KR20100046439A - Organic light emitting display - Google Patents

Abstract

PURPOSE: An organic electroluminescent display device is provided to improve display quality of a panel by preventing a characteristic deviation between a plurality of sub pixels of a unit pixel. CONSTITUTION: An organic electroluminescent display device includes a substrate and a unit pixel(R,G,B). The unit pixel is positioned on the substrate. The unit pixel is comprised of first to third sub pixels. The first to third sub pixels emit light with different colors. A channel area of a driving transistor included in the second sub pixel is greater than the channel area of the driving transistor included in the first or third sub pixel. The second sub pixel is a green sub pixel. An opening region of the second sub pixel is smaller than the opening area of the first or second sub pixel.

Description

Organic Light Emitting Display

The present invention relates to an organic light emitting display device.

An organic light emitting display device used in an organic light emitting display device is a self-light emitting device in which a light emitting layer is formed between two electrodes positioned on a substrate.

The organic light emitting display includes a top emission type, a bottom emission type, or a dual emission type according to a direction in which light is emitted. According to the driving method, it is divided into a passive matrix type and an active matrix type.

In the organic light emitting display device, a plurality of subpixels including a transistor, a capacitor, an organic light emitting diode, and the like are formed in a matrix form on a substrate through a manufacturing process in which a deposition process and an etching process are performed in parallel.

In the organic light emitting display device manufactured through the above process, when a scan signal, a data signal, and a power are supplied to a plurality of subpixels formed in a matrix form, the selected subpixels emit light to display an image on the panel.

Meanwhile, in the plurality of subpixels formed in the panel, red, green, and blue subpixels are configured as one unit pixel. In the case of the organic light emitting display device, a characteristic deviation between the red, green, and blue subpixels constituting the unit pixel occurs during the manufacturing process. As described above, when the characteristic deviation between the sub-pixels constituting the unit pixel occurs, luminance is unevenly displayed on the panel and the display quality is lowered.

Embodiments of the present invention for solving the above-described problems of the background art provide an organic light emitting display device that can improve display quality of a panel by solving a problem caused by variation in emission efficiency between subpixels constituting a unit pixel. It is.

Embodiments of the present invention as a means for solving the above problems, the substrate; And a unit pixel including three or more subpixels positioned on the substrate and emitting different colors, wherein an area of a channel of the driving transistor included in at least one subpixel of the unit pixels is included in another subpixel. An organic light emitting display device is characterized in that it is wider than a channel area of a transistor.

The subpixel having a large area of the channel of the driving transistor may be a green subpixel.

The opening area of the green subpixel may be relatively smaller than the opening area of another subpixel.

The aperture regions of the three or more subpixels may differ one or more.

The opening area of the blue subpixel among the unit pixels may be relatively larger than the opening area of other subpixels.

The opening area of the blue subpixel may be the largest and the opening area of the green subpixel may be the smallest among the unit pixels.

On the other hand, in another aspect, an embodiment of the present invention, a substrate; And a unit pixel including a plurality of subpixels positioned on a substrate to emit different colors, wherein the plurality of subpixels have at least one area of an opening region and a channel of a driving transistor. Provide a display device.

The unit pixel may have the largest area of the channel of the driving transistor included in the green subpixel.

Among the unit pixels, the opening area of the blue subpixel may be the largest, and the opening area of the green subpixel may be the smallest.

The unit pixel may include red, green, and blue subpixels.

According to an embodiment of the present invention, the channel area (W × L) of the driving transistor included in the subpixel having the highest luminous efficiency among the subpixels included in the unit pixel is relatively larger than the channel area of the driving transistor included in the other subpixel. It is effective in making the brightness uniformity and display quality of the panel wider. Embodiments of the present invention improve the luminance uniformity and display quality to improve stain defects, and to improve the white balance life due to deterioration due to long-term operation of the panel, and in a high temperature / low temperature environment. There is an effect of improving the display quality performance.

Hereinafter, with reference to the accompanying drawings, the specific content for the practice of the present invention will be described.

1 is a schematic plan view of an organic light emitting display device.

As shown in FIG. 1, the organic light emitting display device includes a display unit 130 that is disposed on the substrate 110 and includes unit pixels R, G, and B including a plurality of sub pixels emitting different colors. It may include.

The substrate 110 may be selected as a material for forming an element having excellent mechanical strength or dimensional stability. As the material of the substrate 110, a glass plate, a metal plate, a ceramic plate or a plastic plate (polycarbonate resin, acrylic resin, vinyl chloride resin, polyethylene terephthalate resin, polyimide resin, polyester resin, epoxy resin, silicone resin, fluorine) Resin, etc.) is mentioned.

The unit pixels R, G, and B disposed on the substrate 110 are vulnerable to moisture or oxygen. Accordingly, the sealing substrate 140 may be provided, and the adhesive member 150 may be formed on the outer substrate 110 of the display unit 130 to encapsulate the substrate 110 and the sealing substrate 140. Here, the material of the sealing substrate 140 may be the same or different materials from the substrate 110.

The unit pixels R, G, and B may include three subpixels emitting different colors, such as red, green, and blue subpixels, but may further include subpixels emitting different colors. When the unit pixels R, G, and B include red, green, and blue sub pixels, when the red, green, and blue sub pixels all emit light, the unit pixels R, G, and B may represent white. All subpixels included in the unit pixels R, G, and B may include transistors and organic light emitting diodes positioned on the transistors, respectively.

All of the subpixels included in the unit pixels R, G, and B may be driven by the driver 160 positioned on the substrate 110 to represent an image. The driver 160 may generate a scan signal and a data signal in response to various signals supplied from the outside, and may supply the generated signal to the display unit 130.

The driver 160 may include a scan driver for supplying a scan signal to the display unit 130 and a data driver for supplying a data signal to the display unit 130. Here, the driver 160 is schematically illustrated as an example that the scan driver and the data driver are formed on one chip, but at least one of the scan driver and the data driver is separated from the substrate 110 or the outside of the substrate 110. Can be located.

Hereinafter, various circuit configurations of the subpixels included in the unit pixels R, G, and B shown in FIG. 1 will be described.

2 is a circuit configuration diagram of a subpixel having a 2T1C structure.

Referring to FIG. 2, a subpixel having a 2T (capacitor) structure has a gate connected to the scan line SCAN, one end connected to the data line DATA, and the other end connected to the first node A. Between the transistor STFT, the driving transistor DTFT having a gate connected to the first node A and one end connected to the first power line VDD, and between the first power line VDD and the first node A. The organic light emitting diode OLED may include a capacitor CST connected to the second electrode and an organic light emitting diode OLED having a first electrode connected to the other end of the driving transistor DTFT and a second electrode connected to the second power supply line VSS.

Here, the transistor STFT is turned on by the scan signal supplied through the scan line SCAN and transfers the data signal supplied through the data line DATA. The capacitor CST stores the data signal supplied through the transistor STFT. In addition, the driving transistor DTFT drives in response to the data signal stored in the capacitor CST. When the driving transistor DTFT is driven, the organic light emitting diode OLED emits light by a current supplied through the first power line VDD.

3 is a circuit diagram of a subpixel having a 3T1C structure.

Referring to FIG. 3, a subpixel having a 3T1C structure has a first transistor STFT1 having a gate connected to the first scan line SCAN1, one end connected to the data line DATA, and the other end connected to the first node A. ), A second transistor STFT2 having a gate connected to the second scan line SCAN2, one end connected to the third power line VREF, and the other end connected to the first node A, and a first node A ), A driving transistor DTFT connected to a gate thereof and one end connected to a first power wiring VDD, a capacitor CST connected between the first power wiring VDD and the first node A, and a driving transistor ( The organic light emitting diode OLED may include an organic light emitting diode OLED having a first electrode connected to the other end of the DTFT and a second electrode connected to the second power line VSS.

Here, the first transistor STFT1 is turned on by the first scan signal supplied through the first scan wiring SCAN1 and transfers the data signal supplied through the data wiring DATA. The second transistor STFT2 is turned on by the second scan signal supplied through the second scan line SCAN2 and transfers the reference voltage supplied through the third power line VREF. The capacitor CST stores the data signal supplied through the transistor STFT. In addition, the driving transistor DTFT drives in response to the data signal stored in the capacitor CST. When the driving transistor DTFT is driven, the organic light emitting diode OLED emits light by a current supplied through the first power line VDD.

4 is a circuit diagram of a subpixel having a 4T2C structure.

Referring to FIG. 4, a sub-pixel having a 4T2C structure has a first transistor STFT1 having a gate connected to the first scan line SCAN1, one end connected to the data line DATA, and the other end connected to the first node A. ), A first capacitor CST1 connected between the first node A and the first power line VDD, and a second capacitor CST2 connected between the first node A and the second node B. And a driving transistor DTFT connected to a gate of the second node B, one end of which is connected to the first power line VDD, and the other end of which is connected to the third node C, and a second scan line SCAN2. A gate is connected, one end is connected to the second node B, and the other end is connected to the second node STFT2 and the third scan wiring SCAN3, and the third node C is connected to the third node CFT. ) And an organic light emitting diode (OLED) having one end connected to the third transistor (STFT3), the first electrode is connected to the other end of the third transistor (STFT3) and the second electrode is connected to the second power supply line (VSS).There.

Here, the first transistor STFT1 is turned on by the first scan signal supplied through the first scan wiring SCAN1 and transfers the data signal supplied through the data wiring DATA. The first capacitor CST1 maintains a difference voltage between the voltage supplied through the first power line VDD and the voltage supplied through the first transistor STFT1. The second capacitor CST2 stores the data signal supplied through the first transistor STFT1 and the data signal based on the voltage held in the first capacitor CST1. The second transistor STFT2 is turned on by the second scan signal supplied through the second scan wiring SCAN2 and controls the threshold voltage of the driving transistor DTFT. In addition, the driving transistor DTFT drives in response to the data signal stored in the second capacitor CST2. The third transistor STFT3 is turned on by the third scan signal supplied through the third scan wiring SCAN3 and controls a current flowing through the driving transistor DTFT. When the driving transistor DTFT is driven and the third transistor STFT3 is turned on, the organic light emitting diode OLED emits light by a current supplied through the first power line VDD.

5 is a circuit diagram illustrating a subpixel having a 5T1C structure.

Referring to FIG. 5, a subpixel having a 5T1C structure has a first transistor STFT1 having a gate connected to the first scan line SCAN1, one end connected to the data line DATA, and the other end connected to the first node A. Referring to FIG. ), A capacitor CST connected between the first node A and the second node B, a gate connected to the second node B, and one end connected to the first power line VDD, and a third A driving transistor DTFT having the other end connected to the node C, a gate connected to the third scan line SCAN3, one end connected to the first node A, and the other end connected to the third power line VREF. A third transistor (STFT3), a gate connected to the second transistor (STFT2), a second scan wiring (SCAN2), one end connected to the second node (B), and the other end connected to the third node (C), and a third A fourth transistor STFT4 having a gate connected to the scan line SCAN3 and one end connected to the third node C, a first electrode connected to the other end of the fourth transistor ST4, and a second power line The organic light emitting diode OLED may be connected to the VSS.

Here, the first transistor STFT1 is turned on by the first scan signal supplied through the first scan wiring SCAN1 and transfers the data signal supplied through the data wiring DATA. The second transistor ST2 is turned on by the third scan signal supplied through the third scan line SCAN3 and transfers the reference voltage supplied through the third power line VREF. The capacitor CST stores the data signal supplied through the first transistor STFT1. The third transistor STFT3 is turned on by the second scan signal supplied through the second scan line SCAN2 and controls the threshold voltage of the driving transistor DTFT. In addition, the driving transistor DTFT drives in response to the data signal stored in the capacitor CST. The fourth transistor STFT4 is turned on by the third scan signal supplied through the third scan wiring SCAN3 and controls the current flowing through the driving transistor DTFT. When the driving transistor DTFT is driven and the fourth transistor STFT4 is turned on, the organic light emitting diode OLED emits light by the current supplied through the first power line VDD.

6 is a circuit diagram illustrating a subpixel having a 5T2C structure.

Referring to FIG. 6, a sub-pixel having a 5T2C structure has a first transistor STFT1 having a gate connected to the first scan line SCAN1, one end connected to the data line DATA, and the other end connected to the first node A. ), A first capacitor CST1 connected between the first node A and the first power line VDD, and a second capacitor CST2 connected between the first node A and the second node B. And a second transistor STFT2 having a gate connected to the second scan line SCAN2, one end connected to the third power line VREF, and the other end connected to the first node A, and a second node B. A gate is connected, one end is connected to the first power line VDD, and the other end is connected to the third node C, and the gate is connected to the second scan line SCAN2, and the second node B is connected. ) Is connected to the third transistor (STFT3), the other end of which is connected to the third node (C) and the fourth transistor (the gate of which is connected to the third scan wiring (SCAN3) and one end of the third node (C). STFT4 ) And an organic light emitting diode OLED having a first electrode connected to the other end of the fourth transistor ST4 and a second electrode connected to the second power line VSS.

Here, the first transistor STFT1 is turned on by the first scan signal supplied through the first scan wiring SCAN1 and transfers the data signal supplied through the data wiring DATA. The second transistor ST2 is turned on by the second scan signal supplied through the second scan line SCAN2 and transfers the reference voltage supplied through the third power line VREF. The first capacitor CST1 maintains a difference voltage between the voltage supplied through the first power line VDD and the voltage supplied through the first transistor STFT1. The second capacitor CST2 stores the data signal supplied through the first transistor STFT1 and the data signal based on the voltage held in the first capacitor CST1. In addition, the driving transistor DTFT drives in response to the data signal stored in the second capacitor CST2. The third transistor STFT4 is turned on by the second scan signal supplied through the second scan wiring SCAN3 and controls the threshold voltage of the driving transistor DTFT. The fourth transistor STFT4 is turned on by the third scan signal supplied through the third scan wiring SCAN3 and controls the current flowing through the driving transistor DTFT. When the driving transistor DTFT is driven and the fourth transistor STFT4 is turned on, the organic light emitting diode OLED emits light by the current supplied through the first power line VDD.

The circuit configuration of the subpixels included in the unit pixels R, G, and B may be configured in various ways as described with reference to FIGS. 2 to 6. However, this is merely to illustrate an example of the embodiment, and the circuit configuration of the subpixels is not limited to FIGS. 2 to 6.

On the other hand, the red, green, and blue subpixels included in the unit pixels R, G, and B generate light emission efficiency variations depending on the material of the light emitting layer included in the organic light emitting diode OLED. If the luminous efficiency deviation occurs between the subpixels constituting the unit pixels R, G, and B, the luminance of the panel appears unevenly, and thus the display quality is deteriorated.

In order to solve this problem, the embodiment of the present invention increases the channel area of the driving transistor included in the subpixel. Here, when the channel area of the driving transistor included in the subpixel is increased, the width and length of the channel are equally or similarly increased at a constant ratio.

Hereinafter, changes in the threshold voltage and mobility characteristics of the device as the channel area of the driving transistor increases.

FIG. 7 is a relationship diagram between channel area and threshold voltage uniformity, and FIG. 8 is a relationship diagram between channel area and mobility uniformity. (CV is a coefficient variable in FIGS. 7 and 8.)

7 and 8, it can be seen that the uniformity of the device is improved as the channel area of the driving transistor increases. As such, as the channel area of the driving transistor increases, the uniformity of the device is improved. However, when the channel area of the driving transistors included in all the subpixels is increased in this manner, the aperture ratio of all the subpixels becomes narrow.

In order to solve the problem as described above, an embodiment of the present invention provides a driving transistor in which the area of the channel of the driving transistor included in the subpixel having the highest luminous efficiency among the unit pixels R, G, and B is included in another subpixel. It is formed larger than the channel area of.

In general, the subpixel which most predominantly affects luminance and image quality uniformity is the green subpixel G. This is because the luminous efficiency of the green sub-pixel G is the highest, and the ratio of the green sub-pixel G to the white balance among the luminance ratios of the unit pixels R, G, and B is the largest.

Therefore, in the exemplary embodiment of the present invention, the channel area of the driving transistor included in the green subpixel G is larger than the channel area of the driving transistor included in the other subpixels to improve the uniformity without reducing the aperture ratio of the entire subpixel. Widen. However, in the exemplary embodiment of the present invention, only the subpixel having the highest luminous efficiency among the unit pixels R, G, and B is the green subpixel G. The channel area of the driving transistor included in at least one of the pixels may be widened.

Hereinafter, a method of improving luminance uniformity will be described in more detail through a plan view of 2T1C shown in FIG. 2 and a plan view of 5T1C shown in FIG. 5 of FIG. 2 to FIG. 6 to help understand the embodiments of the present invention. do.

9 is a planar structure diagram of a unit pixel constituted by a 2T1C subpixel structure, and FIG. 10 is a planar structure diagram of a unit pixel constituted by a 5T1C subpixel structure.

Referring to FIG. 9, unit pixels R, G, and B including red, green, and blue subpixels having a 2T1C subpixel structure are illustrated. Referring to FIG. 10, red, green, having a 5T1C subpixel structure, are illustrated. And unit pixels R, G, and B including blue sub pixels.

9 and 10, CH1 represents a channel region of the driving transistor DTFT included in the red subpixel R, and CH2 represents a channel region of the driving transistor DTFT included in the green subpixel G. In FIG. CH3 represents a channel region of the driving transistor DTFT included in the blue subpixel B. In FIG.

Referring to CH1 to CH3 of FIG. 9, the channel areas of the driving transistor DTFT included in the green subpixel G among the unit pixels R, G and B are included in the red and blue subpixels R and B. It can be seen that it is formed larger than the channel area of the driving transistor DTFT.

Referring to CH1 to CH3 of FIG. 10, the channel area of the driving transistor DTFT included in the green sub-pixel G is formed to be the widest, and the channel area of the driving transistor DTFT included in the red sub-pixel R is represented. It can be seen that the narrowest formation.

As such, the reason for varying the area of the channel of the driving transistor DTFT is that it is configured under the assumption that the sub-pixel which most influences the image quality uniformity is the green sub-pixel G. In this case, when the channel area of the driving transistor DTFT included in the green sub-pixel G is formed to be wider than the channel area of the driving transistor DTFT included in the other sub-pixels, uniformity can be achieved without reducing the aperture ratio of the entire sub-pixel. Can be improved.

When increasing the channel area of the driving transistor DTFT included in the green subpixel G, the opening area of the green subpixel G may be smaller than the opening area of other subpixels in order to adjust the white balance of the panel. Here, when the channel area of the specific subpixel is changed, the opening area of the subpixel having low luminous efficiency may be larger than the opening area of the subpixel having high luminous efficiency.

Therefore, it is possible to change the opening area of one of the red, green and blue subpixels or the opening area of all of the red, green and blue subpixels to adjust the white balance of the panel.

As an example, like the 2T1C subpixel illustrated in FIG. 9, the opening regions of the red subpixel R and the blue subpixel B are the same, and the opening regions of the green subpixel G are represented by the red subpixel ( R) and the blue subpixel B are smaller than the opening area. In this case, the driving transistor included in the green sub-pixel G while reducing the opening area of the green sub-pixel G under the assumption that the luminous efficiency of the red sub-pixel R and the blue sub-pixel B is similar. DTFT) is an example of increasing the channel area.

As another example, like the 5T1C subpixel illustrated in FIG. 10, all of the opening regions of the red subpixel R, the green subpixel G, and the blue subpixel B are different. This makes the opening area of the blue subpixel B the largest and the opening area of the green subpixel G the smallest. In this case, under the assumption that the luminous efficiency of the green sub-pixel G is the best and the luminous efficiency of the blue sub-pixel B is the lowest, the opening area of the green sub-pixel G is made smaller and the green sub-pixel G is at the same time. In this case, the channel area of the driving transistor DTFT included in FIG. 1 is increased.

Therefore, the method for adjusting the white balance of the panel is one or more of a method of changing the area of the channel of the driving transistor included in each of the red, green, and blue subpixels, or a method of changing the opening area of the red, green, and blue subpixels. Can be used.

As described above, according to the exemplary embodiment of the present invention, the channel area (W × L) of the driving transistor included in the subpixel having the highest luminous efficiency among the subpixels included in the unit pixel is relatively smaller than that of the driving transistor included in the other subpixel. It is effective in making the brightness uniformity and display quality of the panel wider. Embodiments of the present invention improve the luminance uniformity and display quality to improve stain defects, and to improve the white balance life due to deterioration due to long-term operation of the panel, and in a high temperature / low temperature environment. There is an effect of improving the display quality performance.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical configuration of the present invention described above may be modified in other specific forms by those skilled in the art to which the present invention pertains without changing its technical spirit or essential features. It will be appreciated that it may be practiced. Therefore, the embodiments described above are to be understood as illustrative and not restrictive in all aspects. In addition, the scope of the present invention is shown by the claims below, rather than the above detailed description. Also, it is to be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present invention.

1 is a schematic plan view of an organic light emitting display device.

2 is a circuit configuration diagram of a subpixel having a 2T1C structure.

3 is a circuit configuration diagram of a subpixel having a 3T1C structure.

4 is a circuit configuration diagram of a subpixel having a 4T2C structure.

5 is a circuit configuration diagram of a subpixel having a 5T1C structure.

6 is a circuit configuration diagram of a subpixel having a 5T2C structure.

7 is a relationship between channel area and threshold voltage uniformity.

8 is a relationship diagram for channel area and mobility uniformity.

9 is a planar structure diagram of a unit pixel composed of a 2T1C subpixel structure.

10 is a planar structural diagram of a unit pixel composed of a 5T1C subpixel structure;

<Explanation of symbols on main parts of the drawings>

110: substrate 130: display unit

140: sealing substrate 150: adhesive member

160: drive unit

Claims (10)

Board; And A unit pixel including three or more subpixels positioned on the substrate and emitting different colors; The area of the channel of the driving transistor included in at least one sub-pixel of the unit pixels is larger than the channel area of the driving transistor included in another sub-pixel. The method of claim 1, A subpixel having a large area of a channel of the driving transistor is An organic light emitting display device, wherein the organic light emitting display device is a green subpixel. The method of claim 2, The opening area of the green subpixel is An organic light emitting display device, characterized in that it is relatively smaller than the opening area of another subpixel. The method of claim 1, The opening area of the three or more subpixels is An organic light emitting display device, characterized in that at least one other. The method of claim 1, The opening area of the blue subpixel of the unit pixel is An organic light emitting display device, wherein the organic light emitting display device is larger than an opening area of another subpixel. The method of claim 1, And an opening area of the blue subpixel is the largest and the opening area of the green subpixel is the smallest of the unit pixels. Board; And A unit pixel including a plurality of subpixels positioned on the substrate and emitting different colors; The plurality of subpixels, An organic light emitting display device, characterized in that at least one area of an opening region and a channel of a driving transistor is different. The method of claim 7, wherein The unit pixel, An organic light emitting display device, wherein the area of a channel of a driving transistor included in a green subpixel is largest. The method of claim 7, wherein And an opening area of the blue subpixel is the largest and the opening area of the green subpixel is the smallest of the unit pixels. The method according to claim 1 or 7, The unit pixel, An organic light emitting display device comprising red, green, and blue subpixels.

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