KR102414311B1 - Organic light emitting display device and method for controlling luminance of the organic light emitting display device - Google Patents

Abstract

In embodiments of the present invention, a plurality of data lines and a plurality of gate lines are disposed, a plurality of subpixels defined by a plurality of data lines and a plurality of gate lines are arranged in a display panel, and a sensing voltage is measured from the display panel. A sensor comprising: a sensing unit outputting sensing data for at least one sub-pixel among the plurality of sub-pixels; and a controller receiving the sensing data to determine a temperature change of the display panel, and controlling the luminance of the display panel according to the temperature change It relates to an organic light emitting display device and a luminance control method thereof.

Description

Organic light emitting display device and its luminance control method

The present invention relates to an organic light emitting display device and a luminance control method thereof.

As the information society develops, the demand for display devices for displaying images is increasing in various forms. Various display devices such as an organic light emitting display device (OLED) are being used.

The organic light emitting display device, which has recently been in the spotlight, uses an organic light emitting diode (OLED) that emits light by itself, and thus has a fast response speed, and has a large contrast ratio, luminous efficiency, luminance, and viewing angle.

Each sub-pixel disposed in the organic light emitting display panel of the organic light emitting display device basically includes a driving transistor for driving the organic light emitting diode, a switching transistor for transferring a data voltage to the gate node of the driving transistor, and a constant voltage for one frame time. It may be configured to include a capacitor that serves to maintain the.

Such an organic light emitting diode display displays an image by controlling the brightness of the organic light emitting diode with the driving current of the driving transistor determined based on the data voltage output from the data driver.

In the organic light emitting display panel, the temperature of the entire area or a portion of the panel may be increased depending on various conditions such as driving time, voltage level of data voltage, and characteristic values of driving transistors.

Meanwhile, the characteristics of the organic light emitting diode in each sub-pixel on the organic light emitting display panel may change at a high temperature. Such a change in characteristics of the organic light emitting diode may cause a screen abnormality of the organic light emitting display panel or induce a luminance deviation between sub-pixels due to a temperature difference for each region, thereby causing luminance non-uniformity of the organic light emitting display panel.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an organic light emitting display device capable of sensing the temperature of an organic light emitting display panel and a luminance control method thereof.

Another object of the embodiments of the present invention is an organic light emitting display device capable of suppressing a change in characteristics of an organic light emitting diode by sensing the temperature of the organic light emitting display panel and controlling the luminance of the organic light emitting display panel, and a luminance control method thereof is to provide

Another object of the embodiments of the present invention is to provide an organic light emitting display panel capable of controlling the temperature of the organic light emitting display panel as a whole or for each region by sensing the temperature of the organic light emitting display panel at the pixel or sub-pixel level without a separate temperature sensor. An object of the present invention is to provide a light emitting display device and a luminance control method thereof.

Another object of embodiments of the present invention is to provide an organic light emitting display device capable of improving image quality and lifespan by suppressing deterioration and afterimage generation of an organic light emitting display panel due to temperature, and a luminance control method thereof.

In one aspect, in the organic light emitting display device according to embodiments of the present invention, a plurality of data lines and a plurality of gate lines are disposed, and a plurality of subpixels defined by the plurality of data lines and the plurality of gate lines are provided. a driving transistor arranged in each sub-pixel, each subpixel having an organic light emitting diode, a first node to which a data voltage is applied, a second node connected to the first electrode of the organic light emitting diode, and a third node to which a driving voltage is applied; The display panel may include a display panel in which a storage capacitor connected between the first node and the second node of the driving transistor is disposed.

The organic light emitting diode display may include a sensing unit that senses the voltage of the first electrode of the organic light emitting diode during a sensing driving period for each of the subpixels and outputs a sensed value corresponding to the sensed voltage.

The organic light emitting display device may include a controller that controls luminance of an entire area or a partial area of the display panel based on the sensed values of each of the plurality of sub-pixels.

Here, the sensed value may be varied by changing the ratio of the amount of current flowing through each of the organic light emitting diode and the driving transistor according to a change in temperature.

The controller may obtain a change value corresponding to the temperature change of the display panel by comparing the sensed value, in which the amount of change increases as the temperature change of the display panel increases, with a preset initial sensed value.

Each subpixel is electrically connected between a corresponding data line of the plurality of data lines and a first node of the driving transistor, the first transistor supplying a data voltage to the first node of the driving transistor, and the organic light emitting diode A second transistor electrically connected between the first electrode of the diode and the reference voltage line may be further included.

The sensing unit electrically connects an analog-to-digital converter for outputting the sensed value corresponding to the sensed voltage, an initialization switch for supplying a preset reference voltage to the reference voltage line, and the reference voltage line to the analog-to-digital converter It may further include a sampling switch.

The voltage of the first electrode of the organic light emitting diode may correspond to a resistance ratio of the resistance value of the driving transistor and the resistance value of the organic light emitting diode that varies according to temperature.

If the difference between the sensed value and the preset initial sensed value of more than a preset number of sub-pixels among the plurality of sub-pixels is greater than or equal to a preset reference change value, the controller controls the luminance to decrease the luminance of the entire display panel. can

If a difference between the sensed value and a preset initial sensed value of a preset number or more of the plurality of sub-pixels is greater than or equal to a preset reference change value, the display panel includes a sub-pixel equal to or greater than the reference change value The luminance may be controlled so that the luminance of the region is lowered.

The controller performs the on-sensing process based on the average value or distribution of the sensed values obtained while varying the timing at which the sensing unit senses the voltage of the first electrode during the on-sensing process of the initial driving of the display panel. Thereafter, during a real-time sensing process, a temperature sampling timing designating a timing at which the sensing unit senses the voltage of the first electrode is set and stored, and the sensed value at the set temperature sampling timing is stored as the initial sensed value. can

If the organic light emitting diode display device is powered on within a predetermined time after being powered off, the controller does not reset the temperature sampling timing during the on-sensing process, and stores the temperature sampling timing and the initial sensed value stored before the power off can keep

The sensing unit may measure a sensing voltage of a subpixel corresponding to a predetermined color among the plurality of subpixels under the control of the controller, and output the sensed value.

In another aspect, the method for controlling the luminance of an organic light emitting diode display according to embodiments of the present invention senses a voltage at the first electrode of the organic light emitting diode during a sensing driving period for each sub-pixel, and corresponds to the sensed voltage It may include the step of obtaining a sensed value.

The method of controlling the luminance of the organic light emitting display device may include controlling the luminance of an entire region or a partial region of the display panel based on the sensed values of each of a plurality of sub-pixels.

Acquiring the sensing value may include initializing the first node of the driving transistor and the first electrode of the organic light emitting diode to a data voltage and a reference voltage, respectively, and setting the first electrode of the organic light emitting diode to a threshold voltage of the organic light emitting diode. A stabilizing step of lowering to a level, a tracking step of changing the voltage of the first electrode of the organic light emitting diode that is turned on by applying a data voltage to the first node of the driving transistor, and the voltage of the first electrode of the organic light emitting diode It may include a sampling step of sensing.

In another aspect, in the organic light emitting display device according to embodiments of the present invention, a plurality of data lines and a plurality of gate lines are disposed, and a plurality of sub-pixels are defined by the plurality of data lines and the plurality of gate lines. is arranged, each sub-pixel includes an organic light emitting diode, a first node to which a data voltage is applied, a second node connected to the first electrode of the organic light emitting diode, and a third node to which a driving voltage is applied; A display panel in which a storage capacitor connected between a first node and a second node of the driving transistor is disposed, and the data voltage applied to the first node of the driving transistor is adjusted according to a temperature change of the display panel to adjust the display panel It may include a controller that controls the luminance of the entire region or a partial region of the , and performs luminance reduction control when the temperature rises above a certain level.

According to the embodiments of the present invention as described above, it is possible to provide an organic light emitting display device capable of sensing the temperature of each pixel of an organic light emitting display panel and a luminance control method thereof.

Further, according to embodiments of the present invention, an organic light emitting display device capable of suppressing a change in characteristics of an organic light emitting diode by sensing the temperature of the organic light emitting display panel and controlling the luminance of the organic light emitting display panel, and luminance control thereof method can be provided.

In addition, according to embodiments of the present invention, it is possible to adjust the temperature of the organic light emitting display panel as a whole or for each area by sensing the temperature of the organic light emitting display panel at the pixel or sub-pixel level without a separate temperature sensor. An organic light emitting display device and a luminance control method thereof can be provided.

In addition, according to embodiments of the present invention, an organic light emitting display device capable of improving image quality and lifespan by suppressing deterioration and afterimage generation of an organic light emitting display panel due to temperature regardless of image data, and a luminance control method thereof can provide

1 is a schematic system configuration diagram of an organic light emitting diode display 100 according to embodiments of the present invention.
2 is an exemplary diagram of a sub-pixel structure of the organic light emitting display device 100 and a structure for sensing a temperature of the sub-pixel according to embodiments of the present invention.
FIG. 3 is a diagram for explaining a threshold voltage sensing driving method for the driving transistor DRT of the organic light emitting diode display 100 according to embodiments of the present invention.
4 is a diagram for explaining a mobility sensing driving method for a driving transistor DRT of the organic light emitting diode display 100 according to embodiments of the present invention.
5 and 6 are diagrams for explaining a temperature sensing driving method for a sub-pixel of the organic light emitting diode display 100 according to embodiments of the present invention.
7 is a diagram illustrating a sensing timing of the organic light emitting diode display 100 according to embodiments of the present invention.
8 is a diagram for explaining a method of setting a temperature sampling timing in a temperature sensing driving method.
9 and 10 are diagrams for explaining a luminance control method for controlling a temperature according to embodiments of the present invention.
11 illustrates a luminance control method of an organic light emitting display device according to embodiments of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same reference numerals as much as possible even though they are indicated in different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description may be omitted.

In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the elements from other elements, and the essence, order, order, or number of the elements are not limited by the terms. When it is described that a component is “connected”, “coupled” or “connected” to another component, the component may be directly connected or connected to the other component, but other components may be interposed between each component. It should be understood that each component may be “interposed” or “connected”, “coupled” or “connected” through another component.

1 is a schematic system configuration diagram of an organic light emitting diode display 100 according to embodiments of the present invention.

Referring to FIG. 1 , in the organic light emitting diode display 100 according to embodiments of the present invention, a plurality of data lines DL and a plurality of gate lines GL are disposed, and a plurality of data lines DL and An organic light emitting display panel 110 in which a plurality of sub-pixels (SP) defined by a plurality of gate lines GL are arranged, a data driver 120 driving a plurality of data lines DL; It includes a gate driver 130 for driving the plurality of gate lines GL, and a controller 140 for controlling the data driver 120 and the gate driver 130 .

The controller 140 supplies various control signals to the data driver 120 and the gate driver 130 to control the data driver 120 and the gate driver 130 .

The controller 140 starts scanning according to the timing implemented in each frame, converts the input image data input from the outside to match the data signal format used by the data driver 120, and outputs the converted image data, , to control the data operation at an appropriate time according to the scan.

The controller 140 may be a timing controller used in a typical display technology or a control device that further performs other control functions including a timing controller. In the present invention, the controller 140 may include a temperature control unit that performs a temperature control process for determining and controlling the temperature of the sub-pixel. Also, the controller 140 may include a compensator that performs a compensation process for compensating for a characteristic value deviation between subpixels.

The controller 140 may be implemented as a separate component from the data driver 120 , or may be implemented as an integrated circuit together with the data driver 120 .

The data driver 120 drives the plurality of data lines DL by supplying data voltages to the plurality of data lines DL. Here, the data driver 120 is also referred to as a 'source driver'.

The data driver 120 may include at least one source driver integrated circuit (SDIC) to drive a plurality of data lines.

Each source driver integrated circuit SDIC may include a shift register, a latch circuit, a digital to analog converter (DAC), an output buffer, and the like.

Each source driver integrated circuit SDIC may further include an analog-to-digital converter (ADC) in some cases.

The gate driver 130 sequentially drives the plurality of gate lines GL by sequentially supplying scan signals to the plurality of gate lines GL. Here, the gate driver 130 is also referred to as a 'scan driver'.

The gate driver 130 may include at least one gate driver integrated circuit (GDIC).

Each gate driver integrated circuit GDIC may include a shift register, a level shifter, and the like.

The gate driver 130 sequentially supplies a scan signal of an on voltage or an off voltage to the plurality of gate lines GL under the control of the controller 140 .

When a specific gate line is opened by the gate driver 130 , the data driver 120 converts the image data received from the controller 140 into an analog data voltage and supplies it to the plurality of data lines DL.

As shown in FIG. 1 , the data driver 120 may be positioned on only one side (eg, upper or lower side) of the organic light emitting display panel 110 , and in some cases, the organic light emitting diode display may be configured according to a driving method or a panel design method. It may be located on both sides (eg, upper and lower sides) of the display panel 110 .

As shown in FIG. 1 , the gate driver 130 may be located only on one side (eg, left or right) of the organic light emitting display panel 110 , and in some cases, an organic light emitting device according to a driving method, a panel design method, etc. It may be located on both sides (eg, left and right) of the light emitting display panel 110 .

The above-described controller 140 includes, along with the input image data, a vertical synchronization signal (Vsync), a horizontal synchronization signal (Hsync), an input data enable (DE: Data Enable) signal, various types including a clock signal (CLK), and the like. Timing signals are received from the outside (eg host system).

The controller 140 receives timing signals such as a vertical synchronization signal (Vsync), a horizontal synchronization signal (Hsync), an input DE signal, and a clock signal to control the data driver 120 and the gate driver 130, Various control signals are generated and output to the data driver 120 and the gate driver 130 .

For example, in order to control the gate driver 130 , the controller 140 includes a gate start pulse (GSP), a gate shift clock (GSC), and a gate output enable signal (GOE: Various gate control signals (GCS: Gate Control Signal) including Gate Output Enable) are output.

Here, the gate start pulse GSP controls the operation start timing of one or more gate driver integrated circuits constituting the gate driver 130 . The gate shift clock GSC is a clock signal commonly input to one or more gate driver integrated circuits, and controls shift timing of a scan signal (gate pulse). The gate output enable signal GOE specifies timing information of one or more gate driver integrated circuits.

In addition, the controller 140 controls the data driver 120 , a source start pulse (SSP), a source sampling clock (SSC), and a source output enable signal (SOE: Source Output). Enable) and output various data control signals (DCS: Data Control Signal).

Here, the source start pulse SSP controls the data sampling start timing of one or more source driver integrated circuits constituting the data driver 120 . The source sampling clock SSC is a clock signal that controls sampling timing of data in each of the source driver integrated circuits. The source output enable signal SOE controls the output timing of the data driver 120 .

Each sub-pixel SP arranged in the organic light emitting display panel 110 includes an organic light emitting diode (OLED) which is a self-emissive element, and a driving transistor for driving the organic light emitting diode (OLED). It is composed of circuit elements such as

The type and number of circuit elements constituting each sub-pixel SP may be variously determined according to a provided function and a design method.

2 is an exemplary diagram of a sub-pixel structure of the organic light emitting display device 100 and a structure for sensing a temperature of the sub-pixel according to embodiments of the present invention.

Referring to FIG. 2 , in the organic light emitting diode display 100 according to the embodiments of the present invention, each sub-pixel SP basically includes an organic light emitting diode (OLED) and an organic light emitting diode (OLED) driving device. A driving transistor (DRT), a first transistor T1 for transferring a data voltage to a first node N1 corresponding to a gate node of the driving transistor DRT, and a second transistor T1 for providing a sensing function It may include a transistor T2 and a storage capacitor (Cst) that maintains a data voltage corresponding to the image signal voltage or a voltage corresponding thereto for one frame time.

An organic light emitting diode (OLED) may include a first electrode (eg, an anode electrode or a cathode electrode), an organic layer, and a second electrode (eg, a cathode electrode or an anode electrode).

A ground voltage EVSS may be applied to the second electrode of the organic light emitting diode OLED.

The driving transistor DRT drives the organic light emitting diode (OLED) by supplying a driving current to the organic light emitting diode (OLED).

The driving transistor DRT has a first node N1 , a second node N2 , and a third node N3 .

The first node N1 of the driving transistor DRT is a node corresponding to a gate node and may be electrically connected to a source node or a drain node of the first transistor T1 .

The second node N2 of the driving transistor DRT may be electrically connected to the first electrode of the organic light emitting diode OLED, and may be a source node or a drain node.

The third node N3 of the driving transistor DRT is a node to which the driving voltage EVDD is applied, and may be electrically connected to a driving voltage line DVL supplying the driving voltage EVDD, and has a drain. It can be a node or a source node.

The driving transistor DRT and the first transistor T1 may be implemented as an n-type or a p-type as in the example of FIG. 2 .

The first transistor T1 may be electrically connected between the data line DL and the first node N1 of the driving transistor DRT, and may be controlled by receiving the scan signal SCAN through the gate line as the gate node. have.

The first transistor T1 is turned on by the scan signal SCAN to transfer the data voltage Vdata supplied from the data line DL to the first node N1 of the driving transistor DRT. .

The storage capacitor Cst may be electrically connected between the first node N1 and the second node N2 of the driving transistor DRT.

This storage capacitor Cst is not a parasitic capacitor (eg, Cgs, Cgd) which is an internal capacitor existing between the first node N1 and the second node N2 of the driving transistor DRT, It is an external capacitor intentionally designed outside the driving transistor (DRT).

The second transistor T2 is electrically connected between the second node N2 of the driving transistor DRT and a reference voltage line RVL supplying a reference voltage Vref, and a gate node It may be controlled by receiving a sensing signal SENSE, which is a kind of raw scan signal.

The second transistor T2 may effectively control the voltage state of the second node N2 of the driving transistor DRT in the subpixel SP.

The second transistor T2 is turned on by the sensing signal SENSE to apply the reference voltage Vref supplied through the reference voltage line RVL to the second node N2 of the driving transistor DRT.

Also, the second transistor T2 may be used as one of the voltage sensing paths for the second node N2 of the driving transistor DRT.

Meanwhile, the scan signal SCAN and the sensing signal SENSE may be separate gate signals. In this case, the scan signal SCAN and the sensing signal SENSE may be respectively applied to the gate node of the first transistor T1 and the gate node of the second transistor T2 through different gate lines.

In some cases, the scan signal SCAN and the sensing signal SENSE may be the same gate signal. In this case, the scan signal SCAN and the sensing signal SENSE may be commonly applied to the gate node of the first transistor T1 and the gate node of the second transistor T2 through the same gate line.

Meanwhile, looking at the components for sensing and controlling the temperature of the subpixel 210 , the organic light emitting diode display 100 according to embodiments of the present invention detects the temperature of the subpixel through voltage sensing. A temperature control process of controlling the temperature of the display panel by determining the temperature or temperature change of each sub-pixel by using the sensing unit 220 that generates and outputs the sensing value, and varies the luminance of the sub-pixel based on this. It may include a temperature control unit 230 for performing the operation, a memory unit 240 for storing the sensed value, and the like.

The sensing unit 220 may be implemented by including at least one analog to digital converter (ADC). The sensing value output from the sensing unit 220 may be, for example, in a low voltage differential signaling (LVDS) data format.

Each analog to digital converter (ADC) may be included in each source driver integrated circuit SDIC included in the data driver 120 , and in some cases, external to the source driver integrated circuit SDIC. may be included in

The temperature controller 230 (or control compensation unit) may be included in the controller 140 , and in some cases, may be provided outside the controller 140 . The temperature controller 230 may also be referred to as a temperature control processor.

The memory unit 240 receives the sensing value from the sensing unit and stores it. For example, the memory unit 240 may be configured to store an initial sensed value obtained at an initial stage of driving when the display panel changes from an off state to an on state.

However, the data stored by the memory unit 240 is not limited thereto. For example, the memory unit 240 may store a timing of turning on the sampling switch SAM to obtain an initial sensed value as temperature sampling timing information.

Here, the temperature sampling timing information is information used to acquire a real-time sensing value while the organic light emitting display panel is driven after the initial driving period when the display panel is changed from an off state to an on state.

Meanwhile, the second transistor T2 and the sensing unit 220 may be used not only to control the temperature of the sub-pixels but also to compensate for a characteristic value deviation between the sub-pixels.

In the case of the organic light emitting diode display 100 according to the embodiments of the present invention, as the driving time of each sub-pixel SP increases, the circuit elements such as the organic light emitting diode (OLED) and the driving transistor (DRT) are Degradation may proceed.

Accordingly, unique characteristic values of circuit elements such as organic light emitting diodes (OLED) and driving transistors (DRT) may change. Here, the intrinsic characteristic value of the circuit element may include a threshold voltage of the organic light emitting diode (OLED), a threshold voltage of the driving transistor (DRT), mobility of the driving transistor (DRT), and the like.

A change in a characteristic value of a circuit element may cause a change in luminance of a corresponding sub-pixel. Accordingly, the change in the characteristic value of the circuit element can be used in the same concept as the change in the luminance of the sub-pixel.

In addition, the degree of change in the characteristic value between the circuit elements may be different from each other according to the difference in the degree of deterioration of each circuit element.

The difference in the degree of change in the characteristic value between the circuit elements may cause a deviation in the characteristic value between the circuit elements, which may cause a luminance deviation between sub-pixels. Accordingly, the characteristic value deviation between circuit elements may be used as the same concept as the luminance deviation between sub-pixels.

Changes in the characteristic values of circuit elements (change in sub-pixel luminance) and deviations in characteristic values between circuit elements (luminance deviation between sub-pixels) cause problems such as lowering the accuracy of sub-pixel luminance expression or causing screen abnormalities. can do it

The organic light emitting display device 100 according to embodiments of the present invention provides a sensing function for sensing the temperature and characteristic values of a sub-pixel and a compensation function for controlling the temperature of the sub-pixel and compensating for characteristic values using the sensing result. can do.

Although not shown, the organic light emitting diode display 100 according to embodiments of the present invention may further include a compensator that performs a compensation process for compensating for a characteristic value deviation between sub-pixels.

When a compensator is further included, the temperature controller 230 may be configured as a control compensator that is integrated with the compensator. That is, the temperature controller 230 illustrated in FIG. 2 may be replaced with a control compensator that performs both temperature control and compensation for deviations in characteristic values between sub-pixels.

In this specification, sensing the temperature of the sub-pixel means sensing the characteristic change according to the temperature of the circuit elements (the driving transistor DRT, the second transistor T2, and the organic light emitting diode (OLED)) in the sub-pixel. can mean In particular, it may mean sensing a relative characteristic change based on the characteristic at the initial driving temperature of the display panel 110 .

Referring to FIG. 2 , the organic light emitting diode display 100 according to embodiments of the present invention includes an initialization switch SPRE that controls whether a reference voltage Vref is applied to a reference voltage line RVL, and a reference A sampling switch SAM for controlling whether the voltage line RVL is connected to the sensing unit 220 may be included.

The initialization switch SPRE is configured such that the second node N2 of the driving transistor DRT in the subpixel SP enters a voltage state that reflects a desired characteristic value of the circuit element. ) is a switch to control the voltage application state.

When the initialization switch SPRE is turned on, the reference voltage Vref is supplied to the reference voltage line RVL through the turned-on second transistor T2 to the second node N2 of the driving transistor DRT. ) can be approved.

The sampling switch SAM is turned on to electrically connect the reference voltage line RVL and the sensing unit 220 .

The sampling switch SAM has an on-off timing such that it is turned on when the second node N2 of the driving transistor DRT in the subpixel SP reaches a voltage state that reflects the desired characteristic value of the circuit element. Controlled.

For example, in the present invention, the on-off timing of the sampling switch SAM may be controlled according to the temperature sampling timing information stored in the memory unit 240 when the temperature sensing is driven.

When the sampling switch SAM is turned on, the sensing unit 220 may sense the voltage of the connected reference voltage line RVL.

When the sensing unit 220 senses the voltage of the reference voltage line RVL, when the second transistor T2 is turned on, the voltage sensed by the sensing unit 220 is the voltage of the driving transistor DRT. It may correspond to the voltage of the second node N2.

If a line capacitor exists on the reference voltage line RVL, the voltage sensed by the sensing unit 220 may be a voltage charged in the line capacitor on the reference voltage line RVL. Here, the reference voltage line RVL is also referred to as a sensing line.

For example, the voltage sensed by the sensing unit 220 may be a voltage value for sensing a resistance ratio between the driving transistor DRT and the organic light emitting diode OLED of the subpixel that varies according to temperature.

In addition, the voltage sensed by the sensing unit 220 is a voltage value Vdata-Vth or Vdata-ΔVth including a threshold voltage Vth or a threshold voltage deviation ΔVth of the driving transistor DRT, where Vdata is data voltage for sensing driving) or a voltage value for sensing the mobility of the driving transistor DRT.

Meanwhile, as an example, one reference voltage line RVL may be disposed in each subpixel column, or may be disposed in each of two or more subpixel columns.

For example, if one pixel consists of 4 sub-pixels (red sub-pixel, white sub-pixel, green sub-pixel, and blue sub-pixel), the reference voltage line RVL has 4 sub-pixel columns (red sub-pixel column). , one for each pixel column including a white subpixel column, a green subpixel column, and a blue subpixel column).

The organic light emitting diode display 100 according to embodiments of the present invention may be configured to perform both temperature control and compensation for variation in characteristic values between sub-pixels.

Hereinafter, the threshold voltage sensing driving of the driving transistor DRT, the mobility sensing driving, and the temperature sensing driving of the subpixel will be briefly described.

FIG. 3 is a diagram for explaining a threshold voltage sensing driving method for the driving transistor DRT of the organic light emitting diode display 100 according to embodiments of the present invention.

The threshold voltage sensing driving of the driving transistor DRT may be performed through a sensing process including an initialization step, a tracking step, and a sampling step.

The initialization step is a step of initializing the first node N1 and the second node N2 of the driving transistor DRT.

In this initialization step, the first transistor T1 and the second transistor T2 are turned on, and the initialization switch SPRE is turned on.

Accordingly, each of the first node N1 and the second node N2 of the driving transistor DRT is initialized to the threshold voltage sensing driving data voltage Vdata and the reference voltage Vref (V1 = Vdata, V2). =Vref).

In this case, the low potential voltage EVSS may be a voltage such that a voltage difference between the anode electrode and the cathode electrode of the organic light emitting diode OLED is lower than the threshold voltage of the organic light emitting diode OLED. Alternatively, at least one of the threshold voltage sensing driving data voltage Vdata and the reference voltage Vref has a voltage difference between the anode electrode and the cathode electrode of the organic light emitting diode (OLED) that is lower than the threshold voltage of the organic light emitting diode (OLED). It may be a voltage that makes it possible.

That is, the organic light emitting diode (OLED) does not emit light because the voltage difference between the anode electrode and the cathode electrode of the organic light emitting diode is lower than the threshold voltage of the organic light emitting diode (OLED).

Accordingly, as shown in FIG. 3 , the characteristics of the organic light emitting diode (OLED) are not reflected when the threshold voltage sensing operation is performed.

In the tracking step, the voltage V2 of the second node N2 of the driving transistor DRT is reached until the voltage of the second node N2 of the driving transistor DRT reaches a threshold voltage or a voltage state reflecting the change thereof. is a step to change

That is, the tracking step is a step of tracking the voltage of the second node N2 of the driving transistor DRT capable of reflecting the threshold voltage or its change.

In this tracking step, the initialization switch SPRE is turned off or the second transistor T2 is turned off, so that the second node N2 of the driving transistor DRT is floated.

Accordingly, the voltage V2 of the second node N2 of the driving transistor DRT increases.

The voltage V2 of the second node N2 of the driving transistor DRT rises and then gradually decreases and becomes saturated.

The saturated voltage of the second node N2 of the driving transistor DRT may correspond to the difference between the data voltage Vdata and the threshold voltage Vth or the difference between the data voltage Vdata and the threshold voltage deviation ΔVth. .

When the voltage V2 of the second node N2 of the driving transistor DRT is saturated, a sampling operation may be performed.

The sampling step is a step of measuring the threshold voltage of the driving transistor DRT or a voltage reflecting the change, and the sensing unit 220 uses the voltage of the reference voltage line RVL, that is, the second voltage of the driving transistor DRT. This is a step of sensing the voltage of the node N2.

In this sampling step, the sampling switch SAM is turned on, and the sensing unit 220 is connected to the reference voltage line RVL, and the voltage of the reference voltage line RVL, that is, the second voltage of the driving transistor DRT. The voltage V2 of the second node N2 is sensed.

The voltage Vsen sensed by the sensing unit 220 is a voltage Vdata-Vth obtained by subtracting the threshold voltage Vth from the data voltage Vdata or a voltage obtained by subtracting the threshold voltage deviation ΔVth from the data voltage Vdata ( Vdata-ΔVth). Here, Vth may be a positive threshold voltage or a negative threshold voltage.

4 is a diagram for explaining a mobility sensing driving method for a driving transistor DRT of the organic light emitting diode display 100 according to embodiments of the present invention.

The mobility sensing driving of the driving transistor DRT may be performed through a sensing process including an initialization step, a tracking step, and a sampling step.

The initialization step is a step of initializing the first node N1 and the second node N2 of the driving transistor DRT.

In this initialization step, the first transistor T1 and the second transistor T2 are turned on, and the initialization switch SPRE is turned on.

Accordingly, each of the first node N1 and the second node N2 of the driving transistor DRT is initialized to the mobility sensing driving data voltage Vdata and the reference voltage Vref (V1 = Vdata, V2 = Vref).

Similarly to the threshold voltage sensing driving, at least one of the low potential voltage EVSS, the mobility sensing driving data voltage Vdata and the reference voltage Vref is the anode electrode of the organic light emitting diode (OLED) even during the mobility sensing driving operation. It may be a voltage such that a voltage difference between the voltage and the cathode electrode is lower than the threshold voltage of the organic light emitting diode (OLED).

Therefore, even when the mobility sensing is driven, as shown in FIG. 4 , the organic light emitting diode (OLED) does not emit light, and thus the characteristics of the organic light emitting diode (OLED) are not reflected.

In the tracking step, the voltage V2 of the second node N2 of the driving transistor DRT is reached until the voltage of the second node N2 of the driving transistor DRT becomes a voltage state reflecting the mobility or its change. is a step to change

That is, the tracking step is a step of tracking the voltage of the second node N2 of the driving transistor DRT that can reflect mobility or its change.

In this tracking step, the initialization switch SPRE is turned off or the second transistor T2 is turned off, so that the second node N2 of the driving transistor DRT is floated. At this time, the first transistor T1 may be turned off, and the first node N1 of the driving transistor DRT may also be floated.

Accordingly, the voltage V2 of the second node N2 of the driving transistor DRT starts to rise.

A rising speed of the voltage V2 of the second node N2 of the driving transistor DRT depends on the current capability (ie, mobility) of the driving transistor DRT.

As the driving transistor DRT has a large current capability (mobility), the voltage V2 at the second node N2 of the driving transistor DRT rises more steeply.

After the tracking step is performed for a predetermined time Δt, that is, after the voltage V2 of the second node N2 of the driving transistor DRT rises for a predetermined predetermined time Δt, the sampling step may be performed.

During the tracking step, the rising speed of the voltage V2 of the second node N2 of the driving transistor DRT corresponds to the voltage change amount ΔV for a predetermined time Δt.

In the sampling step, the sampling switch SAM is turned on, and the sensing unit 220 and the reference voltage line RVL are electrically connected.

Accordingly, the sensing unit 220 senses the voltage of the reference voltage line RVL, that is, the voltage V2 of the second node N2 of the driving transistor DRT.

The voltage Vsen sensed by the sensing unit 220 is a voltage that is increased by the voltage change amount ΔV for a predetermined time Δt from the initialization voltage Vref, and is a voltage corresponding to mobility.

5 and 6 are diagrams for explaining a temperature sensing driving method for a sub-pixel of the organic light emitting diode display 100 according to embodiments of the present invention.

The temperature sensing driving of the subpixel may be performed as a temperature sensing process including an initialization step S1 , a stabilization step S2 , a tracking step S3 , and a sampling step S4 .

The initialization step S1 is a step of initializing the first node N1 and the second node N2 of the driving transistor DRT.

In the initialization step S1 , the first transistor T1 and the second transistor T2 are turned on in response to the scan signal SCAN and the sensing signal SENSE, and the initialization switch SPRE is turned- come on

Accordingly, each of the first node N1 and the second node N2 of the driving transistor DRT is initialized to the sensing driving data voltage Vdata and the reference voltage Vref (V1 = Vdata, V2 = Vref). . That is, a voltage corresponding to a voltage difference between the sensing driving data voltage Vdata and the reference voltage Vref may be stored in the storage capacitor Cst.

However, unlike the threshold voltage sensing driving or mobility sensing driving, in the temperature sensing driving, the voltage difference between the anode electrode and the cathode electrode of the organic light emitting diode (OLED) is lowered to be higher than the threshold voltage of the organic light emitting diode (OLED). At least one of the potential voltage EVSS, the sensing driving data voltage Vdata, and the reference voltage Vref may be adjusted.

For example, during threshold voltage sensing driving or mobility sensing driving of the driving transistor DRT, the sensing driving data voltage Vdata is applied to 4V so that the organic light emitting diode (OLED) is not turned on, while sensing driving during temperature sensing driving The data voltage Vdata may be applied to 6V so that the organic light emitting diode OLED is turned on.

Therefore, in the temperature sensing driving shown in FIG. 5 , unlike in FIGS. 3 and 4 , the organic light emitting diode (OLED) is reflected in the circuit.

However, in the initialization step, since the first electrode (the second node N2 of the driving transistor DRT) of the organic light emitting diode OLED is initialized to the level of the reference voltage Vref, the organic light emitting diode OLED is induced according to the voltage level of the reference voltage Vref. The light emitting diode OLED may not be turned on.

In the stabilization step S2, the organic light emitting diode OLED has a voltage state corresponding to the threshold value of the organic light emitting diode OLED such that the voltage of the first electrode (the second node N2 of the driving transistor DRT) becomes a voltage state. , is the second initialization step.

In the stabilization step S2 , the initialization switch SPRE is turned off, and the first transistor T1 and the second transistor T2 are turned off.

Accordingly, by the voltage stored in the storage capacitor Cst in the initialization step S1 , the driving transistor DRT supplies a driving current to the organic light emitting diode OLED in the stabilization step S2 . Accordingly, a voltage difference between the anode electrode and the cathode electrode of the organic light emitting diode (OLED) becomes a voltage higher than the threshold voltage of the organic light emitting diode (OLED), and the organic light emitting diode (OLED) is turned on. And in the stabilization step S2, the voltage of the first electrode of the organic light emitting diode (OLED) drops to the threshold voltage level of the organic light emitting diode (OLED).

After dropping to the threshold voltage level of the organic light emitting diode (OLED), the tracking step (S3) may proceed.

In the tracking step S3 , the first transistor T1 and the second transistor T2 are turned on again, while the initialization switch SPRE maintains a turned-off state.

As the first transistor T1 is turned on and the sensing driving data voltage Vdata is applied to the first node N1 of the driving transistor DRT, the organic light emitting diode OLED is driven as the first electrode. supply current. Accordingly, in the organic light emitting diode OLED, the voltage V2 of the first electrode increases, and the organic light emitting diode OLED is driven by the driving current to emit light.

In this case, in the organic light emitting diode (OLED), the rising speed of the voltage V2 of the first electrode varies depending on the temperature characteristics of the driving transistor (DRT) and the organic light emitting diode (OLED).

The amount of current transmitted between the driving transistor DRT and the organic light emitting diode OLED may be different from each other according to temperature. That is, the driving transistor DRT and the organic light emitting diode OLED may be interpreted as resistance elements whose resistance value varies according to temperature.

Therefore, even when the sensing driving data voltage Vdata is applied to the first node of the driving transistor DRT at the same voltage level, the rate of increase of the voltage V2 of the second node N2 of the driving transistor DRT is the current temperature. in the driving transistor (DRT) and the organic light emitting diode (OLED) is changed according to the resistance ratio of the resistance value.

As the temperature of the sensed sub-pixel increases, the voltage V2 of the first electrode of the organic light emitting diode OLED rises more steeply.

After the tracking step S3 proceeds for a predetermined time Δt, that is, after the voltage V2 of the first electrode of the OLED rises for a predetermined time Δt, the sampling step S4 is performed can proceed.

During the tracking step S3 , the rising speed of the voltage V2 of the second node N2 of the driving transistor DRT corresponds to the voltage change amount ΔV for a predetermined time Δt.

In the sampling step S4 , the sampling switch SAM is turned on, and the sensing unit 220 and the reference voltage line RVL are electrically connected.

Accordingly, the sensing unit 220 senses the voltage of the reference voltage line RVL, that is, the organic light emitting diode OLED senses the voltage V2 of the first electrode.

The voltage Vsen sensed by the sensing unit 220 is a voltage that is increased by the voltage change amount ΔV from the initialization voltage Vref for a predetermined time Δt, and corresponds to the temperature of the subpixel.

According to the temperature sensing driving, the threshold voltage sensing driving, or the mobility sensing driving as described above with reference to FIGS. 3 to 6 , the sensing unit 220 senses a voltage Vsen for temperature sensing, threshold voltage sensing, or mobility sensing. ) is converted to a digital value, and a sensed value including the converted digital value (sensed value) is generated and output.

In FIG. 6 , it is assumed that the scan signal SCAN and the sensing signal SENSE are the same gate signal. In this case, the scan signal SCAN and the sensing signal SENSE may be commonly applied to the gate node of the first transistor T1 and the gate node of the second transistor T2 through the same gate line.

However, the scan signal SCAN and the sensing signal SENSE may be separate gate signals. In this case, the scan signal SCAN and the sensing signal SENSE may be respectively applied to the gate node of the first transistor T1 and the gate node of the second transistor T2 through different gate lines.

Meanwhile, the sensed value output from the sensing unit 220 may be provided to the temperature control unit 230 or the compensator. In some cases, the sensed value may be provided to the temperature controller 230 or the compensator through the memory unit 240 .

The temperature controller 230 may detect a temperature or a change in temperature of a corresponding sub-pixel based on the sensed value provided by the sensing unit 220 , and may perform a temperature control process.

Here, the temperature change of the sub-pixel may mean that the current sensed value is changed based on the previous sensed value or that the current sensed value is changed based on the initial sensed value.

Here, the initial sensing value may be an initial setting value set and stored during manufacturing of the organic light emitting display device, or may be an initial driving setting value set and stored at the initial stage of driving the organic light emitting display device.

The temperature control process is a process of setting a luminance control value for lowering the temperature of the organic light emitting display panel, storing the set luminance control value in the memory unit 240, or changing the image data (Data) to the luminance control value. may include

The temperature controller 230 may change the image data Data through a temperature control process and supply the changed data to the corresponding source driver integrated circuit SDIC in the data driver 120 .

Accordingly, the corresponding source driver integrated circuit SDIC converts the image data changed by the temperature controller 230 into a data voltage through a digital to analog converter (DAC) and supplies it to the corresponding sub-pixel, so that the sub-pixel The luminance of light emitted from the organic light emitting diode (OLED) is lowered, and as a result, the temperature of the corresponding sub-pixel is lowered.

Accordingly, a change in characteristics of the organic light emitting diode (OLED) due to temperature can be suppressed, and the image quality and lifespan of the organic light emitting diode display 100 can be improved.

Here, when one reference voltage line RVL is disposed in each sub-pixel column, the sensing unit 220 drives transistors of a specific sub-pixel in each of a plurality of pixels on the gate line GL driven by the scan signal SCAN. The voltage V2 of the second node N2 of the DRT is sensed.

For example, when one pixel includes four sub-pixels (a red sub-pixel, a white sub-pixel, a green sub-pixel, and a blue sub-pixel), the sensing unit 220 may generate a gate line driven by the scan signal SCAN. The voltage V2 of the second node N2 of the driving transistors DRT of the plurality of red sub-pixels may be applied through the reference voltage line RVL according to a specified order on the GL and may be sensed. Then, the voltage V2 of the second node N2 of the driving transistor DRT of the white subpixel, the green subpixel, and the blue subpixel may be sequentially applied through the reference voltage line RVL to be sensed.

However, if four reference voltage lines RVL are arranged in each sub-pixel column corresponding to the number of sub-pixels constituting each pixel, the sensing unit 220 controls the gate line GL driven by the scan signal SCAN. It is possible to sense the voltage V2 of the second node N2 of the driving transistor DRT for all sub-pixels of .

That is, the sensing unit 220 determines one gate line GL driven by the scan signal SCAN according to the number of subpixels constituting one pixel and the number of corresponding reference voltage lines RVL. Sensing may be performed multiple times on the gate line GL. Accordingly, the temperature controller 230 that receives the sensing value from the sensing unit 220 and sets the luminance control value may also calculate a plurality of luminance control values for one gate line GL.

Also, the sensing unit 220 may sense the temperature of only some lines under the control of the controller 140 . For example, the sensing unit 220 may temperature-sens only sub-pixels of a specific color.

For example, when one pixel is composed of four sub-pixels (a red sub-pixel, a white sub-pixel, a green sub-pixel, and a blue sub-pixel), the sensing unit 220 may include sub-pixels for two colors (for example, , the temperature sensing time may be reduced by performing temperature sensing only on the red subpixel and the blue subpixel).

Here, temperature sensing is performed on subpixels for two colors to prevent errors that may occur when temperature sensing only subpixels for a single color. In this case, temperature sensing may be performed on sub-pixels (eg, red sub-pixels and blue sub-pixels) for colors vulnerable to high temperatures. However, it is also possible to perform temperature sensing on subpixels for other colors.

7 is a diagram illustrating a sensing timing of the organic light emitting diode display 100 according to embodiments of the present invention.

Referring to FIG. 7 , in the organic light emitting diode display 100 according to embodiments of the present invention, when a power on signal is generated, the temperature of each sub-pixel and the sub-pixel disposed on the display panel 110 . A characteristic value of the driving transistor DRT may be sensed. This sensing process is called "On-Sensing Process".

In addition, when a power off signal is generated, the temperature of each sub-pixel disposed on the display panel 110 and a driving transistor in the sub-pixel before an off-sequence such as power off is performed. It is also possible to sense the characteristic value of (DRT). This sensing process is referred to as "Off-Sensing Process".

In addition, after the power-on signal is generated and before the power-off signal is generated, the temperature of each sub-pixel disposed on the display panel 110 and the characteristic value of the driving transistor DRT in the sub-pixel for each blank time during display driving It can also be sensed. Such a sensing process is called a "real-time sensing process".

The real-time sensing process may be performed for each blank time between active times based on the vertical synchronization signal Vsync.

Since the temperature sensing of the sub-pixel and the sensing of the mobility of the driving transistor DRT need only a short time, the display may be performed after the power-on signal is generated before the display driving starts, or after the power-off signal is generated. It can be performed when it is not running.

In addition, the temperature sensing of the sub-pixel and the sensing of the mobility of the driving transistor (DRT) may be performed in real time by using a short blank time while the display is being driven.

That is, the temperature sensing of the sub-pixel and the sensing of the mobility of the driving transistor DRT may be performed as an on-sensing process before a power-on signal is generated and the display starts driving, and the power-off signal is During the period during which the display is not driven due to the occurrence of the display, the off-sensing process may be performed, or the real-time sensing process may be performed for every short blank time during display driving.

During the real-time sensing process, the sensing of the temperature of the sub-pixel and the sensing of the mobility of the driving transistor DRT may be alternately performed every blank time or may be performed according to a predetermined sequence.

In contrast, since the threshold voltage sensing Vth sensing of the driving transistor DRT requires a long voltage saturation time Vsat of the second node N2 of the driving transistor DRT, temperature sensing or driving of the sub-pixel is required. Compared to sensing the mobility of the transistor DRT, it takes a relatively long time.

In consideration of this point, the threshold voltage sensing of the driving transistor DRT should be performed using a timing that does not interfere with the user's viewing.

Therefore, in general, the threshold voltage sensing of the driving transistor DRT may be performed after a power off signal is generated according to a user input, etc., while the display is not driven, that is, in a situation in which the user does not intend to watch. .

However, in some cases, the threshold voltage sensing of the driving transistor DRT may also be performed through an on-sensing process or a real-time sensing process.

8 is a diagram for explaining a method of setting a temperature sampling timing in a temperature sensing driving method.

As described with reference to FIG. 5 , in the organic light emitting display device 100 according to embodiments of the present invention, after the tracking step S3 is performed for a predetermined time Δt, the sampling switch SAM is turned on. can be configured. Here, the predetermined time Δt may be referred to as a temperature sampling timing.

In this case, the voltage V2 of the second node N2 of the driving transistor DRT sensed by the sensing unit 220 may output a sensing value corresponding to the temperature change compared to the initial set temperature to the corresponding sub-pixel. Here, the initial set temperature may be a set temperature when the organic light emitting display device 100 is manufactured.

However, in some cases, it may be more necessary to analyze the relative temperature change of the organic light emitting display device 100 with respect to the initial driving temperature of the organic light emitting display device 100 .

In particular, since the temperature rises in most cases while the organic light emitting diode display 100 is being driven, it is important to accurately detect the temperature rise.

Therefore, it is necessary to set the temperature sampling timing so that the sensing value obtained during the temperature sensing operation can accurately reflect the possible high temperature.

8 is a graph illustrating a voltage change of the second node N2 of the driving transistor DRT according to a sensing time during temperature sensing driving. For temperature sensing, the sensing unit 220 converts the sensed sensing voltage Vsen into a digital value.

For example, the sensing unit 220 may have an analog-to-digital conversion range (ADC Range) from a digital value 0 corresponding to m [V] to a digital value 1023 corresponding to M [V].

In the display panel 110 , the temperature sensing values for all sub-pixels have a certain distribution 500 . This distribution 500 may correspond to a temperature distribution in all sub-pixels of the display panel 110 .

Accordingly, the temperature controller 230 may set the temperature sampling timing so that the average value or distribution of the initial sensed values, which are the sensed values obtained at the initial stage of driving of the organic light emitting diode display 100 , is included in the preset reference range Ref_Range.

For example, the temperature control unit 230 may perform the temperature sensing operation a plurality of times during the on-sensing process. In addition, the temperature control unit 230 obtains sensing values for a plurality of sub-pixels while varying the timing at which the sampling switch (SAM) is turned on after the tracking step (S3) is performed when the temperature sensing is driven a plurality of times. can

The temperature controller 230 may calculate an average value of a plurality of acquired sensing values, and determine a temperature sampling timing in which the average value of the calculated sensing values is included in a preset reference range Ref_Range.

In addition, when it is determined that the temperature sampling timing in which the average value of the sensed values is included in the reference range Ref_Range is determined, the temperature controller 230 may store the determined temperature sampling timing together with the sensed value in the memory 240 .

As another example, the temperature controller 230 may determine and store the temperature sampling timing in which the sensed values of a preset ratio (eg, 90%) or more are included in the reference range Ref_Range among the plurality of acquired sensed values.

In this case, the temperature controller 230 may set the reference range Ref_Range to accurately detect the temperature rise of the organic light emitting display device 100 in the analog-to-digital conversion range (ADC Range) of the sensing unit 220 .

For example, when the analog-to-digital conversion range (ADC Range) is from the digital value (0) to the digital value (1023), the temperature controller 230 sets the reference range (Ref_Range) from the digital value 100 to the digital value 150. range can be set. That is, due to the temperature rise, the reference range Ref_Range may be set so that a rise margin of the sensing value is sufficient.

Also, an average sensed value that is an average value of the sensed values may be stored in the memory 240 .

This is because it is assumed that the temperature difference for each area of the display panel 110 is not large at the initial stage of driving when the on-sensing process is performed in the organic light emitting display device 100, so that the average sensed value can be determined as a representative value of all the sensed values. Because.

Thereafter, the temperature controller 230 turns on the sampling switch SAM at the temperature sampling timing set after the tracking step S3 in the real-time sensing process. That is, when the sensing unit 220 senses the temperature, the temperature controller 230 prevents an error due to time from occurring in preparation for the initial driving of the organic light emitting display device 100 .

In addition, the temperature controller 230 may calculate a change value by comparing a sensed value received during the real-time-sensing process with an initial sensed value (or an average sensed value).

That is, the temperature controller 230 may determine a change in the temperature of the sub-pixels of the organic light emitting display device 100 being driven based on the initial driving temperature of the organic light emitting display device 100 .

On the other hand, when the organic light emitting display device 100 is powered on within a short time after being powered off, the driving initial temperature sensing may not be performed.

As described above, the driving initial temperature sensing performed during the on-sensing process is to set a temperature sampling timing and obtain an initial sensed value. However, when the organic light emitting diode display 100 is powered on within a short time after being powered off, the plurality of subpixels of the display panel 110 are not sufficiently cooled from heat due to previous driving. Accordingly, a large temperature deviation may occur between a plurality of sub-pixels, and it is difficult to obtain reliable temperature sampling timing.

Accordingly, when the organic light emitting diode display 100 is powered on within a short time after being powered off, the temperature sensing driving may be controlled to be performed using the temperature sampling timing and the initial sensed value stored before the temperature controller 330 .

9 and 10 are diagrams for explaining a luminance control method for controlling a temperature according to embodiments of the present invention.

As described above, the temperature controller 230 may receive the sensed value and determine the temperature or temperature change of the plurality of sub-pixels of the display panel 110 . Here, the temperature change may be determined as a change value of the sensed value with respect to a preset initial sensed value, or may be determined as a change value of the sensed value with respect to the initial driving sensing value.

Referring to FIG. 9 , the temperature controller 230 determines whether the change value is equal to or greater than a preset reference change value, and when the change value is equal to or greater than the reference change value, sets a luminance control value for lowering the temperature of the organic light emitting display panel. have.

And by performing a process of changing the corresponding image data (Data) with the luminance control value and supplying the data to the corresponding source driver integrated circuit (SDIC) in the data driver 120, the luminance of light emitted from the display panel can be lowered. have. Accordingly, the temperature of the display panel is lowered.

At this time, as shown in (a) of FIG. 10 , the temperature controller 230 determines the region HTA in which the change value is equal to or greater than the preset reference change value, and sets the region HTA as the luminance reduction region LRA. can In addition, only the luminance of the luminance reduction area LRA may be reduced by setting a luminance control value for the luminance reduction area LRA. Also, as shown in (b) of FIG. 10 , the temperature controller 230 converts the entire display panel to a luminance reduction region even when the region HTA in which the change value is equal to or greater than the preset reference temperature change value is a partial region of the display panel. (LRA) can be set. In addition, the luminance of the entire panel area may be reduced by setting a luminance control value for the luminance reduction area LRA.

When the temperature controller 230 sets a luminance control value for only a partial region of the display panel 110 and reduces the luminance of the corresponding region only, the user may recognize a change in the displayed image. In contrast, when the luminance of the entire area of the display panel 110 is reduced, the user is relatively unaware of the change in the image.

Accordingly, the temperature controller 230 may control the luminance of the entire area of the display panel 110 to be reduced even when the change value of the partial area is equal to or greater than the reference change value.

Also, the temperature controller 230 may cause the luminance of the display panel 110 to gradually decrease, making it difficult for the user to recognize the luminance change.

11 illustrates a luminance control method of an organic light emitting display device according to embodiments of the present invention.

Referring to FIG. 11 , the organic light emitting display device 100 is powered on by supplying power ( S810 ). The powered-on organic light emitting diode display 100 performs an on-sensing process, and at this time, it may be determined whether to perform initial temperature sensing (S815). At this time, the temperature control unit 230 of the controller 140 determines whether to perform the initial temperature sensing according to whether to use the initial sensing value and the temperature sampling timing set at the time of manufacturing, or to use the sensing value and the temperature sampling timing at the initial stage of driving. can be discerned. In addition, the temperature controller 230 may determine whether to perform the initial temperature sensing according to a time from when the power is previously turned off to when the power is turned on.

If it is determined that the initial temperature sensing is performed, the temperature controller 230 may perform a temperature sensing operation during the on-sensing process to obtain an initial sensing value and temperature sampling timing information ( S820 ). Here, the temperature controller 230 may perform the temperature sensing operation a plurality of times. The temperature controller 230 may acquire a temperature sampling timing in which an average value of initial sensed values or a sensed value equal to or greater than a preset ratio (eg, 90%) is included in the reference range Ref_Range. In addition, the temperature controller 230 may acquire a sensed value at the acquired temperature sampling timing as an initial sensed value.

However, if it is determined that the initial temperature sensing is performed, the temperature control unit 230 receives the initial sensing value and temperature sampling timing information stored in advance in the memory 240 and applies the received initial temperature sensing timing information thereafter (S825).

Here, the initial sensing value and temperature sampling timing information may be initial sensing value and temperature sampling timing information set during manufacturing. Alternatively, it may be an initial sensing value and temperature sampling timing information obtained during a previous on-sensing process.

In addition, the temperature controller 230 acquires a sensed value using the temperature sampling timing information obtained during the real-time-sensing process (S830).

And a change value is calculated by comparing the initial sensed value with the sensed value obtained during the real-time-sensing process (S835). Here, the change value may be calculated as a difference between the initial sensed value and the real-time sensed value.

The temperature controller 230 determines whether the calculated change value is equal to or greater than a preset reference change value (S840). If the change value is equal to or greater than the reference change value, the temperature controller 230 sets the luminance reduction area LRA and the luminance control value to decrease the luminance of the display panel (S845). In this case, the temperature controller 230 may reduce the luminance by setting an area including the sub-pixels determined to have a change value equal to or greater than the reference change value as the luminance reduction area LRA. Also, the temperature controller 230 may reduce the luminance by setting the entire display panel as the luminance reduction area LRA.

Also, the temperature controller 230 may gradually decrease the luminance to prevent the user from recognizing the luminance change.

Then, the controller 140 determines whether the organic light emitting display device 100 is powered off (S850).

If it is determined that the power is off, the temperature controller 230 stores the initial sensed value and the temperature sampling timing information to be used when the power is turned on later. In this case, the initial sensed value and the temperature sampling timing information may be stored in the nonvolatile memory.

As a result, the organic light emitting display device and the luminance control method according to the embodiments of the present invention can sense the temperature of each pixel of the organic light emitting display panel.

In addition, the organic light emitting display device and the luminance control method according to the embodiments of the present invention are capable of suppressing a change in characteristics of an organic light emitting diode by sensing the temperature of the organic light emitting display panel and controlling the luminance of the organic light emitting display panel. can

In addition, the organic light emitting display device and the luminance control method according to the embodiments of the present invention sense the temperature of the organic light emitting display panel at the pixel or sub-pixel level without using a separate temperature sensor, so that the organic light emitting display panel The temperature can be adjusted for the whole or for each area.

In addition, the organic light emitting display device and the luminance control method according to the embodiments of the present invention can improve image quality and lifespan by suppressing deterioration and afterimage generation of the organic light emitting display panel due to temperature regardless of image data. An organic light emitting display device and a luminance control method thereof can be provided.

That is, when the image displayed on the organic light emitting diode display is a still image or a moving image, deterioration of the organic light emitting display panel and generation of an afterimage according to temperature can be suppressed regardless of whether the image is a high luminance image or a low luminance image.

The above description and the accompanying drawings are merely illustrative of the technical spirit of the present invention, and those of ordinary skill in the art to which the present invention pertains can combine configurations within a range that does not depart from the essential characteristics of the present invention. , various modifications and variations such as separation, substitution and alteration will be possible. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100: organic light emitting display device 210: sub-pixel
110: organic light emitting display panel 220: sensing unit
120: data driver 230: temperature control unit
130: gate driver 240: memory unit
140: timing controller

Claims (17)

A plurality of data lines and a plurality of gate lines are disposed, a plurality of subpixels defined by the plurality of data lines and the plurality of gate lines are arranged, and an organic light emitting diode and a data voltage are applied to each subpixel. A driving transistor having a first node, a second node connected to the first electrode of the organic light emitting diode, and a third node to which a driving voltage is applied, and a storage capacitor connected between the first node and the second node of the driving transistor are disposed display panel;
a sensing unit sensing the voltage of the first electrode of the organic light emitting diode during a sensing driving period for each subpixel and outputting a sensed value corresponding to the sensed voltage; and
In the on-sensing process of the initial driving of the display panel, the average value of the sensed values obtained while varying the timing at which the sensing unit senses the voltage of the first electrode or a sensing value equal to or greater than a preset ratio is included in the reference range Obtaining a temperature sampling timing, setting the sensed value at the temperature sampling timing as an initial sensed value, and after the on-sensing process, a sensing value in which the change amount increases as the temperature change of the display panel increases during the real-time sensing process and a controller configured to obtain a change value corresponding to a temperature change of the display panel by comparing the preset initial sensed value, and control luminance of an entire area or a partial area of the display panel according to the change value, ,
The sensed value is
An organic light emitting display device in which a ratio of an amount of current flowing through each of the organic light emitting diode and the driving transistor is changed according to a change in temperature. delete According to claim 1,
Each subpixel is
a first transistor electrically connected between a corresponding data line of the plurality of data lines and a first node of the driving transistor and supplying a data voltage to the first node of the driving transistor; and
Further comprising a second transistor electrically connected between the first electrode of the organic light emitting diode and a reference voltage line,
The sensing unit
an analog-to-digital converter outputting the sensed value corresponding to the sensed voltage;
an initialization switch for supplying a preset reference voltage to the reference voltage line; and
and a sampling switch electrically connecting the reference voltage line to the analog digital converter. According to claim 1,
The voltage of the first electrode of the organic light emitting diode is
An organic light emitting diode display corresponding to a resistance ratio of a resistance value of the driving transistor and a resistance value of the organic light emitting diode that varies according to temperature. According to claim 1,
the controller is
If the difference between the sensed value and the preset initial sensed value of the sub-pixels greater than or equal to a preset number among the plurality of sub-pixels is equal to or greater than a preset reference change value, the organic light emitting device controls the luminance to decrease the luminance of the entire display panel. display device. According to claim 1,
the controller is
If the difference between the sensed value and the preset initial sensed value of at least a preset number of sub-pixels among the plurality of sub-pixels is greater than or equal to a preset reference change value, in the display panel, in an area including sub-pixels equal to or greater than the reference change value An organic light emitting display device that controls luminance to decrease luminance. delete 7. The method of claim 6,
the controller is
When the organic light emitting display device is powered on within a predetermined time after being powered off,
An organic light emitting diode display for maintaining a temperature sampling timing and an initial sensing value stored before the power-off without resetting the temperature sampling timing during an on-sensing process. According to claim 1,
The sensing unit
An organic light emitting display device that measures a sensing voltage of a red subpixel and a blue subpixel that are vulnerable to high temperature among the plurality of subpixels under the control of the controller, and outputs the sensed value. A plurality of data lines and a plurality of gate lines are disposed, a plurality of subpixels defined by the plurality of data lines and the plurality of gate lines are arranged, and an organic light emitting diode and a data voltage are applied to each subpixel. A driving transistor having a first node, a second node connected to the first electrode of the organic light emitting diode, and a third node to which a driving voltage is applied, and a storage capacitor connected between the first node and the second node of the driving transistor are disposed In the luminance control method of an organic light emitting display device including a display panel,
acquiring a sensed value while varying a timing for sensing the voltage of the first electrode during an on-sensing process;
obtaining a temperature sampling timing in which an average value of the sensed values or a sensed value equal to or greater than a preset ratio is included in a reference range;
setting the sensed value at the temperature sampling timing as an initial sensed value;
in a real-time sensing process, sensing a voltage at the first electrode of the organic light emitting diode during a sensing driving period for each subpixel, and obtaining a sensed value corresponding to the sensed voltage;
obtaining a change value corresponding to a temperature change of the display panel by comparing the sensed value of each of the plurality of subpixels with the preset initial sensed value;
controlling the luminance of an entire area or a partial area of the display panel to be lowered according to the change value;
The sensed value is
A luminance control method of an organic light emitting display device in which a ratio of an amount of current flowing through each of the organic light emitting diode and the driving transistor is changed according to a change in temperature. 11. The method of claim 10,
The step of obtaining the sensed value is
initializing a first node of the driving transistor and a first electrode of the organic light emitting diode to a data voltage and a reference voltage, respectively;
a stabilizing step of lowering the first electrode of the organic light emitting diode to a level corresponding to a threshold voltage of the organic light emitting diode;
a tracking step of applying the data voltage to a first node of the driving transistor to change a voltage of a first electrode of the organic light emitting diode that is turned on; and
and a sampling step of sensing the voltage of the first electrode of the organic light emitting diode. 11. The method of claim 10,
The voltage of the first electrode of the organic light emitting diode is
A luminance control method of an organic light emitting diode display corresponding to a resistance ratio of the resistance value of the driving transistor and the resistance value of the organic light emitting diode that varies according to temperature. delete 11. The method of claim 10,
The step of controlling the luminance to be lowered is
If the difference between the sensed value and the preset initial sensed value of the sub-pixels greater than or equal to a preset number among the plurality of sub-pixels is equal to or greater than a preset reference change value, the organic light emitting device controls the luminance to decrease the luminance of the entire display panel. A method of controlling the luminance of a display device. 11. The method of claim 10,
The step of controlling the luminance to be lowered is
If the difference between the sensed value and the preset initial sensed value of at least a preset number of sub-pixels among the plurality of sub-pixels is greater than or equal to a preset reference change value, in the display panel, in an area including sub-pixels equal to or greater than the reference change value A luminance control method of an organic light emitting display device for controlling luminance such that luminance is lowered.
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