KR102484070B1 - Organic light emitting display device - Google Patents

Abstract

The present embodiments relate to an organic light emitting display capable of sensing ambient illumination, in which an illumination sensing section is set between display driving sections and an illumination sensing voltage is applied in a direction opposite to a direction in which a driving voltage is applied to an organic light emitting diode (OLED) during the illumination sensing section. The ambient illuminance can be measured using the applied illuminance sensing voltage and the photocurrent flowing through the organic light emitting diode by an external light source. According to the present embodiments, by using an organic light emitting diode in each pixel as a light receiving element, it is possible to measure ambient illumination without adding a separate illuminance sensor, and the type, number, and location of light receiving elements are adjusted according to the light receiving efficiency to generate an image. Display and illuminance sensing are possible at the same time.

Description

Organic light emitting display device {ORGANIC LIGHT EMITTING DISPLAY DEVICE}

The present embodiments relate to an organic light emitting display device, and relate to an organic light emitting display device that senses illumination around the organic light emitting display device.

An organic light emitting display device that has recently been in the limelight as a display device uses an organic light emitting diode (OLED) that emits light by itself, and has advantages such as fast response speed, high contrast ratio, luminous efficiency, luminance, and viewing angle.

Such an organic light emitting display device displays an image by arranging pixels including organic light emitting diodes (OLEDs) and driving transistors for driving them in a matrix form and controlling the brightness of pixels driven by a scan signal according to the gradation of data. do.

These organic light emitting display devices have recently been equipped with an illuminance sensor in a direction in which an image is displayed in order to sense ambient illuminance of the organic light emitting display device, and the illuminance sensor is located outside the organic light emitting display panel in the form of an IC.

Since the illuminance sensor IC is located outside the organic light emitting display panel, a narrow bezel becomes an obstacle, and it is difficult to apply the illuminance sensor IC to products using a circular organic light emitting display panel, such as a circular smart watch.

In addition, the illuminance sensor IC is generally composed of a light receiving sensor part of a photodiode, but the light receiving efficiency is not good in a typical Mixed-Mode IC process.

Therefore, most illuminance sensor ICs are manufactured by the CMOS image sensor (CIS) process, and a lens is sometimes formed during the package to increase the light receiving efficiency. As a result, when compared to the same area, the price is higher than that of normal process ICs.

Therefore, there is a need for an illuminance sensing means that can be applied regardless of the shape of the organic light emitting display panel of the organic light emitting display device, provides high light receiving efficiency, and can sense ambient illumination of the organic light emitting display device.

An object of the present embodiments is to provide an organic light emitting display device capable of effectively and actively processing an image according to an external illuminance of the organic light emitting display device.

An object of the present embodiments is to provide an organic light emitting display device that can be applied regardless of the shape of an organic light emitting display panel of the organic light emitting display device, overcomes the limitation of a narrow bezel, and can sense ambient illumination.

An object of the present embodiments is to provide an organic light emitting display device capable of sensing ambient illumination and providing high light receiving efficiency.

In one aspect, the present embodiments provide an organic light emitting display device including an organic light emitting display panel on which a plurality of pixels are disposed, and the plurality of pixels include an organic light emitting diode and a driving transistor for driving the organic light emitting diode.

At least one of the plurality of pixels disposed on the organic light emitting display panel of the organic light emitting display device has a driving voltage applied during the display driving period and opposite to the direction in which the driving voltage is applied during the illuminance sensing period separated from the display driving period. and an organic light emitting diode to which an illuminance sensing voltage is applied in a direction.

The controller may further include an illuminance measuring unit that senses a voltage between an input terminal of the illuminance sensing voltage and the organic light emitting diode in the illuminance sensing section and measures the illuminance based on the sensed voltage.

The illuminance measuring unit may include a resistor positioned between an input terminal of the illuminance sensing voltage and the organic light emitting diode, and may sense a voltage between the resistor and the organic light emitting diode in an illuminance sensing section.

In this case, the illuminance measurer may compare the sensed voltage with the reference voltage and measure the illuminance based on a difference between the reference voltage and the sensed voltage.

Alternatively, the illuminance measurer may include a capacitor connected between an input terminal of the illuminance sensing voltage and the organic light emitting diode, and may sense a change in voltage between the input terminal of the illuminance sensing voltage and the capacitor in the illuminance sensing section.

At this time, the illuminance measurement unit charges a capacitor by the current flowing between the input terminal of the illuminance sensing voltage and the organic light emitting diode in the illuminance sensing section, compares the voltage between the input terminal of the illuminance sensing voltage and the capacitor with the reference voltage, If the voltage between the input terminal and the capacitor is the same as the reference voltage, the charged capacitor can be discharged and the counting number can be increased by 1.

In addition, illuminance may be measured based on the increased counting number for a predetermined time period.

Here, the illuminance measurement unit may charge the capacitor by amplifying a current flowing between an input terminal of the illuminance sensing voltage and the organic light emitting diode in the illuminance sensing section.

In another aspect, according to the present embodiment, in an organic light emitting display device including an organic light emitting display panel on which a plurality of pixels are disposed, some of the plurality of pixels have a driving voltage during an illuminance sensing period distinct from a display driving period. An illuminance comprising an organic photodiode to which an illuminance sensing voltage is applied in a direction opposite to the applied direction, sensing a voltage between an input terminal of the illuminance sensing voltage and the organic photodiode in an illuminance sensing section, and measuring the illuminance based on the sensed voltage. An organic light emitting display device including a measuring unit is provided.

According to the present embodiments, a reverse voltage is applied to an organic light emitting diode disposed in a pixel during an illuminance sensing period distinct from a display driving period, and a photocurrent generated by the applied reverse voltage is measured to measure a pixel in an organic light emitting display panel. It is possible to provide an organic light emitting display device that senses ambient illumination using the present invention.

According to the present embodiments, an organic light emitting display device capable of sensing the ambient light without adding a separate light sensor can be provided by sensing the ambient light using the organic light emitting diode disposed in the pixel of the organic light emitting display panel. .

According to the present embodiments, it is possible to provide an organic light emitting display device capable of sensing the ambient light by overcoming the limitations of the shape of the organic light emitting display panel and the narrow bezel by sensing the ambient light without adding a separate light sensor. there is.

1 is a diagram showing a schematic configuration of an organic light emitting display device according to the present embodiments.
2 is a diagram showing an example of a pixel structure disposed on an organic light emitting display panel of an organic light emitting display device according to the present embodiments.
3 is a diagram schematically illustrating a structure for sensing an illuminance using an organic light emitting diode in a pixel disposed on an organic light emitting display panel of an organic light emitting display device according to the present embodiments.
4 is a diagram illustrating a first embodiment of a structure of an illuminance measuring unit of an organic light emitting display device according to the present embodiments.
5A and 5B are views for explaining a method of sensing illuminance by the illuminance measuring unit according to the first embodiment.
6 is a diagram illustrating a second embodiment of a structure of an illuminance measuring unit of an organic light emitting display device according to the present embodiments.
7A and 7B are diagrams for explaining a method of sensing an illuminance by an illuminance measurer according to a second embodiment.
8 is a diagram illustrating an example of a section in which the organic light emitting display device according to the present embodiments senses illumination.
9A and 9B are diagrams illustrating examples of pixel positions for sensing illuminance in an organic light emitting display device according to the present embodiments.
10A and 10B are diagrams illustrating examples of elements used as light receiving sensors in the organic light emitting display device according to the present embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention are described in detail below with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same numerals as much as possible even if they are displayed on 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), and (b) may be used. These terms are only used to distinguish the component from other components, and the nature, sequence, order, or number of the corresponding component is not limited by the term. When an element is described as being “connected,” “coupled to,” or “connected” to another element, that element is or may be directly connected to that other element, but intervenes between each element. It will be understood that may be "interposed", or each component may be "connected", "coupled" or "connected" through other components.

1 shows a schematic configuration of an organic light emitting display device 100 according to the present embodiments.

Referring to FIG. 1 , an organic light emitting display device 100 according to the present embodiments includes a plurality of gate lines GL and a plurality of data lines DL and a plurality of pixels P and Pixel. The organic light emitting display panel 110, the gate driver 120 driving the plurality of gate lines GL, the data driver 130 driving the plurality of data lines DL, the gate driver 120, and the data A controller 140 controlling the driver 130 and the like are included.

The gate driver 120 sequentially drives the plurality of gate lines GL by sequentially supplying scan signals to the plurality of gate lines GL.

The data driver 130 drives the plurality of data lines DL by supplying data voltages to the plurality of data lines DL.

The controller 140 controls the gate driver 120 and the data driver 130 by supplying various control signals to the gate driver 120 and the data driver 130 .

The gate driver 120 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 to operate the plurality of gate lines GL. run sequentially.

The gate driver 120 may be positioned on only one side of the organic light emitting display panel 110 or on both sides depending on a driving method.

In addition, the gate driver 120 may include one or more gate driver integrated circuits.

Each gate driver integrated circuit is connected to a bonding pad of the organic light emitting display panel 110 by a tape automated bonding (TAB) method or a chip on glass (COG) method, or It can be implemented as a GIP (Gate In Panel) type and directly disposed on the organic light emitting display panel 110 .

In addition, it may be integrated and disposed on the organic light emitting display panel 110, or may be implemented in a chip on film (COF) method mounted on a film connected to the organic light emitting display panel 110.

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

The data driver 130 may include at least one source driver integrated circuit to drive a plurality of data lines DL.

Each source driver integrated circuit is connected to a bonding pad of the organic light emitting display panel 110 by a tape automated bonding (TAB) method or a chip on glass (COG) method, or It may be directly disposed on the organic light emitting display panel 110 or may be integrated and disposed on the organic light emitting display panel 110 .

In addition, each source driver integrated circuit may be implemented in a Chip On Film (COF) method. In this case, one end of each source driver integrated circuit is bonded to at least one source printed circuit board, and the other end is bonded to the organic light emitting display panel 110 .

The controller 140 generates various timing signals including a vertical sync signal (Vsync), a horizontal sync signal (Hsync), an input data enable (DE) signal, and a clock signal (CLK) together with the input image data. Receive from outside (e.g. host system).

The controller 140 converts the input video data input from the outside to suit the data signal format used by the data driver 130 and outputs the converted video data, as well as the gate driver 120 and the data driver 130. In order to control the gate driver ( 120) and the data driver 130.

For example, in order to control the gate driver 120, the controller 140 includes a gate start pulse (GSP), a gate shift clock (GSC), and a gate output enable signal (GOE: It outputs various gate control signals (GCS: Gate Control Signal) including Gate Output Enable) and the like.

Here, the gate start pulse GSP controls the operation start timing of one or more gate driver integrated circuits constituting the gate driver 120 . The gate shift clock (GSC) is a clock signal commonly input to one or more gate driver integrated circuits and controls shift timing of scan signals (gate pulses). The gate output enable signal GOE specifies timing information of one or more gate driver integrated circuits.

In addition, the controller 140, in order to control the data driver 130, a source start pulse (SSP: Source Start Pulse), a source sampling clock (SSC: Source Sampling Clock), a source output enable signal (SOE: Source Output It outputs various data control signals (DCS) including Enable) and the like.

Here, the source start pulse SSP controls data sampling start timing of one or more source driver integrated circuits constituting the data driver 130 . The source sampling clock (SSC) is a clock signal that controls sampling timing of data in each source driver integrated circuit. The source output enable signal SOE controls output timing of the data driver 130 .

The controller 140 is a source printed circuit board to which the source driver integrated circuit is bonded and a control printed circuit board connected through a connection medium such as a flexible flat cable (FFC) or a flexible printed circuit (FPC). (Control Printed Circuit Board).

On such a control printed circuit board, a power controller (not shown) supplies various voltages or currents to the organic light emitting display panel 110, the gate driver 120, and the data driver 130 or controls various voltages or currents to be supplied. more can be placed. Such a power controller is also referred to as a power management IC.

In the organic light emitting display device 100, each pixel disposed on the organic light emitting display panel 110 may include circuit elements such as an organic light emitting diode (OLED), two or more transistors, and at least one capacitor. .

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

2 illustrates an example of a pixel structure disposed on the organic light emitting display panel 110 according to the present embodiments.

Referring to FIG. 2 , each pixel includes an organic light emitting diode (OLED) and a driving transistor (DRT) for driving the organic light emitting diode (OLED).

In addition, the first node N1 of the driving transistor DRT is controlled by the storage capacitor Cst electrically connected between the first node N1 and the second node N2 of the driving transistor DRT and the scan signal. ) and a switching transistor SWT electrically connected between the corresponding data line DL.

An organic light emitting diode (OLED) is composed of 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).

For example, the first electrode of the organic light emitting diode OLED may be connected to the second node N2 of the driving transistor DRT, and the base voltage EVSS may be applied to the second electrode of the organic light emitting diode OLED. there is.

The driving transistor DRT is a transistor that drives the organic light emitting diode (OLED) by supplying a driving current to the organic light emitting diode (OLED), and corresponds to a second node N2 corresponding to a source node or a drain node and a gate node. and a third node N3 corresponding to a drain node or a source node.

The switching transistor SWT is a transistor that transfers a data voltage to the first node N1 of the driving transistor DRT, and is electrically connected between the first node N1 of the driving transistor DRT and the data line DL. connected, turned on by a scan signal applied to the gate node, and may transfer a data voltage to the first node N1 of the driving transistor DRT.

The storage capacitor Cst is electrically connected between the first node N1 and the second node N2 of the driving transistor DRT to maintain a constant voltage for one frame.

The present embodiments provide a structure in which an illuminance sensing period is set apart from a period in which each pixel drives to display an image, and a reverse voltage is applied to an organic light emitting diode (OLED) in the illuminance sensing period, thereby providing organic light emitting within a pixel. A diode (OLED) is used to sense ambient illumination.

3 schematically illustrates an example of a pixel structure capable of sensing ambient illumination in the organic light emitting display device 100 according to the present embodiments.

Referring to FIG. 3 , an illuminance sensing voltage Vals is applied to the organic light emitting diode OLED in a pixel in a direction opposite to the direction in which the driving voltage is applied to the organic light emitting diode OLED during the illuminance sensing period.

That is, the driving voltage is applied to the first electrode of the organic light emitting diode (OLED) in the display driving section, the base voltage (EVSS) is applied to the second electrode, and the first electrode of the organic light emitting diode (OLED) is applied in the illuminance sensing section. A ground voltage (GND) is applied and an illuminance sensing voltage (Vals) is applied to the second electrode.

The voltage applied to the organic light emitting diode (OLED) is applied to the organic light emitting diode (OLED) by placing switches on the first and second electrodes of the organic light emitting diode (OLED) and controlling the switches for each display driving section and illuminance sensing section. The applied voltage can also be controlled.

During the illuminance sensing period, the organic light emitting diode (OLED) applies the illuminance sensing voltage Vals to the second electrode, and when the illuminance sensing voltage Vals is applied, a photocurrent flows according to the ambient illuminance.

The organic light emitting display device 100 according to the present embodiments includes the illuminance measurement unit 300 connected between the organic light emitting diode (OLED) and an input terminal of the illuminance sensing voltage Vals, and during the illuminance sensing section, the organic light emitting diode ( OLED) and the input terminal of the illuminance sensing voltage (Vals) to sense the voltage or current so that the ambient illuminance can be measured.

Hereinafter, specific embodiments of the illuminance measurement unit 300 for measuring the ambient illuminance of the organic light emitting display device 100 and a method for measuring the illuminance will be described with reference to drawings.

4 shows an example of a specific structure of the illuminance measuring unit 300 according to the first embodiment.

Referring to FIG. 4 , the illuminance measurement unit 300 according to the first embodiment includes a resistor R positioned between an input terminal of an illuminance sensing voltage Vals and an organic light emitting diode OLED, and the resistor R and an amplifier 310 connected to a node a(Na) between the organic light emitting diode (OLED). And, it includes an analog-to-digital converter 320 that converts the voltage amplified by the amplifier 310 into a 16-bit code.

When the illuminance sensing voltage Vals is applied to the second electrode of the organic light emitting diode (OLED) in the illuminance sensing section, photocurrent flows according to ambient illuminance.

The photocurrent increases as the ambient illumination becomes brighter, and when the photocurrent flows by an external light source, the photocurrent is converted into a voltage by the resistor R.

That is, when the photocurrent flows according to the external light source, the voltage of the node a (Na) changes according to the photocurrent and the size of the resistance R, and the voltage of the node a (Na) can be expressed as in Equation 1 below.

As shown in Equation 1, the voltage of node a(Na) decreases as the photocurrent increases and the voltage of node a(Na) increases as the photocurrent decreases. Therefore, the voltage of node a(Na) is sensed during the illuminance sensing period. By doing this, it is possible to measure the ambient illumination.

The amplifier 310 amplifies the voltage of the node a (Na) and transfers it to the analog-to-digital converter 320, and the analog-to-digital converter 320 converts the amplified value into a 16-bit code.

Therefore, during the illuminance sensing period, the illuminance sensing voltage Vals is applied in the opposite direction to the direction in which the driving voltage is applied to the organic light emitting diode (OLED), and the applied illuminance sensing voltage Vals and the photocurrent generated by the external light source are applied. By sensing the voltage of the node a (Na) according to the pixel, it is possible to measure the ambient illumination using the organic light emitting diode (OLED) in the pixel.

In the case of the illuminance measurement unit 300 according to the first embodiment, since a resistor R, an amplifier 310, and an analog-to-digital converter 320 are required, the data driver 130 may be implemented as a one-chip. can

5A and 5B are for explaining a method of measuring ambient illumination by the illuminance measurement unit 300 according to the first embodiment, FIG. 5A shows a case of low illumination and FIG. 5B shows a case of high illumination. will be.

Referring to FIG. 5A , the illuminance sensing voltage Vals is applied to the second electrode of the organic light emitting diode (OLED) in the illuminance sensing section. In addition, a photocurrent flows through the organic light emitting diode (OLED) by the applied illuminance sensing voltage (Vals) and an external light source.

Since the resistor R is disposed between the input terminal of the illuminance sensing voltage Vals and the organic light emitting diode OLED, the voltage at the node a (Na) changes according to the magnitude of the photocurrent.

In the case of low illumination, since the amount of the external light source is small, the photocurrent flowing in the illumination sensing section is reduced. When the photocurrent is small, the voltage at the node a(Na) is high, so when comparing the reference voltage Vref and the voltage at the node a(Na), the difference has a small value.

Therefore, the voltage of the node a (Na) sensed in the illuminance sensing section is compared with the reference voltage (Vref), and the ambient illumination can be measured based on the difference between the voltage of the node a (Na) and the reference voltage (Vref). there is.

FIG. 5B shows the case of high illuminance. In the case of high illuminance, since the amount of external light sources is large, the photocurrent flowing through the organic light emitting diode (OLED) increases in the illuminance sensing section.

As the photocurrent increases, the voltage at the node a(Na) decreases, and the difference between the reference voltage Vref and the voltage at the node a(Na) increases.

Therefore, the ambient illumination can be measured as bright as the difference between the reference voltage Vref and the voltage of the node a(Na).

According to the first embodiment, a method of sensing the voltage at the node a (Na) according to the photocurrent generated by the external light source and the illuminance sensing voltage Vals applied in the reverse direction of the organic light emitting diode (OLED) in the illuminance sensing section is provided. It enables easy measurement of ambient illumination.

6 shows an example of a specific structure of the illuminance measuring unit 300 according to the second embodiment.

Referring to FIG. 6 , the illuminance measurement unit 300 according to the second embodiment includes a capacitor C connected between an input terminal of the illuminance sensing voltage Vals and an organic light emitting diode OLED, and an illuminance sensing voltage Vals It includes a comparator 330 connected to the node b (Nb) between the input terminal of and the capacitor C, and a counter 340 connected to the comparator 330.

The illuminance measuring unit 300 according to the second embodiment is not a method of converting photocurrent generated by an external light source into a voltage, but a method of converting photocurrent into a code capable of directly measuring illuminance, which is generated by an external light source. The capacitor (C) is charged by the photocurrent and the voltage change of the node b (Nb) is sensed.

At this time, the first transistor M1 is disposed between the input terminal of the illuminance sensing voltage Vals and the organic light emitting diode OLED, and the second transistor M2 connected to the first transistor M1 is disposed so that the light is detected by an external light source. The generated photocurrent may be amplified to charge the capacitor C.

In the illuminance sensing section, when the illuminance sensing voltage (Vals) is applied to the second electrode of the organic light emitting diode (OLED) and a photocurrent flows by an external light source, the voltage (Vgs) according to the amount of photocurrent is captured by the first transistor (M1). do. If this is applied to the gate of the second transistor M2 whose W/L is greater by K times, the current flowing through the second transistor M2 can be amplified by K times the photocurrent flowing through the first transistor M1.

The capacitor C is charged by the amplified photocurrent, and the voltage at the node b (Nb) changes as the capacitor C is charged.

For example, when the amount of the external light source is small, the photocurrent is small and the capacitor C is charged slowly. Therefore, since it takes a long time to charge the capacitor C, the voltage at the node b (Nb) gradually changes.

On the other hand, when the amount of external light source is small, the capacitor C is quickly charged because the photocurrent is large, and the voltage at the node b (Nb) changes rapidly because the charging time of the capacitor C is short.

The comparator 330 compares the voltage of the node b (Nb) with the reference voltage (Vref) and outputs a high signal when the voltage of the node b (Nb) and the reference voltage (Vref) are equal to the capacitor (C). The switch (SW) is turned on to discharge the capacitor (C).

And, when Hihg is output from the comparator 330, the counter 340 increases the counting number by one.

Therefore, the voltage change speed of node b (Nb) varies according to the charging speed of capacitor (C), and the counting number increases whenever the voltage of node b (Nb) reaches the reference voltage (Vref), so that for a certain period of time The ambient illumination can be measured using the counting number.

At this time, since the illuminance measurement unit 300 according to the second embodiment is composed of a capacitor C, a comparator 330 and a counter 340, it can be implemented in the organic light emitting display panel 110.

7A and 7B are for explaining a method of measuring the illuminance by the illuminance measurement unit 300 according to the second embodiment. FIG. 7A shows a case of low illuminance and FIG. 7B shows a case of high illuminance.

Referring to FIG. 7A , an illuminance sensing voltage Vals is applied to the second electrode of the organic light emitting diode (OLED) in an illuminance sensing period, and a photocurrent flows due to the applied illuminance sensing voltage Vals and an external light source.

The photocurrent is amplified by the first transistor M1 and the second transistor M2 and charged in the capacitor C.

In the case of low light, the amount of external light source is small and the photocurrent is small, so the capacitor (C) is slowly charged. Accordingly, the voltage of the node b (Nb) gradually increases according to the charging rate of the capacitor C as shown in FIG. 7A.

When the voltage of the node b(Nb) increases and becomes equal to the reference voltage Vref, the comparator 330 outputs high to discharge the capacitor C, so the voltage of the node b(Nb) goes down. do.

Then, the counter 340 increases the counting number by 1 due to the high output from the comparator 330 .

In the case of low illumination, since the counting number increased for a certain period of time is small, it may be measured that the ambient illumination is dark according to the counting number.

FIG. 7B shows a case of high illumination, and when the amount of external light sources is large, the photocurrent increases, so that the capacitor C is quickly charged.

Since the capacitor C is charged quickly, the voltage at the node b (Nb) increases rapidly, and when the voltage at the node b (Nb) becomes equal to the reference voltage (Vref), the comparator 330 outputs High. As a result, the voltage at the node b (Nb) decreases. Then, the counter 340 increases the counting number by 1.

As shown in FIG. 7B , in the case of high illumination, the charging speed of the capacitor C is fast and the voltage of the node b (Nb) rises quickly, so the increased counting number for a certain period of time becomes large.

Since the increased counting number for a certain period of time is large, it can be measured that the ambient illumination is bright.

Therefore, during the illuminance sensing period, the capacitor C is charged by applying the illuminance sensing voltage Vals in the direction opposite to the direction in which the driving voltage is applied to the organic light emitting diode OLED, and the photocurrent flowing through the organic light emitting diode OLED. By sensing the amount of change in voltage of node b (Nb) according to the charging speed of , the ambient illumination can be measured.

8 illustrates an example of a section for measuring illuminance in the organic light emitting display device 100 according to the present embodiments.

Referring to FIG. 8 , the organic light emitting display device 100 according to the present embodiments sets an illuminance sensing section between sections in which the display is driven, so that ambient illumination can be measured while an image is displayed.

In the display driving section, the driving voltage is applied to the first electrode of the organic light emitting diode (OLED) disposed in each pixel, and in the illumination sensing section, the illumination sensing voltage (Vals) is applied to the second electrode of the organic light emitting diode (OLED). do.

Therefore, in the illuminance sensing period, each pixel operates as a black frame since a voltage is applied to the second electrode of the organic light emitting diode (OLED).

Then, the ambient illumination is measured according to the photocurrent flowing through the organic light emitting diode (OLED) in the pixel.

Through this, image display and illuminance sensing are time-divided using organic light emitting diodes (OLEDs) in pixels disposed on the organic light emitting display panel 110 so that the ambient illuminance can be measured without a separate illuminance sensor.

9A and 9B show examples of pixel arrangements used to measure illuminance in the organic light emitting display device 100 according to the present embodiments.

Referring to FIG. 9A , a case in which organic light emitting diodes (OLEDs) in all pixels disposed on the organic light emitting display panel 110 are used as light receiving elements for sensing illuminance is illustrated.

When organic light emitting diodes (OLEDs) in all pixels of the organic light emitting display panel 110 are used as light-receiving elements, an illuminance sensing voltage in a reverse direction of the organic light emitting diodes (OLEDs) of all pixels in an illuminance sensing period separated from a display driving period (Vals) are applied.

Since organic light-emitting diodes (OLEDs) arranged in all pixels are used as light-receiving elements, ambient illumination can be measured even when light-receiving efficiency of the organic light-emitting diodes (OLEDs) is low.

Referring to FIG. 9B , a case in which organic light emitting diodes (OLEDs) included in some of the pixels disposed on the organic light emitting display panel 110 are used as light receiving elements is illustrated.

When organic light emitting diodes (OLEDs) in some of the pixels of the organic light emitting display panel 110 are used as light receiving devices, the position and number of pixels used for illuminance sensing may be determined according to the photocurrent flowing in the illuminance sensing section. .

Since only some pixels of the organic light emitting display panel 110 are used for sensing the illuminance, it is possible to measure the ambient illuminance while minimizing the pixels representing the black frame between the display driving sections in which the image is displayed.

On the other hand, when using an organic light-emitting diode (OLED) as a light-receiving element, the light-receiving efficiency may be low due to the existence of an emissive layer located between the electron transport layer and the hole transport layer. there is.

Therefore, when only the organic light-emitting diode (OLED) is used as a light-receiving element and the light-receiving efficiency is low, it is difficult to sense the illuminance, the organic photo diode (OPD) excluding the emissive layer is used in the organic light-emitting diode (OLED). Light reception efficiency may be improved by disposing at some outermost pixels of the organic light emitting display panel 110 .

10A and 10B show examples of light receiving elements used for illuminance sensing in the organic light emitting display device 100 according to the present embodiments.

FIG. 10A shows an organic light emitting diode (OLED), and FIG. 10B shows an organic photodiode (OPD) excluding an emissive layer from the organic light emitting diode (OLED).

When organic photodiodes (OPDs) are used in some of the pixels disposed on the organic light emitting display panel 110, light receiving efficiency can be improved compared to the case where only organic light emitting diodes (OLEDs) are used as light receiving elements.

In addition, since the organic photodiode (OPD) excludes only the emissive layer from the organic light emitting diode (OLED), the organic photodiode (OPD) is placed in some pixels without adding a mask to improve the light receiving efficiency and It is possible to measure ambient illumination.

According to the present embodiments, an image is displayed using photocurrent generated by applying the illuminance sensing voltage Vals in the direction opposite to the direction in which the driving voltage is applied to the organic light emitting diode (OLED) in the illuminance sensing section between the display driving sections. At the same time, the ambient illumination can be measured.

Since the organic light emitting diode (OLED) in the pixel of the organic light emitting display panel 110 is used as a light receiving element, it is possible to measure the illuminance without adding a separate illuminance sensor, and the shape of the organic light emitting display panel 110 and the limitations of the narrow bezel and make it possible to measure illuminance.

In addition, depending on the light-receiving efficiency of the organic light-emitting diode (OLED), the location and number of pixels including the organic light-emitting diode (OLED) used as a light-receiving element are determined to enable illumination sensing. By arranging organic photodiodes (OPDs) in some pixels except for an emissive layer in the diode (OLED), it is possible to measure ambient illumination even when the light receiving efficiency of the organic light emitting diodes (OLEDs) is low.

The above description is merely an example of the technical idea of the present invention, and various modifications and variations can be made to those skilled in the art without departing from the essential characteristics of the present invention. In addition, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain, so the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed according to the claims below, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

100: organic light emitting display device 110: organic light emitting display panel
120: gate driver 130: data driver
140: controller 300: illuminance measuring unit
310: amplifier 320: analog-to-digital converter
330: comparator 340: counter

Claims (10)

An organic light emitting display device including an organic light emitting display panel on which a plurality of pixels are disposed,
At least one pixel among the plurality of pixels,
An organic light emitting diode to which a driving voltage is applied during a display driving period and an illumination sensing voltage is applied in a direction opposite to a direction to which the driving voltage is applied during an illuminance sensing period distinct from the display driving period,
An illuminance measuring unit configured to sense a voltage between an input terminal of the illuminance sensing voltage and the organic light emitting diode in the illuminance sensing section and measure illuminance based on the sensed voltage;
The illuminance measuring unit,
a capacitor connected between the input terminal of the illuminance sensing voltage and the organic light emitting diode and charged by a current flowing between the input terminal of the illuminance sensing voltage and the organic light emitting diode;
It is connected to a node between the input terminal of the illuminance sensing voltage and the capacitor and compares the voltage of the node with a reference voltage. If the voltage of the node is equal to the reference voltage, a first level signal is output, and if not, a second level signal is output. A comparator outputting a signal of a level; and
It is connected between the input end of the illuminance sensing voltage and the node, turns on in response to a first level signal output from the comparator to discharge the capacitor, and turns off in response to a second level signal output from the comparator. a switch configured to charge the capacitor by a current flowing between an input terminal of the illuminance sensing voltage and the organic light emitting diode;
An organic light emitting display device comprising a.
delete delete delete delete According to claim 1,
The illuminance measuring unit,
and a counter which increases a counting number by 1 when the output signal of the first level is output from the comparator.
According to claim 6,
The illuminance measuring unit,
An organic light emitting display device that measures the illuminance according to the counting number increased for a predetermined time period.
According to claim 6,
The illuminance measuring unit,
The organic light emitting display device charges the capacitor by amplifying a current flowing between an input terminal of the illuminance sensing voltage and the organic light emitting diode in the illuminance sensing section.
According to claim 5,
The illuminance measuring unit,
An organic light emitting display device positioned on the organic light emitting display panel where the plurality of pixels are disposed.
An organic light emitting display device including an organic light emitting display panel on which a plurality of pixels are disposed,
Some of the plurality of pixels,
An organic photodiode to which an illuminance sensing voltage is applied in a direction opposite to the direction in which the driving voltage is applied during an illuminance sensing period distinct from a display driving period,
An illuminance measurement unit configured to sense a voltage between an input terminal of the illuminance sensing voltage and the organic photodiode in the illuminance sensing section and measure the illuminance based on the sensed voltage;
The illuminance measuring unit,
a capacitor connected between the input terminal of the illuminance sensing voltage and the organic photodiode and charged by a current flowing between the input terminal of the illuminance sensing voltage and the organic photodiode;
It is connected to a node between the input terminal of the illuminance sensing voltage and the capacitor, and compares the voltage of the node with a reference voltage. If the voltage of the node is equal to the reference voltage, a first level signal is output. A comparator outputting a signal of a level; and
It is connected between the input terminal of the illuminance sensing voltage and the node, turns on in response to a first level signal output from the comparator to discharge the capacitor, and turns off in response to a second level signal output from the comparator. a switch configured to charge the capacitor by a current flowing between an input terminal of the illuminance sensing voltage and the organic photodiode;
An organic light emitting display device comprising a.

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