KR102276627B1 - Organic light emitting diode device - Google Patents

Abstract

By performing compensation to increase the level of the driving signal output from the inside or outside of the pixel to the organic light emitting diode according to the level change of the threshold voltage or the base power, the level of the driving signal due to the change in the threshold voltage or the base power is reduced An organic light emitting display device capable of preventing a voltage drop from occurring in an organic light emitting diode is provided.

Description

Organic light emitting diode device

The present invention relates to an organic light emitting display device, and more particularly, to an organic light emitting display device capable of preventing a voltage drop (IR drop) from occurring in an organic light emitting diode due to a level change of a base power supply (Vss).

Although a liquid crystal display device has been widely used as a flat panel display device until now, the liquid crystal display device requires a backlight as a separate light source, and has technical limitations in brightness, contrast ratio, and viewing angle. Accordingly, interest in organic light emitting diode devices (OLEDs), which are self-luminous and do not require a separate light source, are relatively excellent in brightness, contrast ratio, and viewing angle, etc., is increasing.

The organic light emitting display device includes a light emitting device in which a light emitting layer is formed between a cathode for injecting electrons and an anode for injecting holes, that is, an organic light emitting device. The organic light emitting display device is a display device that displays an image by combining the injected electrons and holes when electrons generated from the cathode and holes generated from the anode of the organic light emitting diode are injected into the light emitting layer to emit light.

1 is an equivalent circuit diagram of one pixel of a conventional organic light emitting diode display.

Referring to FIG. 1 , in the conventional organic light emitting display device, a pixel area is defined by a gate line GL, a data line DL, and a driving power line VDDL arranged to cross each other.

In the pixel region, switching elements of the switching transistor ST and the driving transistor DT, the storage capacitor C, and the organic light emitting element OLED are formed. The switching transistor ST and the driving transistor DT are composed of a thin film transistor (TFT).

The switching transistor ST is switched according to the gate signal supplied through the gate line GL and supplies the data signal supplied through the data line DL to the driving transistor DT.

The driving transistor DT is switched according to the data signal supplied from the switching transistor ST to control the current flowing from the driving power line VDDL to the organic light emitting diode OLED, for example, the driving current.

The storage capacitor C is connected between the gate electrode of the driving transistor DT and the anode electrode of the organic light emitting device OLED, and stores a voltage corresponding to the data signal supplied to the gate electrode of the driving transistor DT, With the stored voltage, the turn-on state of the driving transistor DT is constantly maintained for one frame.

The organic light emitting diode OLED is connected between a source electrode or a drain electrode of the driving transistor DT and the base power line VssL, and emits light by a driving current supplied from the driving transistor DT.

2 is a cross-sectional view schematically illustrating a part of a structure of a conventional organic light emitting display device.

Referring to FIG. 2 , a conventional organic light emitting display device 1 includes a substrate 10 , a driving transistor DT, and an organic light emitting diode (OLED). The substrate 10 is made of an insulating material such as transparent glass, plastic, or polymer film.

The driving transistor DT includes a semiconductor layer 11 , a gate electrode 12 , a source electrode 13 , and a drain electrode 14 . The semiconductor layer 11 of the driving transistor DT is formed on the substrate 10 , and the gate insulating layer 15 is formed on the semiconductor layer 11 . A gate line (not shown) including the gate electrode 12 is formed on the gate insulating layer 15 . An interlayer insulating layer 16 is formed on the gate electrode 12 , and a data line (not shown) including a source electrode 13 and a drain electrode 14 is formed on the interlayer insulating layer 16 . The source electrode 13 and the drain electrode 14 are connected to the semiconductor layer 11 through a contact hole (not shown) formed in the interlayer insulating film 16 . A planarization layer 17 is formed on the source electrode 13 and the drain electrode 14 .

The organic light emitting diode OLED includes a first electrode 22 , an organic light emitting layer 23 , and a second electrode 24 . The first electrode 22 is formed on the planarization layer 17 and is connected to the drain electrode 14 of the driving transistor DT through a contact hole (not shown) formed in the planarization layer 17 . A bank 21 defining a pixel area is formed on the first electrode 22 . The bank 21 is formed to surround the edge of the first electrode 22 . The organic light emitting layer 23 is formed between the first electrode 22 and the second electrode 24 . The organic light emitting layer 23 emits light by combining holes supplied from the first electrode 22 and electrons supplied from the second electrode 24 . The second electrode 24 is formed on the organic light emitting layer 23 . Here, in the conventional organic light emitting display device 1, the driving transistor DT is formed in a top gate structure to maximize the emission area, and the second electrode 24 of the organic light emitting diode OLED is thin. is formed

Accordingly, in the conventional organic light emitting display device 1 , the resistance of the second electrode 24 of the organic light emitting diode OLED increases, and the base power Vss in each pixel due to the high resistance of the second electrode 24 . ) is rising and its level is changed.

As described above, in the conventional organic light emitting display device 1, a change in the driving current input to the organic light emitting diode OLED occurs due to a level change of the base power Vss, which causes a voltage drop of the organic light emitting diode OLED. This causes luminance non-uniformity of the organic light emitting display device. The voltage drop of the organic light emitting diode (OLED) becomes more severe in the large area organic light emitting display device (1).

An object of the present invention is to provide an organic light emitting display device capable of preventing a voltage drop in an organic light emitting device according to a level change of a base voltage in each pixel of the organic light emitting display device.

According to an embodiment of the present invention, there is provided an organic light emitting display device comprising: a driving unit configured to output a driving signal of an organic light emitting diode from a driving power source in response to a first gate signal and a data signal; and a first sensing unit connected to the driving unit and configured to output a first sensing signal according to a level change of the base power in response to a second gate signal and the base power.

According to another aspect of the present invention, there is provided an organic light emitting display device comprising: a driver generating and outputting a driving signal from a driving power source in response to a first gate signal and a data signal; an organic light emitting device emitting light according to the driving signal output from the driving unit; and generating a first compensation signal according to a level change of the base power in response to a second gate signal and base power, and outputting the first compensation signal to the anode electrode of the organic light emitting device to adjust the level of the driving signal It includes a first compensation unit.

According to another aspect of the present invention, there is provided an organic light emitting display device comprising: a driving transistor formed on a substrate; an organic light emitting device formed on the driving transistor and having a first electrode, an organic light emitting layer, and a second electrode; a sensing transistor formed on the substrate to be spaced apart from the driving transistor; and at least one auxiliary electrode formed between the gate electrode of the sensing transistor and the second electrode and providing a base power to the gate electrode through the second electrode.

The organic light emitting display device according to the present invention includes a sensing transistor operating by receiving a base power as a gate voltage in each pixel, senses a level change of the base power using the sensing transistor and outputs the sensed level change to an external circuit, and outputs the base power from the external circuit By performing compensation to increase the level of the driving signal according to the change in power, it is possible to prevent a voltage drop in the organic light emitting diode due to the decrease in the size of the driving signal due to the change in the level of the base power.

In addition, the organic light emitting display device includes a compensation transistor that operates by receiving a base power as a gate voltage in each pixel, and generates a compensation signal according to a change in the level of the base power using this, and outputs it to the organic light emitting device for organic light emission By performing compensation for increasing the level of the driving signal applied to the device, it is possible to prevent a voltage drop in the organic light emitting device due to a decrease in the magnitude of the driving signal due to a change in the level of the base power source.

In addition, the organic light emitting display device includes a threshold voltage sensing transistor or a threshold voltage compensating transistor in each pixel to adjust the size of the data signal according to the level change of the threshold voltage, thereby increasing the level of the driving signal applied to the organic light emitting diode. It is possible to prevent a voltage drop from occurring in the organic light emitting diode.

1 is an equivalent circuit diagram of one pixel of a conventional organic light emitting diode display.
2 is a cross-sectional view schematically illustrating a part of a structure of a conventional organic light emitting display device.
3 is a circuit diagram of one pixel of an organic light emitting diode display according to an exemplary embodiment of the present invention.
FIG. 4 is a timing diagram according to an operation of the pixel circuit shown in FIG. 3 .
5 is a circuit diagram of one pixel of an organic light emitting diode display according to another exemplary embodiment of the present invention.
FIG. 6 is a timing diagram according to an operation of the pixel circuit shown in FIG. 5 .
7 is a cross-sectional view of one pixel area of an organic light emitting diode display according to an exemplary embodiment.

Hereinafter, an organic light emitting display device according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a circuit diagram of one pixel of an organic light emitting diode display according to an exemplary embodiment of the present invention.

Referring to FIG. 3 , the organic light emitting display device 100 may include a plurality of pixels, each of which includes an organic light emitting diode (OLED), a driver 110 and at least two sensing units 120 and 130 . It may include a pixel circuit provided with.

An organic light emitting device (OLED) has a structure in which an anode electrode, an organic thin film and a cathode electrode are stacked, and the organic thin film may include a light emitting layer, an electron transport layer, a hole transport layer, a hole injection layer, and an electron injection layer. The organic light emitting diode OLED may emit light by operating according to the driving signal Id output from the driving unit 110 . The luminance of light emitted from the organic light emitting diode OLED may vary according to the level of the driving signal Id.

The driving unit 110 may include a switching transistor ST, a driving transistor DT, and a capacitor C. The driving unit 110 may generate the driving signal Id according to the driving power VDD applied from the driving power line (not shown), and output the generated driving signal Id to the organic light emitting diode OLED. . The driving signal Id output from the driving unit 110 may be a driving current capable of operating the organic light emitting diode OLED or a driving voltage corresponding thereto.

When the gate electrode of the switching transistor ST is connected to the gate line (not shown) of the organic light emitting display device, the source electrode is connected to the data line (not shown), the drain electrode is connected to the gate electrode of the driving transistor DT. can

A gate electrode of the driving transistor DT may be connected to the switching transistor ST, a drain electrode may be connected to a driving power line (not shown), and a source electrode may be connected to an anode electrode of the organic light emitting diode OLED.

The capacitor C may be connected between the gate electrode of the driving transistor DT and the anode electrode of the organic light emitting diode OLED.

The switching transistor ST may be operated by a gate signal provided through a gate line, for example, a first gate signal Ga, and output a data signal Vdata provided from the data line. The driving transistor DT may be operated by the data signal Vdata to output the driving signal Id according to the driving power VDD provided from the driving power line. The driving signal Id may be output to the anode electrode of the organic light emitting device OLED to drive the organic light emitting device OLED. The capacitor C may be charged with a voltage having a level corresponding to the data signal Vdata while the data signal Vdata is applied to the driving transistor DT. The voltage charged in the capacitor C may keep the turn-on state of the driving transistor DT constant for one frame.

Here, the driving transistor DT may operate as a source-follower. Accordingly, the driving transistor DT may output the driving signal Id of a level excluding the threshold voltage Vth of the driving transistor DT from the data signal Vdata applied to the gate electrode.

The sensing units 120 and 130 may sense the threshold voltage Vth of the driving transistor DT of the driving unit 110 and the base power Vss applied through a base power line (not shown). The sensing units 120 and 130 may include a threshold voltage sensing unit 120 and a base voltage sensing unit 130 .

The threshold voltage sensing unit 120 may include a first sensing transistor ST1 connected to the output of the driving unit 110 . The gate electrode of the first sensing transistor ST1 may be connected to the gate line, and the drain electrode may be connected to the source electrode of the driving transistor DT.

The first sensing transistor ST1 is operated by the second gate signal Gb provided through the gate line, and receives the threshold voltage Vth of the driving transistor DT from the driving signal Id provided through the drain electrode. sensing, and thus outputting the first sensing signal Vth_s. As described above, the driving transistor DT operates as a source-follower. Accordingly, the turned-on first sensing transistor ST1 may output the driving signal Id output from the driving transistor DT as the first sensing signal Vth_s. Here, since the level of the data signal Vdata is preset, the level of the threshold voltage Vth of the driving transistor DT can be known from the first sensing signal Vth_s output from the first sensing transistor ST1. .

The base voltage sensing unit 130 may include a second sensing transistor ST2 connected to the output of the driving unit 110 and a third sensing transistor ST3 connected to the second sensing transistor ST2 .

The gate electrode of the second sensing transistor ST2 may be connected to the gate line together with the gate electrode of the first sensing transistor ST1 , and the drain electrode may be connected to the source electrode of the driving transistor DT. A gate electrode of the third sensing transistor ST3 may be connected to a base power line, and a drain electrode of the third sensing transistor ST3 may be connected to a source electrode of the second sensing transistor ST2.

The second sensing transistor ST2 may be operated by the second gate signal Gb provided through the gate line, and may output the driving signal Id provided through the drain electrode. The third sensing transistor ST3 is operated by the base power Vss provided through the base power line, and senses the base power Vss according to the driving signal Id output from the second sensing transistor ST2. , the second sensing signal Vss_s may be output.

Here, the third sensing transistor ST3 may operate as a source-follower like the driving transistor DT. Accordingly, the third sensing transistor ST3 may output the second sensing signal Vss_s at a level excluding the threshold voltage Vth of the third sensing transistor ST3 from the base power Vss applied to the gate electrode. . Here, the threshold voltage Vth of the third sensing transistor ST3 may be the same as the threshold voltage Vth of the previously sensed driving transistor DT.

Also, the third sensing transistor ST3 may be operated only when the base power Vss is not the ground level GND, that is, has a predetermined level of the base power Vss. Accordingly, the level of the base power Vss can be known from the second sensing signal Vss_s output from the third sensing transistor ST3.

As described above, the pixel circuit of the organic light emitting diode display 100 may sense the threshold voltage Vth and the base voltage Vss through the threshold voltage sensing unit 120 and the base voltage sensing unit 130 . have. The sensing result, that is, the first sensing signal Vth_s of the threshold voltage sensing unit 120 and the second sensing signal Vss_s of the base voltage sensing unit 130, respectively, is a driving circuit (not shown) of the organic light emitting diode display 100 . hour) can be output. The driving circuit may include a timing controller (not shown), and the timing controller may compensate the level of the driving signal Id in each pixel circuit according to the first sensing signal Vth_s and the second sensing signal Vss_s. have. As described above, compensation for the level of the driving signal Id by the external circuit, that is, the timing controller is referred to as external compensation.

FIG. 4 is a timing diagram according to an operation of the pixel circuit shown in FIG. 3 .

3 and 4 , the first gate signal Ga, the second gate signal Gb, and the base power Vss may be applied to the pixel circuit during times t1 to t3 on the time axis t. The first gate signal Ga and the second gate signal Gb may be signals output from different gate lines or the same gate line, and may have the same phase. A ground level may be applied to the base power Vss during time t1 to t2, and a signal having a predetermined level other than the ground level may be applied during time t2 to t3.

The switching transistor ST of the driving unit 110 may be turned on according to the first gate signal Ga to output the data signal Vdata. The driving transistor DT of the driving unit 110 may be turned on according to the data signal Vdata to output the driving signal Id according to the driving power VDD.

The first sensing transistor ST1 of the threshold voltage sensing unit 120 is turned on according to the second gate signal Gb, and the driving transistor DT is turned on from the driving signal Id output from the driving transistor DT. The first sensing signal Vth_s may be output by sensing the threshold voltage Vth. The first sensing signal Vth_s may be output for a period of time t1 to t2.

Meanwhile, the threshold voltage Vth of the ideal driving transistor DT should be close to 0V. However, the threshold voltage Vth may have a predetermined level due to a process or operation problem of the organic light emitting diode display 100 . As such, when the threshold voltage Vth of the driving transistor DT has a predetermined level, the size of the driving signal Id may be reduced in inverse proportion to this. Accordingly, a compensation operation capable of compensating for the magnitude of the driving signal Id according to the sensing result of the threshold voltage Vth, that is, the first sensing signal Vth_s is required.

For example, the first sensing transistor ST1 may output the first sensing signal Vth_s of the first level from the driving signal Id output from the driving transistor DT. The first sensing signal Vth_s may be transmitted to a driving circuit of the organic light emitting diode display 100 , that is, a timing controller. The timing controller may increase and output the data signal Vdata supplied to each pixel circuit according to the first sensing signal Vth_s. Here, the data signal Vdata may be increased by the size of the first sensing signal Vth_s, that is, the first level.

The second sensing transistor ST2 of the base voltage sensing unit 130 is turned on according to the second gate signal Gb, and receives the driving signal Id output from the driving transistor DT by the third sensing transistor ST3 ) can be passed to The third sensing transistor ST3 is turned on according to the base power Vss, and the second sensing is performed by sensing the level of the base power Vss according to the driving signal Id output from the second sensing transistor ST2. A signal Vss_s may be output. The second sensing signal Vss_s may be output during time t2 to time t3.

Meanwhile, the ideal base power (Vss) should be at the ground level. However, the base power Vss may rise to a predetermined level due to a problem in process or operation of the organic light emitting diode display 100 . As such, when the base power Vss has a predetermined level, the magnitude of the driving signal Id may be reduced. Accordingly, a compensation operation capable of compensating for the magnitude of the driving signal Id according to the sensing result of the base power Vss, that is, the second sensing signal Vss_s, is required.

For example, the third sensing transistor ST3 may output the second sensing signal Vss_s of the first level according to the increased base power Vss. The second sensing signal Vss_s may be transmitted to the timing controller of the organic light emitting diode display 100 . The timing controller may increase and output the data signal Vdata supplied to each pixel circuit according to the second sensing signal Vss_s. Here, the data signal Vdata may increase by the magnitude of the second sensing signal Vss_s, that is, the first level.

As described above, the organic light emitting diode display 100 according to the present exemplary embodiment has a threshold voltage capable of sensing the threshold voltage Vth of the driving transistor DT and the magnitude of the base power Vss for each pixel in the pixel circuit. It may include a sensing unit 120 and a base voltage sensing unit 130 . The data signal Vdata in the driving circuit of the organic light emitting diode display 100 according to the threshold voltage Vth and the base power Vss sensed by the threshold voltage sensing unit 120 and the base voltage sensing unit 130, respectively. External compensation that adjusts the level of At this time, as the size of the data signal Vdata increases according to the external compensation, the size of the driving signal Id output from the driving transistor DT also increases, so that a voltage drop in the organic light emitting diode OLED can be prevented. have. Accordingly, it is possible to solve the luminance non-uniformity of the organic light emitting display device 100 .

5 is a circuit diagram of one pixel of an organic light emitting diode display according to another exemplary embodiment of the present invention.

Referring to FIG. 5 , the organic light emitting diode display 101 may include a plurality of pixels, each of which includes an organic light emitting diode (OLED), a driver 111 and at least two compensators 121 and 131 . It may include a pixel circuit having a.

The organic light emitting diode OLED emits light according to the driving signal Id output from the driving unit 111 , and is the same as described above with reference to FIG. 3 .

The driving unit 111 may include a switching transistor ST, a driving transistor DT, and a first capacitor C1. The driving unit 111 may generate the driving signal Id according to the driving power VDD applied from the driving power line (not shown), and output the generated driving signal Id to the organic light emitting diode OLED. .

The switching transistor ST is connected to a gate line (not shown) and a data line (not shown) of the organic light emitting diode display 101 , and is controlled by a gate signal provided through the gate line, for example, the first gate signal Ga. may be operated to output the data signal Vdata provided from the data line.

The driving transistor DT is connected to the switching transistor ST and the driving power line (not shown), is operated according to the data signal Vdata output from the switching transistor ST, and is driven by the driving power VDD. Id) can be printed. The driving transistor DT may be a source-follower, and accordingly, the driving signal Id output from the driving transistor DT is the threshold voltage Vth of the driving transistor DT from the data signal Vdata applied to the gate electrode. ) except for a voltage or a current corresponding thereto.

The first capacitor C1 is connected between the gate electrode of the driving transistor DT and the anode electrode of the organic light emitting diode OLED, and while the data signal Vdata is applied to the driving transistor DT, the data signal Vdata It is possible to charge a voltage of a level corresponding to . The voltage charged in the first capacitor C1 may keep the turn-on state of the driving transistor DT constant for one frame.

The compensators 121 and 131 may compensate the level of the driving signal Id according to the threshold voltage Vth of the driving transistor DT and the base power Vss. The compensators 121 and 131 may include a threshold voltage compensator 121 and a base voltage compensator 131 .

The threshold voltage compensator 121 may include a first compensation transistor CT1 connected to the output of the driving unit 111 . The gate electrode of the first compensation transistor CT1 may be connected to the gate line, the drain electrode may be connected to the source electrode of the driving transistor DT, and the source electrode may be connected to the compensation voltage line (not shown).

The first compensation transistor CT1 operates according to the first gate signal Ga provided through the gate line, and may output the first compensation signal C1 according to the compensation voltage Vref provided from the compensation voltage line. The first compensation signal C1 may be charged in the first capacitor C1 of the driving unit 111 . Accordingly, a voltage having a magnitude obtained by adding the first compensation signal C1 to the data signal Vdata or a current corresponding thereto may be applied to the A node of the driver 111 .

The base voltage compensator 131 may include a second compensation transistor CT2 connected to the driving power line, a third compensation transistor CT3 connected to the second compensation transistor CT2, and a second capacitor C2. .

The gate electrode of the second compensation transistor CT2 may be connected to the gate line, the drain electrode may be connected to the driving power line, and the source electrode may be connected to the drain electrode of the third compensation transistor CT3 . The gate electrode of the third compensation transistor CT3 is connected to a base power line (not shown), the drain electrode is connected to the source electrode of the second compensation transistor CT2, and the source electrode is one end of the second capacitor C2. can be connected to The second capacitor C2 may be connected between the B node, that is, the anode electrode of the organic light emitting device OLED and the third compensation transistor CT3 .

The second compensation transistor CT2 operates according to the second gate signal Gb provided through the gate line, and may output a signal corresponding to the driving voltage provided through the driving power line.

The third compensation transistor CT3 may be a source-follower like the driving transistor DT, and accordingly, the third compensation transistor CT3 is a third sensing transistor ST3 from the base power Vss applied to the gate electrode. The second compensation signal C2 of a level excluding the threshold voltage Vth of may be output.

The second compensation signal C2 may be charged in the second capacitor C2 . Accordingly, a voltage having a magnitude obtained by adding the driving signal Id to the second compensation signal C2 or a current corresponding thereto may be applied to the node B.

As described above, in the pixel circuit of the organic light emitting diode display 101 , the driving signal Id by the threshold voltage Vth and the base power Vss through the threshold voltage compensator 121 and the base voltage compensator 131 . ) can compensate for level changes. As described above, compensation for the level of the driving signal Id in the pixel circuit itself is referred to as internal compensation.

FIG. 6 is a timing diagram according to an operation of the pixel circuit shown in FIG. 5 .

5 and 6 , a gate signal, for example, a first gate signal Ga and a second gate signal Gb, may be applied to the pixel circuit during times t1 to t3 on the time axis t. The first gate signal Ga and the second gate signal Gb may be different signals output from the same gate line. In other words, during one horizontal period (1H) of the organic light emitting diode display 101, the first gate signal Ga may be output for time t1 to t2, and the second gate signal Gb may be output for time t3 to t4. have.

The switching transistor ST of the driving unit 111 may be turned on according to the first gate signal Ga during time t1 to t2 on the time axis t to output the data signal Vdata. The driving transistor DT of the driving unit 111 may operate according to the data signal to output the driving signal Id according to the driving power VDD.

The first compensation transistor CT1 of the threshold voltage compensator 121 is turned on according to the first gate signal Ga during the time axis t time t1 to t2, and the first compensation transistor CT1 according to the compensation voltage Vref provided from the outside is turned on. A compensation signal C1 may be output. The first compensation signal C1 may be charged in the first capacitor C1 together with the data signal Vdata. Accordingly, the data signal Vdata having a magnitude increased by the level (?1) of the first compensation signal C1 may be applied to the node A.

The second compensation transistor CT2 of the base voltage compensator 131 is turned on according to the second gate signal Gb during time t3 to t4 on the time axis t, and is applied to the driving power VDD provided from the driving power line. A corresponding signal can be output. The third compensation transistor CT3 is turned on according to the base power Vss provided from the base power line, and may output the second compensation signal C2 according to the signal output from the second compensation transistor CT2. . The second compensation signal C2 may be charged in the second capacitor C2 together with the driving signal Id. Accordingly, the driving signal Id having a magnitude increased by the level (?2) of the second compensation signal C2 may be applied to the B node.

Accordingly, the level of the driving signal Id is increased by the first level (?I1) by the first compensation signal C1 in the time axis (t) time t1 to t2, and in the time axis (t) time t3 to t4 By the second compensation signal C2, the level may be secondarily increased by the second level ?I2 and output. As described above, the pixel circuit of the present embodiment compensates and outputs the level of the driving signal Id according to the threshold voltage Vth and the base power Vss, thereby preventing a voltage drop in the organic light emitting diode OLED. , it is possible to solve the luminance non-uniformity of the organic light emitting display device 101 .

7 is a cross-sectional view of one pixel area of an organic light emitting diode display according to an exemplary embodiment.

Hereinafter, for convenience of explanation, the organic light emitting display device according to an embodiment of the present invention shown in FIG. 3 will be described below. However, the organic light emitting display device according to another embodiment of the present invention shown in FIG. 5 also has the same structure. can have

Referring to FIG. 7 , the organic light emitting display device 100 according to an embodiment of the present invention has a top emission type, and a driving transistor DT and a sensing transistor ST formed on a substrate 210 . ) and an organic light emitting diode (OLED).

A first semiconductor layer 211 and a second semiconductor layer 221 may be formed on the substrate 210 . The first semiconductor layer 211 and the second semiconductor layer 221 may be formed on the same layer by the same process, but may be spaced apart from each other.

The first semiconductor layer 211 may include a first region 211a made of pure polysilicon and second regions 211b and 211c doped with impurities. The second semiconductor layer 221 may also include a first region 221a of pure polysilicon and second regions 221b and 221c doped with impurities.

A gate insulating layer 231 may be formed on the first semiconductor layer 211 and the second semiconductor layer 221 . A first gate electrode 213 corresponding to the first region 211a of the first semiconductor layer 211 may be formed on the gate insulating layer 231 . Also, the second gate electrode 223 corresponding to the first region 221a of the second semiconductor layer 221 may be formed on the same layer by the same process as that of the first gate electrode 213 .

An interlayer insulating layer 233 may be formed on the first gate electrode 213 and the second gate electrode 223 . A contact hole (not shown) may be formed in the interlayer insulating layer 233 and the gate insulating layer 231 , respectively. For example, in the interlayer insulating layer 233 and the gate insulating layer 231 , the second regions 211b and 211c of the first semiconductor layer 211 and the second regions 221b and 221c of the second semiconductor layer 221 are exposed. Each contact hole may be formed. Also, a contact hole exposing the second gate electrode 223 may be formed in the interlayer insulating layer 233 .

Source electrodes 214 and 224 and drain electrodes 215 and 225 may be formed on the interlayer insulating layer 233 . The source electrodes 214 and 224 are connected to the second regions 211b and 211c of the first semiconductor layer 211 through a contact hole and are connected to the first source electrode 214 and the second region of the second semiconductor layer 221 ( A second source electrode 224 connected to 221b and 221c may be included. The drain electrodes 215 and 225 are connected to the second regions 211b and 211c of the first semiconductor layer 211 through a contact hole and are connected to the first drain electrode 215 and the second region of the second semiconductor layer 221 ( A second drain electrode 225 connected to 221b and 221c may be included.

The first semiconductor layer 211 , the first gate electrode 213 , the first source electrode 214 , and the first drain electrode 215 may form a driving transistor DT. In addition, the second semiconductor layer 221 , the second gate electrode 223 , the second source electrode 224 , and the second drain electrode 225 are a sensing transistor, for example, the third sensing transistor ST3 shown in FIG. 3 . can form.

The driving transistor DT and the third sensing transistor ST3 form a P-type or N-type transistor depending on impurities doped in each semiconductor layer, that is, the first semiconductor layer 211 and the second semiconductor layer 221 . can In the case of the P-type transistor, the first semiconductor layer 211 and the second semiconductor layer 221 may be doped with a group 3 element, such as boron (B). In the case of the N-type transistor, impurities such as phosphorus (P) may be doped into the first semiconductor layer 211 and the second semiconductor layer 221 .

Meanwhile, the first auxiliary electrode 226 may be formed on the interlayer insulating layer 233 . The first auxiliary electrode 226 may be connected to the second gate electrode 223 through a contact hole. The first auxiliary electrode 226 may be formed in the same process as the second source electrode 224 and the second drain electrode 225 .

A protective layer 235 may be formed on the driving transistor DT and the third sensing transistor ST3 . A contact hole 237 exposing the drain electrode of the driving transistor DT, that is, the first drain electrode 215 may be formed in the protective layer 235 . In addition, a contact hole 237 exposing the first auxiliary electrode 226 of the third sensing transistor ST3 may be formed in the protective layer 235 .

A first electrode 241 connected to the first drain electrode 215 through a contact hole 237 may be formed on the protective layer 235 . The first electrode 241 may be formed of indium tin oxide (ITO) or indium zinc oxide (IZO) to transmit light.

In addition, a second auxiliary electrode 251 connected to the second gate electrode 223 through the contact hole 236 may be formed on the protective layer 235 . The second auxiliary electrode 251 may be formed in the same process as the first electrode 241 .

Banks 260 that surround the first electrode 241 and define a pixel area may be formed on both sides of the first electrode 241 . In addition, a multi-layered organic light emitting layer 243 may be formed in the pixel region. Here, when the first electrode 241 is an anode electrode, the organic light emitting layer 243 may include a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer.

A second electrode 245 may be formed on the organic light emitting layer 243 . The second electrode 245 may be formed of ITO or IZO. The second electrode 245 may be a cathode electrode and may be connected to a ground voltage line (not shown).

The first electrode 241 , the organic light emitting layer 243 , and the second electrode 245 may form an organic light emitting diode (OLED).

Meanwhile, a barrier rib 255 may be formed on the second auxiliary electrode 251 . The barrier rib 255 may prevent the organic light emitting layer 243 from being formed on the second auxiliary electrode 251 . The partition wall 255 may be formed to have a reverse taper shape, and the angle of the taper may be freely set. In addition, the second electrode 245 of the organic light emitting diode (OLED) may be formed to surround the barrier rib 255 . Accordingly, one side of the second electrode 245 may be connected to the second auxiliary electrode 251 .

As described above, the organic light emitting display device 100 according to the present embodiment includes a sensing transistor connected to the cathode electrode of the organic light emitting diode OLED, that is, the second electrode 245, that is, the third sensing transistor ST3. may include The third sensing transistor ST3 may be turned on by receiving the base power Vss applied from the outside to the second electrode 245 of the organic light emitting device OLED to the gate electrode, that is, the second gate electrode 223 . have. The turned-on third sensing transistor ST3 may sense the level of the base power Vss and output it to an external, for example, a timing controller (not shown) of the organic light emitting display device 100 .

Meanwhile, the organic light emitting display device 100 according to another embodiment of the present invention shown in FIG. 5 may have a similar structure. For example, the third sensing transistor ST3 described above may be the third compensation transistor CT3 , and the third compensation transistor CT3 is the base power applied to the second electrode 245 of the organic light emitting diode (OLED). It can be turned on by receiving (Vss) as an input. The turned-on third compensation transistor CT3 generates and outputs the second compensation signal C2 according to the signal output from the second compensation transistor CT2, thereby generating the anode electrode of the OLED, that is, the first The magnitude of the driving signal Id input to the electrode 241 may be increased.

Although many matters are specifically described in the foregoing description, these should be construed as examples of preferred embodiments rather than limiting the scope of the invention. Accordingly, the invention should not be defined by the described embodiments, but should be defined by the claims and equivalents to the claims.

100, 101: pixel circuit 110, 111: driver
120: threshold voltage sensing unit 130: base voltage sensing unit
121: threshold voltage compensator 131: base voltage compensator
226: first auxiliary electrode 251: second auxiliary electrode
255: bulkhead

Claims (12)

a driving unit configured to output a driving signal of the organic light emitting diode from a driving power source in response to the first gate signal and the data signal; and
a first sensing unit connected to the driving unit and outputting a first sensing signal according to a level change of the base power in response to a second gate signal and a base power;
The first sensing unit,
a first sensing transistor for outputting the driving signal transmitted from the driving unit in response to the second gate signal; and
and a second sensing transistor configured to output the first sensing signal from the driving signal transmitted from the first sensing transistor in response to the base power. delete According to claim 1,
The first sensing signal is a signal according to a level obtained by subtracting a threshold voltage from the base power source. According to claim 1,
and a second sensing unit connected to the driving unit and configured to output a second sensing signal according to a level change of a threshold voltage from the driving signal in response to a second gate signal. According to claim 1,
An organic light emitting display device in which the level of the data signal is adjusted according to the first sensing signal. a driving unit for generating and outputting a driving signal from a driving power source in response to the first gate signal and the data signal;
an organic light emitting device emitting light according to the driving signal output from the driving unit; and
generating a first compensation signal according to a level change of the base power in response to a second gate signal and base power, and outputting the first compensation signal to the anode electrode of the organic light emitting device to adjust the level of the driving signal including a first compensation unit;
The first compensation unit,
a first compensation transistor connected to the driving power and outputting a first signal according to the driving power in response to the second gate signal; and
and a second compensation transistor for generating and outputting the first compensation signal from the first signal in response to the base power. delete 7. The method of claim 6,
The first compensation signal is a signal according to a level obtained by subtracting a threshold voltage from the base power source. 7. The method of claim 6,
It is connected to the driving unit and generates a second compensation signal according to a level change of a threshold voltage from an externally applied voltage in response to the second gate signal, and outputs the second compensation signal to the driving unit to control the data signal. The organic light emitting display device further comprising a second compensator for adjusting the level. 7. The method of claim 6,
The first gate signal and the second gate signal are respectively output at different times during one horizontal period. a driving unit configured to output a driving signal of the organic light emitting diode from a driving power source in response to the first gate signal and the data signal; and
a first sensing unit connected to the driving unit and outputting a first sensing signal according to a level change of the base power in response to a second gate signal and a base power;
the driving unit
a driving transistor formed on a substrate to output a driving signal of the organic light emitting device;
The organic light emitting device is formed on the driving transistor including a first electrode, an organic light emitting layer and a second electrode,
The first sensing unit
a sensing transistor formed on the substrate to be spaced apart from the driving transistor and outputting a first sensing signal according to a level change of the base power; and
an organic light emitting display including at least one auxiliary electrode formed between the gate electrode of the sensing transistor and the second electrode and providing the base power to the gate electrode of the sensing transistor through the second electrode of the organic light emitting device Device. 12. The method of claim 11,
The sensing transistor is
a semiconductor layer formed on the substrate;
the gate electrode formed on the semiconductor layer;
a source electrode and a drain electrode formed on the gate electrode and connected to the semiconductor layer;
a barrier rib formed on the auxiliary electrode;
The auxiliary electrode is
a first auxiliary electrode formed on the gate electrode and connected to the gate electrode; and
a second auxiliary electrode formed on the first auxiliary electrode and connected to the first auxiliary electrode;
the barrier rib is formed on the second auxiliary electrode;
The second electrode of the organic light emitting device is
The organic light emitting diode display is formed to surround the barrier rib and is connected to the gate electrode through the second auxiliary electrode and the first auxiliary electrode.

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