JP2003084689A - El display device and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an EL (electroluminescence) display device which has a little luminance unevenness or display unevenness accompanying manufacturing variance, and excellent uniformity in image quality. SOLUTION: The organic EL display device is provided with an organic EL element 8 in which an organic EL luminous layer is at least held between a pair of electrode in one pixel, a capacitor 5, a write transistor 4, and two drive transistors 6 and 7 connected in parallel. The two driving transistors 6 and 7 are arranged at each of corners in the diagonal direction of the rectangular pixel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroluminescence (hereinafter abbreviated as EL) display device and electronic equipment, and more particularly to the arrangement of drive transistors in each pixel of an EL display device.

[0002]

2. Description of the Related Art An organic EL display device provided with an organic EL element corresponding to each pixel is capable of self-luminous display with high brightness, capable of being driven at a low DC voltage, and having a high response.
It has excellent display performance because it emits light from a solid organic film, and it is expected to be a display device that will follow liquid crystal display devices in the future because it can make the display device thinner, lighter, and consume less power. Has been done. In particular, the active matrix organic EL whose drive method is the active matrix method
Since the display device includes a transistor and a capacitor for each pixel, high luminance and high definition can be achieved, and multi-gray scale and a large display device can be dealt with.

FIG. 10 is an example of an equivalent circuit diagram showing one pixel of a conventional active matrix type organic EL display device. A gate line 101 (also referred to as a scan line) extends in a horizontal direction, and a source line 102 (also referred to as a data line) and two EL power supply lines 103 which sandwich the source line 102 in a vertical direction (a direction orthogonal to the gate line). Regions that extend and are arranged in a grid pattern and are partitioned by these wirings form one pixel. In the pixel, a writing transistor 104 and a capacitor 1
05, two drive transistors 1 connected in parallel to each other
06 and 107, these drive transistors 106 and 107
The organic EL elements 108 connected to the respective are provided.

The operation of the organic EL display device having such a circuit configuration will be described. First, a scanning signal (voltage) is sequentially applied from the gate driver to the plurality of gate lines 101, and all the write transistors 104 (first TF) connected to the gate line 101 are individually applied.
T) is turned on. Further, a display signal is supplied from the source driver to the source line 102 in synchronization with this scanning.
At this time, since the writing transistor 104 is in the ON state, this display signal is stored in the capacitor 105. Next, the operating state of the drive transistors 106 and 107 (second and third TFTs) is determined by the charge amount of the display signal accumulated in the capacitor 105. For example, when the charge amount of the display signal exceeds the threshold voltage of the drive transistors 106 and 107 and the drive transistors 106 and 107 are turned on, the organic EL is connected from the EL power supply line 103 through the two drive transistors 106 and 107. A current is supplied to the element 108, the organic EL element 108 emits light, and the pixel thereof lights up.

[0005]

By the way, in the case of an active matrix type organic EL display device, in order to cause each organic EL element to emit light by itself, it is necessary to continuously supply a current during the light emission time of the element. The amount of current to be supplied at this time depends on the element area and the light emission luminance, but needs to be about several μA. In order to configure a drive transistor that supplies a current as large as this, a method of increasing the transistor width or connecting a plurality of transistors in parallel can be considered. Although any of these methods may be used, in general, there are variations in the characteristics of transistors, so from the viewpoint of mitigating current variations by using multiple transistors, for example, The 10th International Workshop on
Inorganic and Organic Electroluminescence (EL'00),
As described in 2000, pp347-352, it is preferable to adopt a method of connecting a plurality of transistors in parallel. As a result, it is possible to realize an organic EL display device having less unevenness in brightness and unevenness in display. This example is shown in FIG.

However, in the manufacturing process of the organic EL display device, it is inevitable that various factors such as parameters such as the film thickness of the gate insulating film forming the TFT and the impurity concentration of the semiconductor layer vary to some extent within the substrate surface. That is. If these parameters locally fluctuate on the substrate surface, it is conceivable that the electric characteristics of the TFTs in the region fluctuate and the ON current fluctuates. Here, since the organic EL display device is a current drive type display device, the current variation directly affects the luminance unevenness and the display unevenness, and the luminance unevenness and the display unevenness are caused by the variations in the manufacturing process on the substrate surface. There was a problem that display unevenness occurred. That is, although a design method in which a plurality of driving transistors are connected in parallel is adopted for the purpose of obtaining an organic EL display device with less unevenness in brightness and display, in reality, sufficient image quality uniformity can be obtained due to manufacturing variations. There was a problem of not having.

Although an example of an organic EL display device has been described above, some EL display devices include a display device using an inorganic EL material. Generally, an inorganic EL display device is driven by an AC voltage, but its light emitting mechanism is that light is emitted when electrons tunnel-injected through an electric field across a barrier collide with a light emission center. Therefore, it is important to control the current, and for that reason, it is necessary to suppress the variation of the driving transistor. Further, in order to suppress the driving voltage, thinning the inorganic EL element is one means, but when this means is used, it is important to suppress the variation in current due to the thinning. That is, it is a common problem not only for organic EL display devices but also for inorganic EL display devices to suppress manufacturing variations of drive transistors in order to obtain uniform image quality.

The present invention has been made in order to solve the above problems, and has less unevenness in brightness and unevenness in display due to manufacturing variations as compared with the prior art, and is excellent in uniformity of image quality.
It is an object to provide an L display device.

[0009]

In order to achieve the above-mentioned object, the EL display device of the present invention has at least E between a pair of electrodes in each of a plurality of pixels arranged in a matrix.
An EL display device comprising an EL element in which an L light emitting layer is sandwiched, a capacitor, a writing transistor, and a plurality of driving transistors connected in parallel, wherein the plurality of driving transistors are pixels of a substantially rectangular shape. It is characterized in that it is arranged at each of the corners in the diagonal direction. That is, the EL display device of the present invention is an active matrix type display device, and the “pixel” in the present invention is partitioned by the gate lines and the data lines (or EL element power supply lines) arranged in a grid pattern. Area.

The inventor of the present invention, in an EL display device provided with a plurality of parallel-connected drive transistors in a pixel, has devised the arrangement of the drive transistors in the pixel to cause current variations that lead to uneven brightness and uneven display. It was found that it can be reduced compared to. The contents will be described below.

Usually, in an active matrix type EL display device, one pixel has a rectangular shape, for example R.
EL with three color pixels (red), G (green), and B (blue)
Since one pixel of an image is composed of three pixels in a display device, it is often an elongated rectangular shape in which the dimension of the long side is about several times the dimension of the short side. FIG. 8A is a diagram showing a configuration of a conventional pixel provided with two drive transistors, and a drive transistor is shown by a circle of TR. That is, in the conventional design, the two driving transistors are arranged side by side in the direction along the short side of the pixel (FIG. 10 is an equivalent circuit diagram of the conventional device, but the driving transistors are rectangular even in the actual circuit pattern). Were arranged in the short side direction of the pixels).

Now, assume that a drive transistor TR having a current supply capacity of 100 is formed. However, during the manufacturing process, some variations in manufacturing parameters such as the thickness of the gate insulating film and the impurity concentration of the semiconductor layer occur within the circle of the broken line indicated by the symbol A1. It is assumed that a transistor is formed. Then, even if a normal pixel has a current supply capacity of 200 in total by the two drive transistors, only a current supply capacity of 190 is obtained in the central pixel of FIG. Therefore, this pixel has a 5% lower current supply capability than a normal pixel, which causes uneven brightness and uneven display.

On the other hand, in the EL display device of the present invention, as shown in FIG. 8B, the two driving transistors TR are arranged at the corners of the pixel in the diagonal direction. The distance between the two drive transistors in one pixel is longer than in the case of 8 (a). By doing so, even if variations in manufacturing parameters occur at similar locations occupying the same area as in the case of FIG. 8A,
For example, as shown by the broken line area A2 in FIG.
The current supply capability of only one transistor in one pixel is reduced to 95. Therefore, this pixel G
The current supply capacity of the transistor in 2 is 195, and the decrease in the current supply capacity is 2.5 when compared to a normal pixel.
%. In this way, it is possible to reduce the decrease in the current supply capability for normal pixels as compared with the conventional case of FIG.

Further, when the two drive transistors are arranged at the corners of the pixel in the diagonal direction, the distance between the drive transistors is short between the pixels arranged in the diagonal direction.
For example, as indicated by the broken line area A3 in FIG.
In some cases, two drive transistors are included in the region where the manufacturing parameter varies. However, even in this case, the two drive transistors are provided in different pixels G3 and G4.
Therefore, the variation is shared by the two pixels G3 and G4, and the current supply capability of the transistors in both of the two pixels arranged diagonally becomes 195. Therefore, also in this case, the amount of decrease in the current supply capacity is 2.5% as compared with a normal pixel. In this case, although the current supply capacity is reduced to two pixels, the decrease in the current supply capacity for normal pixels is halved, so that the degree of display unevenness is also reduced when viewed over the entire screen.

As described above, according to the EL display device of the present invention, the distance between the plurality of drive transistors in one pixel is made longer than that of the conventional one, so that the drive transistors due to manufacturing variations in the substrate surface are produced. It is possible to reduce the variation in the current driving capability among the pixels as compared with the related art.
As a result, there is less unevenness in brightness and display than in the past,
An EL display device having excellent image quality uniformity can be provided.

The model shown in FIGS. 8 (a) and 8 (b) is one model case for simplifying the description, and the dimensions of the pixels, the distance between the driving transistors, and manufacturing variations occur. It goes without saying that various cases other than this may be considered depending on the mutual relation of the size and shape of the region. However, in any case, if the distance between a plurality of drive transistors in one pixel is increased, there is a certain degree of probability that the current drive capability of the drive transistor will invariably vary among pixels. It is possible to obtain the effect that the power consumption can be reduced as compared with the conventional one.

Further, it is desirable that the plurality of drive transistors in adjacent substantially rectangular pixels are arranged at different corners in the diagonal direction in each pixel.

As shown in FIG. 9, for example, when two drive transistors TR in adjacent pixels are arranged in different diagonal directions, the drive transistors TR of four pixels are close to each other. Here, similarly to the above, it is assumed that the manufacturing parameters vary within the broken-line circle indicated by symbol A4, and a drive transistor having a current supply capacity of 95 is formed in this region. In this case, 4
The individual driving transistors are different pixels G5, G6, G7,
Since it belongs to G8, the variation is shared by four pixels. As a result, the current supply capability is made uniform over a wider range of pixels than in the case of FIG. 8B, and there is less unevenness in brightness and pixels, and an EL display device with excellent image quality uniformity can be provided. it can.

In another EL display device of the present invention, an EL element in which at least an EL light emitting layer is sandwiched between a pair of electrodes, a capacitor, a writing transistor are provided in each of a plurality of pixels arranged in a matrix. An EL display device including a plurality of drive transistors connected in parallel, wherein the plurality of drive transistors are arranged at respective end portions in a direction in which long sides of substantially rectangular pixels extend. Is characterized by.

Also in this configuration, similar to the above-described configuration in which a plurality of drive transistors are arranged in the diagonal direction of the pixel,
Since the distance between multiple drive transistors in one pixel is longer than before, it is possible to reduce variations in the current drive capacity of the drive transistors due to variations in manufacturing compared to the past, and to reduce uneven brightness and display unevenness An EL display device having excellent uniformity can be obtained.

When a plurality of drive transistors are arranged at the ends of the long side of the pixel in the extending direction, all the drive transistors in one pixel should be connected to the same EL element power supply line. Is desirable.

In the usual structure of the active matrix type EL display device, the extending direction of the gate line is the short side direction of the pixel, and the extending direction of the data line and the EL element power source line is the long side direction of the pixel. In the EL display device, it is necessary to connect the drive transistor to the EL element power supply line. However, in the case of the conventional configuration in which two drive transistors are arranged in the short side direction of the pixel, it is difficult to route the wiring. Due to design considerations, each drive transistor must be connected to a separate EL element power line, and the EL elements must be connected to both sides of the pixel.
It is necessary to arrange the power line for the device. That is, in the area between adjacent pixels, one data line and two EL power supply lines arranged on both sides of the data line, that is, three wiring lines in total are required.

However, the EL display device of the present invention, in particular, an EL device in which a plurality of drive transistors are arranged in the long side direction of a pixel.
According to the display device, it is possible to eliminate the difficulty of routing the wiring, and to connect all of the plurality of drive transistors in one pixel to the same EL element power supply line. In this case, since one EL element power supply line may be arranged on one side of the pixel, if there is a total of two wirings, one data line and one EL power supply line, in the area between adjacent pixels. It will be good. As a result, the wiring area can be made narrower than in the conventional case, and as a result, the aperture ratio can be improved.

Further, it is desirable that the capacitor is arranged in a region that planarly overlaps the data line connected to the write transistor and the EL element power supply line connected to the drive transistor.

Regarding the arrangement of the capacitors, the capacitors may be arranged in an area inside the pixel which does not overlap with the data line or the EL element power supply line in plan view, but in the area where it overlaps with the data line or EL element power supply line in plan view. With the arrangement, the area occupied by the capacitor in the pixel can be reduced, and the aperture ratio can be improved accordingly.

The electronic equipment of the present invention is characterized by including the EL display device of the present invention. According to this configuration, it is possible to realize an electronic device including an EL display unit that has less unevenness in brightness and unevenness in display and is excellent in uniformity of image quality.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION [First Embodiment] A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an equivalent circuit diagram of one pixel constituting the active matrix organic EL display device (EL display device) of the present embodiment, and FIG. 2 is a specific example for realizing the equivalent circuit diagram of FIG. It is a plan view showing an example of a different circuit pattern.

In the organic EL display device of the present embodiment, as shown in FIG. 1, the gate line 1 (scanning line) extends in the lateral direction and sandwiches the source line 2 (data line) and the gate line 1 (data line).
The EL element power supply lines 3 (hereinafter, simply referred to as EL power supply lines) extend in the vertical direction (direction orthogonal to the gate line 1) and are arranged in a grid pattern with each other. It constitutes a pixel. In the pixel, a write transistor 4 electrically connected to the gate line 1 and the source line 2, a capacitor 5 electrically connected to the write transistor 4, a capacitor 5 electrically connected, and connected in parallel with each other. Two driving transistors 6 and 7, and an organic EL electrically connected to these driving transistors 6 and 7
The element 8 is provided. As far as an equivalent circuit is concerned, it is similar to the conventional configuration, but in the case of the present embodiment, the drive transistors 6 and 7 are arranged at respective corners in the diagonal direction of the pixel.

Next, a specific circuit pattern will be described with reference to FIG. In FIG. 2, reference numeral 1 is a gate line, 2 is a source line, and 3 is an EL power supply line. In the following description, for convenience, the region where the gate line 1 is arranged is referred to as a lateral wiring region L,
A region where the source line 2 and the EL power supply line 3 are arranged is referred to as a vertical wiring region V. In the actual pattern, each transistor is composed of a TFT, and in the first TFT which constitutes the writing transistor 4, one end is connected to the source line 2 through the contact hole 9 and the gate line 1 is connected.
A semiconductor layer 10 is provided, the other end of which extends along the vertical wiring region V after intersecting with. Portions extending from the upper portion and the lower portion of the semiconductor layer 10 toward the inside of the pixel (referred to as a first extending portion 10a and a second extending portion 10b, respectively) are provided. The gate electrodes of the 3 TFTs are connected. Further, the portion 10c extending along the vertical wiring region V of the semiconductor layer 10 is the capacitor 5
One electrode is formed, one end of which is connected to the EL power supply line 3 through the contact hole 11 so as to overlap with this portion 10c, and the capacitive electrode 12 which forms the other electrode of the capacitor 5 is provided.

The second constituting one of the driving transistors 6
The TFT has a contact hole 13 at one end.
The semiconductor layer 14 connected to the EL power source line 3 on the left side of the pixel is formed in the upper left corner of the pixel in FIG. 2, and the semiconductor layer 1 of the first TFT is formed through the contact hole 15.
A gate electrode 16 connected to the first extended portion 10 a (drain region) of 0 is provided so as to intersect with the semiconductor layer 14. Further, a relay layer 18 connected to the other end (drain region) of the semiconductor layer 14 of the second TFT through the contact hole 17 is provided, and the relay layer 18 is contacted with the indium tin oxide (Indium Tin Oxide) through the contact hole 19.
The upper end of the pixel electrode 20 formed of a transparent conductive film such as Tin Oxide (hereinafter abbreviated as ITO) is connected. That is, the semiconductor layer 14 of the second TFT and the pixel electrode 20 are electrically connected via the relay layer 18.

In the third TFT which constitutes another one of the drive transistors 7, the semiconductor layer 22 whose one end is connected to the EL power supply line 3 on the right side of the pixel through the contact hole 21 is the pixel in FIG. A long L-shaped gate electrode 24 is formed in the lower right corner of the semiconductor layer 22 and is connected to the second extension 10b (drain region) of the semiconductor layer 10 of the first TFT through the contact hole 23.
It is provided to intersect with. And the third TF
A relay layer 26 connected to the other end (drain region) of the semiconductor layer 22 of T through a contact hole 25 is provided,
The lower end of the pixel electrode 20 is connected to the relay layer 26 through a contact hole 27. That is, the third TFT
The semiconductor layer 22 and the pixel electrode 20 are electrically connected via the relay layer 26.

The solid line 28 in FIG. 2 is the outline of the organic EL light emitting layer, and the alternate long and short dash line 29 is the outline of the light shielding layer (black matrix). In addition, the organic EL element 8 is a pixel electrode 20 that serves as an anode of the organic EL element.
At least the organic EL light emitting layer 28 is sandwiched between a pair of electrodes composed of a metal electrode (not shown) serving as a cathode. In addition to the light emitting layer, layers such as a hole injection layer, a hole transport layer, and an electron transport layer may be sandwiched between the pair of electrodes.

The organic EL display device of this embodiment is different from the conventional one in the planar pattern arrangement, and since the equivalent circuit is the same as the conventional one, the operation of the organic EL display device is also exactly the same as the conventional one. Therefore, the description is omitted.

According to the present embodiment, the two driving transistors 6 and 7 in one pixel are arranged at the corners of the rectangular pixel in the diagonal direction, and the driving transistor is driven as compared with the conventional one shown in FIG. By increasing the distance between the transistors 6 and 7, it is possible to reduce the variation between the pixels of the current driving capability of the drive transistor due to the variation in manufacturing in the substrate surface as compared with the conventional case. Further, if the distance from the driving transistor in another pixel arranged diagonally to the pixel is shorter than the distance between the two driving transistors 6 and 7 in the same pixel, the manufacturing variation in the plane of the substrate will occur. It is possible to share the variation in the current driving capability of the drive transistor due to the above-mentioned difference among the pixels. As a result, it is possible to provide an organic EL display device that has less unevenness in brightness and unevenness in display than conventional ones and is excellent in uniformity of image quality.

Further, in the present embodiment, since the capacitor 5 is arranged in the vertical wiring region V, the area occupied by the capacitor 5 in the pixel can be reduced and the aperture ratio can be improved accordingly.

In this embodiment, the two driving transistors 6 and 7 are arranged only at the same corner portion in the diagonal direction in all the pixels, but different diagonal corners are formed in adjacent pixels. Two drive transistors may be arranged in the section. In that case, the drive transistors of the four pixels are close to each other, and they share variations. Therefore, it is possible to provide an EL display device that has less unevenness in brightness and unevenness in pixels and is excellent in uniformity of image quality.

[Second Embodiment] The second embodiment of the present invention will be described below.
An embodiment will be described with reference to FIGS. 3 and 4. FIG. 3 shows the active matrix type organic EL of this embodiment.
FIG. 4 is an equivalent circuit diagram of one pixel forming the display device.
FIG. 4 is a plan view showing an example of a specific circuit pattern for realizing the equivalent circuit diagram of FIG. 3. While the two driving transistors are arranged in the diagonal direction of the pixel in the first embodiment, the present embodiment is an example in which the two driving transistors are arranged in the long side direction of the pixel. Therefore, FIG. 3 and FIG.
In FIG. 1, the same components as those in FIGS. 1 and 2 are designated by the same reference numerals, and detailed description of the common portions will be omitted.

In the organic EL display device of the present embodiment, as shown in FIG. 3, the gate lines 1, the source lines 2 and the EL power supply lines 3 are arranged in a grid pattern, and the inside of a pixel is divided into these wirings. Further, a writing transistor 4, a capacitor 5, two driving transistors 6 and 7 connected in parallel, and an organic EL element 8 are provided. As far as an equivalent circuit is concerned, it is similar to the conventional configuration and the first embodiment, but in the case of the present embodiment, the drive transistors 6 and 7 are arranged at the ends of the pixel in the long side direction. There is. Further, as a difference from the first embodiment, these drive transistors 6 and 7 are connected to the same EL power supply line 3 (EL power supply line 3 on the left side of the pixel), and in the first embodiment, the vertical direction. The two EL power supply lines 3 provided on both sides of the source line 2 in the wiring region V are one on each side.

Next, a specific circuit pattern will be described with reference to FIG. In the first embodiment, the drive transistors are arranged at the upper left and lower right of the pixel,
In this embodiment, the drive transistors 6 and 7 are arranged at the upper left and lower left of the pixel. Therefore, the pattern configuration on the upper side of the pixel (on the side of the first and second TFTs) is substantially the same as that of the first embodiment (FIG. 2), and on the lower side of the pixel (on the side of the third TFT).
Side) only the pattern configuration is different. In the present embodiment, the second TFT side and the third TFT side are substantially symmetrical.

That is, similarly to the second TFT, the third TFT has the semiconductor layer 22 whose one end is connected to the EL power source line 3 on the left side of the pixel through the contact hole at the lower left corner of the pixel in FIG. Contact hole 23
Through the second extending portion 1 of the semiconductor layer 10 of the first TFT
A gate electrode 24 connected to 0b (drain region) is provided so as to cross the semiconductor layer 10. A relay layer 26 connected to the other end (drain region) of the semiconductor layer 22 of the third TFT through the contact hole 25 is provided, and the relay layer 26 has a contact hole 27.
The lower end of the pixel electrode 20 is connected through.

Also in this embodiment, the two driving transistors 6 and 7 in one pixel are arranged at the ends of the rectangular pixel in the long side direction, and these driving transistors 6 and 7 are arranged.
By increasing the distance between the pixels, it is possible to reduce the variation in the current driving capability of the drive transistor between pixels, and to realize an organic EL display device that has less unevenness in brightness and display than in the past and has excellent image quality uniformity. By arranging the capacitor 5 in the vertical wiring region V, it is possible to obtain the same effect as that of the first embodiment such that the aperture ratio can be improved.

Further, in the present embodiment, the two drive transistors 6 and 7 are arranged at the ends in the long side direction of the pixel, so that the drive transistors 6 and 7 are connected to one common EL power supply line 3. It becomes possible to connect. With this configuration, only one EL power supply line is required for one pixel, and the vertical wiring region can be narrowed, so that the aperture ratio can be further improved as compared with the first embodiment.

[Electronic Device] An example of an electronic device equipped with the organic EL display device of the above embodiment will be described. Figure 5
FIG. 4 is a perspective view showing an example of a mobile phone. In FIG. 5, reference numeral 1000 indicates a mobile phone body, and reference numeral 1001.
Indicates a display unit using the above organic EL display device.

FIG. 6 is a perspective view showing an example of a wrist watch type electronic device. In FIG. 6, reference numeral 1100 indicates a watch main body, and reference numeral 1101 indicates a display unit using the above organic EL display device.

FIG. 7 is a perspective view showing an example of a portable information processing device such as a word processor and a personal computer. In FIG. 7, reference numeral 1200 is an information processing apparatus, reference numeral 1202 is an input unit such as a keyboard, reference numeral 1204 is the information processing apparatus main body, and reference numeral 1206 is a display unit using the above organic EL display device.

Since the electronic equipment shown in FIGS. 5 to 7 is equipped with the organic EL display device of the above-mentioned embodiment, the electronic equipment equipped with the display section with less unevenness in brightness and display and excellent in image quality uniformity. Equipment can be realized.

The technical scope of the present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-described first and second embodiments, an example in which two transistors are used as a plurality of drive transistors has been shown, but three or more transistors may be used. In that case, even if some transistors are arranged in the short side direction, if some transistors are distributed in the diagonal direction or the long side direction, all three or more transistors are arranged in the short side direction. The effect of reducing uneven brightness and uneven display can be obtained. Further, the plane patterns shown in FIGS. 2 and 4 are merely examples, and the specific shape and size of each pattern can be appropriately changed. Furthermore, in the above embodiment, the example of the organic EL display device has been described, but the same configuration can be applied to the inorganic EL display device.

[0048]

As described above in detail, according to the present invention, the arrangement of a plurality of drive transistors in one pixel is devised so that the distance between these drive transistors is made longer than in the conventional case. An EL that can reduce variations in the current drive capacity of transistors between pixels, has less unevenness in brightness and display than before, and has excellent image uniformity.
A display device can be realized. In addition, if the distance between the plurality of drive transistors between pixels is shorter than the distance between two drive transistors within the same pixel, variations in the current drivability of the drive transistors due to manufacturing variations within the substrate surface can be reduced. Since it can be shared between pixels, there is less unevenness in brightness and display compared to the conventional one,
It is possible to realize an organic EL display device having excellent image quality uniformity.

[Brief description of drawings]

FIG. 1 is an equivalent circuit diagram showing one pixel of an organic EL display device of a first embodiment of the present invention.

FIG. 2 is a plan view showing one configuration example of a circuit pattern that realizes the equivalent circuit.

FIG. 3 is an equivalent circuit diagram showing one pixel of the organic EL display device of the second embodiment of the present invention.

FIG. 4 is a plan view showing a configuration example of a circuit pattern that realizes the equivalent circuit.

FIG. 5 is a perspective view showing an example of an electronic apparatus of the present invention including the organic EL display device.

FIG. 6 is a perspective view showing another example of the electronic device.

FIG. 7 is a perspective view showing still another example of the electronic device.

FIG. 8 is a diagram for explaining the operation of the present invention.

FIG. 9 is a diagram for explaining the operation of the present invention.

FIG. 10 is an equivalent circuit diagram showing one pixel of a conventional active matrix type organic EL display device.

[Explanation of symbols]

1 gate line (scan line) 2 Source line (data line) 3 EL power supply line (EL element power supply line) 4 writing transistor 5 capacitors 6,7 drive transistor 8 Organic EL element

Claims (6)

[Claims] 1. An EL element in which at least an EL emission layer is sandwiched between a pair of electrodes, a capacitor, a writing transistor, and a plurality of driving transistors connected in parallel to each other in each of a plurality of pixels arranged in a matrix. An EL display device comprising: a plurality of drive transistors, each of which is arranged at each corner of a substantially rectangular pixel in a diagonal direction. 2. The EL display device according to claim 1, wherein the plurality of drive transistors in adjacent substantially rectangular pixels are arranged at different corners in a diagonal direction in each pixel. 3. An EL element in which at least an EL light emitting layer is sandwiched between a pair of electrodes, a capacitor, a writing transistor, and a plurality of driving transistors connected in parallel to each other in each of a plurality of pixels arranged in a matrix. An EL display device comprising: a plurality of drive transistors, wherein the plurality of drive transistors are arranged at respective end portions in a direction in which long sides of substantially rectangular pixels extend. 4. The EL display device according to claim 3, wherein all of the plurality of drive transistors in one pixel are connected to the same EL element power supply line. 5. The capacitor is arranged in a region that planarly overlaps with a data line electrically connected to the write transistor and an EL element power line electrically connected to the drive transistor. The EL display device according to any one of claims 1 to 4. 6. An electronic apparatus comprising the EL display device according to claim 1. Description: