KR101362033B1 - Light Emitting Display - Google Patents

Abstract

The present invention provides a display device comprising: a display unit including two or more subpixels arranged in a matrix form on a substrate to emit different colors; Monitoring pixels arranged on the outer substrate of the display unit to correspond to emission colors of the sub pixels to monitor the sub pixels; A power supply unit supplying power to the sub pixels; A power distributor that receives one reference power from the power supply and distributes each power to the monitoring pixels; And a control unit connected to a power distributor and supplying a control signal.

EL display, power supply, distributor

Description

Light Emitting Display

1 is a block diagram of a conventional monitoring pixel and a power supply.

2 is a schematic plan view of an electroluminescent display device according to an embodiment of the present invention;

FIG. 3 is a circuit diagram illustrating subpixels of the electroluminescent display of FIG. 2. FIG.

FIG. 4 is a block diagram illustrating a relationship between a power distributor and monitoring pixels included in the electroluminescent display of FIG. 2.

FIG. 5 is a schematic circuit diagram of an area “A” of FIG. 4. FIG.

DESCRIPTION OF THE REFERENCE NUMERALS

110: substrate 120: subpixels

125: monitoring pixels 130: display unit

150: drive unit 170: power supply unit

175: power divider 180: control unit

The present invention relates to an electroluminescent display device.

The electroluminescent device used in the electroluminescent display device was a self-light emitting device having a light emitting layer formed between two electrodes. Electroluminescent devices could be divided into inorganic electroluminescent devices and organic electroluminescent devices according to the material of the light emitting layer.

In addition, the electroluminescent device has a top emission type and a bottom emission type according to the direction in which light is emitted, and a passive matrix type and an active matrix type depending on the driving method. Matrix).

On the other hand, most display devices, as well as electroluminescent devices, have errors in driving power or driving signals for driving the display devices according to changes in the internal or external environment.

Accordingly, after forming the monitoring pixels to monitor the non-display area of the panel and supplying different driving power to them, the driving power compensated according to the degree of deterioration of the monitoring pixels is generated, and the sub pixels arranged in the display area are provided. A method of supplying the pixels has been proposed as shown in FIG. 1.

1 is a block diagram of a conventional monitoring pixel and a power supply.

As shown in FIG. 1, in the conventional EL display device, the monitoring pixels MR, MG, and MB and the power supply units P1, P2, and P3 are connected to receive driving power from different power terminals.

As shown in the figure, the monitoring pixels MR, MG, MB and the power supply units P1, P2, and P3 are each connected in a 1: 1 connection. In such a structure, since three current sources must be provided in the power supply units P1, P2, and P3, the size of the power supply units P1, P2, and P3 is increased, and the electroluminescent display device is manufactured. In order to increase the manufacturing cost, the improvement is required.

An object of the present invention for solving the above problems is to provide an electroluminescent display device that can stabilize the display quality and reduce the cost.

According to an aspect of the present invention, there is provided a display device including two or more subpixels arranged in a matrix form on a substrate to emit different colors; Monitoring pixels arranged on the outer substrate of the display unit to correspond to emission colors of the sub pixels to monitor the sub pixels; A power supply unit supplying power to the sub pixels; A power distributor that receives one reference power from the power supply and distributes each power to the monitoring pixels; And a control unit connected to a power distributor and supplying a control signal.

The sub pixels may comprise red, green and blue sub pixels, and the monitoring pixels may comprise red, green and blue monitoring pixels.

The power divider includes a distributor supplied with one reference power, an output setting unit for setting the output of the distributor to an arbitrary value, and a switch connected between the distributor and the output setting unit for switching by a control signal supplied from the controller. It may include a switch unit.

The distributor may include a first terminal respectively connected to one reference power source, a second terminal respectively connected to the first switch unit, and a third terminal respectively connected to the monitoring pixels.

The first switch unit may be time-division controlled by a control signal.

The power divider may distribute one or more equal or different power to each of the monitoring pixels.

And a second switch unit connected between the third terminal of the distributor and the monitoring pixels, respectively.

The second switch unit may be a switching element for receiving and supplying a control signal from the controller to selectively supply each output value set in the distributor to the monitoring pixels.

The monitoring pixels may each include a sample & hold unit.

The sample and hold unit may include one switch, a capacitor, and a comparator.

The switch of the sample & hold unit can be switched by a control signal supplied from the controller.

The sample and hold unit may sample and hold power supplied to the monitoring pixels, and feed back the power supply unit to adjust the power supplied to the subpixels.

The sample and hold unit may acquire a value changed according to the degree of deterioration of the monitoring pixels.

The divider includes a first divider, a second divider, and a third divider, the first divider is connected to the power stage of the red monitoring pixel, the second divider is connected to the power stage of the green monitoring pixel, and the third divider is blue. It may be connected to the power supply terminal of the monitoring pixel.

The output setting unit may include one of a current source and a voltage source.

The first switch unit and the second switch unit may be two or more.

The driver may include a scan driver configured to supply scan signals and data signals to the subpixels, and a driver including a data driver.

The subpixels may each include one or more transistors, capacitors, and organic light emitting diodes.

<Example 1>

2 is a schematic plan view of an electroluminescent display device according to an embodiment of the present invention.

Referring to FIG. 2, an electroluminescent display device according to an exemplary embodiment of the present invention includes a display unit 130 including two or more subpixels arranged in a matrix on a substrate 110 to emit different colors. do. Two or more subpixels may be formed in three, four, or more according to the purpose. In the present invention, three subpixels, that is, red, green, and blue subpixels 120 will be described as an example.

And monitoring pixels 125 disposed on the outer substrate 110 of the display unit 130 to monitor the red, green, and blue subpixels 120. In the present invention, since three subpixels are described as an example, the monitoring pixels 125 also describe three monitoring pixels, that is, red, green, and blue monitoring pixels 125 as an example.

 The red, green, and blue monitoring pixels 125 may be disposed for each scan line S1..Sn of the display unit 130 or may be selectively disposed only for one half of the scan line.

And a power supply unit 170 for supplying power to the red, green, and blue subpixels 120.

And a power distributor 175 which receives one reference power from the power supply unit 170 and distributes the power to the red, green, and blue monitoring pixels 125.

The controller 180 supplies a control signal to the power distributor 175.

The red, green and blue subpixels 120 may each include one or more transistors, capacitors and organic light emitting diodes, and the red, green and blue monitoring pixels 125 may include one or more transistors and organic light emitting diodes. Can be.

These red, green and blue subpixels 120 and red, green and blue monitoring pixels 125 may emit red, green and blue, respectively. However, the red, green and blue subpixels 120 and the red, green and blue monitoring pixels 125 may emit other colors as well.

The power supply unit 170 includes a red, green, and blue subpixels 120, a red, green, and blue monitoring pixels 125, and a scan driver (not shown) and a data driver (not shown) included in the driver 150. ) Can be powered. However, as described above, the red, green, and blue monitoring pixels 125 are supplied with one reference power from the power supply unit 170 to distribute the power to the red, green, and blue monitoring pixels 125, respectively. Supplied via 175.

The driver 150 may separate the scan driver (not shown) and the data driver (not shown) from each other and arrange the scan driver (not shown) on one side and the other side of the substrate 110 as well as the driver 150 on an external device. And may be electrically connected to the substrate 110.

On the other hand, the electrical connection between the substrate 110 and the external device 160 may be electrically connected by a flexible cable (eg, FPC) 165, etc., the flexible cable 165 is located on the substrate 110 The driving signal and power may be supplied to the sub-pixels 120 and the monitoring pixels 125 through the driver 150 and the signal lines 140 attached to the pad unit 155 and disposed on the substrate 110. To help.

For reference, the driving unit 150 is disposed on the substrate 110, which is called a chip on glass (COG) method. In addition, a driving on film (COF) method in which the driving unit 150 is disposed on the flexible cable 165 is provided. The back substrate 110, the driver 150, and the external device 160 may be flexibly designed according to a design method.

In addition, the external device 160 described above may include a power supply unit 170. It may also include a power divider 175 that distributes power to the red, green and blue monitoring pixels 125. In addition, the control unit 180 may supply a control signal to the switch unit included in the power distributor 175.

Here, the external device 160 may further include an image memory, a processor, and the like in addition to the aforementioned device.

3 is a circuit diagram illustrating subpixels of the electroluminescent display of FIG. 2.

The circuit diagram of the subpixels illustrated in FIG. 3 is a circuit diagram of general subpixels for better understanding of the description, and the electroluminescent display device according to the present invention is not limited thereto.

As shown in FIG. 3, the sub pixel circuit configuration of the display unit includes a switching transistor TFT1 having a gate connected to the scan line SCAN and a first electrode connected to the data line DATA in common, and a switching transistor TFT1. A capacitor C connected between a gate connected to the second electrode and a first electrode connected to the first power line VDD, and between the gate of the driving transistor TFT2 and the first power line VDD. And a light emitting diode D connected between the second electrode of the driving transistor TFT2 and the second power line GND.

Here, the light emitting diode D may be an organic light emitting diode in which the light emitting layer is formed of an organic material layer, but may also be an inorganic light emitting diode in which the light emitting layer is formed of an inorganic material layer.

In addition to the description of the structure of the organic light emitting diode, the organic light emitting diode is formed between the organic light emitting layer (HIL), the hole transport layer (HTL), the electron transport layer (ETL) and the electron injection layer (EIL). EML) is included.

In general, the common film is selectively formed between the first electrode (pixel electrode) and the cathode of the driving transistor TFT2 serving as the anode electrode.

As shown in FIG. 2, one sub-pixel 120 having such a circuit configuration includes one organic light emitting diode. Each of the subpixels emits red (R), green (G), and blue (B), and the subpixels 120 emitting red, green, and blue may be defined as one pixel.

On the other hand, the transistor included in the sub-pixel 120 may be driven in a linear region or a saturation region by the driving signal supplied from the driver 150, the electroluminescent display device according to the present invention It is advantageous to adopt a digital driving method for driving the transistor included in the sub-pixel 120 in a linear region. Here, the digital driving method refers to a method of driving the light emitting diode D by simply turning on or off a transistor.

Meanwhile, the electroluminescent display device according to an embodiment of the present invention distributes power to each of the monitoring pixels 125 by using a power distributor 175 that receives one reference power from the power supply unit 170, and monitors the power. The power supplied to the pixels 125 is sampled and held to adjust the power supplied to the sub pixels 120 disposed in the display unit 130.

The relationship between the red, green, and blue subpixels 120, the red, green, and blue monitoring pixels 125, the power supply unit 170, the control unit 180, and the power distributor 175 will be described below to help understand the description. A description with reference to the block diagram shown in FIG.

4 is a block diagram illustrating a driving relationship between a power distributor and monitoring pixels included in the electroluminescent display of FIG. 2.

Referring to FIG. 4, the power supply unit 170 is connected to the power terminals of the red, green, and blue subpixels 120R, 120G, and 120B, and the red, green, and blue subpixels 120R, 120G, and 120B are connected to each other. ) Supply independent power to each.

The power divider 175 receives one reference power (Vm) from the power supply unit 170 and sets the power, and then distributes power to each of the red, green, and blue monitoring pixels 125R, 125G, and 125B. Supply. The power divider 175 is controlled by a control signal supplied from the controller 180 to set the output power as well as to adjust the power distribution time.

The power of the red, green, and blue monitoring pixels 125R, 125G, and 125B, which receive power from the power distributor 175, is fed back to the power supply unit 170 through the feedback stages FB_R, FB_G, and FB_G. And the power to be supplied to the blue subpixels 120R, 120G, and 120B.

Circuit configuration schematically illustrating the relationship between the red, green, and blue subpixels 120R, 120G, and 120B, the red, green, and blue monitoring pixels 125R, 125G, and 125B, the power supply unit 170, and the power divider 175. It will be described in more detail with reference to FIG.

FIG. 5 is a schematic circuit diagram illustrating region “A” of FIG. 4.

Referring to area “A” of FIG. 5, the power distributor 175 includes three or more distributors Div1, Div2, and Div3 that receive one reference power supply Vm from the power supply unit 170, and the distributors Div1, One output setting unit (DAC) for setting the output current of the Div2, Div3) to an arbitrary value, and a first switch unit connected to the divider (Div1, Div2, Div3) and the output setting unit (DAC) for switching. S1, S2, S3). Although the illustrated output setting unit DAC is advantageously formed in the form of a current source, it may also be formed in the form of a voltage source.

Here, the distributors Div1, Div2, and Div3 have first terminals d11, d21, and d31 connected to one reference power source Vm, and second terminals connected to the first switch units S1, S2, and S3, respectively. (d12, d22, d32) and third terminals d13, d23, and d33 connected to the red, green, and blue monitoring pixels 125R, 125G, and 125B, respectively.

Such a divider Div1, Div2, Div3 can be configured in the form of a current mirror circuit or a sample & hold circuit.

On the other hand, the first switch unit (S1, S2, S3) may be time-division controlled by receiving the control signal from the controller 180 described above. Although the first switch units S1, S2, and S3 are shown as general switching elements in the drawing, this may be formed as a multiplexer.

According to this configuration, the first divider Div1, the second divider Div2, and the third divider Div3 connected to the reference power source Vm may include the output setting unit DAC and the first switch units S1, S2, By the switching operation of S3), the output currents that can be output respectively can be set to arbitrary values.

When the setting of the output setting unit DAC is changed every time the first switch unit S1, S2, S3 switches, the first divider Div1, the second divider Div2, and the third divider Div3 This is because different values of power are charged.

Accordingly, each of the first divider Div1, the second divider Div2, and the third divider Div3 included in the power divider 175 may have one of the red, green, and blue monitoring pixels 125R, 125G, and 125B. The same or different power can be distributed.

Meanwhile, the second switch unit S4R is disposed between the third terminal of the first distributor Div1, the second distributor Div2, and the third distributor Div3 and the red, green, and blue monitoring pixels 125R, 125G, and 125B. , S4G, S4B) are located.

The second switch units S4R, S4G, and S4B display red, green, and blue output currents set in each of the distributors, that is, the first divider Div1, the second divider Div2, and the third divider Div3. A switching element for selectively supplying to the monitoring pixels 125R, 125G, and 125B.

The second switch units S4R, S4G, and S4B are held during the period in which the current set by the output setting unit DAC is filled in each of the first divider Div1, the second divider Div2, and the third divider Div3. It would be advantageous to be turned on after maintaining the state.

Switching of the second switch units S4R, S4G, and S4B may be controlled by receiving a control signal from the controller 180 described above, and may be selectively switched in conjunction with other control devices.

Meanwhile, as the second switch units S4R, S4G, and S4B switch, the red, green, and blue monitoring pixels 125R, 125G, and 125B emit light as well as the power flowing to them. Sample & hold via (SH1, SH2, SH3).

When the second switch units S4R, S4G, and S4B perform a switching operation, the red, green, and blue monitoring pixels 125R, 125G, and 125B emit light together with the subpixels disposed on the display, but they do not appear on the panel. Do not. In addition, it may be efficient to drive the red, green, and blue monitoring pixels 125R, 125G, and 125B to have a duty ratio of about 40% with respect to the subpixels disposed in the display unit. It may vary.

The sample and hold units SH1, SH2, and SH3 are designed to sample the power supplied to the red, green, and blue monitoring pixels 125R, 125G, and 125B.

The sample and hold portions SH1, SH2, and SH3 include one switch S5R, S5G, and S5B, capacitors C1, C2, and C3, and comparators OP1, OP2, and OP3, respectively. The circuit configuration is possible by sampling and holding the power supplied to the red, green and blue monitoring pixels 125R, 125G and 125B. The switches S5R, S5G, and S5B of the sample and hold units SH1, SH2, and SH3 may be controlled by receiving a control signal from the controller 180 described above, and may also be switched in conjunction with other control devices. have.

In addition, the sample & hold unit (SH1, SH2, SH3), as well as sample and hold the power supplied from each of the distributor, that is, the first distributor (Div1), the second distributor (Div2) and the third distributor (Div3) In order to feed back the supply unit 170 and adjust the power supplied to the red, green, and blue subpixels 120R, 120G, and 120B, their output stages are provided via the power supply unit 170 through the feedback stages FB_R, FB_G, and FB_B. Is connected to.

According to such a configuration, when the red, green, and blue monitoring pixels 125R, 125G, and 125B are powered by the power distributor 175, the red, green, and blue monitoring pixels 125R, 125G, and 125B are then supplied. After the sample & hold of the power flowing through), the power to be supplied to the red, green, and blue subpixels 120R, 120G, and 120B can be adjusted based on the sampled & hold.

However, the sample & hold unit (SH1, SH2, SH3) can be changed depending on the driving method in regular or irregular time. That is, the sampling time and the hold time can be changed depending on which section of the section in which the driver 150 supplies the data signal to the red, green, and blue subpixels 120R, 120G, and 120B.

The sample & hold unit SH1, SH2, SH3 can acquire a value changed according to the deterioration degree of the red, green, and blue monitoring pixels 125R, 125G, and 125B. Here, it is advantageous to sample the red, green and blue monitoring pixels 125R, 125G, 125B at the same time point in order to obtain a value changed according to the degree of degradation, but individual sampling may also be considered.

Accordingly, the red, green, and blue monitoring pixels 125R, 125G, and 125B are similar to or equivalent to changes in the red, green, and blue subpixels 120R, 120G, and 120B over time (changes in device due to temperature, degradation, etc.). Make sure you have one condition.

For reference, the sample & hold unit SH1, SH2, SH3 may be disposed in all of the red, green, and blue monitoring pixels 125R, 125G, and 125B, but some or all of them may be disposed in the power supply unit 170. have.

As described above, the power supplied to the red, green, and blue subpixels 120R, 120G, and 120B is adjusted according to the state of the red, green, and blue monitoring pixels 125R, 125G, and 125B. The problem can be minimized.

Therefore, when power is supplied to the red, green, and blue monitoring pixels 125R, 125G, and 125B by using the power divider 175, the cost of the power supply unit 170 design may be reduced. In addition to the reduction, the display quality of the EL display device can be stabilized. And first of all, it is possible to design the power supply small while reducing the phenomenon that the output power of the power supply unit 170 is uneven.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention 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 indicated by the following claims rather than the detailed description. Also, all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

As described above, the present invention has the effect of providing an electroluminescent display device capable of stabilizing display quality and reducing cost.

Claims (18)

A display unit including two or more subpixels arranged in a matrix on a substrate to emit different colors; Monitoring pixels arranged on the outer substrate of the display unit to correspond to emission colors of the sub pixels to monitor the sub pixels; A power supply unit supplying power to the sub pixels; A power divider which receives one reference power from the power supply and distributes each power to the monitoring pixels; And And a control unit connected to the power distributor to supply a control signal. The method of claim 1, The subpixels comprise red, green and blue subpixels, And the monitoring pixels comprise red, green and blue monitoring pixels. The method of claim 1, The power divider is connected to the distributor supplied with the one reference power, an output setting unit for setting the output of the distributor to an arbitrary value, and is connected between the distributor and the output setting unit is supplied from the controller An electroluminescent display device comprising a first switch unit for switching by a control signal. The method of claim 3, The splitter includes a first terminal connected to the one reference power source, a second terminal connected to the first switch unit, and a third terminal connected to the monitoring pixels, respectively. The method of claim 3, And the first switch unit is time-division controlled by the control signal. 3. The method of claim 2, And the power divider distributes one or more equal or different power to each of the monitoring pixels. 5. The method of claim 4, And a second switch unit connected between the third terminal of the distributor and the monitoring pixels, respectively. The method of claim 7, wherein And the second switch unit is a switching element for receiving a control signal from the controller and selectively supplying each output value set to the distributor to the monitoring pixels. The method of claim 1, The monitoring pixels each include a sample & hold portion, The sample and hold portion includes a switch, a capacitor, and a comparator, And the switch of the sample and hold unit is switched by a control signal supplied from the control unit. delete delete 10. The method of claim 9, And the sample and hold unit samples and holds the power supplied to the monitoring pixels, and feeds back the power supply unit to adjust the power supplied to the sub pixels. 10. The method of claim 9, And the sample and hold unit acquires a value changed according to the degree of deterioration of the monitoring pixels. The method of claim 3, The distributor includes a first distributor, a second distributor, and a third distributor, And the first divider is connected to a power supply terminal of a red monitoring pixel, the second divider is connected to a power supply terminal of a green monitoring pixel, and the third divider is connected to a power supply terminal of a blue monitoring pixel. The method of claim 3, And the output setting unit includes one of a current source and a voltage source. 9. The method of claim 8, And at least two of the first switch unit and the second switch unit. delete delete

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