Backlight device and display apparatus including the same

Abstract

A backlight device and a display apparatus including the same are disclosed. The backlight device includes a substrate and a plurality of light emitters on the substrate. Each of the plurality of light emitters includes a brightness controller disposed on the substrate and a pad unit disposed on the substrate. The brightness controller generates a light emission current, a light emitting diode is allowed to be disposed on the pad unit, and the light emitting diode emits light based on the light emission current.

Description

[0001] This application claims priority to and all benefits derived therefrom of Korean Patent Application No. 10-2019-0088520, filed on July 22, 2019, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0002] One or more embodiments relate to a backlight device and a display device including the backlight device, and more specifically, to a backlight device including a light-emitting diode (“LED”) and a display device including the backlight device. Background Technology

[0003] Display devices, serving as user interfaces, have become indispensable in electronic devices. Flat panel displays are widely used as display devices in electronic devices to make them lighter, thinner, shorter, smaller, and with lower power consumption.

[0004] A liquid crystal display (“LCD”) device is a type of flat panel display device. An LCD device displays images by adjusting the amount of light from an external source. Therefore, an LCD device includes a backlight unit that includes an additional light source (e.g., a backlight lamp) for emitting light onto the liquid crystal panel. Summary of the Invention

[0005] Recently, light-emitting diodes (“LEDs”), with desired characteristics such as low power consumption, environmental friendliness, and slim design, have been widely used as light sources for backlight units. However, light sources including LEDs may struggle to maintain uniformity of brightness and color across the entire area of ​​a display device. Additionally, improvements in instantaneous current control within LEDs are desired.

[0006] One or more embodiments relate to a backlight device with improved brightness uniformity and lifespan.

[0007] One or more embodiments include a backlight device capable of compensating for deviations in the threshold voltage of a driving thin-film transistor.

[0008] One or more embodiments include a display device that includes the backlight device described above.

[0009] According to an embodiment, the backlight device includes a substrate and a plurality of light emitters located on the substrate. In such an embodiment, each of the plurality of light emitters includes a brightness controller disposed on the substrate, a pad unit disposed on the substrate, and a light-emitting diode, wherein the brightness controller generates a light-emitting current, the light-emitting diode is allowed to be disposed on the pad unit, and the light-emitting diode emits light based on the light-emitting current.

[0010] According to an embodiment, the backlight device includes a substrate; a thin-film transistor including a semiconductor layer, a gate electrode, a first connection electrode, and a second connection electrode, wherein the semiconductor layer is disposed on the substrate and has a first region and a second region, the gate electrode at least partially overlaps with the semiconductor layer, the first connection electrode is electrically connected to the first region, and the second connection electrode is electrically connected to the second region; a pad unit including a first pad and a second pad, wherein the second pad is connected to the first connection electrode; a data line disposed on the substrate, wherein the data line transmits a data voltage to the gate electrode; a first power line disposed on the substrate, wherein the first power line transmits a first driving voltage to the first pad; and a second power line disposed on the substrate and connected to the second connection electrode.

[0011] According to an embodiment, the display device includes a backlight unit and a display panel disposed on the backlight unit, wherein a plurality of pixels are disposed in the display panel. In such an embodiment, the backlight unit includes a substrate and a plurality of light emitters disposed on the substrate. In such an embodiment, each of the plurality of light emitters includes a thin-film transistor disposed on the substrate, wherein the thin-film transistor generates a light-emitting current; a pair of pads located on the substrate; and a light-emitting diode disposed on the pair of pads and connected in series with the thin-film transistor, such that the light-emitting diode emits light based on the light-emitting current. Attached Figure Description

[0012] The above and other features of the embodiments of this disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings, wherein:

[0013] Figure 1 This is a schematic block diagram of a backlight device according to an embodiment;

[0014] Figure 2 This is a schematic circuit diagram of a light emitter according to an embodiment;

[0015] Figure 3 This is a schematic cross-sectional view of a light emitter according to an embodiment;

[0016] Figure 4 This is a schematic block diagram of a backlight device according to an alternative embodiment;

[0017] Figure 5 These are schematic block diagrams of a display device according to an embodiment; and

[0018] Figure 6 It is shown in the figure. Figure 5 A schematic cross-sectional view of a portion of the display device. Detailed Implementation

[0019] The invention will now be described more fully below with reference to the accompanying drawings, in which various embodiments are illustrated. However, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure is thorough and complete, and fully conveys the scope of the invention to those skilled in the art. Throughout the specification, the same reference numerals refer to the same elements.

[0020] It should be understood that when an element is referred to as being "on" another element, the element may be directly on the other element, or there may be an intermediate element between them. Conversely, when an element is referred to as being "directly" on another element, there is no intermediate element.

[0021] It should be understood that although the terms “first,” “second,” “third,” etc., may be used herein to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or part from another. Therefore, the “first element,” “component,” “region,” “layer,” or “part” discussed below may be referred to as a second element, component, region, layer, or part without departing from the teachings of this document.

[0022] For ease of illustration, the dimensions of the elements in the accompanying drawings may be enlarged. In other words, this disclosure is not limited thereto because the dimensions and thicknesses of the parts in the drawings are arbitrarily shown for ease of interpretation.

[0023] It should be understood that when a layer, region, or component is referred to as being “connected to” or “coupled to” another layer, region, or component, it can be “directly connected to or coupled to” another layer, region, or component, or it can be “indirectly connected to or coupled to” another layer, region, or component using an intermediate element located between them.

[0024] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a” and “the (described)” are intended to include the plural forms, including “at least one,” unless the context clearly indicates otherwise. “Or” means “and / or.” As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. It should also be understood that the terms “comprising” and variations thereof, or “including” and variations thereof, when used in this specification, specify the presence of stated features, areas, integrals, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, areas, integrals, steps, operations, elements, components, and / or combinations thereof.

[0025] As used herein, the terms "corresponding" or "as opposed to" can mean, depending on the context, arranged in the same column and / or the same row, or connected to the same column and / or the same row. For example, "corresponding" second component among a plurality of second components means that the first component is connected to a second component arranged in the same column and / or the same row as the first component. For example, when a plurality of pixel circuits and a plurality of light-emitting diodes are arranged on a substrate in the row direction and the column direction, respectively, "light-emitting diode connected to corresponding pixel circuit" means that the light-emitting diode is connected to a pixel circuit among the plurality of pixel circuits arranged in the same column and the same row as the light-emitting diode.

[0026] For ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” and “above” may be used herein to describe the relationship between one element or feature and another, as illustrated in the accompanying drawings. It should be understood that, in addition to the orientations depicted in the drawings, spatial relative terms are also intended to cover different orientations of the device in use or operation. For example, if the device in the drawings is flipped, an element described as “below” or “under” other elements or features would then be positioned “above” other elements or features. Thus, the exemplary term “below” can encompass both the above and below orientations. The device may be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relative descriptive terms used herein should be interpreted accordingly.

[0027] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It should also be understood that terms defined, for example, in commonly used dictionaries, shall be interpreted as having the same meaning as they have in the relevant field and in the context of this disclosure, and shall not be interpreted in an ideal or overly formal sense unless expressly defined herein.

[0028] Exemplary embodiments are described herein with reference to cross-sectional views as schematic illustrations of idealized embodiments. Therefore, variations in the shapes illustrated should be anticipated due to factors such as manufacturing techniques and / or tolerances. Consequently, the embodiments described herein should not be construed as limited to the specific shapes of the regions illustrated herein, but should include, for example, deviations in shape due to manufacturing processes. For instance, regions illustrated or described as flat may generally have rough and / or non-linear characteristics. Furthermore, the acute angles illustrated may be rounded. Therefore, the regions illustrated in the figures are schematic in nature, and their shapes are not intended to illustrate the precise shapes of the regions, nor are they intended to limit the scope of the claims.

[0029] In the following, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0030] Figure 1This is a schematic block diagram of a backlight device according to an embodiment.

[0031] refer to Figure 1 An embodiment of the backlight device includes a substrate 110 and a plurality of light emitters (referred to as “EM” in the figures) 120 located on the substrate 110.

[0032] The substrate 110 may be an insulating substrate comprising a transparent glass material or a transparent plastic material, wherein the transparent glass material has silicon oxide (SiO2) as its main component. In an embodiment, the substrate 110 may be a glass substrate or a plastic substrate. In an alternative embodiment, the substrate 110 may be a conductive substrate comprising a thin-film metal material. The substrate 110 may be a flexible substrate or a rigid substrate.

[0033] A buffer layer (not shown) may be disposed or arranged on the substrate 110. In such embodiments, the buffer layer effectively prevents the diffusion of impurity ions from the substrate 110 or the penetration of moisture or external air from the substrate 110, and provides a flat surface for the substrate 110. For example, the buffer layer may comprise an inorganic insulating material such as silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, titanium oxide, or titanium nitride. For example, the buffer layer may comprise an organic insulating material such as polyimide, polyester, or acrylic. Alternatively, the buffer layer may comprise a stack of layers comprising the aforementioned materials, or may comprise a stack comprising layers comprising organic insulating materials and layers comprising inorganic insulating materials.

[0034] The light emitters 120 can be disposed or arranged on the substrate 110. The light emitters 120 can be arranged substantially in a matrix. The light emitters 120 can be arranged in the row direction and column direction with predetermined intervals or preset spaces between them.

[0035] There is no particular limitation on the number of light emitters 120. In one embodiment, for example, thousands of light emitters 120 may be used. In an embodiment, the number of light emitters 120 may be determined such that each of the light emitters 120 can be disposed or arranged on the substrate 110 to illuminate tens to hundreds of pixels when the backlight device provides light to the display panel. Each of the light emitters 120 may include a brightness controller and a pad unit. (See reference...) Figure 2 Detailed description of light emitter 120.

[0036] In this embodiment, multiple data lines DL, multiple first power lines PL1, and multiple second power lines PL2 can be disposed or arranged on the substrate 110. The light emitter 120 can be connected to the data lines DL, the first power lines PL1, and the second power lines PL2, respectively. In one embodiment, for example, the data lines DL, the first power lines PL1, and the second power lines PL2 can be connected to the light emitter 120. The data lines DL, the first power lines PL1, and the second power lines PL2 connected to the light emitter 120 can be referred to as the corresponding data line DL of the light emitter 120 in the data lines DL, the corresponding first power line PL1 of the light emitter 120 in the first power lines PL1, and the corresponding second power line PL2 of the light emitter 120 in the second power lines PL2. In this embodiment, each of the data lines DL, the first power lines PL1, and the second power lines PL2 can correspond one-to-one with the light emitter 120. In such an embodiment, the number of each of the data lines DL, the number of the first power lines PL1, and the number of the second power lines PL2 can be the same as the number of light emitters 120.

[0037] The data line DL can transmit data voltages used to control the brightness of light emitted from the light emitter 120. A first power line PL1 can transmit a first driving voltage to the light emitter 120. A second power line PL2 can transmit a second driving voltage to the light emitter 120. According to an embodiment, the level of the first driving voltage may be higher than the level of the second driving voltage, but is not limited thereto. Alternatively, the level of the second driving voltage may be higher than the level of the first driving voltage. Hereinafter, for ease of description, embodiments in which the level of the first driving voltage is higher than the level of the second driving voltage will be described in detail. In such embodiments, the first driving voltage may be represented, for example, VDD, and the second driving voltage may be represented, for example, VSS.

[0038] According to an embodiment, the backlight device may further include a driver board 130. The driver board 130 may be connected to the substrate 110, outputting a data voltage to the data line DL, and providing a first driving voltage and a second driving voltage to the first power line PL1 and the second power line PL2, respectively. The driver board 130 may be a flexible printed circuit board (“FPCB”). A source integrated circuit (“IC”) chip may be disposed on or mounted on the driver board 130, and the source IC chip may output the data voltage to the data line DL. Power pads and wiring may be disposed on or arranged on the driver board 130, and the power pads receive the first driving voltage and the second driving voltage from the outside, and the wiring connects the power pads to the first power line PL1 and the second power line PL2. A microcontroller or timing controller, etc., may be disposed on or mounted on the driver board 130, and the microcontroller or timing controller is configured to drive the display panel.

[0039] The driver board 130 may be referred to as an external device connected to the substrate 110 to drive the light emitter 120. In one embodiment, for example, the driver board 130 may include a first driver board and a second driver board, with a source IC chip configured to output a data voltage to the data line DL disposed or mounted on the first driver board, and a power supply chip configured to generate a first drive voltage and a second drive voltage disposed or mounted on the second driver board. According to an alternative embodiment, the driver board 130 may include a third driver board, which includes a sensor configured to sense the magnitude of the drive current flowing through each of the light emitters 120.

[0040] Figure 2 This is a schematic circuit diagram of the light emitter 120 according to an embodiment.

[0041] refer to Figure 2 The light emitter 120 may include a brightness controller 121 and a pad unit 122, on which light-emitting diodes (LEDs) are disposed or mounted. A data line DL, a first power line PL1, and a second power line PL2 can be connected to the light emitter 120. Figure 2 One of the light emitters 120 disposed or arranged on the substrate 110 is shown. Other light emitters 120 on the substrate 110 may have the same characteristics as... Figure 2 The circuit configuration of the light emitter 120 shown is basically the same as that of the light emitter 120 shown.

[0042] The brightness controller 121 may include a thin-film transistor (TFT) configured to generate a light-emitting current flowing from the drain electrode DE to the source electrode SE based on a data voltage applied to the gate electrode GE via the data line DL. The TFT can generate a light-emitting current with a magnitude corresponding to the level of the data voltage applied to the gate electrode GE. A larger light-emitting current can be generated when the level of the data voltage applied to the gate electrode GE becomes higher. The light-emitting current can flow from the first power line PL1 to the second power line PL2 via a light-emitting diode (LED).

[0043] A thin-film transistor (TFT) may include a gate electrode GE, a source electrode SE, and a drain electrode DE. The gate electrode GE may be connected to a corresponding data line DL to receive data voltage. In an embodiment, as shown... Figure 2 As shown, the drain electrode DE can be connected to the cathode of the LED. The cathode of the LED can be referred to as the second electrode. The source electrode SE can be connected to the corresponding second power supply line PL2. The anode of the LED can be referred to as the first electrode and connected to the corresponding first power supply line PL1. The drain electrode DE can be referred to as the first connection electrode. The source electrode SE can be referred to as the second connection electrode.

[0044] A light-emitting diode (LED) is connected in series with a thin-film transistor (TFT). The LED emits light in response to the drive current generated by the TFT in the brightness controller 121. In an embodiment, as... Figure 2 As shown, a light-emitting diode (LED) may include multiple LEDs connected in series with each other. Figure 2 An embodiment in which two light-emitting diodes (LEDs) are connected to each other is shown. However, this is merely exemplary. In alternative embodiments, a single LED or three or more LEDs may be connected in series to a thin-film transistor (TFT). An embodiment in which two LEDs are connected in series will be described in detail below. In these embodiments, various modifications can be made to the number of LEDs included in the light emitter 120, taking into account the brightness of the LEDs, the driving capability of the TFT, and the radiation structure of the backlight device.

[0045] The pad unit 122 may include pads on which light-emitting diodes (LEDs) are disposed or mounted. The pad unit 122 may include a pair of pads comprising a first pad and a second pad, wherein the first pad is connected to a first electrode of the LED, and the second pad is connected to a second electrode of the LED. In an embodiment, as... Figure 2 As shown, pad unit 122 may include two pairs of pads, and two light-emitting diodes (LEDs) are respectively disposed on or mounted on the two pairs of pads. Each pad in a pair of pads may be separated from each other to dissipate heat.

[0046] In an embodiment, such as Figure 2 As illustrated, the thin-film transistor (TFT) can be an n-type metal-oxide-semiconductor field-effect transistor (“MOSFET”). However, this is merely exemplary. In alternative embodiments, the TFT can be implemented as a p-type MOSFET. In such embodiments, the level of the second drive voltage can be higher than the level of the first drive voltage. In such embodiments, the connection of the light-emitting diode (LED) can be performed in the reverse manner described above. In such embodiments, the anode of the LED can be connected to the drain electrode DE, and the cathode of the LED can be connected to the first power supply line PL1. In such embodiments, when the level of the data voltage applied to the gate electrode GE is low, the TFT implemented as a p-type MOSFET can generate a large luminous current. The luminous current flows from the source electrode SE through the LED to the drain electrode DE.

[0047] Figure 3 This is a schematic cross-sectional view of the light emitter 120 according to an embodiment.

[0048] refer to Figure 2 and Figure 3 An embodiment of the light emitter 120 includes a brightness controller 121, a light-emitting diode (LED), and a pad (PAD) on which the LED is disposed or mounted.

[0049] The brightness controller 121 may include a substrate 101, a semiconductor layer 102 located on the substrate 101, a gate electrode 104, a first connection electrode 106c, and a second connection electrode 106d. The substrate 101 and... Figure 1 The substrate 110 shown can be the same substrate or different substrates.

[0050] The substrate 101 may be a base substrate on which pad units 122 and a brightness controller 121 including a thin-film transistor (TFT) may be provided or formed by semiconductor processes. A buffer layer may be disposed or stacked on the substrate 101.

[0051] Semiconductor layer 102 includes a source region SR and a drain region DR, both doped with impurities to achieve conductivity. Semiconductor layer 102 includes an active region Act located between the source region SR and the drain region DR. The drain region DR may be referred to as the first region. The source region SR may be referred to as the second region.

[0052] In an embodiment, a polycrystalline silicon layer (not shown) can be formed by depositing a semiconductor material layer (not shown), such as an amorphous silicon layer, on a substrate 101 and then crystallizing the semiconductor material layer. For example, the amorphous silicon can be crystallized using at least one of various methods such as rapid thermal annealing (“RTA”), solid-state crystallization (“SPC”), excimer laser annealing (“ELA”), metal-induced crystallization (“MIC”), metal-induced lateral crystallization (“MILC”), or sequential lateral solidification (“SLS”). The polycrystalline silicon layer formed as described above can be patterned using a photolithography process to form an active pattern. According to an alternative embodiment, the amorphous silicon layer can be patterned and then crystallized to form an active pattern. Selective ion implantation can be performed on the source region SR and the drain region DR to implant impurities. As a result, the source region SR, the active region Act, and the drain region DR can be formed in the active pattern.

[0053] In one embodiment, semiconductor layer 102 may include, but is not limited to, silicon-based elemental semiconductors. In an alternative embodiment, semiconductor layer 102 may include compound semiconductors, such as oxide semiconductors or organic material semiconductors.

[0054] The gate insulating layer 103 may be disposed or arranged on the semiconductor layer 102. The gate insulating layer 103 may include oxides, nitrides, oxynitrides or combinations thereof.

[0055] Gate electrode 104 may be disposed or arranged on gate insulating layer 103, and gate electrode 104 at least partially overlaps with active region Act of semiconductor layer 102. Conductive material layer (not shown) is disposed or stacked on gate insulating layer 103. The conductive material layer may be patterned by photolithography and etching processes to form gate electrode 104. Gate electrode 104 may include, but is not limited to, metals or metal alloys such as molybdenum (Mo), molybdenum tungsten (MoW), or aluminum (Al) alloys. Alternatively, gate electrode 104 may have a stacked structure including Mo / Al / Mo.

[0056] During the process of implanting impurities into the source region SR and the drain region DR, the gate electrode 104 can be used as a mask. The active region Act is the semiconductor layer 102 located between the source region SR and the drain region DR. The active region Act can be defined as the portion overlapping with the gate electrode 104.

[0057] Interlayer insulating layer 105 may be disposed or arranged on gate electrode 104. Contact holes may be defined in gate insulating layer 103 and interlayer insulating layer 105, wherein the contact holes expose source region SR and drain region DR of semiconductor layer 102, respectively.

[0058] The electrode material layer can be disposed or stacked on the interlayer insulating layer 105. The electrode material layer may include metals such as Mo, chromium (Cr), tungsten (W), aluminum-neodymium (Al-Nd), titanium (Ti), MoW, or Al.

[0059] The electrode material layer can be patterned into a first wiring 106a, a second wiring 106b, a first connecting electrode 106c, and a second connecting electrode 106d. The first connecting electrode 106c and the second connecting electrode 106d can be connected to the drain region DR and the source region SR, respectively, via contact holes in the gate insulating layer 103 and the interlayer insulating layer 105.

[0060] One end of the first wiring 106a and one end of the second wiring 106b can form a pair of pads on which a light-emitting diode (LED) can be disposed or mounted. This end of the first wiring 106a can be referred to as the first pad. This end of the second wiring 106b can be referred to as the second pad. The other end of the second wiring 106b and one end of the first connecting electrode 106c can also form a pair of pads on which an LED can be disposed or mounted. This other end of the second wiring 106b can be referred to as the first pad. This end of the first connecting electrode 106c can be referred to as the second pad. The first connecting electrode 106c can connect the second pad to the drain region DR. The first pad can be connected to the first electrode of the LED, for example, the anode. The second pad can be connected to the second electrode of the LED, for example, the cathode.

[0061] The protective layer 107 may be disposed or arranged on the first wiring 106a, the second wiring 106b, the first connecting electrode 106c, and the second connecting electrode 106d to expose the pads (PADs). The protective layer 107 may be referred to as a planarization layer or a passivation layer. The protective layer 107 may include inorganic insulating materials or organic insulating materials.

[0062] Light-emitting diodes (LEDs) can be individually mounted or mounted on a pair of pads. LEDs can be small LEDs. Although in Figure 3 Not shown in the figure, but the first wiring 106a can be connected to the first power line PL1, and the second connection electrode 106d can be connected to the second power line PL2. The gate electrode 104 can be connected to the data line DL.

[0063] Despite Figure 3 Although not shown in the figure, auxiliary wiring located on the same layer as the gate electrode 104 can be disposed or arranged below the first wiring 106a and the second wiring 106b. The auxiliary wiring can be connected to the first wiring 106a and the second wiring 106b via contact plugs.

[0064] Figure 4 This is a schematic block diagram of a backlight device according to an alternative embodiment.

[0065] refer to Figure 4 An embodiment of the backlight device includes a substrate 110, a light emitter 120 located on the substrate 110, and a driving board 130. For ease of explanation, Figure 4 Only a single light emitter 120 is shown disposed on the substrate 110. However, as Figure 1 As shown, multiple light emitters 120 can be arranged in a matrix on the substrate 110. The light emitters 120 are related to the above reference. Figure 2 and Figure 3 The described light emitter 120 is substantially the same, and any repeated detailed descriptions will be omitted. For ease of explanation, Figure 4 A single data line DL, a single first power line PL1, and a single second power line PL2, all arranged on the substrate 110 and connected to the light emitter 120, are shown. However, as... Figure 1 As shown, multiple data lines DL, multiple first power lines PL1, and multiple second power lines PL2 can be connected to multiple optical transmitters 120.

[0066] The driver board 130 may include a voltage controller 132, a power supply 131, and a sensor 133. The driver board 130 includes a first resistor R1 and a second resistor R2 connected in series between the second power supply line PL2 and the power supply 131. In embodiments where multiple second power supply lines PL2 are provided, the driver board 130 may include multiple first resistors R1 and multiple second resistors R2.

[0067] Power supply 131 can supply a first drive voltage VDD to the first power line PL1 and a second drive voltage VSS to the second power line PL2. Power supply 131 can generate the first drive voltage VDD and the second drive voltage VSS. According to an alternative embodiment, power supply 131 receives the first drive voltage VDD and the second drive voltage VSS from the outside and transmits the first drive voltage VDD and the second drive voltage VSS to the first power line PL1 and the second power line PL2, respectively.

[0068] Voltage controller 132 can output data voltage to each of the data lines DL. Voltage controller 132 can control the brightness of light emitter 120 by controlling the level of the data voltage. According to an embodiment, it may be desirable for some areas of the display panel to display completely black. In such an embodiment, voltage controller 132 can provide a non-emitting data voltage to the light emitter 120 corresponding to the area to be displayed completely black. Therefore, some areas can display completely black without any light leakage.

[0069] The voltage at sensing node Ns between the first resistor R1 and the second resistor R2 can be sensed by sensor 133. A voltage drop is reflected in the voltage at sensing node Ns, and this voltage drop corresponds to a value obtained by multiplying the drive current generated by the thin-film transistor (TFT) by the resistance value of the second resistor R2. Sensor 133 can sense the magnitude of the drive current based on the voltage at sensing node Ns. Sensor 133 can provide information related to the sensed voltage at sensing node Ns or the magnitude of the sensed drive current to voltage controller 132. Voltage controller 132 can adjust the level of the data voltage based on the information related to the voltage at sensing node Ns or the magnitude of the drive current.

[0070] In one embodiment, for example, when voltage controller 132 applies a data voltage (e.g., 5 volts (V)) to light emitter 120, light emitter 120 can be configured to emit light with a brightness of 100. When the magnitude of the drive current sensed by sensor 133 is the magnitude of the current corresponding to brightness 90, voltage controller 132 can increase the magnitude of the data voltage applied to light emitter 120, causing light emitter 120 to emit light with a brightness of 100. Such processing can be performed in real time. In one embodiment, for example, voltage controller 132 can increase or decrease the data voltage until the magnitude of the drive current sensed by sensor 133 becomes the magnitude of the current corresponding to the target brightness. Voltage controller 132 can be implemented as a source IC with multiple channels, such that multiple data voltages are output to multiple data lines DL.

[0071] Thin-film transistors (TFTs) may have different threshold voltages due to manufacturing tolerances, for example. Furthermore, the magnitude of the threshold voltage can vary over time due to degradation. According to an embodiment, the magnitude of the drive current generated by the TFT can be sensed, and the data voltage can be adjusted based on the sensed magnitude of the drive current. Therefore, the light emitter 120 can emit light with precise brightness. In such an embodiment, the resistance values ​​of the second resistors R2 can be identical.

[0072] The resistance values ​​of the first resistor R1 can be different from each other. In an embodiment, the lengths of the first power line PL1 and the second power line PL2 can be different from each other depending on the position of the light emitter 120 on the substrate 110. In one embodiment, for example, the lengths of the first power line PL1 and the second power line PL2 connected to the light emitter 120 adjacent to the driver board 130 can be relatively small, such that the sum of the line resistances of the first power line PL1 and the second power line PL2 connected to such a light emitter 120 can be relatively small. In such an embodiment, the lengths of the first power line PL1 and the second power line PL2 connected to the light emitter 120 away from the driver board 130 can be relatively large, such that the sum of the line resistances of the first power line PL1 and the second power line PL2 connected to such a light emitter 120 can be relatively large. The first resistor R1 can have a resistance value for compensating for the sum of the line resistances of the first power line PL1 and the second power line PL2.

[0073] In one embodiment, the resistance value of the first resistor R1 can be designed such that the sum of the resistance values ​​of the first power line PL1, the second power line PL2, and the first resistor R1 is constant for light emitters 120 at different locations. Therefore, the voltage at the sensing node Ns sensed by the sensor 133 can accurately reflect the drive current flowing through all light emitters 120. According to an alternative embodiment, the sum of the lengths of the first power line PL1 and the second power line PL2 for light emitters 120 at different locations can be designed to be constant, such that the resistance values ​​of the first power line PL1 and the second power line PL2 are constant. In such an embodiment, at least one of the first power line PL1 and the second power line PL2 can have a zigzag shape to increase the resistance value.

[0074] Figure 4An embodiment is shown in which the power supply 131, voltage controller 132, and sensor 133 are disposed on or mounted on a driver board 130 or included in a driver board 130. However, this is merely exemplary. In alternative embodiments, the voltage controller 132 may be disposed on or mounted on the driver board 130, while the sensor 133 and a power generator configured to generate a first drive voltage VDD and a second drive voltage VSS may be disposed on or mounted on a driver board configured to drive a display panel. In embodiments, the driver board constituting the backlight device and the driver board configured to drive the display panel may be integrated into a single driver board.

[0075] Figure 5 This is a schematic block diagram of a display device 1000 according to an embodiment.

[0076] refer to Figure 5 An embodiment of the display device 1000 includes a backlight unit 100 and a display panel 200. The display panel 200 is disposed or arranged on the backlight unit 100. Multiple pixels may be disposed or arranged in the display panel 200.

[0077] Backlight unit 100 can correspond to Figures 1 to 4 The backlight device. The backlight unit 100 includes a substrate and a plurality of light emitters located on the substrate.

[0078] Each of the light emitters is disposed or arranged on a substrate. Each of the light emitters includes a thin-film transistor, a pair of pads located on the substrate, and a light emitter. In such an embodiment, the thin-film transistor generates a light-emitting current, and the light emitter is disposed or mounted on the pair of pads and connected in series with the thin-film transistor, thereby emitting light in response to the light-emitting current.

[0079] When light is emitted from the light emitter of the backlight unit 100 toward the display panel 200 and the transmittance of the pixels is adjusted based on the received image data, the display panel 200 can display an image. The display panel 200 may be a liquid crystal display panel including a liquid crystal layer.

[0080] The controller 300 can drive the backlight unit 100 and the display panel 200. The controller 300 may include, for example: Figure 4 The voltage controller 132 and sensor 133 are shown. Controller 300 may include a timing controller (not shown), a scan driver, and a data driver, and the timing controller drives the display panel 200. Controller 300 may further include... Figure 4 Power supply 131.

[0081] Figure 6 It is shown in the figure. Figure 5 A schematic cross-sectional view of a portion of the display device 1000.

[0082] refer to Figure 5 and Figure 6 An embodiment of the display device 1000 includes a backlight unit 100 and a display panel 200, wherein the display panel 200 is a liquid crystal display panel located on the backlight unit 100. In an embodiment, the display device 1000 may include a color filter (not shown) disposed or arranged between the backlight unit 100 and the liquid crystal display panel 200 or disposed or arranged on the liquid crystal display panel 200.

[0083] The backlight unit 100 provides light L for displaying images on the liquid crystal display panel 200. The backlight unit 100 includes a substrate 110 and a plurality of light emitters 120 located on the substrate 110. Each light emitter 120 includes a light-emitting diode (LED), a pad unit 122, and a brightness controller 121. In such an embodiment, the LED emits light L, the LED is disposed on or mounted on the pad unit 122, and the brightness controller 121 controls the brightness of the LED.

[0084] The liquid crystal display panel 200 includes a lower substrate 210, a pixel circuit 220 located on the lower substrate 210, a pixel electrode 230, a liquid crystal layer 240, and a common electrode 250. The pixel circuit 220 includes first to third pixels PX1, PX2, and PX3. Each of the first to third pixels PX1, PX2, and PX3 controls the pixel electrode 230 that is set or arranged thereon.

[0085] The lower substrate 210 may comprise glass or a transparent plastic material. A lower polarizer (not shown) may be disposed or arranged on the lower surface of the lower substrate 210, and the lower polarizer transmits only light of a specific polarization emitted from the backlight unit 100. In one embodiment, for example, the lower polarizer may be a polarizer configured to transmit linearly polarized light in a first direction.

[0086] The pixel circuit 220 may include a plurality of thin-film transistors (not shown) and gate lines and data lines configured to apply gate signals and data signals to the plurality of thin-film transistors, respectively.

[0087] Pixel electrode 230 can be connected to the source or drain electrode of the thin-film transistor in pixel circuit 220 to receive data voltage.

[0088] A common electrode 250 may be disposed or arranged on the liquid crystal layer 240. An upper polarizer (not shown) may be disposed or arranged on the common electrode 250. The upper polarizer may be a polarizer configured to transmit linearly polarized light in a second direction, the linearly polarized light in the second direction being perpendicular to the linearly polarized light in the first direction transmitted by the lower polarizer. However, this is merely exemplary. Alternatively, both the upper and lower polarizers may be configured to transmit light of the same polarization.

[0089] A liquid crystal layer 240 is disposed or arranged between a pixel electrode 230 and a common electrode 250. In an embodiment, the alignment of liquid crystal molecules in the liquid crystal layer 240 is adjusted based on a voltage applied between the pixel electrode 230 and the common electrode 250. In such an embodiment, the region of the liquid crystal layer 240 between the pixel electrode 230 and the common electrode 250 is controlled, based on the voltage applied between the pixel electrode 230 and the common electrode 250, to either a conduction mode in which the polarization of incident light changes or a cutoff mode in which the polarization of incident light does not change. In an embodiment, the degree of change in the polarization of incident light is adjusted so that intermediate gray levels can be represented.

[0090] When light L, controlled by the liquid crystal layer 240 on the first pixel PX1, passes through the first color filter layer, light L is displayed as light of a first color (e.g., red). When light L, controlled by the liquid crystal layer 240 on the second pixel PX2, passes through the second color filter layer, light L is displayed as light of a second color (e.g., green). When light L, controlled by the liquid crystal layer 240 on the third pixel PX3, passes through the third color filter layer, light L is displayed as light of a third color (e.g., blue).

[0091] When light L emitted from the backlight unit 100 is provided to the liquid crystal display panel 200, the light L passing through the liquid crystal display panel 200 can be selectively transmitted or blocked in each pixel area based on image information, thereby selectively incident on the color filter. The color filter selectively transmits only some colors of the light L passing through the liquid crystal display panel 200 according to pixels PX1, PX2, or PX3, enabling the display of color images.

[0092] According to an embodiment, pads and thin-film transistors are directly disposed or arranged on a glass substrate, light-emitting diodes (LEDs) can be disposed or mounted on the pads, and the thin-film transistors can control the brightness of the LEDs. Therefore, manufacturing costs can be reduced, and product reliability and lifespan can be improved. Deviations in voltage drop due to differences in wiring length and deviations in the threshold voltage of the thin-film transistors can be effectively compensated. Therefore, the brightness uniformity of the backlight device can be improved. According to an embodiment, a display device including a backlight unit in which brightness uniformity is improved can improve display quality.

[0093] It should be understood that the embodiments described herein are to be considered in a descriptive sense only and not for limiting purposes. The description of features or aspects in each embodiment should generally be considered applicable to other similar features or aspects in other embodiments. Although one or more embodiments have been described with reference to the accompanying drawings, those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope defined by the appended claims.

Claims

1. A backlight device, comprising: substrate; Data lines are located on the substrate; The first power line is located on the substrate; The second power line is located on the substrate; A thin-film transistor is disposed on the substrate, wherein a light-emitting current having a magnitude corresponding to the level of the data voltage applied to the gate electrode of the thin-film transistor via the data line flows between the first power line and the second power line; At least one light-emitting element is disposed on the substrate, connected between the first power line and the thin-film transistor, and emits light based on the light-emitting current; as well as The driver board is connected to the substrate. The drive board includes: The power supply outputs a drive voltage between a first pin connected to the first power line and a second pin connected to the second power line; The first resistor and the second resistor are connected in series between the second power line and the second pin; The sensing unit senses the sensing voltage across the second resistor; and A voltage controller adjusts the level of the data voltage based on the sensed voltage and outputs the data voltage to the data line.

2. The backlight device according to claim 1, The thin-film transistor includes: A semiconductor layer disposed on the substrate; The gate electrode that at least partially overlaps with the semiconductor layer; A first connection electrode connected to the first power line via the at least one light-emitting element; and The second connection electrode is connected to the second power line.

3. The backlight device according to claim 1, further comprising a first pad and a second pad, wherein the at least one light-emitting element is surface-mounted on the first pad and the second pad.

4. The backlight device according to claim 1, wherein, As the lengths of the first and second power lines increase, the first resistor has a smaller resistance value.

5. The backlight device according to claim 1, wherein, The power supply outputs a first driving voltage to the first power line and a second driving voltage to the second power line.

6. The backlight device according to claim 1, wherein, The at least one light-emitting element includes a plurality of light-emitting elements, and the plurality of light-emitting elements are connected in series between the first power line and the second power line.

7. The backlight device according to claim 6, further comprising a plurality of pads, wherein the plurality of light-emitting elements are surface-mounted on the plurality of pads.

8. A display device, comprising: A backlight unit includes: a substrate; data lines located on the substrate; a first power line and a second power line located on the substrate; a thin-film transistor disposed on the substrate, wherein a light-emitting current having a magnitude corresponding to the level of a data voltage applied to the gate electrode of the thin-film transistor via the data lines flows between the first power line and the second power line; and at least one light-emitting element disposed on the substrate, connected between the first power line and the thin-film transistor, and emitting light based on the light-emitting current. A display panel disposed on the backlight unit, wherein a plurality of pixels are disposed in the display panel; and The driver board is connected to the backlight unit. The drive board includes: The power supply outputs a drive voltage between a first pin connected to the first power line and a second pin connected to the second power line; The first resistor and the second resistor are connected in series between the second power line and the second pin; The sensing unit senses the sensing voltage across the second resistor; and A voltage controller adjusts the level of the data voltage based on the sensed voltage and outputs the data voltage to the data line.

9. The display device according to claim 8, further comprising a first pad and a second pad, wherein the at least one light-emitting element is surface-mounted on the first pad and the second pad.

10. The display device according to claim 8, wherein, The backlight unit includes a plurality of light emitters arranged on the substrate, and each of the plurality of light emitters includes the thin-film transistor and the at least one light-emitting element.

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