JP4815727B2 - EL display device and electronic apparatus - Google Patents

Description

[0001]
BACKGROUND 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 in the EL display device.
[0002]
[Prior art]
An organic EL display device provided with an organic EL element corresponding to each pixel has high brightness and self-emission, can be driven by a DC low voltage, has a high response speed, and emits light by a solid organic film. For this reason, the display performance is excellent, and the display device can be reduced in thickness, weight, and power consumption. Therefore, it is expected as a display device that will follow the liquid crystal display device in the future. In particular, an active matrix organic EL display device with an active matrix drive method includes a transistor and a capacitor for each pixel, so that high brightness and high definition can be achieved. It can cope with the conversion.
[0003]
FIG. 10 is an example of an equivalent circuit diagram showing one pixel of a conventional active matrix organic EL display device. A gate line 101 (also referred to as a scanning line) extends in the horizontal direction, and a source line 102 (also referred to as a data line) and two EL power supply lines 103 sandwiching the source line 102 (also referred to as a data line) extend in a vertical direction (a direction perpendicular to the gate line). A region extending and arranged in a grid pattern and partitioned by these wirings constitutes one pixel. In the pixel, a writing transistor 104, a capacitor 105, two driving transistors 106 and 107 connected in parallel to each other, and an organic EL element 108 connected to these driving transistors 106 and 107 are provided.
[0004]
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 to turn on all the write transistors 104 (first TFTs) connected to the gate lines 101 for each one. State. In addition, 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 turned on, this display signal is accumulated in the capacitor 105. Next, the operation 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 element is connected from the EL power line 103 via 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 is lit.
[0005]
[Problems to be solved by the invention]
By the way, in the case of an active matrix organic EL display device, in order to cause each organic EL element to emit light itself, it is necessary to continuously supply 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 approximately several μA is required. In order to configure a driving transistor that supplies such a large current, a method of increasing the transistor width or connecting a plurality of transistors in parallel can be considered. Any of these methods may be used, but generally, there are variations in transistor characteristics. From the viewpoint of reducing current variation by using multiple transistors, for example, The 10th International Workshop on Inorganic and Organic Electroluminescence ( EL'00), 2000, pp347-352, it is desirable to adopt a method of connecting a plurality of transistors in parallel. Thereby, an organic EL display device with small luminance unevenness and display unevenness can be realized. This example is shown in FIG.
[0006]
However, in the manufacturing process of the organic EL display device, it is inevitable that various factors such as the film thickness of the gate insulating film constituting the TFT and the impurity concentration of the semiconductor layer vary to some extent within the substrate surface. . If these parameters vary locally within the substrate surface, it is conceivable that the electrical characteristics of the TFTs in that region vary and appear as variations in on-current. Here, since the organic EL display device is a current-driven display device, the current variation directly affects the luminance unevenness and the display unevenness, and the luminance unevenness and the unevenness in the manufacturing process within the substrate surface. There was a problem that display unevenness occurred. In other words, while adopting a design method in which a plurality of drive transistors are connected in parallel for the purpose of obtaining an organic EL display device with small brightness unevenness and display unevenness, sufficient image quality uniformity can actually be obtained due to manufacturing variations. There was no problem.
[0007]
As mentioned above, although the example of the organic EL display device has been described, some EL display devices include a display device using an inorganic EL material. In general, an inorganic EL display device is driven by an alternating voltage, but its light emission mechanism is such that light is emitted when electrons injected through a tunnel through a barrier through an electric field collide with a light emission center. Therefore, it is important to control the current, and for this reason, it is necessary to suppress the variation of the driving transistor. Further, in order to suppress the drive voltage, thinning the inorganic EL element is one means. When this means is used, means for suppressing the variation in current accompanying the thinning becomes important. That is, it is a common problem not only for an organic EL display device but also for an inorganic EL display device to suppress the manufacturing variation of the drive transistor in order to obtain uniformity in image quality.
[0008]
The present invention has been made to solve the above-described problems, and provides an EL display device that has less luminance unevenness and display unevenness due to manufacturing variations than the conventional one and has excellent image quality uniformity. Objective.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, an EL display device of the present invention includes an EL element in which at least an EL light emitting layer is sandwiched between a pair of electrodes, a capacitor, and a plurality of pixels arranged in a matrix, An EL display device including a writing transistor and a plurality of driving transistors connected in parallel, wherein the plurality of driving transistors are arranged at each of diagonal corners of a substantially rectangular pixel. And That is, the EL display device of the present invention is an active matrix display device, and the “pixel” in the present invention is partitioned by gate lines and data lines (or EL element power supply lines) arranged in a grid pattern. Refers to the area.
[0010]
The present inventor, in an EL display device having a plurality of parallel-connected drive transistors in a pixel, has a current variation that leads to uneven luminance and uneven display by devising the arrangement of the drive transistor in the pixel compared to the conventional case. I found that it can be reduced. The contents will be described below.
[0011]
In general, an active matrix EL display device has a rectangular pixel shape. For example, an EL display device including three color pixels of R (red), G (green), and B (blue) has three types. Since one pixel of the image is composed of pixels, the long side is often in the form of a long and narrow rectangle having a size of several times the short side. FIG. 8A is a diagram showing a configuration of a conventional pixel including two drive transistors, and a drive transistor is indicated by a circle with a symbol TR. That is, in the conventional design, two drive transistors are arranged side by side in the direction along the short side of the pixel (FIG. 10 is an equivalent circuit diagram of a conventional device, but the drive transistor is rectangular even in an actual circuit pattern. Were lined up in the short-side direction.
[0012]
Assume that a driving transistor TR having a current supply capability of 100 is formed. However, some manufacturing parameters such as the thickness of the gate insulating film and the impurity concentration of the semiconductor layer vary within the circle indicated by the broken line A1 during the manufacturing process, and the current supply capability is 95. Assume that a transistor is formed. Then, even if a normal pixel has a current supply capability of 200 with two drive transistors, only a current supply capability of 190 is obtained in the center pixel of FIG. Therefore, this pixel has a 5% reduction in current supply capability compared to a normal pixel, which causes uneven brightness and display unevenness.
[0013]
On the other hand, in the EL display device of the present invention, as shown in FIG. 8B, the two drive transistors TR are respectively arranged at the corners in the diagonal direction of the pixel. ), The distance between the two drive transistors in one pixel becomes longer. In this way, even if the manufacturing parameters vary at the same location occupying the same area as in FIG. 8A, for example, as shown by the broken line area indicated by the reference A2 in FIG. Only the current supply capability of one transistor in one pixel is reduced to 95. Therefore, the current supply capability of the transistor in the pixel G2 is 195, and the decrease in the current supply capability when compared with a normal pixel is 2.5%. In this way, the decrease in current supply capability for normal pixels can be reduced compared to the conventional case of FIG.
[0014]
Further, when two drive transistors are arranged at the corners in the diagonal direction of the pixels, there are places where the distance between the drive transistors is short between pixels arranged in an oblique direction. For example, reference numeral A3 in FIG. There may be a case where two drive transistors are included in a region where the manufacturing parameter varies, such as a broken line region. However, even in this case, since the two drive transistors belong to different pixels G3 and G4, the variation is divided between the two pixels G3 and G4, and the current supply capability of the transistors in the two pixels arranged in the oblique direction. Are both 195. Accordingly, in this case as well, the decrease in current supply capability when compared with normal pixels is 2.5%. In this case, although the number of pixels in which the current supply capability is reduced is two, the decrease in the current supply capability for normal pixels is halved, so that the degree of display unevenness is also reduced when viewed through the entire screen.
[0015]
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 increased as compared with the conventional one, so that the current drive of the drive transistor accompanying the manufacturing variation in the substrate surface is achieved. It is possible to reduce the variation in capacity between pixels as compared to the conventional case. As a result, it is possible to provide an EL display device that has less luminance unevenness and display unevenness than the conventional one and is excellent in image quality uniformity.
[0016]
Note that the model shown in FIGS. 8A and 8B is one model case for simplifying the description, and is the size of the pixel, the distance between the driving transistors, and the region where the manufacturing variation occurs. Of course, various other cases can be considered depending on the mutual relationship between the size and the shape. However, in any case, as long as the distance between a plurality of drive transistors in one pixel is increased, the current drive capability of the drive transistor varies from pixel to pixel. Thus, the effect of reducing the amount of the conventional method can be obtained.
[0017]
In addition, it is desirable that the plurality of driving transistors in adjacent substantially rectangular pixels are disposed at different diagonal corners in each pixel.
[0018]
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 the four pixels are close to each other. Here, similarly to the above, it is assumed that manufacturing parameters vary within a broken-line circle indicated by reference numeral A4, and a drive transistor having a current supply capability of 95 is formed in this region. In this case, since the four drive transistors belong to different pixels G5, G6, G7, and G8, the variation is shared by the four pixels. As a result, it is possible to provide an EL display device in which current supply capability is made uniform over a wider range of pixels than in the case of FIG. 8B, luminance unevenness and pixel unevenness are further reduced, and image quality is excellent in uniformity. it can.
[0019]
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, and a writing transistor are connected in parallel to each of a plurality of pixels arranged in a matrix. An EL display device including a plurality of drive transistors, wherein the plurality of drive transistors are arranged at each of end portions in a direction in which a long side of a substantially rectangular pixel extends. To do.
[0020]
Also in this configuration, as in the above-described configuration in which a plurality of drive transistors are arranged in the diagonal direction of the pixel, the distance between the plurality of drive transistors in one pixel is longer than in the past, so that the drive transistor due to manufacturing variations is increased. The variation in current driving capability can be reduced as compared with the conventional case, and there can be obtained an EL display device with less luminance unevenness and display unevenness and excellent image quality uniformity.
[0021]
Further, in the case where a plurality of driving transistors are arranged at an end portion in the extending direction of the long side of the pixel, it is desirable that all of the plurality of driving transistors in one pixel are connected to the same EL element power supply line.
[0022]
In the normal configuration of the active matrix 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 supply line is the long side direction of the pixel. In the EL display device, it is necessary to connect the driving transistor to the EL element power line. For example, in the case of the conventional configuration in which two driving transistors are arranged in the short side direction of the pixel, it is difficult to route the wiring. Due to design reasons, each drive transistor must be connected to another EL element power line, and the EL element power lines need to be arranged on both sides of the pixel. That is, a total of three wirings are required in the area between adjacent pixels, one data line and two EL power supply lines arranged on both sides of the data line.
[0023]
However, according to the EL display device of the present invention, in particular, an EL display device in which a plurality of drive transistors are arranged in the long side direction of the pixel, there is no difficulty in routing the wiring, and all of the plurality of drive transistors in one pixel are eliminated. Can be connected to the same EL element power supply line. In this case, since one EL element power line may be arranged on one side of the pixel, if there is a total of two wires, one data line and one EL power line, in the region between adjacent pixels. It will be good. As a result, the wiring area can be narrowed compared to the conventional case, and as a result, the aperture ratio can be improved.
[0024]
In addition, it is desirable that the capacitor be disposed in a region that overlaps the data line connected to the writing transistor and the EL element power supply line connected to the driving transistor in a plane.
[0025]
With regard to the arrangement of the capacitors, the capacitor may be arranged in an area inside the pixel that does not overlap with the data line or the EL element power line in a plane, but if it is arranged in an area overlapping with the data line or the EL element power line in a plane. The area occupied by the capacitor in the pixel can be reduced, and the aperture ratio can be improved accordingly.
[0026]
An electronic apparatus according to the present invention includes the above-described EL display device according to the present invention.
According to this configuration, it is possible to realize an electronic device including an EL display unit that has less luminance unevenness and display unevenness and excellent image quality uniformity.
[0027]
DETAILED DESCRIPTION OF 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 top view which shows an example of a simple circuit pattern.
[0028]
In the organic EL display device of the present embodiment, as shown in FIG. 1, the gate line 1 (scanning line) extends in the horizontal direction, and the source line 2 (data line) and the two ELs sandwiching the source line 2 (data line). The element power supply lines 3 (hereinafter simply referred to as EL power supply lines) extend in the vertical direction (direction perpendicular to the gate lines 1) and are arranged in a lattice pattern, and a region partitioned by these wirings constitutes one pixel. is doing. In the pixel, the write transistor 4 electrically connected to the gate line 1 and the source line 2, the capacitor 5 electrically connected to the write transistor 4, and the capacitor 5 are electrically connected and connected in parallel to each other. Two drive transistors 6 and 7 and an organic EL element 8 electrically connected to these drive transistors 6 and 7 are provided. As long as it is viewed as an equivalent circuit, it is similar to the conventional configuration, but in the case of this embodiment, each of the drive transistors 6 and 7 is disposed at each corner of the pixel in the diagonal direction.
[0029]
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, a region where the gate line 1 is arranged is defined as a lateral wiring region L, a source line 2 and an EL power supply. A region where the line 3 is arranged is referred to as a vertical wiring region V. In the actual pattern, each transistor is composed of a TFT. In the first TFT constituting the write transistor 4, one end is connected to the source line 2 through the contact hole 9, crosses the gate line 1, and then the other end. Is provided along the vertical wiring region V. Parts extending from the upper part and the lower part of the semiconductor layer 10 toward the inside of the pixel (referred to as a first extending part 10a and a second extending part 10b, respectively) are provided. The gate electrode of the TFT 3 is connected. Further, a portion 10c extending along the vertical wiring region V of the semiconductor layer 10 constitutes one electrode of the capacitor 5, and one end thereof is connected to the EL power supply line 3 through the contact hole 11 so as to overlap the portion 10c. A capacitor electrode 12 connected and constituting the other electrode of the capacitor 5 is provided.
[0030]
In the second TFT constituting one of the driving transistors 6, a semiconductor layer 14 having one end connected to the EL power supply line 3 on the left side of the pixel through the contact hole 13 is formed at the upper left corner of the pixel in FIG. A gate electrode 16 connected to the first extension portion 10a (drain region) of the semiconductor layer 10 of the first TFT through the contact hole 15 is provided so as to intersect the semiconductor layer 14. 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. The relay layer 18 has an indium tin oxide (Indium Tin Oxide,) through the contact hole 19. The upper end of the pixel electrode 20 made of a transparent conductive film such as ITO (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.
[0031]
Further, in the third TFT constituting the other one of the drive transistors 7, the semiconductor layer 22 having one end connected to the EL power supply line 3 on the right side of the pixel through the contact hole 21 has a lower right side of the pixel in FIG. A long L-shaped gate electrode 24 formed at the corner of the first TFT and connected to the second extension 10 b (drain region) of the semiconductor layer 10 of the first TFT through the contact hole 23 intersects the semiconductor layer 22. It is provided as follows. A relay layer 26 connected to the other end (drain region) of the semiconductor layer 22 of the third TFT is provided through the contact hole 25, and the lower end of the pixel electrode 20 is connected to the relay layer 26 through the contact hole 27. Yes. That is, the semiconductor layer 22 of the third TFT and the pixel electrode 20 are electrically connected through the relay layer 26.
[0032]
2 is the contour of the organic EL light emitting layer, and the one-dot chain line indicated by the reference symbol 29 is the contour of the light shielding layer (black matrix). The organic EL element 8 has at least an organic EL light emitting layer 28 sandwiched between a pair of electrodes composed of a pixel electrode 20 serving as an anode of the organic EL element and a metal electrode (not shown) serving as a cathode. In addition to the light emitting layer, a layer such as a hole injection layer, a hole transport layer, or an electron transport layer may be sandwiched between the pair of electrodes.
[0033]
The organic EL display device of the present embodiment is different from the conventional one in the planar pattern arrangement, and the equivalent circuit is not different from the conventional one. Therefore, the operation of the organic EL display device is exactly the same as the conventional one. Description is omitted.
[0034]
According to the present embodiment, the two drive transistors 6 and 7 in one pixel are arranged at the corners in the diagonal direction of the rectangular pixel, and the drive transistors 6 and 6 are compared with the conventional one shown in FIG. By making the distance between 7 longer, it is possible to reduce the inter-pixel variation in the current driving capability of the drive transistor due to the manufacturing variation in the substrate surface as compared with the conventional case. Further, if the distance between the drive transistor in another pixel lined up in the diagonal direction with respect to the pixel is shorter than the distance between the two drive transistors 6 and 7 in the same pixel, the manufacturing variation in the substrate surface will occur. The variation in the current drive capability of the drive transistor due to the can be shared between the pixels. As a result, it is possible to provide an organic EL display device that has less luminance unevenness and display unevenness than the conventional one and is excellent in image quality uniformity.
[0035]
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.
[0036]
In the present embodiment, two drive transistors 6 and 7 are arranged only at the same diagonal corner in all pixels. However, 2 pixels are arranged at different diagonal corners in each adjacent pixel. One drive transistor may be arranged. In that case, the drive transistors of the four pixels are close to each other, and they share a variation. Therefore, it is possible to provide an EL display device with even less luminance unevenness and pixel unevenness and excellent image quality uniformity.
[0037]
[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS.
FIG. 3 is an equivalent circuit diagram of one pixel constituting the active matrix organic EL display device of the present embodiment, and FIG. 4 is an example of a specific circuit pattern for realizing the equivalent circuit diagram of FIG. FIG. In contrast to the first embodiment in which two drive transistors are arranged in the diagonal direction of the pixel, the present embodiment is an example in which two drive transistors are arranged in the long side direction of the pixel. Therefore, in FIGS. 3 and 4, the same reference numerals are given to the same components as those in FIGS. 1 and 2, and detailed description of the common parts is omitted.
[0038]
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 lattice pattern, and writing is performed in the pixels partitioned by these wirings. A transistor 4, a capacitor 5, two drive transistors 6 and 7 connected in parallel, and an organic EL element 8 are provided. As long as it is viewed as an equivalent circuit, it is the same as the conventional configuration and the first embodiment. However, in the case of this embodiment, the drive transistors 6 and 7 are arranged at the respective ends in the long side direction of the pixel. Yes. Further, as a difference from the first embodiment, the 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 Two EL power supply lines 3 provided on both sides of the source line 2 in the wiring region V are provided on one side.
[0039]
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 the present embodiment, the drive transistors 6 and 7 are arranged at the upper left and lower left of the pixel. Accordingly, the pattern configuration on the upper side (first and second TFT sides) of the pixel is substantially the same as that of the first embodiment (FIG. 2), and only the pattern configuration on the lower side (third TFT side) of the pixel. Is different. In this embodiment mode, the second TFT side and the third TFT side are substantially symmetrical.
[0040]
That is, similarly to the second TFT, the third TFT is provided with a semiconductor layer 22 having one end connected to the EL power supply line 3 on the left side of the pixel through the contact hole at the lower left corner of the pixel in FIG. A gate electrode 24 connected to the second extending portion 10 b (drain region) of the semiconductor layer 10 of the first TFT through the hole 23 is provided so as to intersect the semiconductor layer 10. A relay layer 26 connected to the other end (drain region) of the semiconductor layer 22 of the third TFT is provided through the contact hole 25, and the lower end of the pixel electrode 20 is connected to the relay layer 26 through the contact hole 27. Yes.
[0041]
Also in this embodiment, the two drive transistors 6 and 7 in one pixel are arranged at the ends of the rectangular pixels in the long side direction, and the distance between the drive transistors 6 and 7 is increased. Capacitor 5 can be provided in vertical wiring region V, which can reduce the variation in current driving capability of the drive transistor between pixels, and can realize an organic EL display device with less luminance unevenness and display unevenness and superior image quality uniformity. The effect similar to 1st Embodiment that an aperture ratio can be improved by having arrange | positioned can be acquired.
[0042]
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 the common single EL power supply line 3. Is possible. With this configuration, only one EL power supply line is required for one pixel, and the vertical wiring region can be narrowed. Therefore, the aperture ratio can be further improved as compared with the first embodiment.
[0043]
[Electronics]
Examples of electronic devices including the organic EL display device of the above embodiment will be described.
FIG. 5 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 organic EL display device.
[0044]
FIG. 6 is a perspective view showing an example of a wristwatch type electronic device. In FIG. 6, reference numeral 1100 indicates a watch body, and reference numeral 1101 indicates a display unit using the organic EL display device.
[0045]
FIG. 7 is a perspective view showing an example of a portable information processing apparatus such as a word processor or a personal computer. In FIG. 7, reference numeral 1200 denotes an information processing apparatus, reference numeral 1202 denotes an input unit such as a keyboard, reference numeral 1204 denotes an information processing apparatus body, and reference numeral 1206 denotes a display unit using the above organic EL display device.
[0046]
The electronic device shown in FIGS. 5 to 7 includes the organic EL display device according to the above embodiment, and thus realizes an electronic device including a display portion with less luminance unevenness and display unevenness and excellent image quality uniformity. can do.
[0047]
The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the first and second embodiments, an example in which two transistors are used as the plurality of driving transistors has been described, but three or more transistors may be used.
In this 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. In addition, the effect of reducing luminance unevenness and display unevenness can be obtained. The planar patterns shown in FIGS. 2 and 4 are merely examples, and the specific shape and size of each pattern can be changed as appropriate. Furthermore, in the above-described 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]
【The invention's effect】
As described above in detail, according to the present invention, the arrangement of a plurality of drive transistors in one pixel is devised, and the distance between these drive transistors is made longer than before. Therefore, it is possible to realize an EL display device that has less luminance unevenness and display unevenness than conventional ones and is excellent in image quality uniformity. Further, if the distance between the plurality of drive transistors between the pixels is shorter than the distance between the two drive transistors in the same pixel, the variation in the current drive capability of the drive transistors due to manufacturing variations within the substrate surface can be reduced. Since the pixels can be shared, it is possible to realize an organic EL display device with less luminance unevenness and display unevenness and superior image quality uniformity as compared with the related art.
[Brief description of the drawings]
FIG. 1 is an equivalent circuit diagram showing one pixel of an organic EL display device according to a first embodiment of the present invention.
FIG. 2 is a plan view showing a configuration example of a circuit pattern for realizing an equivalent circuit.
FIG. 3 is an equivalent circuit diagram showing one pixel of an organic EL display device according to a second embodiment of the present invention.
FIG. 4 is a plan view showing a configuration example of a circuit pattern for realizing an equivalent circuit.
FIG. 5 is a perspective view showing an example of an electronic apparatus according to the invention including the organic EL display device.
FIG. 6 is a perspective view showing another example of the electronic apparatus.
FIG. 7 is a perspective view showing still another example of the electronic apparatus.
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 organic EL display device.
[Explanation of symbols]
1 Gate line (scanning line)
2 Source line (data line)
3 EL power line (EL element power line)
4 Write transistor
5 capacitors
6,7 Drive transistor
8 Organic EL elements

Claims (6)

Each of the plurality of pixels arranged in a matrix is provided with 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. An EL display device,
2. An EL display device, wherein the plurality of drive transistors are disposed at each of diagonal corners of a substantially rectangular pixel. 2. The EL display device according to claim 1, wherein the plurality of driving transistors in adjacent substantially rectangular pixels are arranged at corners in different diagonal directions in the respective pixels. Each of the plurality of pixels arranged in a matrix is provided with 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. An EL display device,
2. The EL display device according to claim 1, wherein the plurality of driving transistors are arranged at respective end portions in a direction in which a long side of a substantially rectangular pixel extends. 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. 2. The capacitor according to claim 1, wherein the capacitor is arranged in a region overlapping with a data line electrically connected to the write transistor and an EL element power line electrically connected to the drive transistor. 5. The EL display device according to any one of items 4 to 4. An electronic apparatus comprising the EL display device according to any one of claims 1 to 5.

Images