Patent ID: 12217707

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings. Like reference numerals may refer to like elements throughout the accompanying drawings.

It will be understood that when a component such as a film, a region, a layer, etc., is referred to as being “on”, “connected to”, “coupled to”, or “adjacent to” another component, it can be directly on, connected, coupled, or adjacent to the other component, or intervening components may be present. It will also be understood that when a component is referred to as being “between” two components, it can be the only component between the two components, or one or more intervening components may also be present. It will also be understood that when a component is referred to as “covering” another component, it can be the only component covering the other component, or one or more intervening components may also be covering the other component. Other words used to describe the relationships between components should be interpreted in a like fashion.

It will be further understood that when a component is referred to as being ‘on’, ‘connected to’, ‘coupled to’, or ‘adjacent to’ another component, it can be directly on, connected to, coupled to, or adjacent to the other component, or intervening components may also be present. It will also be understood that when a component is referred to as being ‘between’ two components, it can be the only component between the two components, or one or more intervening components may also be present.

As used herein, the term “about” is inclusive of the stated value and means within an acceptable range of deviation for the particular value as determined by one of ordinary skill in the art, considering the measurement in question and the error associated with measurement of the particular quantity (e.g., the limitations of the measurement system). For example, “about” may mean within one or more standard deviations as understood by one of the ordinary skill in the art. Further, it is to be understood that while parameters may be described herein as having “about” a certain value, according to embodiments, the parameter may be exactly the certain value or approximately the certain value within a measurement error as would be understood by a person having ordinary skill in the art.

FIG.1is a plan view illustrating a display device according to an embodiment.

InFIG.1, a first direction DR1, a second direction DR2, and a third direction DR3are denoted. The first direction DR1is a direction parallel to one side of a display device1in a plan view, and may be, for example, a transverse direction of the display device1. The second direction DR2is a direction parallel to the other side of the display device1in contact with one side of the display device1in a plan view, and may be a longitudinal direction of the display device1. Hereinafter, for convenience of explanation, one side in the first direction DR1refers to a right direction in a plan view, the other side in the first direction DR1refers to a left direction in a plan view, one side in the second direction DR2refers to an upper direction in a plan view, and the other side in the second direction DR2refers to a lower direction in a plan view. The third direction DR3may be a thickness direction of the display device1.

However, it is to be understood that directions described with reference to embodiments refer to relative directions, and embodiments are not limited thereto.

Unless otherwise defined, the terms “above” and “upper surface” expressed with respect to the third direction DR3as used herein refer to a display surface side with respect to a display panel10, and the terms “below” and “lower surface”, and “rear surface” expressed with respect to the third direction DR3as used herein refer to a side opposite to a display surface with respect to the display panel10.

Referring toFIG.1, the display device1may include various electronic devices providing a display screen. Examples of the display device1may include, but are not limited to, mobile phones, smartphones, tablet personal computers (PCs), mobile communication terminals, electronic notebooks, electronic books, personal digital assistants (PDAs), portable multimedia players (PMPs), navigation devices, ultra mobile PCs (UMPCs), televisions, game machines, wrist watch-type electronic devices, head-mounted displays, monitors of personal computers, laptop computers, vehicle instrument boards, digital cameras, camcorders, external billboards, electric signs, various medical devices, various inspection devices, various home appliances including display areas, such as refrigerators and washing machines, Internet of Things (IoT) devices, or the like. Representative examples of a display device1to be described later may include smartphones, tablet PCs, laptop computers, or the like, but are not limited thereto.

The display device1may include a display panel10, a panel driving circuit20, a circuit board30, and a read-out circuit40.

The display device1includes the display panel10having an active area AAR and a non-active area NAR. The active area AAR includes a display area in which a screen is disposed and an image is displayed. The active area AAR may completely overlap the display area. A plurality of pixels PX displaying an image may be disposed in the display area. Each pixel PX may include a light emitting element ‘EL’ (seeFIG.4).

In addition, the active area AAR further includes a fingerprint sensing area. The fingerprint sensing area is an area in which light is responded to, and is an area configured to sense an amount, a wavelength, or the like, of incident light. The fingerprint sensing area may overlap the display area. As an example, the fingerprint sensing area may be disposed only in a limited area utilized for fingerprint recognition within the active area AAR. In this case, in an embodiment, the fingerprint sensing area may overlap a portion of the display area, but does not overlap another portion of the display area. As another example, the fingerprint sensing area may be defined as an area exactly the same as the active area AAR. In this case, the entire surface of the active area AAR may be utilized as an area for fingerprint sensing. A plurality of photosensors PS responding to light may be disposed in the fingerprint sensing area. Each photosensor PS may include a photoelectric conversion element PD (seeFIG.4) that senses incident light and converts the incident light into an electrical signal.

The non-active area NAR is disposed around the active area AAR. The non-active area NAR may be a bezel area. The non-active area NAR may surround all sides (four sides inFIG.1) of the active area AAR, but is not limited thereto.

The panel driving circuit20may be disposed in the non-active area NAR. The panel driving circuit20may drive the plurality of pixels PX and/or the plurality of photosensors PS. The panel driving circuit20may output signals and voltages for driving the display panel10. The panel driving circuit20may be formed as an integrated circuit (IC) and be mounted on the display panel10. Signal lines for transferring signals between the panel driving circuit20and the active area AAR may be further disposed in the non-active area NAR. As another example, the panel driving circuit20may be mounted on the circuit board30.

In addition, signal lines or the read-out circuit40for applying signals to the active area AAR may be disposed in the non-active area NAR. The read-out circuit40may be connected to the respective photosensors PS through the signal lines, and may receive currents flowing to the respective photosensors PS to sense a user's fingerprint input. The read-out circuit40may be formed as an integrated circuit (IC) and may be attached to a display circuit board in a chip on film (COF) manner, but is not limited thereto. For example, according to embodiments, the read-out circuit40may be attached onto the non-active area NAR of the display panel10in a chip on glass (COG) manner, a chip on plastic (COP) manner, or an ultrasonic bonding method.

The circuit board30may be attached to one end of the display panel10using an anisotropic conductive film (ACF). Lead lines of the circuit board30may be electrically connected to pad parts of the display panel10. The circuit board30may be a flexible printed circuit board or a flexible film such as a chip on film.

FIG.2is a block diagram of the display device1according to an embodiment.

Referring toFIG.2, the display device1includes a processor70, the panel driving circuit20, and the read-out circuit40.

The processor70supplies an image signal RGB supplied from outside of the display device1and a plurality of control signals to a timing controller21. The processor70may further include a graphics processing unit (GPU) that provides graphics for the image signal RGB provided from outside of the display device1. The image signal RGB is an image source on which graphics processing has been completed by the GPU, and may be provided to the timing controller21. As an example, the image signal RGB may have a frequency of about 120 Hz. As another example, the image signal RGB may have a frequency of about 30 Hz.

The plurality of control signals supplied from the processor70include a first mode control signal MO1and a second mode control signal MO2, a clock signal, an enable signal, and the like.

The first mode control signal MO1may include a signal for displaying a general image. The second mode control signal MO2may include a signal of a sensing mode for sensing a fingerprint F of a finger. The second mode control signal MO2may include respective frame periods. For example, the second mode control signal MO2may be a signal for controlling the display panel10so that the display panel10is driven during a first frame period and a second frame period. For example, the second mode control signal MO2may be a signal for controlling some pixels PX to emit light and some other pixels PX not to emit light during the first frame period. In addition, the second mode control signal MO2may be a signal for performing control to read the fingerprint F of the finger through digital sensed data sensed by some photosensors PS and exclude digital sensed data sensed by some other photosensors PS during the first frame period.

The processor70provides the first mode control signal MO1to the timing controller21to display the image on the display panel10. The processor70provides the second mode control signal MO2to the timing controller21to sense a user's fingerprint. The timing controller21drives the pixels PX and the photosensors PS of the display panel10according to the second mode control signal MO2.

The panel driving circuit20includes a data driver22driving the pixels PX of the display panel10, a scan driver23driving the pixels PX and the photosensors PS, and the timing controller21controlling driving timings of the data driver22and the scan driver23. In addition, the panel driving circuit20may further include a power supply unit24and an emission driver25.

The timing controller21receives the image signal supplied from the outside of the display device1. The timing controller21may output image data DATA and a data control signal DCS (including DCS1and DCS2) to the data driver22. In addition, the timing controller21may generate a scan control signal SCS that controls an operation timing of the scan driver23and an emission control signal ECS that controls an operation timing of the emission driver25. For example, the timing controller21may generate the scan control signal SCS and the emission control signal ECS, output the scan control signal SCS to the scan driver23through a scan control line, and output the emission control signal ECS to the emission driver25through an emission control line.

When the timing controller receives the first mode control signal MO1, the timing controller may generate a first data control signal DCS1. The timing controller may output the first data control signal DCS1to the data driver22. In addition, when the timing controller receives the second mode control signal MO2, the timing controller may generate a second data control signal DCS2. The timing controller may output the second data control signal DCS2to the data driver22. As described above, the second mode control signal MO2may be a signal used to perform control to alternate the first frame period and the second frame period.

The data driver22may convert the image data DATA into analog data voltages and output the analog data voltages to data lines DL. The scan driver23may generate scan signals according to the scan control signal SCS, and sequentially output the scan signals to scan lines SL.

The power supply unit24may generate a driving voltage ELVDD (seeFIG.4) and supply the driving voltage ELVDD to a source voltage line VL, and may generate a common voltage ELVSS (seeFIG.4) and supply the common voltage ELVSS to the source voltage line VL. The source voltage line VL may include a driving voltage line and a common voltage line. The driving voltage ELVDD may be a high potential voltage for driving light emitting elements and photoelectric conversion elements, and the common voltage may be a low potential voltage for driving the light emitting elements and the photoelectric conversion elements. That is, the driving voltage may have a higher potential than the common voltage.

In addition, the emission driver25may generate emission control signals according to the emission control signal ECS and sequentially output the emission control signals to emission control lines EML. While it has been illustrated that the emission driver25exists separately from the scan driver23, the disclosure is not limited thereto, and the emission driver may be included in the scan driver23according to embodiments.

The read-out circuit40may be connected to the respective photosensors PS through read-out lines ROL, and may receive currents flowing to the respective photosensors PS to sense a user's fingerprint input. The read-out circuit40may generate digital sensed data according to a magnitude of a current sensed by each photosensor PS and transmit the digital sensed data to the processor70, and the processor70may determine whether a fingerprint coincides with a user's fingerprint through a comparison with a preset fingerprint by analyzing the digital sensed data. When the preset fingerprint and the digital sensed data transmitted from the read-out circuit40are the same as each other, set functions may be performed.

The display panel10further includes a plurality of pixels PX, a plurality of photosensors PS, a plurality of scan lines SL connected to the plurality of pixels PX and the plurality of photosensors PS, a plurality of data lines DL and a plurality of emission control lines EML connected to the plurality of pixels PX, and a plurality of read-out lines ROL connected to the plurality of photosensors PS.

Each of the plurality of pixels PX may be connected to at least one of the scan lines SL, any one of the data lines DL, at least one of the emission control lines EL, and the source voltage line VL.

Each of the plurality of photosensors PS may be connected to any one of the scan lines SL, any one of the read-out lines ROL, and the source voltage line VL.

The plurality of scan lines SL may connect the scan driver23to the plurality of pixels PX and the plurality of photosensors PS, respectively. The plurality of scan lines SL may provide the scan signals output from the scan driver23to the plurality of pixels PX and the plurality of photosensors PS, respectively.

The plurality of data lines DL may connect the data driver22to the plurality of pixels PX, respectively. The plurality of data lines DL may provide the image data output from the data driver22to the plurality of pixels PX, respectively.

The plurality of emission control lines EML may connect the emission driver25to the plurality of pixels PX, respectively. The plurality of emission control lines EML may provide the emission control signals output from the emission driver25to the plurality of pixels PX, respectively.

The plurality of read-out lines ROL may connect the plurality of photosensors PS to the read-out circuit40, respectively. The plurality of read-out lines ROL may provide a sensed current generated according to a photocurrent output from each of the plurality of photosensors PS to the read-out circuit40. Accordingly, the read-out circuit40may sense the user's fingerprint.

A plurality of source voltage lines VL may connect the power supply unit24to the plurality of pixels PX and the plurality of photosensors PS, respectively. The plurality of source voltage lines VL may provide the driving voltage ELVDD or the common voltage ELVSS from the power supply unit24to the plurality of pixels PX and the plurality of photosensors PS, respectively.

FIG.3is an illustrative view illustrating fingerprint sensing of the display device according to an embodiment.

Referring toFIG.3, the display device1may further include a window WDL disposed on the display panel10. The display panel10may include a substrate SUB, a display layer DPL disposed on the substrate SUB and including the pixels PX and the photosensors PS, and an encapsulation layer TFE disposed on the display layer DPL.

When a user's finger comes into contact with an upper surface of the window WDL of the display device1, light output from the pixels PX of the display panel10may be reflected from ridges RID of the fingerprint F of the user and valleys VAL between the ridges RID. In this case, a ridge RID portion of the fingerprint F is in contact with the upper surface of the window WDL, whereas a valley VAL portion of the fingerprint F is not in contact with the window WDL. That is, the upper surface of the window WDL is in contact with air in the valley VAL portion.

In this case, a refractive index of the fingerprint F and a refractive index of the air are different from each other, and thus, an amount of light reflected from the ridge RID of the fingerprint F and an amount of light reflected from the valley VAL of the fingerprint F may be different from each other. Accordingly, the ridge RID portion and the valley VAL portion of the fingerprint F may be derived based on a difference between amounts of the reflected light, that is, light incident on the photosensors PS. Since the photosensors PS output electrical signals (e.g., sensed currents) according to the difference between the amounts of light, a fingerprint F pattern of the finger may be identified.

However, when the photosensors PS adjacent to the plurality of pixels PX output the sensed currents, portions of emission currents for emitting light from the plurality of pixels PX may leak to the photosensors PS adjacent to the plurality of pixels. Accordingly, the sensed currents of the photosensors PS adjacent to the plurality of pixels may become different from each other, and the fingerprint F pattern of the finger may be incorrectly identified. This will be described below in further detail with reference toFIG.4.

FIG.4is a circuit diagram illustrating a pixel and a photosensor according to an embodiment.

InFIG.4, a circuit diagram of a pixel PX connected to a k-th scan initialization line GILk, a k-th scan line GWLk, a k-th scan control line GCLk, a k−1-th scan line GWLk−1, and a j-th data line DLj and a photosensor PS connected to the k-th scan line GWLk, a k-th reset control line RSTLk, and a q-th read-out line ROLq is illustrated, were k, j and q are positive integers.

The pixel PX may include a light emitting element EL, a plurality of switch elements, and a first capacitor Cst. The light emitting element EL includes light emitting parts PX1, PX2, PX3, and PX4(seeFIG.5) emitting light. The switch elements include first to sixth transistors T1, T2, T3, T4, T5, and T6.

A driving transistor DT may include a gate electrode, a first electrode, and a second electrode. The driving transistor DT controls a drain-source current Isd (hereinafter, referred to as a “driving current”) flowing between the first electrode and the second electrode according to a data voltage applied to the gate electrode. The driving current Isd flowing through a channel of the driving transistor DT is proportional to the square of a difference between a voltage Vgs between the first electrode and the gate electrode and a threshold voltage of the driving transistor DT as represented in Equation 1.
Isd=k′×(Vsg−Vth)2[Equation 1]

Here, Isd is the driving current and refers to a source-drain current flowing through the channel of the driving transistor DT, k′ refers to a proportional coefficient determined by a structure and physical characteristics of the driving transistor, Vsg refers to the voltage between the first electrode and the gate electrode of the driving transistor, and Vth refers to the threshold voltage of the driving transistor.

The light emitting element EL emits light according to the driving current Isd. The larger the driving current Isd, the larger the amount of light emitted from the light emitting element EL.

The light emitting element EL may be, for example, an organic light emitting diode including an organic light emitting layer disposed between an anode electrode and a cathode electrode. Alternatively, the light emitting element EL may be a quantum dot light emitting element including a quantum dot light emitting layer disposed between an anode electrode and a cathode electrode. Alternatively, the light emitting element EL may be an inorganic light emitting element including an inorganic semiconductor disposed between an anode electrode and a cathode electrode. When the light emitting element EL is the inorganic light emitting element, the light emitting element EL may include a micro light emitting diode or a nano light emitting diode. InFIG.16, the anode electrode of the light emitting element EL corresponds to pixel electrodes571and572, and the cathode electrode of the light emitting element EL corresponds to a common electrode590.

The anode electrode of the light emitting element EL may be connected to a second electrode of the fifth transistor T5and a first electrode of the sixth transistor T6, and the cathode electrode of the light emitting element EL may be connected to a common voltage line VSL to which the common voltage ELVSS is applied.

The first transistor T1is turned on by a k-th scan signal of the k-th scan line GWLk to connect the first electrode of the driving transistor DT to the j-th data line DLj. Accordingly, a data voltage of the j-th data line DLj may be applied to the first electrode of the driving transistor DT. A gate electrode of the first transistor T1may be connected to the k-th scan line GWLk, a first electrode of the first transistor T1may be connected to the j-th data line DLj, and a second electrode of the first transistor T1may be connected to the first electrode of the driving transistor DT.

The second transistor T2is turned on by a k-th scan control signal of the k-th scan control line GCLk to connect the gate electrode and the second electrode of the driving transistor DT to each other. When the gate electrode and the second electrode of the driving transistor DT are connected to each other, the driving transistor DT is driven as a diode. A gate electrode of the second transistor T2may be connected to the k-th scan control line GCLk, a first electrode of the second transistor T2may be connected to the gate electrode of the driving transistor DT, and a second electrode of the second transistor T2may be connected to the second electrode of the driving transistor DT.

The third transistor T3is turned on by a k-th scan initialization signal of the k-th scan initialization line GILk to connect the gate electrode of the driving transistor DT to a first initialization voltage line VIL1. Accordingly, a first initialization voltage VINT of the first initialization voltage line VIL1may be applied to the gate electrode of the driving transistor DT. A gate electrode of the third transistor T3may be connected to the k-th scan initialization line GILk, a first electrode of the third transistor T3may be connected to the first initialization voltage line VIL1, and a second electrode of the third transistor T3may be connected to the gate electrode of the driving transistor DT.

The fourth transistor T4is turned on by a k-th emission control signal of a k-th emission control line EMLk to connect the first electrode of the driving transistor DT to a driving voltage line VDL to which the driving voltage ELVDD is applied. A gate electrode of the fourth transistor T4may be connected to the k-th emission control line EMLk, a first electrode of the fourth transistor T4may be connected to the driving voltage line VDL, and a second electrode of the fourth transistor T4may be connected to the first electrode of the driving transistor DT.

The fifth transistor T5is turned on by a k-th emission control signal of the k-th emission control line EMLk to connect the second electrode of the driving transistor DT to the anode electrode of the light emitting element EL. A gate electrode of the fifth transistor T5may be connected to the k-th emission control line EMLk, a first electrode of the fifth transistor T5may be connected to the second electrode of the driving transistor DT, and the second electrode of the fifth transistor T5may be connected to the anode electrode of the light emitting element EL.

When both the fourth transistor T4and the fifth transistor T5are turned on, the driving current Isd of the driving transistor DT according to the voltage applied to the gate electrode of the driving transistor DT may flow to the light emitting element EL.

The sixth transistor T6is turned on by a k−1-th scan signal of the k−1-th scan line GWLk−1 to connect the anode electrode of the light emitting element EL to a second initialization voltage line VIL2. A second initialization voltage VAINT of the second initialization voltage line VIL2may be applied to the anode electrode of the light emitting element EL. A gate electrode of the sixth transistor T6may be connected to the k−1-th scan line GWLk−1, the first electrode of the sixth transistor T6may be connected to the anode electrode of the light emitting element EL, and a second electrode of the sixth transistor T6may be connected to the second initialization voltage line VIL2.

The first capacitor Cst is formed between the gate electrode of the driving transistor DT and the driving voltage line VDL. A first capacitor electrode of the first capacitor Cst may be connected to the gate electrode of the driving transistor DT, and a second capacitor electrode of the first capacitor Cst may be connected to the driving voltage line VDL.

When the first electrode of each of the driving transistor DT and the first to sixth transistors T1, T2, T3, T4, T5, and T6is a source electrode, the second electrode of each of the driving transistor DT and the first to sixth transistors T1, T2, T3, T4, T5, and T6may be a drain electrode. Alternatively, when the first electrode of each of the driving transistor DT and the first to sixth transistors T1, T2, T3, T4, T5, and T6is a drain electrode, the second electrode of each of the driving transistor DT and the first to sixth transistors T1, T2, T3, T4, T5, and T6may be a source electrode.

An active layer of each of the driving transistor DT and the first to sixth transistors T1, T2, T3, T4, T5, and T6may be made of any one of, for example, polysilicon, amorphous silicon, and an oxide semiconductor. For example, the active layer of each of the driving transistor DT, the first transistor T1, and the fourth to sixth transistors T4to T6may be made of polysilicon. The active layer of each of the second transistor T2and the third transistor T3may be made of an oxide semiconductor. In this case, the driving transistor DT, the first transistor T1, and the fourth to sixth transistors T4to T6may be formed as P-channel metal oxide semiconductor field effect transistors (MOSFETs), and the second transistor T2and the third transistor T3may be formed as N-channel MOSFETs.

Each of the plurality of photosensors PS may include a photoelectric conversion element PD, a plurality of sensing transistors, and various signal lines. The photoelectric conversion element PD includes light sensing parts PS1and PS2(seeFIG.8) that sense external light. The plurality of sensing transistors may include first to third sensing transistors LT1, LT2, and LT3.

Each of the photoelectric conversion elements PD may be a photodiode including a sensing anode electrode, a sensing cathode electrode, and a photoelectric conversion layer disposed between the sensing anode electrode and the sensing cathode electrode. Each of the photoelectric conversion elements PD may convert light incident from outside of the display device1into an electrical signal. The photoelectric conversion element PD may be an inorganic photodiode or a phototransistor made of a pn-type or pin-type inorganic material. Alternatively, the photoelectric conversion element PD may be an organic photodiode including an electron donating material generating donor ions and an electron accepting material generating acceptor ions. InFIG.16, the sensing anode electrode of the photoelectric conversion element PD corresponds to light receiving electrodes573and574, and the sensing cathode electrode of the photoelectric conversion element PD corresponds to a common electrode590.

The photoelectric conversion element PD may generate photocharges when it is exposed to external light, and the generated photocharges may be accumulated in the sensing anode electrode of the photoelectric conversion element PD. In this case, a voltage of a first node N1electrically connected to the sensing anode electrode580(seeFIG.16) may increase. When the photoelectric conversion element PD and the q-th read-out line ROLq are connected to each other according to a turn-on of the first and third sensing transistors LT1and LT3, a sensing voltage may be accumulated at a third node N3between the q-th read-out line ROLq and the third sensing transistor LT3in proportion to the voltage of the first node N1in which the charges are accumulated.

The first sensing transistor LT1may be turned on by the voltage of the first node N1applied to a gate electrode thereof to connect the second initialization voltage line VIL2and a first electrode of the third sensing transistor LT3to each other. The gate electrode of the first sensing transistor LT1may be connected to the first node N1, a first electrode of the first sensing transistor LT1may be connected to the second initialization voltage line VIL2, and a second electrode of the first sensing transistor LT1may be connected to the first electrode of the third sensing transistor LT3. The first sensing transistor LT1may be a source follower amplifier that generates a source-drain current in proportion to a quantity of charges of the first node N1input to a gate electrode thereof. While it has been illustrated that the first electrode of the first sensing transistor LT1is connected to the second initialization voltage line VIL2, the disclosure is not limited thereto, and the first electrode of the first sensing transistor LT1may be connected to the driving voltage line VDL or the first initialization voltage line VIL1according to embodiments.

The second sensing transistor LT2may be turned on by a k-th reset control signal of the k-th reset control line RSTLk to connect the first node N1to a reset voltage line VRL for applying a reset voltage Vrst. A gate electrode of the second sensing transistor LT2may be connected to the k-th reset control line RSTLk, a first electrode of the second sensing transistor LT2may be connected to the reset voltage line VRL, and a second electrode of the second sensing transistor LT2may be connected to the first node N1.

The third sensing transistor LT3may be turned on by a k-th scan signal of the k-th scan line GWLk to connect the second electrode of the first sensing transistor LT1and the q-th read-out line ROLq to each other. A gate electrode of the third sensing transistor LT3may be connected to the k-th scan line GWLk, the first electrode of the third sensing transistor LT3may be connected to the second electrode of the first sensing transistor LT1, and a second electrode of the third sensing transistor LT3may be connected to the third node N3and the q-th read-out line ROLq.

An active layer of each of the first to third sensing transistors LT1, LT2, and LT3may be made of any one of, for example, polysilicon, amorphous silicon, and an oxide semiconductor. For example, the active layers of the first sensing transistor LT1and the third sensing transistor LT3may be made of polysilicon. The active layer of the second sensing transistor LT2may be made of an oxide semiconductor. In this case, the first sensing transistor LT1and the third sensing transistor LT3may be formed as P-channel MOSFETs, and the second sensing transistor LT2may be formed as an N-channel MOSFET.

However, as described above, when the light emitting element EL emits the light according to the emission current, a leakage current LL may be generated from the light emitting element EL to the photoelectric conversion element PD adjacent to the light emitting element EL. The leakage current LL may be a portion of the emission current generated when the light emitting element EL emits the light. The leakage current LL may flow to the sensing anode electrode of the photoelectric conversion element PD through an electron transport layer disposed on the anode electrode of the light emitting element EL and the sensing anode electrode580of the photoelectric conversion element PD. That is, the leakage current LL may be generated from the anode electrode of the light emitting element EL to the sensing anode electrode of the photoelectric conversion element PD through the electron transport layer.

Accordingly, the voltage of the first node N1connected to the sensing anode electrode of the photoelectric conversion element PD may be different from a voltage generated by generating the photocharges when the photoelectric conversion element PD is exposed to the external light. That is, the voltage of the first node N1may include an influence of the sensed current and the leakage current LL. Accordingly, when light is sensed by the photoelectric conversion element PD adjacent to the light emitting element EL, the fingerprint F pattern of the finger may be incorrectly identified.

FIG.5is a plan view illustrating an arrangement relationship between pixels and photosensors according to an embodiment.

Referring toFIG.5, a plurality of pixels PX and a plurality of photosensors PS may be repeatedly disposed in the display device1.

The plurality of pixels PX may include first sub-pixels PX1, second sub-pixels PX2, third sub-pixels PX3, and fourth sub-pixels PX4. For example, the first sub-pixels PX1may emit light of a red wavelength, the second sub-pixels PX2and the fourth sub-pixels PX4may emit light of a green wavelength, and the third sub-pixels PX3may emit light of a blue wavelength. The plurality of pixels PX may include a plurality of emission areas that emit light, respectively. The plurality of photosensors PS may include a plurality of light sensing areas that sense light incident thereon.

The first sub-pixels PX1, the second sub-pixels PX2, the third sub-pixels PX3, and the fourth sub-pixels PX4and the plurality of photosensors PS may be alternately arranged in the first direction DR1and the second direction DR2crossing the first direction DR1. In an embodiment, the first sub-pixels PX1and the third sub-pixels PX3may be alternately arranged while forming a first row along the first direction DR1, and the second sub-pixels PX2and the fourth sub-pixels PX4may be repeatedly arranged along the first direction in a second row adjacent to the first row. Pixels PX belonging to the first row may be misaligned with pixels PX belonging to the second row in the first direction DR1. Arrangements of the first row and the second row may be repeated up to an n-th row.

For example, the first sub-pixel PX1and the fourth sub-pixel PX4may be arranged in a first diagonal direction DD1crossing the first direction DR1and the second direction DR2, and the second sub-pixels PX2and the third sub-pixels PX3may be arranged in the first diagonal direction DD1. The second sub-pixels PX2and the third sub-pixels PX3may be arranged in a second diagonal direction DD2crossing the first diagonal direction DD1, and the first sub-pixels PX1and the fourth sub-pixels PX4may be arranged in the second diagonal direction DD2. The first diagonal direction DD1may be a direction obliquely inclined between the first and second directions DR1and DR2, and the second diagonal direction DD2may be a direction orthogonal to the first diagonal direction DD1. For example, the first diagonal direction DD1may be a direction inclined with respect to the first direction DR1and the second direction DR2by about 45°, but is not limited thereto.

The photosensors PS may be disposed between the first sub-pixels PX1and the third sub-pixels PX3forming the first row and may be spaced apart from each other. The first sub-pixels PX1, the photosensors PS, and the third sub-pixels PX3may be alternately arranged along the first direction DR1. The photosensors PS may be disposed between the second sub-pixels PX2and the fourth sub-pixels PX4forming the second row and be spaced apart from each other. The second sub-pixels PX2, the photosensors PS, and the fourth sub-pixels PX4may be alternately arranged along the first direction DR1. The number of photosensors PS in the first row may be the same as the number of photosensors PS in the second row. Arrangements of the first row and the second row may be repeated up to an n-th row.

Sizes of emission areas of respective fingerprint display pixels may be different from each other. Sizes of emission areas of the second sub-pixels PX2and the fourth sub-pixels PX4may be smaller than those of emission areas of the first sub-pixels PX1or the third sub-pixels PX3. While it has been illustrated inFIG.5that the respective pixels PX have an octagonal shape, the disclosure is not limited thereto, and the respective pixels PX have may have a rectangular shape, a quadrangular shape, a circular shape, or other polygonal shapes according to embodiments.

One fingerprint display pixel unit APXU may include one first sub-pixel PX1, one second sub-pixel PX2, one third sub-pixel PX3, and one fourth sub-pixel PX4. The fingerprint display pixel unit APXU refers to a group of color pixels capable of expressing a gradation.

FIG.6is a flowchart illustrating a method of reading a fingerprint by the display device according to an embodiment.FIG.7is a plan view illustrating pixels emitting light and sensible photosensors during a first frame period according to an embodiment.FIG.8is an enlarged plan view of portion B ofFIG.7according to an embodiment.FIG.9is a plan view illustrating pixels emitting light and sensible photosensors during a second frame period according to an embodiment.FIG.10is a graph illustrating an amount of leakage current according to luminance according to an embodiment.

Referring toFIG.6, first, when a mode of the display device1is set to a sensing mode for sensing a fingerprint (S110), the processor70may start a first frame period (S120). First sensing pixels DPX1emit light during the first frame period, and the processor70reads the fingerprint according to digital sensed data of first photosensors PS1(S130).

Hereinafter, pixels that emit light during the first frame period are defined as first sensing pixels DPX1, and pixels that do not emit light during the first frame period are defined as second sensing pixels DPX2. In addition, sensors reading a fingerprint image according to digital sensed data generated by sensing light during the first frame period are defined as first photosensors PS1, and photosensors PS excluding the generated digital sensed data are defined as second photosensors PS2. That is, according to an embodiment, during the first frame period, the first sensing pixels DPX1may emit the light and the second sensing pixels DPX2do not emit the light. In addition, in an embodiment, the fingerprint image may be read according to the digital sensed data obtained by the first photosensors PS1and the digital sensed data obtained by the second photosensors PS2is not used.

Referring toFIG.7, sensing pixels DPX emitting light and sensible photosensors PS during the first frame period are illustrated.

The first sensing pixels DPX1may be arranged in odd columns. The odd columns may extend along the second direction DR2. InFIG.7, the first sensing pixels DPX1may be arranged along the second direction DR2in a first column RX1, a third column RX3, and a fifth column RX5of first to sixth columns RX1to RX6. The first sensing pixels DPX1may be arranged alternately with the second photosensors PS2in the odd columns as illustrated inFIG.7. In addition, the first sensing pixels DPX1may be arranged alternately with the second sensing pixels DPX2along first to fourth rows CX1to CX4. The first sensing pixels DPX1may emit green light. The first sensing pixels DPX1may be the second sub-pixels PX2or the fourth sub-pixels PX4.

The second sensing pixels DPX2may be arranged in even columns. The even columns may extend along the second direction DR2. InFIG.7, the second sensing pixels DPX2may be arranged along the second direction DR2in the second column RX2, the fourth column RX4, and the sixth column RX6of the first to sixth columns RX1to RX6. The second sensing pixels DPX2may be arranged alternately with the first photosensors PS1in the even columns. In addition, the second sensing pixels DPX2may be arranged alternately with the first sensing pixels DPX1along the first to fourth rows CX1to CX4. The second sensing pixels DPX2may neighbor (e.g., be adjacent to) the first sensing pixels DPX1in the first direction DR1.

The first photosensors PS1may be arranged in the even columns. The even columns may extend along the second direction DR2. InFIG.7, the first photosensors PS1may be arranged along the second direction DR2in the second column RX2, the fourth column RX4, and the sixth column RX6of the first to sixth columns RX1to RX6. In addition, the first photosensors PS1may be arranged alternately with the second sensing pixels DPX2in the even columns. In addition, the first photosensors PS1may neighbor (e.g., be adjacent to) the second sensing pixels in the second direction DR2.

The second photosensors PS2may be arranged in the odd columns. The odd columns may extend along the second direction DR2. InFIG.7, the second photosensors PS2may be arranged along the second direction DR2in the first column RX1, the third column RX3, and the fifth column RX5of the first to sixth columns RX1to RX6. In addition, the second photosensors PS2may be arranged alternately with the first sensing pixels DPX1in the odd columns. In addition, the second photosensors PS2may be neighbor (e.g., be adjacent to) the first sensing pixels in the second direction DR2. The second photosensors PS2and the first photosensors PS1may neighbor (e.g., be adjacent to) each other in the first direction DR1.

However, the first sensing pixels DPX1, the second sensing pixels DPX2, the first photosensors PS1, and the second photosensors PS2are not limited to being arranged in the first to sixth columns RX1to RX6, and may be arranged in K columns and rows, where K is a positive integer.

Referring toFIG.8, as described above, due to arrangement positions and planar shapes of the first sensing pixels DPX1, the second sensing pixels DPX2, the first photosensors PS1, and the second photosensors PS2, a distance DD15between a center C1of a 1a-th first sensing pixel DPX1aand a center C5of a 1b-th sensing pixel DPX1bmay be substantially the same as a distance DD37between a center C3of a 2a-th sensing pixel DPX2aand a center C7of a 2b-th sensing pixel DPX2b. In addition, a distance DD48between a center C4of a 1a-th photosensor PS1aand a center C8of a 1b-th photosensor PS1bmay be substantially the same as a distance DD26between a center C2of a 2a-th photosensor PS2aand a center C6of a 2b-th photosensor PS2b.

Hereinafter, distances between the sensing pixels DPX and the photosensors PS are defined as distances between the center C1of the 1a-th first sensing pixel DPX1a, the center C5of the 1b-th sensing pixel DPX1b, the center C3of the 2a-th sensing pixel DPX2a, the center C7of the 2b-th sensing pixel DPX2b, the center C4of the 1a-th photosensor PS1a, the center C8of the 1b-th photosensor PS1b, the center C2of the 2a-th photosensor PS2a, and the center C6of the 2b-th photosensor PS2b.

Due to the arrangement positions and the planar shapes of the first sensing pixels DPX1, the second sensing pixels DPX2, the first photosensors PS1, and the second photosensors PS2, a first distance DD14between the 1a-th sensing pixel DPX1aand the 1a-th photosensor PS1aadjacent to the 1a-th sensing pixel DPX1aamong the first photosensors PS1may be greater than a second distance DD12between the 1a-th sensing pixel DPX1aand the 2a-th photosensor PS2aadjacent to the 1a-th sensing pixel DPX1aamong the second photosensors PS2.

In addition, a fifth distance DD13between the 1a-th sensing pixel DPX1aand the 2a-th sensing pixel adjacent to the 1a-th sensing pixel DPX1aamong the second sensing pixels DPX2may be the same as the distance DD15between the 1a-th sensing pixel DPX1aand the 1b-th sensing pixels DPX1badjacent to the 1a-th sensing pixel DPX1aamong the first sensing pixels DPX1. The fifth distance DD13may be the same as the distance DD37between the 2a-th sensing pixel and the 2b-th sensing pixel adjacent to the 2a-th sensing pixel among the second sensing pixels DPX2. The fifth distance DD13may be smaller than the first distance DD14and greater than the second distance DD12.

A third distance DD23between the 2a-th sensing pixel and the 2a-th photosensor PS2aadjacent to the 2a-th sensing pixel among the second photosensors PS2may be greater than a fourth distance DD34between the 2a-th sensing pixel and the 1a-th photosensor PS1aadjacent to the 2a-th sensing pixel among the first photosensors PS1. In addition, the third distance DD23may be greater than the second distance DD12, and the first distance DD14may be greater than the fourth distance DD34. In addition, the first distance DD14may be the same as the third distance DD23, and the second distance DD12may be the same as the fourth distance DD34.

A sixth distance DD24between the 1a-th photosensor PS1aand the 2a-th photosensor PS2aadjacent to the 1a-th photosensor PS1aamong the second photosensors PS2may be the same as the distance DD48between the 1a-th photosensor PS1aand the 1b-th photosensors PS1badjacent to the 1a-th photosensor PS1aamong the first photosensors PS1. In addition, the sixth distance DD24may be smaller than the distance DD26between the 2a-th photosensor PS2aand the 2b-th photosensor PS2badjacent to the 2a-th photosensor PS2aamong the second photosensors PS2. The sixth distance DD24may be greater than the second distance DD12and smaller than the first distance DD14.

Referring back toFIG.6, the processor70may start a second frame period (S140). The second sensing pixels DPX2emit light during the second frame period, and the processor70reads the fingerprint according to digital sensed data of the second photosensors PS2(S150).

Referring toFIG.9, pixels PX emitting light and sensible photosensors PS during the second frame period are illustrated.

Pixels that emit light during the second frame period are defined as second sensing pixels DPX2, and pixels that do not emit light during the second frame period are defined as first sensing pixels DPX1. In addition, sensors reading a fingerprint image according to digital sensed data generated by sensing light during the second frame period are defined as second photosensors PS2, and photosensors PS excluding the generated digital sensed data are defined as first photosensors PS1. That is, in an embodiment, during the second frame period, the second sensing pixels DPX2may emit the light and the first sensing pixels DPX1do not emit the light. In addition, in an embodiment, the fingerprint image may be read according to the digital sensed data obtained by the second photosensors PS2and the digital sensed data obtained by the first photosensors PS1is not used.

Accordingly, the first sensing pixels DPX1may emit the light during the first frame period, and the second sensing pixels DPX2may emit the light during the second frame period. In addition, the fingerprint image may be read according to the first photosensors PS1during the first frame period, and the fingerprint image may be read according to the second photosensors PS2during the second frame period. That is, when the pixels PX emit the light in the sensing mode, the fingerprint image may be read according to the photosensors PS that are not adjacent to the pixels PX emitting the light.

Referring back toFIG.7, finally, the processor70may alternately repeat the first frame period and the second frame period in the sensing mode.

Referring toFIG.10, a first leakage current LL1(seeFIG.16) refers to a leakage current LL flowing to the second photosensor PS2adjacent to the sensing pixel when the sensing pixel emits the light. A second leakage current LL2(seeFIG.16) refers to a leakage current LL flowing to the first photosensor PS1according to an embodiment of the disclosure when the sensing pixel DPX emits the light.

When the light emitting element EL emits light with the same luminance, a magnitude of the second leakage current LL2is smaller than that of the first leakage current LL1. For example, when the light emitting element EL emits light with a luminance of about 120 nits, the second leakage current LL2flowing to the first photosensor PS1may be about 14 μA, and the first leakage current LL1flowing to the second photosensor PS2adjacent to the sensing pixel may be about 16 μA. That is, when the fingerprint is read through the digital sensed data of the first photosensor PS1according to an embodiment of the disclosure, a magnitude of the leakage current LL may be smaller than when the fingerprint is read through the digital sensed data of the second photosensor PS2adjacent to the sensing pixel emitting the light.

Accordingly, in an embodiment, when the sensing pixels DPX emit the light, the fingerprint may be accurately read through the digital sensed data of the photosensors PS that are not adjacent to the sensing pixels DPX.

FIG.11is a plan view illustrating pixels emitting light and sensible photosensors during a first frame period according to an embodiment.FIG.12is a plan view illustrating pixels emitting light and sensible photosensors during a second frame period according to an embodiment.FIG.13is a plan view illustrating pixels emitting light and sensible photosensors during a third frame period according to an embodiment.

An embodiment according toFIGS.11to13is different from an embodiment according toFIGS.7to10in that it includes first sensing pixels DPX1, second sensing pixels DPX2, third sensing pixels DPX3, first photosensors PS1, second photosensors PS2, and third photosensors PS3. Accordingly, for convenience of explanation, a further description of elements and technical aspects previously described will be omitted.

A sensing mode may include a first frame period, a second frame period, and a third frame period. The first frame period, the second frame period, and the third frame period may be sequentially repeated in the sensing mode.

Hereinafter, pixels emitting light during the first frame period are defined as first sensing pixels DPX1, pixels emitting light during the second frame period are defined as second sensing pixels DPX2, and pixels emitting light during the third frame period are defined as third sensing pixels DPX3. In addition, sensors reading a fingerprint image according to digital sensed data generated by sensing light during the first frame period are defined as first photosensors PS1, sensors reading a fingerprint image according to digital sensed data generated by sensing light during the second frame period are defined as second photosensors PS2, and sensors reading a fingerprint image according to digital sensed data generated by sensing light during the third frame period are defined as third photosensors PS3. For example, in an embodiment, during the first frame period, the first sensing pixels DPX1may emit the light and the second sensing pixels DPX2and the third sensing pixels DPX3do not emit the light. In addition, the digital sensed data obtained by the second photosensors PS2and the third photosensors PS3are not used in an embodiment.

A plurality of columns may include 3N-th columns (where N is a positive integer), 3N−1-th columns, and 3N−2-th columns.

The first sensing pixels DPX1may be arranged in the 3N−2-th columns (where N is a positive integer). The 3N−2-th columns may extend along the second direction DR2. InFIGS.11to13, the first sensing pixels DPX1may be arranged along the second direction DR2in a first column RX1and a fourth column RX4of first to sixth columns RX1to RX6. In addition, the first sensing pixels DPX1may be arranged alternately with the second photosensors PS2in the 3N−2-th columns. In addition, the first sensing pixels DPX1may be arranged alternately with the second sensing pixels DPX2and the third sensing pixels DPX3along first to fourth rows CX1to CX4. The first sensing pixels DPX1may emit green light. The first sensing pixels DPX1may be the second sub-pixels PX2or the fourth sub-pixels PX4.

The second sensing pixels DPX2may be arranged in the 3N−1-th columns. The 3N−1-th columns may extend along the second direction DR2. InFIGS.11to13, the second sensing pixels DPX2may be arranged along the second direction DR2in the second column RX2and the fifth column RX5of the first to sixth columns RX1to RX6. In addition, the second sensing pixels DPX2may be arranged alternately with the third photosensors PS3in the 3N−1-th columns. In addition, the second sensing pixels DPX2may be arranged alternately with the third sensing pixels DPX3and the first sensing pixels DPX1along the first to fourth rows CX1to CX4. The second sensing pixels DPX2may neighbor (e.g., be adjacent to) the first sensing pixels DPX1in the first direction DR1.

The third sensing pixels DPX3may be arranged in the 3N-th columns. The 3N-th columns may extend along the second direction DR2. InFIGS.11to13, the third sensing pixels DPX3may be arranged along the second direction DR2in the third column RX3and the sixth column RX6of the first to sixth columns RX1to RX6. In addition, the third sensing pixels DPX3may be arranged alternately with the first photosensors PS1in the 3N-th columns. In addition, the third sensing pixels DPX3may be arranged alternately with the first sensing pixels DPX1and the second sensing pixels DPX2along the first to fourth rows CX1to CX4. The third sensing pixels DPX3may neighbor (e.g., be adjacent to) the first sensing pixels DPX1in the first direction DR1.

The first photosensors PS1may be arranged in the 3N-th columns. InFIGS.11to13, the first photosensors PS1may be arranged along the second direction DR2in the third column RX3and the sixth column RX6of the first to sixth columns RX1to RX6. In addition, the first photosensors PS1may be arranged alternately with the third sensing pixels DPX3in the 3N-th columns.

The second photosensors PS2may be arranged in the 3N−2-th columns. InFIGS.11to13, the second photosensors PS2may be arranged along the second direction DR2in the first column RX1and the fourth column RX4of the first to sixth columns RX1to RX6. In addition, the second photosensors PS2may be arranged alternately with the first sensing pixels DPX1in the 3N−2-th columns.

The third photosensors PS3may be arranged in the 3N−1-th columns. InFIGS.11to13, the third photosensors PS3may be arranged along the second direction DR2in the second column RX2and the fifth column RX5of the first to sixth columns RX1to RX6. In addition, the third photosensors PS3may be arranged alternately with the second sensing pixels DPX2in the 3N−1-th columns.

However, the first sensing pixels DPX1, the second sensing pixels DPX2, the third sensing pixels DPX3, the first photosensors PS1, the second photosensors PS2, and third photosensors PS3are not limited to being arranged in the first to sixth columns RX1to RX6, and may be arranged in K columns and rows (where K is a positive integer) according to embodiments.

An arrangement relationship between the respective sensing pixels DPX and photosensors PS according to the second frame period and the third frame period is substantially the same as that of an embodiment according toFIGS.7to10, except that light is emitted from 3N columns, as described above. Thus, for convenience of explanation, a further description of elements and technical aspects previously described will be omitted.

FIG.14is a plan view illustrating pixels emitting light and sensible photosensors during a first frame period according to an embodiment.FIG.15is a plan view illustrating pixels emitting light and sensible photosensors during a second frame period according to an embodiment.

An embodiment according toFIGS.14and15is substantially the same as an embodiment according toFIGS.7to10except for arrangements of the first sensing pixels DPX1and the second sensing pixels DPX2emitting the light and arrangements of the first photosensors PS1and the second photosensors PS2during the first frame period and the second frame period. Thus, for convenience of explanation, a further description of elements and technical aspects previously described will be omitted.

Referring toFIGS.14and15, the sensing mode may include a first frame period and a second frame period. The first frame period and the second frame period may be sequentially repeated in the sensing mode.

Hereinafter, pixels that emit light during the first frame period are defined as first sensing pixels DPX1, and pixels that emit light during the second frame period are defined as second sensing pixels DPX2. In addition, sensors reading a fingerprint image according to digital sensed data generated by sensing light during the first frame period are defined as first photosensors PS1, and sensors reading a fingerprint image according to digital sensed data generated by sensing light during the second frame period are defined as second photosensors PS2. That is, in an embodiment, during the first frame period, the first sensing pixels DPX1may emit the light and the second sensing pixels DPX2do not emit the light. In addition, in an embodiment, the digital sensed data obtained by the second photosensors PS2is not used.

Referring toFIG.14, a plurality of columns may include 3N-th columns (where N is a positive integer), 3N−1-th columns, and 3N−2-th columns.

The first sensing pixels DPX1may be arranged in the 3N−2-th columns (where N is a positive integer). The 3N−2-th columns may extend along the second direction DR2. InFIGS.14and15, the first sensing pixels DPX1may be arranged along the second direction DR2in a first column RX1and a fourth column RX4of first to sixth columns RX1to RX6. In addition, the first sensing pixels DPX1may be arranged alternately with the second photosensors PS2in the 3N−2-th columns. In addition, the first sensing pixels DPX1may be arranged alternately with the second sensing pixels DPX2along first to fourth rows CX1to CX4. The first sensing pixels DPX1may emit green light. The first sensing pixels DPX1may be the second sub-pixels PX2or the fourth sub-pixels PX4.

The second sensing pixels DPX2may be arranged in the 3N−1-th columns and the 3N-th columns. The 3N−1-th columns and the 3N-th columns may extend along the second direction DR2. InFIGS.14and15, the second sensing pixels DPX2may be arranged along the second direction DR2in the second column RX2, the third column RX3, the fifth column RX5, and the sixth column RX6of the first to sixth columns RX1to RX6. In addition, the second sensing pixels DPX1may be arranged alternately with the first photosensors PS1and the second photosensors PS2in the 3N−1-th columns and the 3N-th columns. In addition, the second sensing pixels DPX2may be arranged alternately with the first sensing pixels DPX1along the first to fourth rows CX1to CX4. The second sensing pixels DPX2may neighbor (e.g., be adjacent to) the first sensing pixels DPX1in the first direction DR1.

The first photosensors PS1may be arranged in the 3N−1-th columns and the 3N-th columns. InFIGS.14and15, the first photosensors PS1may be arranged along the second direction DR2in the second column RX2, the third column RX3, the fifth column RX5, and the sixth column RX6of the first to sixth columns RX1to RX6. In addition, the first photosensors PS1may be arranged alternately with the second photosensors PS2in the 3N−1-th columns and the 3N-th columns.

The second photosensors PS2may be arranged in the 3N−2-th columns. InFIGS.14and15, the second photosensors PS2may be arranged along the second direction DR2in the first column RX1and the fourth column RX4of the first to sixth columns RX1to RX6. In addition, the second photosensors PS2may be arranged alternately with the first sensing pixels DPX1in the 3N−2-th columns.

However, the first sensing pixels DPX1, the second sensing pixels DPX2, the first photosensors PS1, and the second photosensors PS2are not limited to being arranged in the first to sixth columns RX1to RX6, and may be arranged in K columns and rows (where K is a natural number) according to embodiments.

An arrangement relationship between the respective sensing pixels DPX and photosensors PS according to the second frame period is substantially the same as that ofFIG.14as described above. Thus, for convenience of explanation, a further description of elements and technical aspects previously described will be omitted.

FIG.16is a cross-sectional view illustrating pixels and photosensors according to an embodiment.

Referring toFIG.16, a buffer layer510is disposed on a substrate SUB. The buffer layer510may include, for example, silicon nitride, silicon oxide, silicon oxynitride, or the like.

A first thin film transistor TFT1and a second thin film transistor TFT2may be disposed on the buffer layer510. The first thin film transistor TFT1and the second thin film transistor TFT2may be disposed in a thin film transistor layer TFTL.

A plurality of thin film transistors TFT1and TFT2may include, respectively, semiconductor layers A1and A2, a gate insulating layer521disposed on portions of the semiconductor layers A1and A2, gate electrodes G1and G2disposed on the gate insulating layer521, an interlayer insulating film522covering each of the semiconductor layers A1and A2and each of the gate electrodes G1and G2, and source electrodes S1and S2and drain electrodes D1and D2disposed on the interlayer insulating film522.

The semiconductor layers A1and A2may form channels of the first thin film transistor TFT1and the second thin film transistor TFT2, respectively. The semiconductor layers A1and A2may include polycrystalline silicon. In an embodiment, the semiconductor layers A1and A2may include, for example, single crystal silicon, low-temperature polycrystalline silicon, amorphous silicon, or an oxide semiconductor. The oxide semiconductor may include, for example, a binary compound (ABx), a ternary compound (ABxCy), or a quaternary compound (ABxCyDz) containing, for example, indium, zinc, gallium, tin, titanium, aluminum, hafnium (Hf), zirconium (Zr), magnesium (Mg), and the like. The semiconductor layers A1and A2may include channel regions and source regions and drain regions doped with impurities, respectively.

The gate insulating layer521is disposed on the semiconductor layers A1and A2. The gate insulating layer521electrically insulates a first gate electrode G1and a first semiconductor layer A1from each other, and electrically insulates a second gate electrode G2and a second semiconductor layer A2from each other. The gate insulating layer521may be made of an insulating material such as, for example, silicon oxide (SiOx), silicon nitride (SiNx), or metal oxide.

The first gate electrode G1of the first thin film transistor TFT1and the second gate electrode G2of the second thin film transistor TFT2are disposed on the gate insulating layer521. The gate electrodes G1and G2may be formed above the channel regions of the semiconductor layers A1and A2, that is, on positions of the gate insulating layer521overlapping the channel regions, respectively.

The interlayer insulating film522may be disposed on the gate electrodes G1and G2. The interlayer insulating film522may include an inorganic insulating material such as, for example, silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride, hafnium oxide, or aluminum oxide. In addition, in an embodiment, the interlayer insulating film522may include a plurality of insulating films, and may further include a conductive layer disposed between the insulating films and forming a capacitor second electrode.

The source electrodes S1and S2and the drain electrodes D1and D2are disposed on the interlayer insulating film522. A first source electrode S1of the first thin film transistor TFT1may be electrically connected to the drain region of the first semiconductor layer A1through a contact hole penetrating through the interlayer insulating film522and the gate insulating layer521. A second source electrode S2of the second thin film transistor TFT2may be electrically connected to the drain region of the second semiconductor layer A2through a contact hole penetrating through the interlayer insulating film522and the gate insulating layer521. Each of the source electrodes S1and S2and the drain electrodes D1and D2may include one or more metals selected from the group including, for example, of aluminum (Al), molybdenum (Mo), platinum (Pt), palladium (Pd), silver (Ag), magnesium (Mg), gold (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), calcium (Ca), titanium (Ti), tantalum (Ta), tungsten (W), and copper (Cu).

A planarization layer530may be formed on the interlayer insulating film522so as to cover each of the source electrodes S1and S2and the drain electrodes D1and D2. The planarization layer530may be made of an organic insulating material or the like. The planarization layer530may have a flat surface and include contact holes exposing any one of the source electrodes S1and S2and any one of the drain electrodes D1and D2.

A light emitting element layer EEL may be disposed on the planarization layer530. The light emitting element layer EEL may include a first light emitting element EL1, a second light emitting element EL2, a first photoelectric conversion element PD1, a second photoelectric conversion element PD2, and a bank layer BK. The first light emitting element EL1may include a first pixel electrode571, a first emission layer581, and a common electrode590, and the second light emitting element EL2may include a second pixel electrode572, a second emission layer582, and the common electrode590. In addition, the first photoelectric conversion element PD1may include a first light receiving electrode573, a first photoelectric conversion layer583, and the common electrode590, and the second photoelectric conversion element PD2may include a second light receiving electrode574, a second photoelectric conversion layer584, and the common electrode590.

A pixel electrode57aof the first light emitting element EL1and the second light emitting element EL2may be disposed on the planarization layer530. For example, the pixel electrode57amay include the first pixel electrode571of the first light emitting element EL1and the second pixel electrode572of the second light emitting element EL2. In addition, the pixel electrode57amay be provided for each pixel. The pixel electrode57amay be connected to the first source electrode S1or the first drain electrode D1of the first thin film transistor TFT1through a contact hole penetrating through the planarization layer530.

The pixel electrode57aof the light emitting element EL may have a single-layer structure of, for example, molybdenum (Mo), titanium (Ti), copper (Cu), or aluminum (Al) or have a stacked film structure, for example, a multilayer structure of ITO/Mg, ITO/MgF, ITO/Ag, or ITO/Ag/ITO including indium-tin-oxide (ITO), indium-zinc-oxide (IZO), zinc oxide (ZnO), or indium oxide (In2O3), and silver (Ag), magnesium (Mg), aluminum (Al), platinum (Pt), lead (Pb), gold (Au), or nickel (Ni), but is not limited thereto.

In addition, a light receiving electrode57bof the first photoelectric conversion element PD1and the second photoelectric conversion element PD2may be disposed on the planarization layer530. For example, the light receiving electrode57bmay include the first light receiving electrode573of the first photoelectric conversion element PD1and the second light receiving electrode574of the second photoelectric conversion element PD2. The light receiving electrode57bmay be provided for each photosensor. The light receiving electrode57bmay be connected to the second source electrode S2or the second drain electrode D2of the second thin film transistor TFT2through a contact hole penetrating through the planarization layer530.

The light receiving electrode57bof the first photoelectric conversion element PD1and the second photoelectric conversion element PD2may have a single-layer structure of, for example, molybdenum (Mo), titanium (Ti), copper (Cu), or aluminum (Al) or have a multilayer structure of, for example, ITO/Mg, ITO/MgF, ITO/Ag, or ITO/Ag/ITO, but is not limited thereto.

A first hole injection layer HIL1and a hole transport layer HTL may be sequentially disposed on the pixel electrode57aand the light receiving electrode57b. The first hole injection layer HIL1and the hole transport layer HTL may be disposed below each of the first emission layer581and the second emission layer582when the first emission layer581and the second emission layer582are made of an organic material. Each of the first hole injection layer HIL1and the hole transport layer HTL may be a single layer or multiple layers made of an organic material.

The bank layer BK may be disposed on the hole transport layer HTL. The bank layer BK may include openings formed in areas overlapping the pixel electrode57aand exposing the pixel electrode57a. Areas in which the exposed pixel electrode57aand the first and second emission layers581and582overlap each other may be defined as emission areas emitting different light according to each pixel PX.

In addition, the bank layer BK may include openings formed in areas overlapping the light receiving electrode57band exposing the light receiving electrode57b. The openings exposing the light receiving electrode57bmay provide a space in which a photoelectric conversion layer58bof each photosensor PS is formed.

The bank layer BK may include an organic insulating material such as, for example, a polyacrylates resin, an epoxy resin, a phenolic resin, a polyamides resin, a polyimides resin, an unsaturated polyesters resin, a polyphenyleneethers resin, a polyphenylenesulfides resin, or benzocyclobutene (BCB). As another example, the bank layer BK may also include an inorganic material such as, for example, silicon nitride.

The first emission layer581of the first light emitting element EL1exposed by the opening of the bank layer BK may be disposed on the hole transport layer HTL. In addition, the second emission layer582of the second light emitting element EL2may be disposed on the hole transport layer HTL. The first emission layer581and the second emission layer582may include a high molecular material or a low molecular material, and may emit red, green, or blue light for each pixel PX. The light emitted from the first emission layer581and the second emission layer582may contribute to image display or function as a light source incident on the photosensor PS.

Second hole injection layers HIL2of the first photoelectric conversion element PD1and the second photoelectric conversion element PD2exposed by the openings of the bank layer BK may be disposed on the hole transport layer HTL. The second hole injection layers HIL2may be disposed below the first photoelectric conversion layer583and the second photoelectric conversion layer584when the first photoelectric conversion layer583and the second photoelectric conversion layer584are made of an organic material. The second hole injection layer HIL2may be a single layer or multiple layers made of an organic material.

The first photoelectric conversion layer583may be disposed on the second hole injection layer HIL2of the first photoelectric conversion element PD1exposed by the opening of the bank layer BK. An area in which the exposed second hole injection layer HIL2and the first photoelectric conversion layer583overlap each other may be defined as a light sensing area of each fingerprint photosensor PS1. The first photoelectric conversion layer583may generate photocharges in proportion to incident light. The incident light may be light emitted from the first emission layer581and then reflected to enter the first photoelectric conversion layer583or may be light provided from outside of the display device1regardless of the first emission layer581. Charges generated and accumulated in the first photoelectric conversion layer583may be converted into electrical signals utilized for sensing.

In addition, the second photoelectric conversion layer584may be disposed on the second hole injection layer HIL2of the second photoelectric conversion element PD2exposed by the opening of the bank layer BK. An area in which the exposed second hole injection layer HIL2and the second photoelectric conversion layer584overlap each other may be defined as a light sensing area of each second photosensor PS2. The second photoelectric conversion layer584may generate photocharges in proportion to incident light. The incident light may be light emitted from the second emission layer582and then reflected to enter the second photoelectric conversion layer584, or may be light provided from outside of the display device1regardless of the second emission layer582. Charges generated and accumulated in the second photoelectric conversion layer584may be converted into electrical signals utilized for sensing.

The first photoelectric conversion layer583and the second photoelectric conversion layer584may include an electron donating material and an electron accepting material. The electron donating material may generate donor ions in response to light, and the electron accepting material may generate acceptor ions in response to light. When the first photoelectric conversion layer583and the second photoelectric conversion layer584are made of an organic material, the electron donating material may include a compound such as, for example, subphthalocyanine (SubPc) or dibutylphosphate (DBP), but is not limited thereto. The electron accepting material may include a compound such as, for example, fullerene, a fullerene derivative, or perylene diimide, but is not limited thereto.

Alternatively, when the first photoelectric conversion layer583and the second photoelectric conversion layer584are made of an inorganic material, the first photoelectric conversion element PD1and the second photoelectric conversion element PD2may be pn-type or pin-type phototransistors. For example, each of the first photoelectric conversion layer583and the second photoelectric conversion layer584may have a structure in which an N-type semiconductor layer, an I-type semiconductor layer, and a P-type semiconductor layer are sequentially stacked.

The common electrode590may be disposed on the first emission layer581, the second emission layer582, the first photoelectric conversion layer583, the second photoelectric conversion layer584, and the bank layer BK. The common electrode590may be disposed throughout the plurality of pixels PX and the plurality of photosensors PS in a form in which it covers the first emission layer581, the second emission layer582, the first photoelectric conversion layer583, the second photoelectric conversion layer584, and the bank layer BK. The common electrode590may include a material layer having a small work function, for example, Li, Ca, LiF/Ca, LiF/Al, Al, Mg, Ag, Pt, Pd, Ni, Au, Nd, Ir, Cr, BaF, Ba, or compounds or mixtures thereof (e.g., a mixture of Ag and Mg, etc.). Alternatively, the common electrode590may include, for example, transparent metal oxide, for example, indium-tin-oxide (ITO), indium-zinc-oxide (IZO), or zinc oxide (ZnO).

The common electrode590may be disposed in common on the first emission layer581, the second emission layer582, the first photoelectric conversion layer583, and the second photoelectric conversion layer584, but is not limited thereto. In this case, cathode electrodes of the first light emitting element EL1and the second light emitting element EL2and sensing cathode electrodes of the first photoelectric conversion element PD1and the second photoelectric conversion element PD2may be electrically connected to each other. For example, a common voltage line connected to the cathode electrodes of the first light emitting element EL1and the second light emitting element EL2may also be connected to the sensing cathode electrodes of the first photoelectric conversion element PD1and the second photoelectric conversion element PD2.

An encapsulation layer TFEL may be disposed on the light emitting element layer EEL. The encapsulation layer TFEL may include at least one inorganic film to prevent or reduce oxygen or moisture from penetrating into each of the first emission layer581, the second emission layer582, the first photoelectric conversion layer583, and the second photoelectric conversion layer584. In addition, the encapsulation layer TFEL may include at least one organic film that protects each of the first emission layer581, the second emission layer582, the first photoelectric conversion layer583, and the second photoelectric conversion layer584from foreign materials such as, for example, dust. For example, the encapsulation layer TFEL may be formed in a structure in which a first inorganic film611and an organic film612are sequentially stacked. Each of the first inorganic film611and the second inorganic film613may be formed as multiple films in which one or more inorganic films of, for example, a silicon nitride layer, a silicon oxynitride layer, a silicon oxide layer, a titanium oxide layer, and an aluminum oxide layer are alternately stacked. The organic film612may be an organic film made of, for example, an acrylic resin, an epoxy resin, a phenolic resin, a polyamide resin, a polyimide resin, or the like.

A window WDL may be disposed on the encapsulation layer TFEL. The window WDL may be disposed on the display device1and may protect components of the display device1. The window WDL may be made of, for example, glass or plastic.

FIG.17is a cross-sectional view illustrating a method of sensing a gesture according to an embodiment.

Each of the first sensing pixels DPX1emits an electromagnetic wave EMW for a gesture according to a transmission signal. The electromagnetic wave EMW for a gesture may have a frequency of about 10 GHz to about 100 GHz or may have a frequency of about 39 GHz to about 60 GHz. As illustrated inFIG.17, the electromagnetic wave EMW emitted from each of the first sensing pixels DPX1may be reflected from a user OBJ or an object such as a pen positioned to be spaced apart from the window WDL by about 1 m.

Each of the first photosensors PS1may receive a reception signal received according to the electromagnetic wave EMW reflected from the user OBJ or the object such as the pen. Here, a time interval may exist between a time when the electromagnetic waves EMW are transmitted by the first sensing pixels DPX1and a time when the electromagnetic waves EMW are received by the first photosensors PS1. In addition, in a frequency of each reception signal according to the reflected electromagnetic wave EMW, a frequency shift of a transmission signal may occur due to the Doppler effect. The frequency shift is determined based on a relative velocity of the first sensing pixels DPX1and the user OBJ or the object such as the pen.

Accordingly, the processor may recognize a user's approach gesture through digital sensed data according to the first photosensors PS1.

Also, in an embodiment, when the photosensors PS adjacent to the plurality of pixels PX output the sensed currents, portions of emission currents for emitting light from the plurality of pixels PX may leak to the photosensors PS adjacent to the plurality of pixels. That is, when the user's approach gesture is recognized through the digital sensed data of the first photosensor PS1according to an embodiment of the disclosure, a magnitude of the leakage current may be smaller than when the user's approach gesture is recognized through the digital sensed data of the second photosensor PS2adjacent to the sensing pixel emitting the light.

Accordingly, in an embodiment, when the sensing pixels DPX emit the light, the user's approach gesture may be accurately recognized through the digital sensed data of the photosensors PS that are not adjacent to the sensing pixels DPX.

FIG.18is a cross-sectional view illustrating a blood pressure measurement method according to an embodiment.

Referring toFIG.18, the display device1may include a window WDL disposed on the display panel10. The display panel10may include a substrate SUB, a pressure layer PRS disposed on the substrate SUB, a display layer DPL disposed on the pressure layer PRS and including the first sensing pixels DPX1and second photosensors PS2, and an encapsulation layer TFEL disposed on the display layer DPL.

When a finger of the user OBJ is in contact with an upper surface of the window WDL of the display device1, the pressure layer PRN may measure a pressure applied by the user OBJ. Accordingly, the processor70may calculate pressure data according to a time. For example, in a process in which the user OBJ brings his/her finger into contact with the upper surface of the window WDL, a pressure sensed by the pressure layer PRS may gradually increase over time to reach a maximum value. When the pressure (e.g., a contact pressure) increases, a blood vessel may be constricted, such that a blood flow rate may be decreased or become 0.

To measure blood pressure, pulse wave information according to a time is utilized together with the pressure data. During systole of the heart, blood ejected from the left ventricle of the heart moves to peripheral tissues, such that a blood volume in the arterial side increases. In addition, during the systole of the heart, red blood cells carry more oxyhemoglobin to the peripheral tissues. During diastole of the heart, there is partial suction of blood from the peripheral tissues toward the heart. In this case, when a peripheral blood vessel is irradiated with light emitted from a display pixel, the irradiated light may be absorbed by the peripheral tissue. Absorbance is dependent on a hematocrit and a blood volume. The absorbance may have a maximum value during the systole of the heart and a minimum value during the diastole of the heart. Since the absorbance is in inverse proportion to an amount of light incident on the second photosensor PS2, absorbance at a corresponding point in time may be estimated through light reception data of the amount of light incident on the second photosensor PS2, and the processor70may calculate the blood pressure of the user OBJ based on the light reception data and a pressure measurement value.

Also, in an embodiment, when the photosensors PS adjacent to the plurality of pixels PX output the sensed currents, portions of emission currents for emitting light from the plurality of pixels PX may leak to the photosensors PS adjacent to the plurality of pixels. That is, when the blood pressure is calculated through the digital sensed data of the first photosensor PS1according to an embodiment of the disclosure, a magnitude of the leakage current may be smaller than when the blood pressure is calculated through the digital sensed data of the second photosensor PS2adjacent to the sensing pixel emitting the light.

Accordingly, in an embodiment, when the sensing pixels DPX emit the light, the blood pressure may be accurately calculated through the digital sensed data of the photosensors PS that are not adjacent to the sensing pixels DPX.

FIG.19is a cross-sectional view illustrating a blood pressure measurement method according to an embodiment.

Referring toFIG.19, when the finger of the user OBJ approaches the upper surface of the window WDL of the display device1, the light output from the pixels PX of the display panel10may be reflected by the fingerprint F of the user OBJ. Also in this case, a refractive index of the fingerprint F and a refractive index of the air are different from each other, and thus, amounts of light reflected from a ridge and a valley of the fingerprint F may be different from each other. Accordingly, the photosensor PS outputs an electrical signal (e.g., a sensed current) based on a difference between amounts of reflected light, that is, light incident on the photosensor PS, and thus, the fingerprint F pattern of the finger may be identified. That is, even though the finger of the user OBJ is not in direct contact with the upper surface of the window WDL and approaches the upper surface of the window WDL, the fingerprint of the user OBJ may be recognized.

Also in an embodiment, when the sensing pixels DPX emit the light, the fingerprint may be accurately read through the digital sensed data of the photosensors PS that are not adjacent to the sensing pixels DPX.

As is traditional in the field of the present disclosure, embodiments are described, and illustrated in the drawings, in terms of functional blocks, units and/or modules. Those skilled in the art will appreciate that these blocks, units and/or modules are physically implemented by electronic (or optical) circuits such as logic circuits, discrete components, microprocessors, hard-wired circuits, memory elements, wiring connections, etc., which may be formed using semiconductor-based fabrication techniques or other manufacturing technologies. In the case of the blocks, units and/or modules being implemented by microprocessors or similar, they may be programmed using software (e.g., microcode) to perform various functions discussed herein and may optionally be driven by firmware and/or software. Alternatively, each block, unit and/or module may be implemented by dedicated hardware, or as a combination of dedicated hardware to perform some functions and a processor (e.g., one or more programmed microprocessors and associated circuitry) to perform other functions.

While the present disclosure has been particularly shown and described with reference to embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present disclosure as defined by the following claims.