Display module and display apparatus having same

Abstract

A display module according to an aspect of the disclosed invention may comprise: a substrate; and a plurality of pixel circuits provided on the substrate, wherein each of the plurality of pixel circuits comprises: an LED; a driving line including a driving TFT connected to an anode terminal of the LED to apply a driving current; a sensing line including a sensing TFT connected to the anode terminal of the LED to sense the driving current; and a variable power supply unit connected to a cathode terminal of the LED to change a voltage supplied during the sensing of the driving current.

Description

Display module and display device including the same

[0001] The disclosed invention relates to a display module that implements an image using an inorganic light-emitting element and a display device including the same.

[0002] In general, a display device is a type of output device that converts acquired or stored electrical information into visual information and displays it to the user, and is used in various fields such as homes and businesses.

[0003] Display devices can be divided into self-luminous displays, in which each pixel emits its own light, and non-luminous displays, which require a separate light source.

[0004] LCD (Liquid Crystal Display) is a typical non-luminous display, and it is structurally complex and has limitations in implementing a thin thickness because it requires a backlight unit that supplies light from the rear of the display panel, a liquid crystal layer that acts as a switch to allow / block light to pass through, and a color filter that changes the supplied light into the desired color.

[0005] On the other hand, self-luminous displays, which feature individual light-emitting elements at each pixel, eliminate the need for components like backlight units and liquid crystal layers, and can even omit color filters. This allows for a simple structure and a high degree of design freedom. Furthermore, they can achieve a thin profile and excellent contrast ratio, brightness, and viewing angle.

[0006] Among self-illuminating displays, micro LED displays consist of multiple micro-sized LEDs. Compared to LCDs, which require backlighting, micro LED displays can offer superior contrast, response time, and energy efficiency.

[0007] Additionally, micro LEDs, which are inorganic light-emitting devices, are brighter, have better luminous efficiency, and have a longer lifespan than OLEDs, which require a separate encapsulation layer to protect the organic material.

[0008] These micro LED displays are typically made by connecting multiple display modules to form a single display. In this case, it is necessary to accurately detect the TFT current flowing within the pixel circuit to compensate for the brightness difference between each display module.

[0009] One aspect of the disclosed invention provides a display module and a display device including the same, which enable more accurate current sensing by preventing current from flowing through an LED during current sensing and varying a reference voltage to prevent the LED from turning on.

[0010] In addition, a display module and a display device including the same are provided, which can increase user convenience by sensing current by utilizing the blank time during operation of the display screen or the time when the display is turned on or off.

[0011] The technical problems to be achieved in this document are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0012] A display module according to one aspect of the disclosed invention includes a substrate; a plurality of pixel circuits provided on the substrate; each of the plurality of pixel circuits may include: an LED; a driving line including a driving TFT connected to an anode terminal of the LED and supplying a driving current; a sensing line including a sensing TFT connected to the anode terminal of the LED and sensing the driving current; and a variable power supply unit connected to a cathode terminal of the LED and changing a voltage supplied while sensing the driving current.

[0013] A display device according to one aspect of the disclosed invention comprises: a frame; a plurality of display modules arranged in a two-dimensional matrix on the frame; each of the plurality of display modules comprising: a substrate; a plurality of pixel circuits provided on the substrate; and each of the plurality of pixel circuits may comprise: an LED; a driving line including a driving TFT connected to an anode terminal of the LED and supplying a driving current; a sensing line including a sensing TFT connected to the anode terminal of the LED and sensing the driving current; and a variable power supply unit connected to a cathode terminal of the LED and changing a voltage supplied while sensing the driving current.

[0014] FIG. 1 is a perspective view showing an example of a display module and a display device including the same according to one embodiment of the present disclosure.

[0015] FIG. 2 is a drawing showing an example of a pixel array constituting a unit module of a display device according to one embodiment of the present disclosure.

[0016] FIG. 3 is a block diagram of a display device according to one embodiment of the present disclosure.

[0017] FIG. 4 is a block diagram illustrating the configuration of a display module included in a display device according to one embodiment of the present disclosure.

[0018] FIG. 5 is a diagram conceptually illustrating how each pixel is driven in a display module according to one embodiment of the present disclosure.

[0019] FIG. 6 is a circuit diagram schematically illustrating a pixel circuit for controlling pixels in a display module according to one embodiment of the present disclosure.

[0020] FIG. 7 is a diagram illustrating that an LED is turned on when current sensing is performed according to one embodiment of the present disclosure.

[0021] FIG. 8 is a diagram showing that a reference voltage supplied during current sensing according to one embodiment of the present disclosure is changed.

[0022] FIGS. 9 to 12 are diagrams showing various circuit structures for accurate current sensing according to one embodiment of the present disclosure.

[0023] FIG. 13 is a diagram showing a current sensing timing according to one embodiment of the present disclosure.

[0024] It should be understood that the various embodiments and terms used in this document are not intended to limit the technical features described in this document to specific embodiments, but rather to include various modifications, equivalents, or substitutes of the embodiments.

[0025] In connection with the description of the drawings, similar reference numerals may be used for similar or related components.

[0026] The singular form of a noun corresponding to an item may include one or more of said items, unless the relevant context clearly indicates otherwise.

[0027] In this document, each of the phrases "A or B", "at least one of A and B", "at least one of A or B", "A, B, or C", "at least one of A, B, and C", and "at least one of A, B, or C" may include any one of the items listed together in that phrase, or all possible combinations thereof.

[0028] The term “and / or” includes any combination of a plurality of related described elements or any one of a plurality of related described elements.

[0029] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish one component from another and do not qualify the components in any other respect (e.g., importance or order).

[0030] When a component (e.g., a first component) is referred to as being "coupled" or "connected" to another component (e.g., a second component), with or without the terms "functionally" or "communicatively," it means that the component can be connected to the other component directly (e.g., wired), wirelessly, or through a third component.

[0031] The terms “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in this document, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0032] When a component is said to be “connected,” “coupled,” “supported,” or “in contact with” another component, this includes not only cases where the components are directly connected, coupled, supported, or in contact, but also cases where the components are indirectly connected, coupled, supported, or in contact through a third component.

[0033] When we say that a component is “on” another component, this includes not only cases where the component is in contact with the other component, but also cases where there is another component between the two components.

[0034] Hereinafter, an embodiment according to the present invention will be described with reference to the attached drawings.

[0035] Throughout the specification, the same reference numerals denote the same components. This specification does not describe all elements of the embodiments, and any content that is general in the technical field to which the present invention pertains or that overlaps between embodiments is omitted. The terms 'part, module, element, block' used in the specification may be implemented in software or hardware, and depending on the embodiments, multiple 'parts, modules, elements, blocks' may be implemented as a single component, or a single 'part, module, element, block' may include multiple components.

[0036] Throughout the specification, when a part is said to be "connected" to another part, this includes not only the case where it is directly connected, but also the case where it is indirectly connected to another component, and an indirect connection includes a connection via a wireless communication network or an electrical connection by wiring, soldering, etc.

[0037] Additionally, when a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0038] Throughout the specification, when we say that an element is "on" another element, this includes not only cases where the element is in contact with the other element, but also cases where another element exists between the two elements.

[0039] Throughout the specification, whenever a component is said to convey or transmit signals or data to another component, this does not preclude the existence of another component between that component and the other component through which it conveys or transmits, unless otherwise specifically stated.

[0040] Throughout the specification, ordinal expressions such as “first” and “second” are used to distinguish between multiple components, and the ordinal numbers used do not indicate the arrangement order, manufacturing order, or importance of the components.

[0041] Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0042] For each step, the identification code is used to refer to each step, and this identification code does not limit the order of each step, and each step may be performed in a different order than specified unless the context clearly indicates a specific order.

[0043] When phrases such as "at least one" follow a list of elements, they can modify the combination of elements. For example, the phrase "at least one of a, b, or c" can be interpreted to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0044] Referring to the attached drawings below, an embodiment of a display module and a display device including the same according to one aspect is described in detail.

[0045] FIG. 1 is a perspective view showing an example of a display module and a display device including the same according to one embodiment of the present disclosure, and FIG. 2 is a drawing showing an example of a pixel array constituting a unit module of a display device according to one embodiment of the present disclosure.

[0046] According to one embodiment, the display device is a self-luminous display device in which light-emitting elements are arranged in each pixel, enabling each pixel to emit light on its own. Therefore, unlike liquid crystal display devices, it does not require components such as a backlight unit or liquid crystal layer, enabling a thin thickness, and its simple structure allows for various design changes.

[0047] In addition, a display device according to one embodiment may employ an inorganic light-emitting element, such as an inorganic light-emitting diode (ILD), as a light-emitting element arranged in each pixel. Inorganic light-emitting elements have a faster response speed than organic light-emitting elements, such as OLED (Organic Light Emitting Diode), and can implement high brightness with low power consumption.

[0048] In addition, unlike organic light-emitting devices, which are vulnerable to moisture and oxygen exposure, require a sealing process, and have low durability, the inorganic light-emitting device does not require a sealing process and is also durable. Hereinafter, the inorganic light-emitting device mentioned in the examples described below refers to an inorganic light-emitting diode.

[0049] In one embodiment, the inorganic light-emitting element employed in the display device may be a micro LED having a short side length of approximately 100 μm, tens of μm, or several μm. By employing micro LEDs in this manner, pixel sizes can be reduced and high resolution can be achieved even within the same screen size.

[0050] Furthermore, manufacturing LED chips in micron-scale sizes can address the inherent problem of inorganic materials breaking when bent. In other words, mounting micro LED chips on a flexible substrate prevents them from breaking even when the substrate bends, making flexible display devices possible.

[0051] Display devices employing micro LEDs can be applied to various fields by taking advantage of their ultra-small pixel size and thin thickness. For example, as illustrated in FIG. 1, a large-area screen can be implemented by tiling multiple display modules (10) equipped with multiple micro LEDs and fixing them to a housing (20). Such a large-area display device can be used as signage, electronic billboards, etc.

[0052] Meanwhile, the three-dimensional coordinate system of the XYZ axes illustrated in Fig. 1 is based on the display device (1), and the plane on which the screen of the display device (1) is located is the XZ plane, and the direction in which the image is output or the light-emitting direction of the inorganic light-emitting element is the +Y direction. Since the coordinate system is based on the display device (1), the same coordinate system can be applied whether the display device (1) is lying down or standing up.

[0053] Generally, the display device (1) is used in a standing position, and the user views the image from the front of the display device (1), so the +Y direction in which the image is output can be called the front, and the opposite direction can be called the rear.

[0054] In addition, the display device (1) is generally manufactured in a lying state. Therefore, it is also possible to refer to the -Y direction of the display device (1) as the downward direction and the +Y direction as the upward direction. That is, in the embodiment described below, the +Y direction may be referred to as the upward direction or forward, and the -Y direction may be referred to as the downward direction or rear.

[0055] Except for the top and bottom surfaces of a flat-type display device (1) or display module (10), the remaining four surfaces are all referred to as side surfaces, regardless of the position of the display device (1) or display module (10).

[0056] In the example of Fig. 1, a case is illustrated where a display device (1) includes a plurality of display modules to implement a large-area screen, but the embodiment of the display device (1) is not limited thereto. It is also possible for the display device (1) to be implemented as a TV, wearable device, portable device, PC monitor, etc., including a single display module (10).

[0057] Referring to FIG. 2, the display module (10) may include a plurality of pixels arranged in a two-dimensional manner, i.e., an M x N (M, N are integers greater than or equal to 2) array of pixels. FIG. 2 conceptually illustrates the pixel array, and it is to be understood that, in addition to the active area where pixels are arranged in the display module (10), a bezel area or wiring area where no image is displayed may also be located.

[0058] In the present embodiment, the fact that certain components are arranged two-dimensionally may include not only cases where the components are arranged on the same plane, but also cases where the components are arranged on different planes that are parallel to each other. Furthermore, cases where the components are arranged on the same plane do not necessarily require that the tops of the arranged components be located on the same plane, and cases where the tops of the arranged components are located on different planes that are parallel to each other may also be included.

[0059] A pixel (P) can be composed of at least three sub-pixels that output light of different colors. For example, a unit pixel (P) can be composed of three sub-pixels (SP(R), SP(G), SP(B)) corresponding to R, G, and B, respectively. Here, a red sub-pixel (SP(R)) can output red light, a green sub-pixel (SP(G)) can output green light, and a blue sub-pixel (SP(B)) can output blue light.

[0060] However, the pixel arrangement of FIG. 2 is merely an example that can be applied to a display module (10) and a display device (1) according to one embodiment, and the sub-pixels may be arranged along the Z-axis direction, may not be arranged in a row, and may be implemented with different sizes of the sub-pixels. A single pixel only needs to include multiple sub-pixels to implement various colors, and there are no restrictions on the size or arrangement of each sub-pixel.

[0061] In addition, a pixel (P) does not necessarily have to be composed of a red sub-pixel (SP(R)) that outputs red light, a green sub-pixel (SP(G)) that outputs green light, and a blue sub-pixel (SP(B)) that outputs blue light, and it is also possible to include a sub-pixel that outputs yellow light or white light. In other words, there are no restrictions on the color or type of light output from each sub-pixel, or the number of sub-pixels.

[0062] Figure 3 is a block diagram of a display device according to one embodiment.

[0063] As described above with reference to FIG. 1, a display device (1) according to one embodiment may include a plurality of display modules (10-1, 10-2, ..., 10-n, where n is an integer greater than or equal to 2), and may include a main controller (300) and a timing controller (500) that control a plurality of display modules (10), a communication unit (430) that communicates with an external device, a source input unit (440) that receives a source image, a speaker (410) that outputs sound, and an input unit (420) that receives a command for controlling the display device (1) from a user.

[0064] The input unit (420) may include a button or a touch pad provided in one area of ​​the display device (1), and when the display device (1) is implemented as a touch screen, the input unit (420) may include a touch pad provided on the front of the display device (1). In addition, the input unit (420) may also include a remote controller.

[0065] The input unit (420) can receive various commands from the user to control the display device (1), such as turning the display device (1) on / off, adjusting the volume, adjusting the channel, adjusting the screen, and changing various settings.

[0066] The speaker (410) may be provided in one area of ​​the main body (20), or a separate speaker module physically separated from the main body (20) may be further provided.

[0067] The communication unit (430) can communicate with a relay server or other electronic devices to send and receive necessary data. The communication unit (430) can adopt at least one of various wireless communication methods such as 3G (3rd Generation), 4G (4th Generation), wireless LAN, Wi-Fi, Bluetooth, Zigbee, WFD (Wi-Fi Direct), UWB (Ultra wideband), Infrared Data Association (IrDA), Bluetooth Low Energy (BLE), Near Field Communication (NFC), and Z-Wave. In addition, it is also possible to adopt a wired communication method such as PCI (Peripheral Component Interconnect), PCI-express, and USB (Universe Serial Bus).

[0068] The source input unit (440) can receive a source signal input from a set-top box, USB, antenna, etc. Accordingly, the source input unit (440) can include at least one selected from a group of source input interfaces including an HDMI cable port, a USB port, an antenna, etc.

[0069] The source signal received by the source input unit (440) can be processed by the main controller (300) and converted into a form that can be output from the display panel (100, see FIG. 4) and speaker (410).

[0070] The main controller (300) and the timing controller (500) may include at least one memory that stores a program and various data for performing the operations described below, and at least one processor that executes the stored program.

[0071] The main controller (300) can process a source signal input through the source input unit (440) to generate a video signal corresponding to the input source signal.

[0072] For example, the main controller (300) may include a source decoder, a scaler, an image enhancer, and a graphics processor. The source decoder may decode a source signal compressed in a format such as MPEG, and the scaler may output image data of a desired resolution through resolution conversion.

[0073] Image enhancers can improve the image quality of image data by applying various correction techniques. The graphics processor can distinguish pixels of image data into RGB data and output them along with control signals, such as a synchronization signal for display timing on the display panel (100). In other words, the main controller (300) can output image data and control signals corresponding to the source signal.

[0074] The operation of the main controller (300) described above is only an example applicable to the display device (1), and it is also possible to perform other operations or omit some of the operations described above.

[0075] The image data and control signals output from the main controller (300) can be transmitted to the timing controller (500).

[0076] The timing controller (500) can convert image data transmitted from the main controller (300) into image data in a form that can be processed by the driver IC (200, see FIG. 4) and generate various control signals, such as timing control signals, necessary to display the image data on the display panel (100).

[0077] Although a display device (1) according to one embodiment does not necessarily have to include a plurality of display modules (10), in the embodiment described below, for the sake of specific explanation, a display device (1) including a plurality of display modules (10) will be used as an example to specifically explain the operation of each component.

[0078] FIG. 4 is a block diagram illustrating a configuration of a display module included in a display device according to one embodiment, and FIG. 5 is a drawing conceptually illustrating a method of driving each pixel in a display module according to one embodiment.

[0079] Referring to FIG. 4, each of the plurality of display modules (10-1, 10-2, ..., 10-n) may include a display panel (100) that displays an image and a driver IC (200) that drives the display panel (100).

[0080] The driver IC (200) can generate a driving signal so that the display panel (100) can display an image based on image data and a timing control signal transmitted from the timing controller (500).

[0081] The driving signal generated by the driver IC (200) may include a gate signal and a data signal, and the generated driving signal is input to the display panel (100).

[0082] As described above, the display device (1) according to one embodiment is a self-luminous display device. Accordingly, an inorganic light-emitting element (120) that emits red, green, or blue light may be arranged in each sub-pixel.

[0083] The inorganic light-emitting element (120) arranged in each sub-pixel can be driven by an AM (Active Matrix) method or a PM (Passive Matrix) method. However, in the embodiment described below, for the sake of specific explanation, a case in which the inorganic light-emitting element (120) is driven by an AM method will be described as an example.

[0084] Referring to FIG. 5, the driver IC (200) may include a scan driver (210) and a data driver (220). The scan driver (210) may output a gate signal for turning on / off a sub-pixel, and the data driver (220) may output a data signal for implementing an image.

[0085] The scan driver (210) can generate a gate signal based on a timing control signal transmitted from the timing controller (500), and the data driver (220) can generate a data signal based on image data transmitted from the timing controller (500).

[0086] The display module (10) may include a pixel circuit (110) for individually controlling each inorganic light-emitting element (120), and a gate signal output from a scan driver (210) and a data signal output from a data driver (220) may be input to the pixel circuit (110).

[0087] For example, when a gate voltage (VGATE), a data voltage (VDATA), and a power voltage (VDD) are input to a pixel circuit (110), the pixel circuit (110) can output a driving current (CD) for driving an inorganic light-emitting element (120).

[0088] The driving current (CD) output from the pixel circuit (110) can be input to the inorganic light-emitting element (120), and the inorganic light-emitting element (120) can emit light by the input driving current (CD) to implement an image.

[0089] FIG. 6 is a circuit diagram schematically illustrating a pixel circuit for controlling a single sub-pixel in a display module according to one embodiment.

[0090] Referring to the example of FIG. 6, the pixel circuit (110) may include a thin film transistor (TR1, TR2) and a capacitor (Cst) that switch or drive an inorganic light emitting element (120).

[0091] For example, the thin film transistors (TR1, TR2) may include a switching transistor (TR1) and a driving transistor (TR2), and the switching transistor (TR1) and the driving transistor (TR2) may be implemented as PMOS type transistors. However, the embodiment of the display module (10) and the display device (1) is not limited thereto, and it is also possible for the switching transistor (TR1) and the driving transistor (TR2) to be implemented as NMOS type transistors.

[0092] Additionally, the thin film transistors (TR1, TR2) may be LTPS (Low Temperature Polycrystalline Silicon) thin film transistors or oxide thin film transistors. Furthermore, the thin film transistors may be a-Si thin film transistors or single-crystal thin film transistors.

[0093] For a specific explanation, the following embodiments will be described using an example of a case implemented with an LTPS PMOS type transistor.

[0094] The gate electrode of the switching transistor (TR1) is connected to the scan driver (210), the source electrode is connected to the data driver (220), and the drain electrode is connected to one end of the capacitor (Cst) and the gate electrode of the driving transistor (TR2). The other end of the capacitor (Cst) can be connected to the first power source (610).

[0095] Additionally, the source electrode of the driving transistor (TR2) is connected to a first power source (610) that supplies a power voltage (VDD), and the drain electrode is connected to the anode of the inorganic light-emitting element (120).

[0096] The cathode of the inorganic light emitting element (120) can be connected to a variable power supply (620) that supplies a reference voltage (VSS). The reference voltage (VSS) is a voltage at a lower level than the power supply voltage (VDD), and a ground voltage or the like can be used to provide grounding.

[0097] Here, the variable power supply (620) can adjust the supplied reference voltage. This will be described later.

[0098] The pixel circuit (110) of the above-described structure can operate as follows. First, when a gate voltage (VGATE) is applied from a scan driver (210) and the switching transistor (TR1) is turned on, a data voltage (VDATA) applied from a data driver (220) can be transmitted to one end of a capacitor (Cst) and the gate electrode of a driving transistor (TR2).

[0099] A voltage corresponding to the gate-source voltage of the driving transistor (TR2) can be maintained for a certain period of time by the capacitor (Cst). The driving transistor (TR2) can cause the inorganic light-emitting element (120) to emit light by applying a driving current (CD) corresponding to the gate-source voltage to the anode of the inorganic light-emitting element (120).

[0100] However, the structure of the pixel circuit (131) described above is only an example applicable to the display module (10) according to one embodiment, and in addition to the example described above, various circuit structures for switching and driving a plurality of inorganic light-emitting elements (120) may be applied.

[0101] In addition, the present embodiment does not place any restrictions on the brightness control method of the inorganic light-emitting element (120). The brightness of the inorganic light-emitting element (120) can be controlled by one of various methods, such as the PAM (Pulse Amplitude Modulation) method, the PWM (Pulse Width Modulation) method, and a hybrid method combining the PAM method and the PWM method. The structure of the pixel circuit (110) can also vary depending on the brightness control method.

[0102] The overall structure and operation of the pixel circuit (110) have been described above. Below, the operation for sensing current within the pixel circuit (110) will be described.

[0103] FIG. 7 is a diagram illustrating that an LED is turned on when current sensing is performed according to one embodiment of the present disclosure.

[0104] To compensate for luminance variations between display modules, it is necessary to accurately sense the minimum aging time and TFT current. To accurately sense this TFT current, the LED (120) must be completely turned off to prevent current from flowing to the LED.

[0105] When a test transistor (TR3) is provided to sense the current generated from the driving TFT (TR2), when current is allowed to flow to the test transistor (TR3) for sensing the current, current can also flow to an LED having a similar resistance value.

[0106] That is, when the LED is on, the current flowing to the test transistor (TR3) is dispersed due to the current flowing to the LED, so the driving TFT current cannot be accurately sensed.

[0107] Therefore, it is necessary to change the circuit structure to lower the voltage applied to the LED than the turn-on voltage and prevent current from flowing to the LED.

[0108] FIG. 8 is a diagram showing that a reference voltage supplied during current sensing according to one embodiment of the present disclosure is changed, and FIG. 9 is a diagram showing a circuit structure for accurate current sensing according to one embodiment of the present disclosure.

[0109] A display module (10) according to the present disclosure may include a plurality of pixel circuits (110) provided on a substrate, and each of the plurality of pixel circuits (110) may include a driving line including a driving TFT (TR2) connected to an anode terminal of an LED (120) to apply a driving current, a sensing line including a sensing TFT (TR6) connected to the anode terminal of the LED (120) to sense the driving current, and a variable power supply unit (620) connected to a cathode terminal of the LED (120) to change a voltage supplied while sensing the driving current.

[0110] The sensing TFT (TR6) may be configured to be turned on while sensing the driving current. Accordingly, while sensing the driving current, the driving current may flow from the driving line to the sensing line.

[0111] The demux TFT (TR4) can receive a data signal from Vsig and distribute the signal. This demux TFT (TR4) can be turned off while sensing the driving current.

[0112] When sensing the driving current, it is necessary to reduce the voltage applied to the LED (120) so that the LED (120) does not turn on.

[0113] To this end, the variable power supply unit (620) can increase the voltage supplied while sensing the driving current by a first voltage. Here, the first voltage can be set to an appropriate value for turning off the LED (120) while sensing the driving current, and for example, the first voltage can be approximately 2 [V] in consideration of the turn-on voltage of the LED (120).

[0114] That is, as shown in Fig. 8, the voltage supplied from the variable power supply can be controlled so that the reference voltage is 0 [V] when driving the display and 2 [V] when sensing the driving current.

[0115] Through this control, the LED may not be turned on while sensing the driving current. While sensing the driving current, the test TFT (TR3) and the demux TFT (TR4) are turned off, and the sensing TFT (TR6) is turned on, so that the driving current can flow from the driving line through the anode terminal of the LED (120) toward the switched-on sensing TFT (TR6). Therefore, it is possible to sense an accurate driving current without the current being distributed to the LED.

[0116] FIGS. 10 to 12 are diagrams showing various circuit structures for accurate current sensing according to one embodiment of the present disclosure.

[0117] Referring to FIGS. 10 and 11, the device may include a driving line including a driving TFT (TR2) that is connected to the anode terminal of an LED (120) and applies a driving current, a sensing line including a sensing TFT (TR6) that is connected to the anode terminal of the LED and senses the driving current, and a variable power supply unit (620) that is connected to the cathode terminal of the LED (120) and changes the voltage supplied while sensing the driving current.

[0118] The variable power supply unit (620) can increase the voltage supplied while sensing the driving current by a first voltage. As described above, the first voltage can be approximately 2 [V] considering the turn-on voltage of the LED (120).

[0119] Through this control, the LED (120) may not be turned on while sensing the driving current. While sensing the driving current, the test TFT (TR3) is turned off, and the sensing TFT (TR6) is turned on, so that the driving current can flow from the driving line through the anode terminal of the LED toward the switched-on sensing TFT (TR6). Therefore, it is possible to sense an accurate driving current without the current being distributed to the LED.

[0120] Referring to FIG. 12, the sensing line can be connected to the anode terminal of the LED (120) and connected to a data line that receives a data signal.

[0121] That is, in the cases of FIGS. 9 to 11, separate sensing lines are connected for each LED unit, and the sensing lines of FIG. 12 are connected for each data line unit, thereby minimizing changes to the existing pixel circuit.

[0122] The variable power supply (620) can increase the voltage supplied while sensing the driving current by the first voltage.

[0123] Through this control, the LED (120) may not be turned on while sensing the driving current. While sensing the driving current, the demux TFT (TR4) and TFT (TR5) are turned off, and the test TFT (TR3) and the sensing TFT (TR6) are turned on, so that the driving current can flow from the driving line to the anode terminal of the LED and the switched-on test TFT (TR3) toward the switched-on sensing TFT (TR6). Therefore, it is possible to sense an accurate driving current without the current being distributed to the LED (120).

[0124] FIG. 13 is a diagram showing a current sensing timing according to one embodiment of the present disclosure.

[0125] Sensing of the driving current can be performed during the blank time between frames of images output from the display or during the loading time while the display is turned on or off.

[0126] That is, the sensing TFT (TR6) can be driven on while the display is turned on or off, or turned on during the blank time between multiple frames of images output from the display.

[0127] By sensing the driving current during a time when the actual screen is not operating and keeping the LED from turning on while sensing the driving current, the user convenience can be increased by maintaining the black screen of the display.

[0128] A display module according to one embodiment may include a substrate; a plurality of pixel circuits provided on the substrate; each of the plurality of pixel circuits may include an LED; a driving line including a driving TFT connected to an anode terminal of the LED and supplying a driving current; a sensing line including a sensing TFT connected to the anode terminal of the LED and sensing the driving current; and a variable power supply unit connected to a cathode terminal of the LED and changing a voltage supplied while sensing the driving current.

[0129] According to the present disclosure, current can be sensed more accurately by preventing current from flowing through an LED during current sensing and varying the reference voltage to prevent the LED from turning on.

[0130] The above variable power supply unit can supply a voltage increased by the first voltage while sensing the driving current.

[0131] The above sensing TFT can be turned on while sensing the driving current.

[0132] The above sensing TFT can be turned on to sense the driving current during a blank time between multiple frames of an image output from the display.

[0133] The above sensing TFT can be turned on to sense the driving current while the display is turned on or off.

[0134] According to the present disclosure, user convenience can be increased by sensing current by utilizing the blank time during operation of the display screen or the time when the display is turned on or off.

[0135] The above driving current can flow from the driving line to the sensing line while sensing the above driving current.

[0136] Each of the plurality of pixel circuits further includes a data line connected to the anode terminal of the LED to receive a data signal, and the sensing line can be connected to a first node on the data line.

[0137] The driving current may flow from the driving line to the sensing line through the first node of the data line while sensing the driving current.

[0138] A display device according to one embodiment may include a frame; a plurality of display modules arranged in a two-dimensional matrix on the frame; each of the plurality of display modules including a substrate; a plurality of pixel circuits provided on the substrate; and each of the plurality of pixel circuits may include an LED; a driving line including a driving TFT connected to an anode terminal of the LED and supplying a driving current; a sensing line including a sensing TFT connected to the anode terminal of the LED and sensing the driving current; and a variable power supply unit connected to a cathode terminal of the LED and changing a voltage supplied while sensing the driving current.

[0139] The above variable power supply unit can supply a voltage increased by the first voltage while sensing the driving current.

[0140] The above sensing TFT can be turned on while sensing the driving current.

[0141] The above sensing TFT can be turned on to sense the driving current during a blank time between multiple frames of an image output from the display.

[0142] The above sensing TFT can be turned on to sense the driving current while the display is turned on or off.

[0143] The above driving current can flow from the driving line to the sensing line while sensing the above driving current.

[0144] Each of the plurality of pixel circuits further includes a data line connected to the anode terminal of the LED to receive a data signal, and the sensing line can be connected to a first node on the data line.

[0145] The driving current may flow from the driving line to the sensing line through the first node of the data line while sensing the driving current.

[0146] According to the disclosed invention, the current can be sensed more accurately by preventing current from flowing through the LED during current sensing and varying the reference voltage to prevent the LED from turning ON.

[0147] Additionally, user convenience can be enhanced by sensing current by utilizing the blank time during operation of the display screen or the time when the display is turned on or off.

[0148] Meanwhile, the disclosed embodiments may be implemented in the form of a recording medium storing computer-executable instructions. The instructions may be stored in the form of program code, and when executed by a processor, may generate program modules to perform the operations of the disclosed embodiments. The recording medium may be implemented as a computer-readable recording medium.

[0149] Computer-readable storage media include all types of storage media that store instructions that can be deciphered by a computer. Examples include read-only memory (ROM), random access memory (RAM), magnetic tape, magnetic disks, flash memory, and optical data storage devices.

[0150] The disclosed embodiments have been described with reference to the attached drawings as described above. Those skilled in the art will understand that the present invention can be implemented in forms other than the disclosed embodiments without altering the technical spirit or essential features of the present invention. The disclosed embodiments are illustrative and should not be construed as limiting.

Claims

1. Substrate; A plurality of pixel circuits provided on the above substrate; Each of the above plurality of pixel circuits, LED; A driving line including a driving TFT that is connected to the anode terminal of the LED and applies a driving current; A sensing line including a sensing TFT that is connected to the anode terminal of the LED and senses the driving current; and A display module including a variable power supply unit that is connected to the cathode terminal of the LED and changes the voltage supplied while sensing the driving current.

2. In paragraph 1, The above variable power supply unit, A display module that supplies a voltage increased by a first voltage while sensing the above driving current.

3. In paragraph 1, The above sensing TFT is, A display module that is turned on while sensing the above driving current.

4. In paragraph 3, The above sensing TFT is, A display module that is turned on to sense driving current during the blank time between multiple frames of images output from the display.

5. In paragraph 3, The above sensing TFT is, A display module that is turned on to sense the driving current while the display is turned on or off.

6. In paragraph 1, The above driving current is, A display module that senses the driving current flowing from the driving line to the sensing line.

7. In paragraph 1, Each of the above plurality of pixel circuits, Further comprising a data line connected to the anode terminal of the LED and receiving a data signal; A display module wherein the sensing line is connected to a first node on the data line.

8. In paragraph 7, The above driving current is, A display module in which the driving current flows from the driving line through the first node of the data line to the sensing line while sensing the driving current.

9. Frame; A plurality of display modules arranged in a two-dimensional matrix in the above frame; Each of the above multiple display modules, substrate; A plurality of pixel circuits provided on the above substrate; Each of the above plurality of pixel circuits, LED; A driving line including a driving TFT that is connected to the anode terminal of the LED and applies a driving current; A sensing line including a sensing TFT that is connected to the anode terminal of the LED and senses the driving current; and A display device including a variable power supply unit that is connected to the cathode terminal of the LED and changes the voltage supplied while sensing the driving current.

10. In paragraph 9, The above variable power supply unit, A display device that supplies a voltage increased by a first voltage while sensing the above driving current.

11. In paragraph 9, The above sensing TFT is, A display device that is turned on while sensing the above driving current.

12. In paragraph 11, The above sensing TFT is, A display device that is turned on to sense driving current during the blank time between multiple frames of images output from the display.

13. In paragraph 11, The above sensing TFT is, A display device that is turned on to sense driving current while the display is turned on or off.

14. In paragraph 9, The above driving current is, A display device in which the driving current flows from the driving line to the sensing line while sensing the driving current.

15. In paragraph 9, Each of the above plurality of pixel circuits, Further comprising a data line connected to the anode terminal of the LED and receiving a data signal; A display device wherein the sensing line is connected to a first node on the data line.

Images