Miniature LED display device

Abstract

Disclosed is a micro LED display device configured to prevent undesired light emission under all driving conditions regardless of a short circuit between a cathode electrode and an anode electrode of a micro LED. The micro LED display device includes: a display panel including a plurality of pixel circuits for driving a plurality of micro LEDs and a micro driver for controlling an operation of each of the plurality of pixel circuits; and a power management circuit configured to manage a level of the bias voltage such that a gap voltage, which is a difference between a negative voltage for selectively driving one of the plurality of micro-LEDs and the bias voltage, is maintained at a value lower than a threshold voltage of each of the plurality of micro-LEDs.

Description

Technical Field

[0001] The present disclosure relates to a micro LED display device. Background Art

[0002] As modern society gradually develops into an information society, the demand for home appliances and various portable electronic devices is increasing. Under this trend, the demand for lightweight and thin display devices is also increasing.

[0003] These display devices are implemented in various forms such as a liquid crystal display (LCD), an organic light emitting display (OLED), and a micro LED display (Micro Light-emitting Diode: Micro LED).

[0004] Among these display devices, organic light emitting displays and micro LED displays employ self-luminous elements and do not require a separate light source such as a backlight used in a liquid crystal display, and thus can be made thinner or used as a display device in various forms. Summary of the Invention

[0005] Micro LED display devices have very high internal quantum efficiency and display high-brightness images while consuming low power. Under this trend, the development of micro LED display devices has been actively carried out recently.

[0006] However, in the case where a micro-LED constituting a pixel is missing due to a process problem, a short circuit may occur between the cathode electrode and the anode electrode, thereby causing other undesirable micro-LEDs to emit abnormal light.

[0007] Therefore, an object of the present disclosure is to provide a micro LED display device that can prevent unwanted light emission under all driving conditions regardless of a short circuit between a cathode electrode and an anode electrode of a micro LED.

[0008] In addition, an object of the present disclosure is to provide a micro-LED display device that can prevent unwanted light emission by controlling a gap voltage, which is a difference between a negative voltage and a bias voltage of one of a plurality of micro-LEDs in a pixel circuit for selectively driving a micro-LED display panel, to a value maintained below a threshold voltage of the micro-LED.

[0009] Furthermore, an object of the present disclosure is to provide a micro LED display device, wherein a gap voltage, which is the difference between a negative voltage and a bias voltage, remains constant even in the presence of a short circuit between a cathode electrode and an anode electrode of a micro LED display panel, thereby preventing undesirable vertical line emission under all driving conditions.

[0010] The objects according to the present disclosure are not limited to the above objects. Other objects and advantages not mentioned according to the present disclosure can be understood based on the following description and can be more clearly understood based on the embodiments according to the present invention. In addition, it will be easily understood that the objects and advantages according to the present disclosure can be achieved using the devices shown in the claims or their combinations.

[0011] One aspect of the present disclosure provides a micro-LED (light-emitting diode) display device, comprising: a display panel including a plurality of pixel circuits for driving a plurality of micro-LEDs and a micro-driver for controlling the operation of each of the plurality of pixel circuits; and a power management circuit configured to manage the level of a bias voltage so that a gap voltage, which is a difference between a negative voltage for selectively driving one of the plurality of micro-LEDs and the bias voltage, is maintained at a value lower than a threshold voltage of each of the plurality of micro-LEDs.

[0012] Another aspect of the present disclosure provides a micro-LED display device, comprising: a display panel, the display panel including: a plurality of pixel circuits for driving a plurality of micro-LEDs; and a micro-driver for controlling the operation of each of the plurality of pixel circuits, wherein the display panel includes: first to sixteenth rows of cathode electrodes, which extend in the row direction of the display panel and are arranged so as to be spaced apart from each other by a predefined interval in the column direction; and a micro-driver disposed between the column direction arrangement of the first to eighth rows of cathode electrodes and the column direction arrangement of the ninth to sixteenth rows of cathode electrodes.

[0013] Another aspect of the present disclosure provides a micro-LED display device, comprising: a display panel, the display panel including: a plurality of pixel circuits for driving a plurality of micro-LEDs; and a micro-driver for controlling the operation of each of the plurality of pixel circuits, wherein each of the plurality of pixel circuits includes: a driving transistor configured to supply a power supply voltage in response to a gate driving voltage; a first transistor configured to form a current path together with the driving transistor in response to a light emitting signal; first to eighth micro-LEDs, each micro-LED having an anode electrode connected to the first transistor; and a switching circuit configured to selectively connect each of the cathode electrodes of the first to eighth micro-LEDs to a power line for a negative voltage or a bias voltage.

[0014] According to an embodiment of the present disclosure, unwanted light emission can be prevented by controlling a gap voltage, which is a difference between a negative voltage for selectively driving one of a plurality of micro LEDs in a pixel circuit and a bias voltage, to be maintained at a value lower than a threshold voltage of the micro LED.

[0015] Furthermore, even in the event of a short circuit between cathode and anode electrodes of the micro LED display panel, the gap voltage, which is the difference between the negative voltage and the bias voltage, remains constant, thereby preventing undesirable vertical line emission under all driving conditions.

[0016] Furthermore, power consumption may be reduced due to the low-power operation of the micro-LEDs.

[0017] The effects of the present disclosure are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic block diagram of a micro LED display device according to some embodiments of the present disclosure.

[0019] Figure 2 is a block diagram of a micro LED display panel according to some embodiments of the present disclosure.

[0020] Figure 3 is a pixel circuit diagram of a micro LED display device according to some embodiments of the present disclosure.

[0021] Figure 4 is a schematic cross-sectional view of a micro LED display panel according to some embodiments of the present disclosure.

[0022] Figure 5is a diagram illustrating a short circuit occurring between an anode electrode and a cathode electrode in a micro LED display panel according to some embodiments of the present disclosure.

[0023] Figure 6 is a circuit diagram illustrating the operation of a pixel circuit of a micro LED display device according to some embodiments of the present disclosure.

[0024] Figure 7 and Figure 8 is a circuit diagram illustrating operation in the absence of micro-LEDs in pixel circuits according to some embodiments of the present disclosure.

[0025] Figure 9 is a block diagram of a power management circuit in a micro LED display device according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0026] The advantages and features of the present disclosure and the methods for achieving the advantages and features will be described with reference to the following and accompanying drawings. Figure 1 The embodiments described in detail below will become apparent. However, the present disclosure is not limited to the embodiments disclosed below, but can be implemented in a variety of different forms. Therefore, these embodiments are set forth only to make the present disclosure complete and to fully inform those skilled in the art of the present disclosure of the scope of the present disclosure, and the present disclosure is limited only by the scope of the claims.

[0027] For the sake of brevity and clarity of explanation, the elements in the accompanying drawings are not necessarily drawn to scale. The same reference numerals in different figures represent the same or similar elements and therefore perform similar functions. In addition, for the sake of brevity of description, descriptions and details of well-known steps and elements are omitted. In addition, in the following detailed description of the present disclosure, many specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be understood that the present disclosure can be practiced without these specific details. In other cases, well-known methods, processes, components and circuits are not described in detail to avoid unnecessarily blurring the various aspects of the present disclosure. Examples of various embodiments are further shown and described below. It will be understood that the description herein is not intended to limit the claims to the specific embodiments described. On the contrary, it is intended to cover alternatives, modifications and equivalents that may be included in the spirit and scope of the present disclosure as defined by the appended claims.

[0028] The shapes, sizes, ratios, angles, numbers, and the like disclosed in the drawings for explaining the embodiments of the present disclosure are illustrative, and the present disclosure is not limited thereto.

[0029] The terms used herein are only intended to describe the purpose of a particular embodiment and are not intended to limit the present disclosure. As used herein, the singular "one" and "an" are intended to also include plural forms, unless the context clearly indicates otherwise. It will also be understood that when used in this specification, the terms "comprise," "have," "contain," and "with" specify the presence of stated features, integers, operations, elements, and / or parts, but do not exclude the presence or addition of one or more other features, integers, operations, elements, parts, and / or parts thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0030] Expressions such as "at least one" when preceding a list of elements may modify the entire list of elements and may not modify the individual elements in the list. When interpreting numerical values, errors or tolerances may occur even if they are not explicitly stated.

[0031] In addition, it will be understood that when a first element or layer is referred to as being "on" a second element or layer, the first element can be directly disposed on the second element, or can be indirectly disposed on the second element with a third element or layer disposed between the first and second elements or layers. It will be understood that when a first element or layer is referred to as being "connected to" or "coupled to" a second element or layer, the first element can be directly connected to or coupled to the second element or layer, or one or more intervening elements or layers can be present therebetween. In addition, it will be understood that when an element or layer is referred to as being "between" two elements or layers, it can be the only element or layer between the two elements or layers, or one or more intervening elements or layers can be present therebetween.

[0032] In descriptions of temporal relationships, such as temporal precedence relationships between two events, such as "after," "subsequently," "before," etc., unless "directly after," "directly after," or "directly before" is indicated, other events may occur in between.

[0033] When a certain embodiment can be implemented differently, the functions or operations specified in a specific block may occur in an order different from the order specified in the flow chart. For example, two consecutive blocks can actually be executed substantially simultaneously, or the two blocks can be executed in reverse order according to the functions or operations involved.

[0034] It will be understood that although the terms "first," "second," and "third," etc., may be used herein to describe various elements, components, regions, layers, and / or time periods, these elements, components, regions, layers, and / or time periods should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or portion from another element, component, region, layer, or portion. Thus, a first element, component, region, layer, or portion described below may be referred to as a second element, component, region, layer, or portion without departing from the spirit and scope of the present disclosure.

[0035] In the case where the embodiment can be realized differently, the function or operation specified in a specific block can be performed in an order different from the order specified in the flow chart. For example, two consecutive blocks can actually be performed substantially simultaneously, or these blocks can be performed in reverse order according to the relevant function or operation.

[0036] The features of the various embodiments of the present disclosure may be partially or completely combined with each other, and may be technically associated with each other or operate with each other. These embodiments may be implemented independently of each other, and may be implemented together in an associated relationship.

[0037] When interpreting numerical values, unless expressly stated otherwise, the values ​​are interpreted as including the error range.

[0038] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention pertains. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and will not be interpreted as having an idealized or overly formal meaning unless expressly defined herein.

[0039] As used herein, "embodiment," "example," "aspect," etc. should not be construed as precluding any aspect or design described as preferred or advantageous over other aspects or designs.

[0040] Furthermore, the term "or" is intended to mean an inclusive or, not an exclusive or. That is, unless specified otherwise or clear from context, the statement "x employs a or b" is intended to mean any of the natural inclusive permutations.

[0041] The terms used in the description set forth below have been selected to be general and common in the relevant technical fields. However, other terms may exist in accordance with the development and / or changes in technology, conventions, preferences of technicians, etc. Therefore, the terms used in the description set forth below should not be understood as limiting the technical concept, but should be understood as examples of terms used to illustrate the embodiments.

[0042] In addition, it will be understood that when a first element or layer is referred to as being "on" a second element or layer, the first element can be directly disposed on the second element, or can be indirectly disposed on the second element with a third element or layer disposed between the first and second elements or layers. It will be understood that when an element or layer is referred to as being "connected to" or "coupled to" another element or layer, it can be directly connected to or coupled to the other element or layer, or one or more intervening elements or layers can be present therebetween. In addition, it will be understood that when an element or layer is referred to as being "between" two elements or layers, it can be the only element or layer between the two elements or layers, or one or more intervening elements or layers can also be present.

[0043] Furthermore, as used herein, when a layer, film, region, plate, etc. is disposed “on” or “on top of” another layer, film, region, plate, etc., the former may be in direct contact with the latter, or another layer, film, region, plate, etc. may be disposed between the former and the latter. As used herein, when a layer, film, region, plate, etc. is disposed directly “on” or “on top of” another layer, film, region, plate, etc., the former is in direct contact with the latter, and no other layer, film, region, plate, etc. is disposed between the former and the latter. Furthermore, as used herein, when a layer, film, region, plate, etc. is disposed “below” or “beneath” another layer, film, region, plate, etc., the former may be in direct contact with the latter, or another layer, film, region, plate, etc. may be disposed between the former and the latter. As used herein, when a layer, film, region, plate, etc. is disposed directly “below” or “beneath” another layer, film, region, plate, etc., the former is in direct contact with the latter, and no other layer, film, region, plate, etc. is disposed between the former and the latter.

[0044] In addition, in specific cases, the terms may be arbitrarily selected by the applicant, and in this case, their detailed meanings will be described in the corresponding description period. Therefore, the terms used in the description as set forth below should not be simply understood based on the names of the terms, but should be understood based on the meanings of the terms and the content of the entire detailed description.

[0045] In the description of signal flow, for example, when a signal is delivered from node A to node B, this may include a case where the signal is transmitted from node A to node B via another node unless the phrase "immediately transmitted" or "directly transmitted" is used.

[0046] Throughout this disclosure, unless stated otherwise, "A and / or B" means A, B, or A and B, and "C to D" means C (inclusive) to D (inclusive) unless stated otherwise.

[0047] Hereinafter, a display device according to each embodiment of the present disclosure is described with reference to the accompanying drawings. When describing an embodiment, descriptions of components in the corresponding embodiment that are the same as or similar to those in the previous embodiment will be omitted.

[0048] Hereinafter, a micro LED display device according to some embodiments will be described.

[0049] Figure 1 is a schematic block diagram of a micro LED display device according to some embodiments of the present disclosure.

[0050] The micro LED display device may include a display panel 100 including a micro driver 120 , a power management circuit 200 , and a timing controller 300 .

[0051] The display panel 100 may include a plurality of pixel circuits 110 and a micro driver 120 for driving the plurality of pixel circuits 100. The plurality of pixel circuits 110 may receive voltages from the power management circuit 200, such as a power supply voltage VDD, a gate driving voltage Vg, a negative voltage VNEG, a bias voltage VBIAS, and other signals.

[0052] In this regard, the power supply voltage VDD, the gate driving voltage Vg, the negative voltage VNEG, and the bias voltage VBIAS can be used to drive a plurality of micro LEDs provided in the pixel circuit 110. In particular, the negative voltage VNEG and the bias voltage VBIAS can be used to selectively drive one of the plurality of micro LEDs.

[0053] Micro-LEDs can refer to LEDs with a side dimension of 100 μm or less. This size corresponds to approximately 1 / 10 or less the size of a typical LED. Micro-LEDs are known to have approximately 20% higher energy efficiency than typical LEDs, and due to their small size, they also have the advantages of low heat generation and low power consumption.

[0054] The power management circuit 200 may generate voltages, such as a power supply voltage VDD, a gate drive voltage Vg, a negative voltage VNEG, a bias voltage VBIAS, and the like, and may provide them to the micro driver 120 and at least one of the plurality of pixel circuits 110 of the display panel 100. For example, the power supply voltage VDD, the gate drive voltage Vg, the negative voltage VNEG, and the bias voltage VBIAS may be applied from the power management circuit 200 to each micro driver 120 via separate power lines. The power management circuit 200 may be provided on a flexible printed circuit board (FPCB) 21.

[0055] In this regard, the power management circuit 200 can manage the potential of the gap voltage, which is the difference between the negative voltage VNEG and the bias voltage VBIAS, to be maintained at a constant value lower than the threshold voltage of the micro LED. The power management circuit 200 can provide the negative voltage VNEG to the display panel 100 and generate the bias voltage VBIAS using the negative feedback voltage VNEG_FB fed back from the display panel 100 and a preset gap voltage.

[0056] The timing controller 300 may receive image data from a host system (not shown) and may receive timing signals such as a vertical synchronization signal, a horizontal synchronization signal, a data enable signal, and a master clock. The timing controller 300 may convert the image data so that it has a format suitable for the size and resolution of the display panel 100 and provide the converted data to the micro driver 120. The timing controller 300 may be provided on a film 31 that connects the FPCB 21 and the display panel 100 to each other.

[0057] Figure 2 is a block diagram of a micro LED display panel according to some embodiments of the present disclosure.

[0058] Reference Figure 2 , the display panel 100 may include first to sixteenth rows of cathode electrodes Row1 to Row16 , a micro driver 120 , and a plurality of pixel circuits 110 .

[0059] The first to sixteenth row cathode electrodes (first to 16th row cathode electrodes) Row1 to Row16 are cathode electrodes CE of the micro LEDs and can extend in the X-axis direction of the display panel 100 and be arranged to be spaced apart from each other at predetermined intervals in the Y-axis direction. A plurality of pixel circuits 110 can be provided on each of the first to sixteenth row cathode electrodes Row1 to Row16 and can be arranged to be spaced apart from each other at predetermined intervals in the X-axis direction. As used herein, the X-axis direction can be the row direction, and the Y-axis direction can be the column direction. For example, the first to sixteenth pixel circuits can be provided on each of the first to sixteenth row cathode electrodes Row1 to Row16 and can be arranged in columns.

[0060] The micro driver 120 may be disposed between the column directional arrangement of the first to eighth rows of cathode electrodes Row1 to Row8 and the column directional arrangement of the ninth to sixteenth rows of cathode electrodes Row9 to Row16. That is, in the column direction, the micro driver 120 may be disposed between the first to eighth rows of cathode electrodes Row1 to Row8 and the ninth to sixteenth rows of cathode electrodes Row9 to Row16, as shown in FIG. Figure 2 shown.

[0061] The micro driver 120 may be connected to each of the plurality of pixel circuits 110 via a first anode electrode line AEL1 and a second anode electrode line AEL2. The first anode electrode line AEL1 may be connected to an anode electrode of a micro LED of each of the plurality of pixel circuits 110. The second anode electrode line AEL2 may be connected to an anode electrode of a redundant micro LED of each of the plurality of pixel circuits 110.

[0062] For example, the first to eighth micro LEDs connected to the micro driver 120 via the first anode electrode line AEL1 may be respectively included in the plurality of pixel circuits 110. The first to eighth redundant micro LEDs connected to the micro driver 120 via the second anode electrode line AEL2 may be respectively included in the plurality of pixel circuits 110.

[0063] In the event of a defect in a micro-LED, a redundant micro-LED can operate in place of the micro-LED. Although not shown in the figure, in a pixel region of the display panel 100 where the pixel circuit 110 is provided, not only gate lines, data lines, and thin film transistors for implementing the micro-LED are formed, but also separate redundant gate lines, redundant data lines, and redundant thin film transistors for driving the redundant micro-LED can be formed.

[0064] For example, each of the first to eighth micro LEDs and each of the first to eighth redundant micro LEDs may be individually operated using different thin film transistors driven based on signals input through different paths.

[0065] For example, each micro driver 120 can drive 16×16 pixel circuits 110 . Figure 2 One micro driver 120 is shown. However, this is for ease of explanation. A plurality of micro drivers 120 may be provided and arranged on the display panel 100 , and the 16×16 pixel circuits 110 may be connected to each of the plurality of micro drivers 120 .

[0066] For example, the anode electrodes of the micro-LEDs can share the source pad of one micro-driver 120 in an 8x1 configuration.

[0067] For example, the cathode electrodes of micro-LEDs can share one cathode electrode in a 1x16 configuration.

[0068] For example, only one of the first to eighth rows of cathode electrodes Row1 to Row8 arranged in the column direction and only one of the ninth to sixteenth rows of cathode electrodes Row9 to Row16 arranged in the column direction may be driven at the same time point. A negative voltage VNEG may be applied to the cathode electrodes of the driven rows, and a bias voltage VBIAS may be applied to the cathode electrodes of the non-driven rows.

[0069] In this regard, the bias voltage VBIAS may be set to a voltage higher than the negative voltage VNEG and may play a role in preventing the forward voltage of the micro LED from exceeding the threshold voltage of the micro LED during times other than the light emitting time.

[0070] Figure 3 is a pixel circuit diagram of a micro LED display device according to some embodiments of the present disclosure.

[0071] Reference Figure 3 Each of the plurality of pixel circuits 110 may include a driving transistor DT, a first transistor T1 , first to eighth micro LEDs, and a switching circuit 112 .

[0072] The driving transistor DT is connected to a power voltage line to which a power voltage VDD is applied, and is configured to provide the power voltage VDD to anode electrodes of the first to eighth micro LEDs in response to a gate driving voltage Vg. The driving transistor DT may be implemented as a thin film transistor.

[0073] The first transistor T1 is connected to the drive transistor DT and is disposed between the drive transistor DT and the anode electrodes of the first to eighth micro-LEDs. The first transistor T1 forms a current path together with the drive transistor DT in response to the emission signal EM. The first transistor T1 can be implemented as a thin film transistor and can be formed in the same layer as the drive transistor DT and within the backplane of the display panel 100. In this regard, the pulse width of the emission signal EM can be controlled by the micro driver 120.

[0074] The anode electrodes of the first to eighth micro-LEDs may be commonly connected to the electrode of the first transistor T1. Each of the cathode electrodes of the first to eighth micro-LEDs may be selectively connected to a power line to which a negative voltage VNEG is applied or a power line to which a bias voltage VBIAS is applied via a switch circuit 112. The first to eighth micro-LEDs may be micro-LEDs corresponding to the first to eighth rows Row1 to Row8, respectively.

[0075] The switch circuit 112 includes a first switch SW1 and a second switch SW2 .

[0076] Each of the first switches SW1 connects each of the cathode electrodes of the first to eighth micro-LEDs to a power line to which a bias voltage VBIAS is applied. Each of the second switches SW2 connects each of the cathode electrodes of the first to eighth micro-LEDs to a power line to which a negative voltage VNEG is applied.

[0077] Each of the second switches SW2 of the switching circuit 112 can apply a negative voltage VNEG to the cathode electrode of the micro-LED intended to emit light. Each of the first switches SW1 can apply a bias voltage VBIAS to the cathode electrode of each of the remaining micro-LEDs intended not to emit light. As used herein, "intended to emit light" means designed to emit light, and "intended not to emit light" means designed not to emit light.

[0078] For example, Figure 2 and Figure 3As shown, when the micro-LEDs in the second row Row2 are intended to emit light, the first switch SW1 connected to the micro-LEDs in the second row Row2 is turned off, the second switch SW2 connected to the micro-LEDs in the second row Row2 is turned on, and the first switches SW1 connected to the micro-LEDs in the first row Row1 and the third row Row3 to the eighth row Row8 are turned on, while the second switches SW2 connected to the micro-LEDs in the first row Row1 and the third row Row3 to the eighth row Row8 are turned off. In this way, the negative voltage VNEG is applied to the cathode electrode of the micro-LED intended to emit light, and the bias voltage VBIAS is applied to the cathode electrodes of the remaining micro-LEDs, so that one target micro-LED among the plurality of micro-LEDs emits light.

[0079] For example, the pixel circuit may be composed of one transistor T1 and eight micro-LEDs, wherein the transistor T1 is driven in response to one emission signal EM that controls the emission time of each driving transistor DT. The switching circuit 112 may be designed to apply a negative voltage VNEG or a bias voltage VBIAS to the cathode electrode of the micro-LED depending on whether the micro-LED is emitting light.

[0080] Figure 4 is a schematic cross-sectional view of a micro LED display panel according to some embodiments of the present disclosure.

[0081] The micro driver 120 may be formed on the substrate 11, the insulating layer 12 may be formed on the substrate 11 and the micro driver 120, and the micro LED layers AE, 13, 14, and CE may be formed on the insulating layer 12. The micro LED layers may include an anode electrode AE, a light emitting layer 14, and a cathode electrode CE. A bank layer 13 may be formed between adjacent pixels to prevent optical interference between adjacent micro LEDs.

[0082] Figure 4 A transistor layer in which thin film transistors such as the driving transistor DT and the first transistor T1 are formed may be further formed between the insulating layer 12 and the bank layer 13 .

[0083] Figure 5 is a diagram illustrating a short circuit occurring between an anode electrode and a cathode electrode in a micro LED display panel according to some embodiments of the present disclosure.

[0084] In the event of a missing micro-LED due to a process issue, a short circuit may occur between the anode electrode AE ​​and the cathode electrode CE during the deposition of the cathode electrode CE. The low potential of the bias voltage VBIAS reduces the gap between the negative voltage VNEG and the bias voltage VBIAS. In this case, even if a short circuit path exists between the anode electrode and the cathode electrode, the bias voltage VBIAS applied to the anode electrode by the short circuit does not exceed the threshold voltage of the micro-LED, allowing the micro-LED to operate normally.

[0085] However, the potential of the bias voltage VBIAS is high, making the gap between the negative voltage VNEG and the bias voltage VBIAS large. In this case, the bias voltage VBIAS applied to the anode electrode through the short-circuit path exceeds the threshold voltage of the micro-LED, causing the micro-LED to emit light when its row is selected.

[0086] Since eight micro LEDs share one source pad of a micro driver, micro LEDs emitting abnormally due to a short circuit between the anode and cathode electrodes can be recognized by the naked eye as a vertical line of eight pixels due to the frequency of the rapid emission signal EM and row selection.

[0087] Figure 6 is a circuit diagram illustrating operation in a normal state in which there is no short circuit between an anode electrode and a cathode electrode in a pixel circuit of a micro LED display device according to some embodiments of the present disclosure.

[0088] A negative voltage VNEG is applied to the cathode electrode of the first micro LED to be emitted, and a bias voltage VBIAS is applied to each of the cathode electrodes of the remaining second to eighth micro LEDs, thereby causing the first micro LED among the first to eighth micro LEDs to emit light. Figure 6 In , Vanode represents the anode voltage applied to the micro LED.

[0089] Figure 7 and Figure 8 is a circuit diagram illustrating an operation when a short circuit occurs between an anode electrode and a cathode electrode in a pixel circuit according to some embodiments of the present disclosure.

[0090] in this regard, Figure 7 Operation is shown when the gap voltage corresponding to the difference between the negative voltage VNEG and the bias voltage VBIAS is lower than the threshold voltage Vth of the micro LED.

[0091] For example, Figure 7As shown, when the negative voltage VNEG is -5V, the bias voltage VBIAS is -3.6V, and the threshold voltage Vth of the micro LED is 1.5V, the potential difference between the negative voltage VNEG and the bias voltage VBIAS is 1.4V, which is lower than the threshold voltage Vth of the micro LED of 1.5V, so that the micro LED does not emit light.

[0092] Figure 8 Operation is shown when the gap voltage corresponding to the difference between the negative voltage VNEG and the bias voltage VBIAS is higher than the threshold voltage Vth of the micro LED.

[0093] For example, Figure 8 As shown, when the negative voltage VNEG is -5V, the bias voltage VBIAS is -2.6V, and the threshold voltage Vth of the micro LED is 1.5V, the potential difference between the negative voltage VNEG and the bias voltage VBIAS is 2.4V, which is higher than the threshold voltage Vth of the micro LED of 1.5V, causing the micro LED to emit abnormal light.

[0094] The micro LED display device according to an embodiment of the present disclosure can be configured to manage the potential of the gap voltage, which is the difference between the negative voltage VNEG and the bias voltage VBIAS, to be maintained at a constant value lower than the threshold voltage Vth of the micro LED, thereby preventing undesirable vertical line emission even when there is a short circuit between the cathode electrode and the anode electrode.

[0095] According to some embodiments, the power management circuit 200 may be configured to receive the negative voltage VNEG as feedback and generate the bias voltage VBIAS based on the feedback so that the potential of the gap voltage, which is the difference between the negative voltage VNEG and the bias voltage VBIAS, is maintained at a constant value below the threshold voltage Vth of the micro LED. Figure 9 This is described in more detail.

[0096] Figure 9 is a block diagram of a power management circuit in a micro LED display device according to some embodiments of the present disclosure.

[0097] Reference Figure 9 , the power management circuit 200 may include a first voltage generating circuit 210 and a second voltage generating circuit 220 .

[0098] The first voltage generating circuit 210 may generate a negative voltage VNEG based on the voltage setting signal V_Set and an input voltage input from the external input power source 30. The first voltage generating circuit 210 may include a digital-to-analog converter 212 and a calculation circuit 214.

[0099] The digital-to-analog converter 212 of the first voltage generating circuit 210 may receive a voltage setting signal V_Set for setting the level of the negative voltage VNEG from the external setting unit 40. In this regard, the voltage setting signal V_Set is a digital signal. In addition, the voltage setting signal V_Set may be an internally preset signal.

[0100] The digital-to-analog converter 212 of the first voltage generating circuit 210 may convert the voltage setting signal V_Set into a corresponding set voltage Vset. The calculation circuit 214 of the first voltage generating circuit 210 may perform calculations on the set voltage Vset and the input voltage to generate a negative voltage VNEG.

[0101] The second voltage generating circuit 220 may generate a bias voltage VBIAS based on the gap setting signal Gap_Set and the negative feedback voltage VNEG_FB, and a reference voltage Vref input from the external input power source 30 .

[0102] The second voltage generating circuit 220 may include: a digital-to-analog converter 222 that receives a gap setting signal Gap_Set from an external setting unit 40 and converts the gap setting signal Gap_Set into a gap voltage VGAP; and a calculation circuit 224 that performs calculation on a reference voltage Vref, the gap voltage VGAP, and a negative feedback voltage VNEG_FB to generate a bias voltage VBIAS.

[0103] The gap setting signal Gap_Set may be defined as a digital signal that enables the gap voltage VGAP to be set to a value lower than a threshold voltage of the micro LEDs.

[0104] A power line for transmitting the negative voltage VNEG from the first voltage generating circuit 210 to the display panel 100 and a power line for transmitting the bias voltage VBIAS from the second voltage generating circuit 220 to the display panel 100 may be connected to the electrostatic discharge circuits 230 and 240 , respectively.

[0105] For example, the power management circuit 200 may be configured to receive a negative feedback voltage VNEG_FB with respect to the negative voltage VNEG from the display panel 100 and may feed back the negative feedback voltage VNEG_FB to an input terminal of the second voltage generating circuit 220 configured to generate the bias voltage VBIAS to generate the bias voltage VBIAS.

[0106] For example, the gap setting signal Gap_Set may be set based on the characteristics of the micro-LED display panel and may be transmitted to an input terminal of a second voltage generating circuit 220 configured to generate a bias voltage VBIAS, wherein the bias voltage VBIAS is set such that the gap voltage VGAP is lower than a threshold voltage of the micro-LED. In other words, the potential of the difference between the negative voltage VNEG and the bias voltage VBIAS may be set to a value lower than the threshold voltage of the micro-LED.

[0107] In one example, the second voltage generating circuit 220 may set a level of the bias voltage VBIAS based on the gap setting signal Gap_Set and the negative feedback voltage VNEG_FB, and output the bias voltage VBIAS.

[0108] In one example, the bias voltage VBIAS generated based on the gap setting signal Gap_Set and the negative feedback voltage VNEG_FB can maintain the set gap voltage at the same level regardless of changes in the setting of the negative voltage VNEG or changes in the level of the negative voltage VNEG due to the load of the display panel 100. This enables the display panel 100 to operate in a state where the gap voltage between the negative voltage VNEG and the bias voltage VBIAS is maintained at a value lower than the threshold voltage of the micro LEDs. This can prevent abnormal light emission under all driving conditions.

[0109] In this way, the power management circuit 200 can manage the gap voltage potential, which is the difference between the negative voltage VNEG and the bias voltage VBIAS, to be maintained at a constant value below the threshold voltage of the micro LED, and can generate the bias voltage VBIAS using the negative feedback voltage VNEG_FB fed back from the display panel 100 and the preset gap voltage.

[0110] According to an embodiment of the present disclosure, unwanted light emission can be prevented by controlling a gap voltage, which is a difference between a negative voltage for selectively driving one of a plurality of micro LEDs in a pixel circuit and a bias voltage, to be maintained at a value lower than a micro LED threshold voltage.

[0111] Furthermore, even in the case where a short circuit exists between the cathode electrode and the anode electrode of the micro LED display panel, the gap voltage, which is the difference between the negative voltage and the bias voltage, remains constant, thereby preventing undesired vertical line light emission under all driving conditions.

[0112] Furthermore, power consumption can be reduced due to the low power operation of the micro LEDs.

[0113] A first aspect of the present invention provides a micro-LED (light-emitting diode) display device, comprising: a display panel including a plurality of pixel circuits for driving a plurality of micro-LEDs and a micro-driver for controlling the operation of each of the plurality of pixel circuits; and a power management circuit configured to manage the level of a bias voltage so that a gap voltage, which is a difference between a negative voltage for selectively driving one of the plurality of micro-LEDs and the bias voltage, is maintained at a value lower than a threshold voltage of each of the plurality of micro-LEDs.

[0114] According to some embodiments of the first aspect, the power management circuit is configured to generate a negative voltage and provide the generated negative voltage to the display panel, and is configured to generate a bias voltage based on the negative feedback voltage fed back from the display panel and a gap setting signal corresponding to the gap voltage.

[0115] According to some embodiments of the first aspect, the power management circuit includes: a first voltage generating circuit configured to generate a negative voltage based on a voltage setting signal and an input voltage input from an external input power supply; and a second voltage generating circuit configured to generate a bias voltage based on a gap setting signal, a negative feedback voltage, and a reference voltage input from the external input power supply.

[0116] According to some embodiments of the first aspect, the second voltage generating circuit includes: a digital-to-analog converter configured to receive a gap setting signal from an external setting unit and convert the gap setting signal into a gap voltage; and a calculation circuit configured to perform calculations on a reference voltage, a gap voltage, and a negative feedback voltage to generate a bias voltage.

[0117] According to some embodiments of the first aspect, the display panel includes: first to sixteenth rows of cathode electrodes, which are arranged so as to be spaced apart from each other by a predetermined interval in the column direction, wherein each of the first to sixteenth rows of cathode electrodes extends in the row direction of the display panel; and the microdriver is disposed between the column direction arrangement of the first to eighth rows of cathode electrodes and the column direction arrangement of the ninth to sixteenth rows of cathode electrodes.

[0118] According to some embodiments of the first aspect, a plurality of pixel circuits are provided on each of the first to sixteenth rows of cathode electrodes and are arranged to be spaced apart from each other by a predetermined interval in the row direction.

[0119] According to some embodiments of the first aspect, the micro driver is connected to each pixel circuit of the plurality of pixel circuits via a first anode electrode line and a second anode electrode line.

[0120] According to some embodiments of the first aspect, the plurality of pixel circuits include: first to eighth micro-LEDs respectively connected to the micro-driver via first anode electrode lines; and first to eighth redundant micro-LEDs respectively connected to the micro-driver via second anode electrode lines.

[0121] According to some embodiments of the first aspect, each pixel circuit in the plurality of pixel circuits includes: a driving transistor configured to supply a power supply voltage in response to a gate driving voltage; a first transistor configured to form a current path together with the driving transistor in response to a light emitting signal; first to eighth micro-LEDs, each micro-LED having an anode electrode connected to the first transistor; and a switching circuit configured to selectively connect each of the cathode electrodes of the first to eighth micro-LEDs to a power line of a negative voltage or a bias voltage.

[0122] According to some embodiments of the first aspect, the switching circuit includes: one or more first switches, each of the first switches being configured to connect each of the cathode electrodes of the first to eighth micro-LEDs to a power line of a bias voltage; and one or more second switches, each of the second switches being configured to connect each of the cathode electrodes of the first to eighth micro-LEDs to a power line of a negative voltage.

[0123] According to some embodiments of the first aspect, the switching circuit is configured to apply a negative voltage to the cathode electrode of the micro LED intended to emit light, and apply a bias voltage to the cathode electrode of each of the remaining micro LEDs intended not to emit light.

[0124] A second aspect of the present disclosure provides a micro-LED display device, comprising: a display panel, the display panel including: a plurality of pixel circuits for driving a plurality of micro-LEDs; and a micro-driver for controlling the operation of each of the plurality of pixel circuits, wherein the display panel includes: first to sixteenth rows of cathode electrodes, which extend in the row direction of the display panel and are arranged so as to be spaced apart from each other by a predefined interval in the column direction; and a micro-driver disposed between the column direction arrangement of the first to eighth rows of cathode electrodes and the column direction arrangement of the ninth to sixteenth rows of cathode electrodes.

[0125] According to some embodiments of the second aspect, the micro-LED display device also includes a power management circuit, which is configured to manage the level of the bias voltage so that the gap voltage, which is the difference between the negative voltage for selectively driving one of a plurality of micro-LEDs and the bias voltage, is maintained at a value lower than the threshold voltage of each micro-LED in the micro-LEDs.

[0126] According to some embodiments of the second aspect, the power management circuit is configured to generate a negative voltage and provide the generated negative voltage to the display panel, and is configured to generate a bias voltage based on the negative feedback voltage fed back from the display panel and a gap setting signal corresponding to the gap voltage.

[0127] According to some embodiments of the second aspect, the power management circuit includes: a first voltage generating circuit, which is configured to generate a negative voltage based on a voltage setting signal and an input voltage input from an external input power supply; and a second voltage generating circuit, which is configured to generate a bias voltage based on a gap setting signal, a negative feedback voltage and a reference voltage input from an external input power supply.

[0128] According to some embodiments of the second aspect, the second voltage generating circuit includes: a digital-to-analog converter configured to receive a gap setting signal from an external setting unit and convert the gap setting signal into a gap voltage; and a calculation circuit configured to perform calculations on a reference voltage, a gap voltage, and a negative feedback voltage to generate a bias voltage.

[0129] A third aspect of the present disclosure provides a micro-LED display device, including a display panel, the display panel including: a plurality of pixel circuits for driving a plurality of micro-LEDs; and a micro-driver for controlling the operation of each of the plurality of pixel circuits, wherein each of the plurality of pixel circuits includes: a driving transistor configured to supply a power supply voltage in response to a gate driving voltage; a first transistor configured to form a current path together with the driving transistor in response to a light emitting signal; first to eighth micro-LEDs, each micro-LED having an anode electrode connected to the first transistor; and a switching circuit configured to selectively connect each of the cathode electrodes of the first to eighth micro-LEDs to a power line of a negative voltage or a bias voltage.

[0130] According to some embodiments of the third aspect, the switching circuit is configured to apply a negative voltage to the cathode electrode of the micro-LED intended to emit light, and to apply a bias voltage to the cathode electrode of each of the remaining micro-LEDs intended not to emit light.

[0131] According to some embodiments of the third aspect, the switching circuit includes: one or more first switches, each of the first switches being configured to connect each of the cathode electrodes of the first to eighth micro-LEDs to a power line of a bias voltage; and one or more second switches, each of the second switches being configured to connect each of the cathode electrodes of the first to eighth micro-LEDs to a power line of a negative voltage.

[0132] According to some embodiments of the third aspect, the micro-LED display device also includes a power management circuit, which is configured to manage the level of the bias voltage so that the gap voltage, which is the difference between the negative voltage and the bias voltage, is maintained at a value lower than the threshold voltage of each of the multiple micro-LEDs.

[0133] Although some embodiments of the present disclosure have been described above with reference to the accompanying drawings, the present disclosure may not be limited to these embodiments and may be implemented in various different forms. A person skilled in the art of the present disclosure will understand that the present disclosure may be implemented in other specific forms without changing the technical ideas or essential features of the present disclosure. Therefore, it should be understood that the embodiments described above are not restrictive in all aspects but illustrative.

Claims

1. A micro LED display device comprising: Display panel, including: a plurality of pixel circuits for driving the plurality of micro LEDs; and a micro driver for controlling the operation of each of the plurality of pixel circuits; and A power management circuit is configured to manage a level of a bias voltage so that a gap voltage, which is a difference between a negative voltage for selectively driving one of the plurality of micro-LEDs and the bias voltage, is maintained at a value lower than a threshold voltage of each of the plurality of micro-LEDs.

2. The micro LED display device according to claim 1, wherein: The power management circuit is configured to generate the negative voltage and provide the generated negative voltage to the display panel, and is configured to generate the bias voltage based on a negative feedback voltage fed back from the display panel and a gap setting signal corresponding to the gap voltage.

3. The micro LED display device according to claim 2, wherein: The power management circuit comprises: a first voltage generating circuit configured to generate the negative voltage based on a voltage setting signal and an input voltage input from an external input power source; and A second voltage generating circuit is configured to generate the bias voltage based on the gap setting signal, the negative feedback voltage, and a reference voltage input from the external input power supply.

4. The micro LED display device according to claim 3, wherein: The second voltage generating circuit includes: a digital-to-analog converter configured to receive the gap setting signal from an external setting unit and convert the gap setting signal into the gap voltage; and A calculation circuit is configured to perform calculation on the reference voltage, the gap voltage, and the negative feedback voltage to generate the bias voltage.

5. The micro LED display device according to claim 1, wherein: The negative voltage is applied to the cathode electrode of the micro LED to emit light, the bias voltage is applied to the cathode electrode of the micro LED not to emit light, and the bias voltage is higher than the negative voltage.

6. The micro LED display device according to claim 1, wherein: The display panel includes: first to sixteenth rows of cathode electrodes are arranged so as to be spaced apart from each other by a predetermined interval in a column direction, wherein each of the first to sixteenth rows of cathode electrodes extends in a row direction of the display panel; and The micro-driver is arranged between the first to eighth rows of cathode electrodes arranged in a column direction and the ninth to sixteenth rows of cathode electrodes arranged in a column direction.

7. The micro LED display device according to claim 6, wherein: The plurality of pixel circuits are provided on each of the first to sixteenth rows of cathode electrodes and are arranged so as to be spaced apart from each other by predetermined intervals in a row direction.

8. The micro LED display device according to claim 7, wherein: The micro driver is connected to each of the plurality of pixel circuits via a first anode electrode line and a second anode electrode line.

9. The micro LED display device according to claim 8, wherein: The plurality of pixel circuits include: first to eighth micro-LEDs connected to the micro-driver via the first anode electrode lines, respectively; and The first to eighth redundant micro-LEDs are respectively connected to the micro-driver via the second anode electrode lines.

10. The micro LED display device according to claim 1, wherein: Each pixel circuit of the plurality of pixel circuits comprises: a drive transistor configured to supply a power supply voltage in response to a gate drive voltage; a first transistor configured to form a current path together with the driving transistor in response to a light emitting signal; first to eighth micro-LEDs, each micro-LED having an anode electrode connected to the first transistor; and A switching circuit is configured to selectively connect each of the cathode electrodes of the first to eighth micro-LEDs to a power line for the negative voltage or the bias voltage.

11. The micro LED display device according to claim 10, wherein: The switching circuit comprises: one or more first switches, each of the first switches being configured to connect each of the cathode electrodes of the first to eighth micro-LEDs to a power line for the bias voltage; and One or more second switches, each of the second switches being configured to connect each of the cathode electrodes of the first to eighth micro-LEDs to a power line for the negative voltage.

12. The micro LED display device according to claim 10, wherein: The switching circuit is configured to apply the negative voltage to the cathode electrode of the micro LED to emit light, and to apply the bias voltage to the cathode electrode of each of the remaining micro LEDs that are not to emit light.

13. A micro LED display device comprising: Display panel, including: a plurality of pixel circuits for driving the plurality of micro LEDs; and a micro driver for controlling the operation of each of the plurality of pixel circuits, Wherein, the display panel includes: first to sixteenth rows of cathode electrodes extending in a row direction of the display panel and arranged so as to be spaced apart from each other by a predefined interval in a column direction; and The micro driver is provided between the column direction arrangement of the first to eighth rows of cathode electrodes and the column direction arrangement of the ninth to sixteenth rows of cathode electrodes.

14. The micro LED display device according to claim 13, wherein: The micro-LED display device also includes a power management circuit configured to manage a level of a bias voltage so that a gap voltage, which is a difference between a negative voltage for selectively driving one of the plurality of micro-LEDs and the bias voltage, is maintained at a value lower than a threshold voltage of each of the plurality of micro-LEDs.

15. The micro LED display device according to claim 14, wherein: The negative voltage is applied to the cathode electrode of the micro LED to emit light, the bias voltage is applied to the cathode electrode of the micro LED not to emit light, and the bias voltage is higher than the negative voltage.

16. The micro LED display device according to claim 15, wherein: The power management circuit is configured to generate the negative voltage and provide the generated negative voltage to the display panel, and is configured to generate the bias voltage based on a negative feedback voltage fed back from the display panel and a gap setting signal corresponding to the gap voltage.

17. The micro LED display device according to claim 16, wherein: The power management circuit comprises: a first voltage generating circuit configured to generate the negative voltage based on a voltage setting signal and an input voltage input from an external input power source; and A second voltage generating circuit is configured to generate the bias voltage based on the gap setting signal, the negative feedback voltage, and a reference voltage input from the external input power supply.

18. The micro LED display device according to claim 17, wherein: The second voltage generating circuit includes: a digital-to-analog converter configured to receive the gap setting signal from an external setting unit and convert the gap setting signal into the gap voltage; and A calculation circuit is configured to perform calculation on the reference voltage, the gap voltage, and the negative feedback voltage to generate the bias voltage.

19. A micro LED display device comprising: Display panel, including: a plurality of pixel circuits for driving the plurality of micro LEDs; and a micro driver for controlling the operation of each of the plurality of pixel circuits, Wherein, each pixel circuit of the plurality of pixel circuits includes: a drive transistor configured to supply a power supply voltage in response to a gate drive voltage; a first transistor configured to form a current path together with the driving transistor in response to a light emitting signal; first to eighth micro-LEDs, each micro-LED having an anode electrode connected to the first transistor; and A switching circuit is configured to selectively connect each of the cathode electrodes of the first to eighth micro-LEDs to a power line for a negative voltage or a bias voltage.

20. The micro LED display device according to claim 19, wherein: The switching circuit is configured to apply the negative voltage to the cathode electrode of the micro LED to emit light, and to apply the bias voltage to the cathode electrode of each of the remaining micro LEDs that are not to emit light.

21. The micro LED display device according to claim 20, wherein: The switching circuit comprises: one or more first switches, each of the first switches being configured to connect each of the cathode electrodes of the first to eighth micro-LEDs to a power line for the bias voltage; and One or more second switches, each of the second switches being configured to connect each of the cathode electrodes of the first to eighth micro-LEDs to a power line for the negative voltage.

22. The micro LED display device according to claim 19, wherein: The micro LED display device further includes a power management circuit configured to manage a level of the bias voltage so that a gap voltage, which is a difference between the negative voltage and the bias voltage, is maintained at a value lower than a threshold voltage of each of the micro LEDs.

Images