one of the plurality of gate signal lines. Electronic devices. 8. The semiconductor device according to claim 1, wherein one of a source region and a drain region of the EL driving transistor is electrically connected to an anode of the EL element. The polarity of the EL driving transistor is a P-channel type. When one of the source region and the drain region of the EL driving transistor is electrically connected to the cathode of the EL element, the EL driving transistor is turned off. An electronic device, wherein the polarity of the transistor is N-channel. 9. The electronic device according to claim 1, wherein the polarity of the switching transistor is the same as the polarity of the EL driving transistor. 10. The electronic device according to claim 1, wherein the gate signal line is formed using aluminum or a material containing aluminum as a main component. 11. The method of controlling the length of the lighting time of the EL element to control n
In the driving method of an electronic device that performs bit gradation control, in the sustain (lighting) period that does not overlap with the address (writing) period, the first connection transistor or the second connection transistor is turned on, A current supply line and a source signal line electrically connected to the source region and the drain region of the first connection transistor; or a current supply line and a source signal line electrically connected to the source region and the drain region of the second connection transistor A driving method for an electronic device, wherein the current supply line and the gate signal line become conductive. 12. The method of controlling the length of the lighting time of the EL element to control n
In the driving method of an electronic device that performs bit gradation control, in the sustain (lighting) period that does not overlap with the address (writing) period, the supply of current to the EL element is performed by a current supply line and a first supply line. A source signal line electrically connected to the current supply line via a connection transistor or a gate signal line electrically connected to the current supply line via a second connection transistor. A method for driving an electronic device. 13. The method of controlling the length of the lighting time of the EL element to obtain n
In a method for driving an electronic device that performs bit gradation control, a current supply line electrically connected to a source region and a drain region of a connection transistor during a period in which a gate signal line in an i-th row is in a non-selected state. And the gate signal line of the i-th row is turned on. 14. An EL display using the electronic device according to claim 1. Description: 15. A video camera using the electronic device according to any one of claims 1 to 10. 16. A head mounted display using the electronic device according to claim 1. Description: 17. A DVD player using the electronic device according to any one of claims 1 to 10. 18. A personal computer using the electronic device according to any one of claims 1 to 10. 19. A mobile phone using the electronic device according to claim 1. Description: 20. A car audio using the electronic device according to any one of claims 1 to 10.