KR102527303B1 - Light emitting diode display - Google Patents

Abstract

A light emitting display device according to an embodiment of the present invention includes a plurality of driving elements on the front surface of a substrate, a plurality of wiring electrodes connected to the plurality of light emitting elements, at least one pad part on the rear surface of the substrate, and a side surface of the substrate. It includes a plurality of routing electrodes electrically connecting the pad part and the wiring electrode through the substrate, and a low-resistance wiring for connecting at least one routing electrode among the plurality of routing electrodes and the pad part on the rear surface of the substrate.

Description

Light emitting display device {LIGHT EMITTING DIODE DISPLAY}

The present invention relates to a light emitting display device, and more particularly, to providing a light emitting display device capable of improving display quality of a multi-display including a plurality of light emitting display devices.

Display devices are widely used as display screens of notebook computers, tablet computers, smart phones, portable display devices, and portable information devices, in addition to display devices of televisions or monitors.

Display devices may be classified into reflective type display devices and emission type display devices. A reflective display device is a display device that displays information by reflecting natural light or light emitted from external lighting on the display device, and a light emitting display device has a light emitting element or a light source built into the display device. A display device that displays information using light emitted from a light emitting element or light source.

The display device includes a plurality of pixels, and each pixel displays an image using a thin film transistor as a switching element.

Representative display devices using thin film transistors include a liquid crystal display and an organic light emitting display. Since the liquid crystal display is not self-emitting, a backlight unit including a separate light source disposed below (rear) the liquid crystal display ( Since it has a backlight unit, the thickness of the display device increases, there are limitations in implementing the display device with various types of designs, and luminance and response speed are degraded.

Accordingly, a self-luminous display device may be implemented thinner than a display device having a built-in light source, and thus, a flexible and foldable display device may be realized.

Due to these advantages, a self-luminous display device such as an organic light emitting display device or an LED device display device has recently become a subject of major research and development.

Among the self-luminous display devices, the organic light emitting display device is a display device made up of pixels including organic light emitting elements. While it does not require a separate light source, defects due to moisture and oxygen are easily generated, so oxygen and moisture penetrate. Various technical configurations to minimize are additionally required.

Recently, research and development of a display device using micro light emitting diodes as a light emitting element, particularly a light emitting display device configured to correspond to a pixel of the display device, has been conducted, and such a light emitting display Since the device has high image quality and high reliability, it is attracting attention as a next-generation display device.

Taking a closer look, LEDs are composed of compound semiconductors such as GaN, so they can inject high currents due to the nature of inorganic materials, so they can implement high brightness, and have low environmental impacts such as heat, moisture, and oxygen, and have high reliability.

In addition, since the LED has an internal quantum efficiency of 90%, which is higher than that of the organic light emitting display device, there is an advantage in implementing a display device capable of displaying a high-brightness image and consuming low power.

In addition, unlike the organic light emitting display device, there is no need for a separate encapsulation film or encapsulation substrate to minimize the permeation of oxygen and moisture, so there is an advantage in that the bezel area, which is a non-display area, can be minimized.

A display device using an LED capable of minimizing a non-display area may be used for a multi-display in which a plurality of display devices are successively formed.

Moreover, it is easy to use as a multi-display because it is possible to minimize the conspicuous phenomenon of junctions between display devices by minimizing the non-display area.

As described above, in the case of a multi-display in which a plurality of display devices are connected, it is important to keep the luminance of each display device constant because afterimages such as waves may be displayed when the luminance of the individual display devices is not constant.

Accordingly, in a light emitting display device using an LED, many research activities are being conducted to minimize sensitive changes in luminance caused by self-resistance of internal electrodes.

As described above, in order to implement a light emitting display device using an LED element as a light emitting element of a unit pixel, several technical details are required. First, an LED element is crystallized on a semiconductor wafer substrate such as sapphire or silicon (Si), and a plurality of crystallized LED chips are moved to a substrate with a driving element, but positioned at a position corresponding to each pixel. An elaborate transfer process for positioning is required.

Although the LED device can be formed using an inorganic material, since an inorganic material such as GaN must be crystallized, the inorganic material must be crystallized on a semiconductor substrate capable of efficiently inducing crystallization of the inorganic material.

The process of crystallizing the LED device is also referred to as epitaxy, epitaxial growth, or epi process. The epitaxial process means growing by taking a specific orientation relationship on the surface of a certain crystal. In order to form the device structure of an LED device, GaN-based compound semiconductors must be stacked in the form of a pn junction diode on a substrate. It grows by inheriting the crystallinity of the layer of

At this time, since the defect inside the crystal acts as a nonradiative center in the electron-hole recombination process, the crystallinity of the crystals forming each layer in the LED device using photon This has a decisive effect on device efficiency.

Currently, the above-described sapphire substrate is mainly used as a substrate, and recently, research activities on substrates based on GaN have been actively conducted.

In this way, due to the high price of semiconductor substrates required for crystallizing inorganic materials such as GaN constituting LED elements on semiconductor substrates, a large amount of LEDs as light emitting pixels of display devices, not LEDs as light sources used for simple lighting or backlighting There is a problem that the manufacturing cost increases when using.

In addition, as described above, the LED element formed on the semiconductor substrate needs a step of transferring to the substrate constituting the display device. In this process, it is difficult to separate the LED element from the semiconductor substrate, and the separated Even when correctly transplanting an LED device to a desired location, there may be many difficulties.

Meanwhile, unlike an organic light emitting display device, a display device using an LED element does not require an encapsulation film or an encapsulation substrate, so the bezel area can be minimized, and a modular type display device using a plurality of display devices is configured. advantageous to do

In implementing a display device using an LED device having the above-mentioned advantages, there is an important technical difficulty in properly aligning the LED device opposing each pixel in the step of transplanting the grown LED device to the substrate of the display device.

Since the interval between pixels in the display device is much wider than the interval between LED devices in the semiconductor substrate, the LED devices in the semiconductor substrate cannot be directly implanted in the display device one-to-one. A step of transplanting a plurality of LED elements on a semiconductor substrate to a substrate of a display device by separating the LED elements from the semiconductor substrate in consideration of a distance (pixel pitch) between pixels is required.

In the step of implanting the LED elements into the display device or other processes, if the intervals of the LED elements are not constant or are not balanced, the image displayed on the display device is distorted, which causes the problem of deteriorating image display quality as a display device. There may be.

In the step of implanting the LED element into the display device, a transfer substrate is used because it is difficult to directly implant the LED element from the semiconductor substrate to the display substrate. However, since the size of the semiconductor substrate is limited, the LED element is implanted in one display device using a plurality of transfer substrates.

At this time, in transplanting the LED elements to the substrate of the display device using a plurality of transfer substrates, there is a problem in that intervals between the LED elements are different due to process errors that may occur while using the plurality of transfer substrates.

In addition to the technical problems as described above, since the LED elements transferred to the substrate have low power consumption and low light efficiency, they are inevitably affected by the electrical characteristics of electrodes disposed on the substrate.

More specifically, a substrate constituting the display device includes a driving element and electric wiring for individually driving a plurality of LED elements to display an image such as an image. The electrical wiring provides an electrical signal and at the same time supplies a current for light-emitting the LED element.

The current for emitting light of the LED element is supplied through the circuit board attached to the board, and the light emission deviation according to the electrical resistance of the power wiring according to the length of the power wiring, that is, the distance between the circuit board supplying power to the board and the LED element. may occur.

Accordingly, in the case of a multi-display composed of a plurality of display devices, when the brightness of the LED element is different from each other according to the electrical resistance of the power wiring disposed on the board, a wave-shaped mura phenomenon may occur. There is a problem that can degrade the overall display quality.

SUMMARY OF THE INVENTION The present invention is to solve the problems of the above-described technology, and as a technical task is to provide a light emitting display device having improved display quality by maintaining a constant current supplied to an LED device in a light emitting display device having an LED element. do.

Solved problems according to an embodiment of the present invention are not limited to the above-mentioned problems, and other problems not mentioned above will be clearly understood by those skilled in the art from the following description.

A light emitting display device having an LED element as a light emitting element according to an embodiment of the present invention is provided. A plurality of driving elements and a plurality of LED elements, which are light emitting elements, are disposed on the entire surface of the substrate, which is a light emitting surface. The driving element and the light emitting element are connected to various wiring electrodes, and the wiring electrode supplies a driving signal and a driving current. Driving current and driving signals applied to the driving element and the light emitting element are provided from a circuit board connected to a pad part disposed on the rear surface of the substrate, and the wiring electrode is electrically connected to the pad part disposed on the rear surface of the substrate. At this time, the wiring electrode The silver is connected to the pad part disposed on the rear surface of the substrate through the routing electrode disposed on the side surface of the substrate. The routing electrode and the pad portion connected through the side surface of the substrate are connected through a low-resistance wire arranged to lower electrical resistance.

In this way, in order to supply a uniform current to the light emitting elements disposed on the substrate, the pad portion disposed on the rear surface of the substrate and the routing electrode disposed on the side surface of the substrate are connected through a low-resistance wire to supply uniform current. .

The light emitting display device according to the exemplary embodiment of the present invention has an effect of improving display quality by including low-resistance wiring capable of minimizing luminance imbalance due to electrical wiring, that is, electric resistance of wiring electrodes.

In addition, the light emitting display device according to the exemplary embodiment of the present invention has an effect of improving productivity by freely designing wiring electrodes by including low-resistance wiring.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

Since the content of the invention described in the problem to be solved, the means for solving the problem, and the effect above does not specify the essential features of the claim, the scope of the claim is not limited by the matters described in the content of the invention.

1 is a schematic plan view of a light emitting display device according to an exemplary embodiment of the present invention.
FIG. 2 is a schematic circuit diagram illustrating a configuration of a unit pixel according to the exemplary embodiment shown in FIG. 1 .
FIG. 3 is a schematic cross-sectional view for explaining the structure of a pixel shown in FIG. 2 .
4 is a cross-sectional view for explaining the structure of the LED element shown in FIGS. 2 and 3;
5A is a schematic plan view illustrating a configuration of a front surface of a substrate of a light emitting display device according to an exemplary embodiment of the present invention.
5B is a schematic plan view for explaining a configuration of a rear surface of a substrate of a light emitting display device according to an exemplary embodiment of the present invention.
FIG. 6 is a schematic diagram for explaining arrangement of low-resistance wiring considering electrical resistance of a power line of a light emitting display device according to an exemplary embodiment of the present invention.
FIG. 7 is a schematic diagram for explaining an arrangement of a low-resistance wire in consideration of electrical resistance of a power line of a light emitting display device according to an exemplary embodiment of the present invention.

Advantages and features of the present invention, and methods of achieving them, will become clear with reference to the detailed description of the following embodiments taken in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, only these embodiments make the disclosure of the present invention complete, and common knowledge in the art to which the present invention belongs. It is provided to fully inform the holder of the scope of the invention, and the present invention is only defined by the scope of the claims.

The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of the present invention are illustrative, so the present invention is not limited to the details shown. Like reference numbers designate like elements throughout the specification. In addition, in describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. When 'includes', 'has', 'consists of', etc. mentioned in this specification is used, other parts may be added unless 'only' is used. In the case where a component is expressed in the singular, the case including the plural is included unless otherwise explicitly stated.

In interpreting the components, even if there is no separate explicit description, it is interpreted as including the error range.

In the case of a description of a positional relationship, for example, 'on top of', 'on top of', 'at the bottom of', 'next to', etc. Or, unless 'directly' is used, one or more other parts may be located between the two parts.

In the case of a description of a temporal relationship, for example, when a temporal precedence relationship is described as 'after', 'continue to', 'after ~', 'before', etc., 'immediately' or 'directly' As long as ' is not used, non-continuous cases may also be included.

In the case of description of the flow relationship of a signal, for example, even in the case of 'a signal is passed from node A to node B', unless 'direct' or 'direct' is used, from node A via another node This may include a case where a signal is transmitted to node B.

Although first, second, etc. are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from another. Therefore, the first component mentioned below may also be the second component within the technical spirit of the present invention.

Each feature of the various embodiments of the present invention can be partially or entirely combined or combined with each other, technically various interlocking and driving are possible, and each embodiment can be implemented independently of each other or can be implemented together in a related relationship. may be

Hereinafter, various configurations of a display device having an LED device according to an embodiment of the present invention will be described in detail with reference to the drawings.

1 is a schematic plan view of a light emitting display device according to an exemplary embodiment of the present invention, and FIG. 2 is a schematic circuit diagram for explaining a configuration of a unit pixel according to an exemplary embodiment shown in FIG. 1 .

Referring to FIGS. 1 and 2 , the light emitting display device 100 according to an exemplary embodiment of the present invention includes a display area AA having a plurality of unit pixels UP and a non-display area IA defined. A substrate 110 is included.

The unit pixel UP may be composed of a plurality of sub-pixels SP1, SP2, and SP3 on the first surface of the substrate 110, that is, the front surface 110a, and each sub-pixel is typically red. ), may be sub-pixels (SP1, SP2, SP3) emitting blue and green light, but are not limited thereto, and may further include sub-pixels emitting white light. .

The substrate 110 is a thin film transistor array substrate, may be made of glass or plastic, and may be a substrate that is divided into two or more layers or a bonding of two or more substrates. The non-display area IA may be defined as an area on the substrate 110 excluding the display area AA, and since it may have a relatively narrow width, it may be defined as a bezel area.

Each of the plurality of unit pixels UP is disposed in the display area AA. At this time, each of the plurality of unit pixels UP is disposed in the display area AA to have a first reference pixel pitch predetermined along the X-axis direction and a predetermined second reference pixel pitch along the Y-axis direction. The first reference pixel pitch may be defined as a distance between the respective center portions of adjacent unit pixels UP, and the second reference pixel pitch may be defined as a distance between the respective center portions of adjacent unit pixels UP in the reference direction, similar to the first reference pixel pitch. It can be defined as the distance between the midsections.

Meanwhile, the distance between the subpixels SP1, SP2, and SP3 constituting the unit pixel UP is also defined as a first reference subpixel pitch and a second reference subpixel pitch similar to the first reference pixel pitch and the second reference pixel pitch. It can be.

In the light emitting display device 100 including the LED element 150 that is an LED element, the width of the non-display area IA may be smaller than the aforementioned pixel pitch or subpixel pitch. Accordingly, as in one embodiment of the present invention, the light emitting display device 100 having the non-display area IA having a length equal to or smaller than the pixel pitch or sub-pixel pitch constitutes a multi-display, that is, a multi-screen display device. In this case, since the non-display area IA is smaller than the pixel pitch or sub-pixel pitch, a multi-screen display device with substantially no or minimized bezel area can be implemented.

As described above, the light emitting display device 100 according to an exemplary embodiment of the present invention, in order to implement a multi-screen display device with substantially or minimized bezel area, has a first reference pixel pitch within the display area AA. , The second reference pixel pitch, the first reference subpixel pitch, and the second reference subpixel pitch may be kept constant, but the display area AA is defined as a plurality of zones and the above-described pitch lengths within each zone are mutually However, by making the pixel pitch of the area adjacent to the non-display area IA wider than that of other areas, the size of the bezel area can be implemented to be smaller than the pixel pitch.

In this way, since the light emitting display device 100 having different pixel pitches may cause image distortion, image processing is performed by sampling image data by comparing the set pixel pitch to an adjacent area, and The bezel area can be minimized while minimizing distortion.

However, in order to minimize the non-display area (IA), a pad area for connection to a circuit unit capable of transmitting and receiving power and data signals to the unit pixel (UP) in which the LED element 150 is located, a drive IC for driving, etc. requires a minimum area for

Meanwhile, with reference to FIG. 2 , the configuration and circuit structure of the sub-pixels SP1 , SP2 , and SP3 constituting the unit pixel UP of the light emitting display device 100 will be described. The pixel driving lines are provided on the first surface of the substrate 110, that is, the front surface 110a, and supply necessary signals to each of the plurality of subpixels SP1, SP2, and SP3. Pixel driving lines according to an exemplary embodiment include a plurality of gate lines GL, a plurality of data lines DL, a plurality of driving power lines DPL, and a plurality of common power lines CPL.

Each of the plurality of gate lines GL is provided on the front surface 110a of the substrate 110 and extends long along the first horizontal axis direction X of the substrate 110 in the second horizontal axis direction. They are spaced at regular intervals along (Y).

The plurality of data lines DL are provided on the front surface 110a of the substrate 110 along with the plurality of gate lines GL, along the second horizontal axis direction Y of the substrate 110. While elongated, they are spaced apart at regular intervals along the first horizontal axis direction (X).

The plurality of driving power lines DPL are provided on the substrate 110 in parallel with each of the plurality of data lines DL, and may be formed together with each of the plurality of data lines DL. Each of the plurality of driving power lines DPL supplies pixel driving power provided from the outside to adjacent subpixels SP.

The plurality of common power lines CPL are provided on the substrate 110 in parallel with each of the plurality of gate lines GL, and may be formed together with each of the plurality of gate lines GL. Each of the plurality of common power lines CPL supplies common power supplied from the outside to adjacent subpixels SP1 , SP2 , and SP3 .

Each of the plurality of subpixels SP1 , SP2 , and SP3 is provided in a subpixel area defined by the gate line GL and the data line DL. Each of the plurality of sub-pixels SP1 , SP2 , and SP3 may be defined as a minimum unit area in which light is actually emitted.

At least three sub-pixels SP1 , SP2 , and SP3 adjacent to each other may constitute one unit pixel UP for color display. For example, one unit pixel UP includes a red sub-pixel SP1, a green sub-pixel SP2, and a blue sub-pixel SP3 adjacent to each other along the first horizontal axis direction X, and improves luminance. For this, a white sub-pixel may be further included.

Optionally, each of the plurality of driving power lines DPL may be provided in each of the plurality of unit pixels UP. In other words, at least three sub-pixels SP1 , SP2 , and SP3 constituting each unit pixel UP share one driving power line DPL. Accordingly, the number of driving power lines for driving each sub-pixel SP1 , SP2 , and SP3 may be reduced, and the aperture ratio of each unit pixel UP may be increased by the number of driving power lines that decreases or The size of the pixel UP may be reduced.

Each of the plurality of sub-pixels SP1 , SP2 , and SP3 according to an embodiment of the present invention includes a pixel circuit PC and an LED device 150 .

The pixel circuit PC is provided in a circuit area defined in each sub-pixel SP and is connected to adjacent gate lines GL, data lines DL, and driving power supply lines DPL. The pixel circuit PC generates a data signal (or voltage) applied to the data line DL in response to a scan pulse applied to the gate line GL, based on the pixel driving power supplied from the driving power line DPL. Controls the current flowing through the LED element 150 according to. A pixel circuit PC according to an exemplary embodiment includes a switching thin film transistor T1, a driving thin film transistor T2, and a capacitor Cst.

The switching thin film transistor T1 includes a gate electrode connected to the gate line GL, a first electrode connected to the data line DL, and a second electrode connected to the gate electrode N1 of the driving thin film transistor T2. Here, the first and second electrodes of the switching thin film transistor T1 may be a source electrode or a drain electrode according to the direction of the current. The switching thin film transistor T1 is switched according to the scan pulse supplied to the gate line GL and supplies the data signal supplied to the data line DL to the driving thin film transistor T2.

The driving thin film transistor T2 is turned on by the voltage supplied from the switching thin film transistor T1 and/or the voltage of the capacitor Cst, thereby controlling the amount of current flowing from the driving power supply line DPL to the LED element 150. . To this end, the driving thin film transistor T2 according to an embodiment of the present invention includes a gate electrode connected to the second electrode N1 of the switching thin film transistor T1, a drain electrode connected to the driving power supply line DPL, and an LED. It includes a source electrode connected to element 150 . The driving thin film transistor T2 controls light emission of the LED element 150 by controlling the data current flowing from the driving power supply line DPL to the LED element 150 based on the data signal supplied from the switching thin film transistor T1. do.

The capacitor Cst is provided in an overlapping region between the gate electrode N1 and the source electrode of the driving thin film transistor T2 to store a voltage corresponding to the data signal supplied to the gate electrode of the driving thin film transistor T2, and store the stored voltage. to turn on the driving thin film transistor T2.

Optionally, the pixel circuit PC may further include at least one compensation thin film transistor for compensating for a change in the threshold voltage of the driving thin film transistor T2 and further include at least one auxiliary capacitor. The pixel circuit PC may additionally receive compensation power such as an initialization voltage according to the number of thin film transistors and auxiliary capacitors. Therefore, since the pixel circuit PC according to an embodiment of the present invention drives the LED element 150 through a current driving method like each sub-pixel of the organic light emitting display device, the pixel circuit of the well-known organic light emitting display device can be changed to

The LED device 150 is mounted on each of the plurality of sub-pixels SP1 , SP2 , and SP3 . The LED device 150 is electrically connected to the pixel circuit PC of the corresponding sub-pixel SP and the common power line CPL, so that the pixel circuit PC, that is, the driving thin film transistor T2 is connected to the common power line CPL. ) emits light due to the current flowing through it. The LED device 150 according to an embodiment of the present invention may be a micro light emitting device or a micro light emitting diode chip that emits any one of red light, green light, blue light, and white light. Here, the micro light emitting diode chip may have a scale of 1 to 100 micrometers, but may have a size smaller than the size of the light emitting area other than the circuit area occupied by the pixel circuit (PC) among the subpixel areas, which is not limited thereto. .

FIG. 3 is a schematic cross-sectional view for explaining the structure of the pixel shown in FIG. 2 and FIG. 4 is a cross-sectional view for explaining the structure of the LED element shown in FIGS. 2 and 3 .

It will be described with reference to FIGS. 3 and 4 but in conjunction with the previous drawings.

Each sub-pixel (SP1, SP2, SP3) of the display device according to an embodiment of the present invention includes a protective layer 113, an LED element 150, planarization layers 115-1 and 115-2, a pixel electrode PE, and a common electrode CE.

First, although the thickness of the substrate 110 is shown as relatively thin in FIG. 3, the thickness of the substrate 110 may be substantially thicker than the total thickness of the layer structure provided on the substrate 110, It may be a substrate composed of a plurality of layers or a plurality of substrates bonded together.

The pixel circuit PC includes a switching thin film transistor T1, a driving thin film transistor T2, and a capacitor C. Since the pixel circuit PC is the same as described above, a detailed description thereof will be omitted, and the structure of the driving thin film transistor T2 will be described below as an example.

The driving thin film transistor T2 includes a gate electrode GE, a semiconductor layer SCL, a source electrode SE, and a drain electrode DE.

The gate electrode GE is disposed on the substrate 110 along with the gate line GL. The gate electrode GE is covered by the gate insulating layer 112 . The gate insulating layer 112 may be formed of a single layer or a plurality of layers made of an inorganic material, and may be formed of silicon oxide (SiOx), silicon nitride (SiNx), or the like.

The semiconductor layer SCL is provided in a preset pattern (or island) shape on the gate insulating layer 112 to overlap the gate electrode GE. The semiconductor layer SCL may be formed of a semiconductor material made of any one of amorphous silicon, polycrystalline silicon, oxide, and organic material, but is not limited thereto.

The source electrode SE is disposed to overlap one side of the semiconductor layer SCL. The source electrode SE is disposed together with the data line DL and the driving power line DPL.

The drain electrode DE overlaps the other side of the semiconductor layer SCL and is spaced apart from the source electrode SE. The drain electrode DE is disposed together with the source electrode SE, and branches or protrudes from an adjacent driving power line DPL.

Additionally, the switching thin film transistor T1 constituting the pixel circuit PC is disposed in the same structure as the driving thin film transistor T2. At this time, the gate electrode of the switching thin film transistor T1 branches or protrudes from the gate line GL, the first electrode of the switching thin film transistor T1 branches or protrudes from the data line DL, and the switching thin film transistor T1 The second electrode of ) is connected to the gate electrode GE of the driving thin film transistor T2 through a via hole provided in the gate insulating layer 112 .

The protective layer 113 is provided on the entire surface of the substrate 110 to cover the sub-pixel SP, that is, the pixel circuit PC. The protective layer 113 provides a flat surface while protecting the pixel circuit PC. The protective layer 113 according to an embodiment of the present invention may be made of an organic material such as benzocyclobutene or photo acryl, but is preferably made of a photo acryl material for convenience in processing.

In the LED device 150 according to an embodiment of the present invention, an adhesive member 114 may be disposed on the protective layer 113 . In addition, a concave portion may be disposed in the protective layer 113, and the inclined surface due to the concave portion in the protective layer 113 promotes light emitted from the LED device 150 in a specific direction to improve luminous efficiency. can do.

The LED element 150 is electrically connected to the pixel circuit PC and the common power line CPL, so that it emits light by current flowing from the pixel circuit PC, that is, the driving thin film transistor T2 to the common power line CPL. . As shown in the LED element 150 according to an embodiment of the present invention, FIG. 4, the light emitting layer EL, the first electrode (or anode terminal, E1), and the second electrode (or cathode terminal, E2) are include

The emission layer EL emits light according to recombination of electrons and holes according to a current flowing between the first electrode E1 and the second electrode E2. The light emitting layer EL according to an exemplary embodiment includes a first semiconductor layer 151 , an active layer 153 , and a second semiconductor layer 155 .

The first semiconductor layer 151 provides electrons to the active layer 153 . The first semiconductor layer 151 according to an embodiment of the present invention may be made of an n-GaN-based semiconductor material, and the n-GaN-based semiconductor material may be GaN, AlGaN, InGaN, or AlInGaN. Here, Si, Ge, Se, Te, or C may be used as an impurity used for doping the first semiconductor layer 151 .

The active layer 153 is provided on one side of the first semiconductor layer 151 . The active layer 153 has a multi-quantum well (MQW) structure including a well layer and a barrier layer having a higher band gap than the well layer. The active layer 153 according to an embodiment of the present invention may have a multi-quantum well structure such as InGaN/GaN.

The second semiconductor layer 155 is provided on the active layer 153 and provides holes to the active layer 153 . The second semiconductor layer 155 according to an embodiment of the present invention may be made of a p-GaN-based semiconductor material, and the p-GaN-based semiconductor material may be GaN, AlGaN, InGaN, or AlInGaN. Here, as an impurity used for doping the second semiconductor layer 155, Mg, Zn, or Be may be used.

The first electrode E1 is provided on the second semiconductor layer 155 . The first electrode E1 is connected to the source electrode SE of the driving transistor T2.

The second electrode E2 is provided on the other side of the first semiconductor layer 151 to be electrically separated from the active layer 153 and the second semiconductor layer 155 . The second electrode E2 is connected to the common power line CPL.

Each of the first and second electrodes E1 and E2 according to an embodiment of the present invention is one of a metal material such as Au, W, Pt, Si, Ir, Ag, Cu, Ni, Ti, or Cr, or an alloy thereof. It may be made of materials including the above. Each of the first and second electrodes E1 and E2 according to another embodiment may be made of a transparent conductive material, and the transparent conductive material may be indium tin oxide (ITO) or indium zinc oxide (IZO). Not limited to this.

Additionally, each of the first semiconductor layer 151 , the active layer 153 , and the second semiconductor layer 155 may be provided in a structure in which they are sequentially stacked on the semiconductor substrate 110 . Here, the semiconductor substrate includes a semiconductor material such as a sapphire substrate or a silicon substrate. After the semiconductor substrate is used as a growth substrate for growing the first semiconductor layer 151, the active layer 153, and the second semiconductor layer 155, respectively, from the first semiconductor layer 151 by a substrate separation process. can be separated Here, the substrate separation process may be laser lift off or chemical lift off. Accordingly, as the semiconductor substrate for growth is removed from the LED device 150, the LED device 150 may have a relatively thin thickness, and thus may be accommodated in each sub-pixel SP.

As such, the LED element 150 emits light according to recombination of electrons and holes according to the current flowing between the first electrode E1 and the second electrode E2.

The LED device 150 includes a first part (or front part, FP) having first and second electrodes E1 and E2 connected to the pixel circuit PC, and a second part opposite to the first part FP. part (or rear part, RP). Here, the first part FP may have a smaller size than the second part RP, and in this case, the LED device 150 has an upper side corresponding to the first part FP and the second part RP. It may have a trapezoidal cross section having a corresponding base.

The planarization layers 115 - 1 and 115 - 2 are disposed on the protective layer 113 to cover the LED device 150 . That is, the planarization layers 115-1 and 115-2 may cover all of the front surface of the protective layer 113, where the LED device 150 and the structure 160 shown in FIG. 5A are disposed, and the rest of the front surface. It is disposed on the protective layer 113 to have a thickness of about.

The planarization layers 115-1 and 115-2 may be formed of one layer, and as shown, a planarization layer having a multi-layer structure composed of a first planarization layer 115-1 and a second planarization layer 115-2 ( 115-1, 115-2).

As such, the planarization layers 115 - 1 and 115 - 2 provide a flat surface on the protective layer 113 . In addition, the planarization layers 115-1 and 115-2 serve to fix the position of the LED element 150.

The pixel electrode PE connects the first electrode E1 of the LED device 150 to the source electrode SE of the driving thin film transistor T2 and may be defined as an anode electrode. The pixel electrode PE according to an embodiment of the present invention is provided on the entire surface of the planarization layers 115-1 and 115-2 overlapping the first electrode E1 of the LED device 150 and the driving thin film transistor T2. . The pixel electrode PE is electrically connected to the source electrode SE of the driving thin film transistor T2 through the first circuit contact hole CCH1 provided through the passivation layer 113 and the planarization layers 115-1 and 115-2. and electrically connected to the first electrode E1 of the LED device 150 through the first electrode contact hole ECH1 provided in the planarization layers 115-1 and 115-2. Accordingly, the first electrode E1 of the LED device 150 is electrically connected to the source electrode SE of the driving thin film transistor T2 through the pixel electrode PE. The pixel electrode PE is made of a transparent conductive material when the light emitting diode display is a top emission type, and is made of a light reflective conductive material when the light emitting diode display is a bottom emission type. can Here, the transparent conductive material may be indium tin oxide (ITO) or indium zinc oxide (IZO), but is not limited thereto. The light reflecting conductive material may be Al, Ag, Au, Pt, or Cu, but is not limited thereto. The pixel electrode PE made of the light reflective conductive material may be formed of a single layer including the light reflective conductive material or a multi-layer stack of the single layers.

The common electrode CE electrically connects the second electrode E2 of the LED device 150 and the common power supply line CPL, and may be defined as a cathode electrode. The common electrode CE is provided on the entire surface of the planarization layers 115 - 1 and 115 - 2 overlapping the common power line CPL while overlapping the second electrode E2 of the LED device 150 . Here, the common electrode CE may be made of the same material as the pixel electrode PE.

One side of the common electrode CE according to an embodiment of the present invention passes through the gate insulating layer 112, the protective layer 113, and the planarization layers 115-1 and 115-2 overlapping the common power line CPL. It is electrically connected to the common power line CPL through the provided second circuit contact hole CCH2. The other side of the common electrode CE according to an embodiment of the present invention is a second electrode contact hole ECH2 provided in the planarization layers 115-1 and 115-2 so as to overlap the second electrode E2 of the LED device 150. It is electrically connected to the second electrode E2 of the LED element 150 through. Accordingly, the second electrode E2 of the LED element 150 is electrically connected to the common power line CPL through the common electrode CE.

According to an exemplary embodiment, the pixel electrode PE and the common electrode CE include first and second circuit contact holes CCH1 and CCH2 and first and second electrode contact holes ECH1 and ECH2. An electrode patterning process using a deposition process of depositing an electrode material on the flattening layers 115-1 and 115-2, a photolithography process, and an etching process may be simultaneously provided. Accordingly, in one embodiment of the present invention, since the pixel electrode PE and the through electrode CE connecting the LED element 150 to the pixel circuit PC can be simultaneously disposed, the electrode connection process can be simplified. A process time for connecting the LED element 150 and the pixel circuit PC is greatly reduced, and through this, the productivity of the LED display device can be improved.

According to one embodiment of the present invention, the light emitting diode display device further includes a transparent buffer layer 116 .

The transparent buffer layer 116 is provided on the substrate 110 to cover the entirety of the planarization layers 115-1 and 115-2 on which the pixel electrode PE and the common electrode CE are provided, thereby protecting the LED element 150 from external impact. and protects the pixel circuit (PC). Accordingly, each of the pixel electrode PE and the common electrode CE is provided between the planarization layers 115 - 1 and 115 - 2 and the transparent buffer layer 116 . The transparent buffer layer 116 according to an embodiment of the present invention may be an optical clear adhesive (OCA) or an optical clear resin (OCR), but is not limited thereto.

The light emitting display device according to an exemplary embodiment of the present invention may further include a reflective layer 111 provided under the light emitting area of each subpixel SP.

The reflective layer 111 is provided on the substrate 110 to overlap the light emitting region including the LED device 150 . The reflective layer 111 according to an embodiment of the present invention may be made of the same material as the gate electrode GE of the driving thin film transistor T2 and may be provided on the same layer as the gate electrode GE, but is not limited thereto. The reflective layer 111 may be made of the same material as any one electrode of the electrodes constituting the driving thin film transistor T2.

The reflective layer 111 reflects light incident from the LED device 150 toward the first portion FP of the LED device 150 . Accordingly, the light emitting display device according to an exemplary embodiment includes the reflective layer 111 and thus has a top emission structure. However, when the light emitting diode display device according to an exemplary embodiment of the present invention has a bottom emission structure, the reflective layer 111 may be omitted or disposed above the LED element 150 .

Optionally, the reflective layer 111 may be made of the same material as the source/drain electrodes SE/DE of the driving thin film transistor T2 and may be provided on the same layer as the source/drain electrodes SE/DE.

The LED element 150 mounted on each sub-pixel SP of the light emitting display device according to an exemplary embodiment of the present invention may be disposed at a position corresponding to an upper portion of the reflective layer 111 .

The adhesive member 114 is interposed between the protective layer 113 of each sub-pixel (SP) and the LED element 150, and the bottom of the concave portion of the flattening layers 115-1 and 115-2 corresponding to the LED element 150. By adhering to the surface, the LED element 150 is primarily fixed.

The adhesive member 114 according to an embodiment of the present invention is in contact with the second part (RP) of the LED element 150, that is, the back surface of the first semiconductor layer 310, and is disposed during the mounting process of the LED element 150 It is possible to minimize the implantation process defect of the LED element 150 by preventing the position of the LED element 150 from being distorted and at the same time allowing the LED element 150 to be smoothly separated from the intermediate substrate used for transplantation.

The adhesive member 114 according to an embodiment of the present invention is dotted on each sub-pixel (SP) and spreads by the pressing force applied during the mounting process of the micro light emitting device, thereby forming the second portion of the LED device 150 ( RP) can be attached. Accordingly, the position of the LED element 150 may be primarily fixed by the adhesive member 114 . Therefore, according to the present embodiment, the mounting process of the micro light emitting device is performed by simply attaching the LED device 150 to the surface, so that the mounting process time of the micro light emitting device can be greatly reduced.

In addition, the adhesive member 114 allows the structure 160 (shown in FIG. 5A) to be aligned with the second structure 170 (shown in FIG. 5B) and disposed on the protective layer 113. That is, the adhesive member 114 is provided to cover the entire surface of the protective layer 113 except for the contact holes so that the LED device 150 and the structure 160 are disposed on the protective layer 113. perform a function

In other words, the adhesive member 114 is interposed between the protective layer 113 and the planarization layers 115-1 and 115-2, and is interposed between the LED device 150 and structure 160 and the protective layer 113. . The adhesive member 114 according to this other example is coated with a constant thickness on the entire surface of the protective layer 113, but a portion of the adhesive member 114 coated on the entire surface of the protective layer 113 in which contact holes are to be provided is a contact Removed upon placement of holes. Accordingly, in one embodiment of the present invention, the process time for disposing the adhesive member 114 is shortened by coating the entire surface of the protective layer 113 with a constant thickness immediately before the mounting process of the micro light emitting device. can be shortened

In one embodiment of the present invention, since the adhesive member 114 is provided on the entire surface of the protective layer 113, the planarization layers 115-1 and 115-2 of this example are provided to cover the adhesive member 114.

In another embodiment of the present invention, the LED element 150 has a concave portion for separately accommodating the LED element 150, and may be positioned inside the concave portion through the adhesive member 114. However, the concave portion for accommodating the above-described LED element 150 may be deleted according to various process conditions for implementing the display device.

A process of mounting a micro-sized light emitting device according to an embodiment of the present invention is a process of mounting a red micro light emitting device on each of the red sub-pixels SP1 and a process of mounting a green micro light emitting device on each of the green sub-pixels SP2. It may include a process of mounting, and a process of mounting a blue micro light emitting element on each of the blue subpixels SP3, and a process of mounting a white micro light emitting element on each of the white subpixels. there is.

Also, a process of mounting a micro light emitting device according to an embodiment of the present invention may include only a process of mounting a white micro light emitting device on each of the subpixels. In this case, the substrate 110 includes a color filter layer overlapping each sub-pixel. The color filter layer may be arranged to transmit only white light having a wavelength of a color corresponding to a corresponding sub-pixel.

A process of mounting a micro light emitting device according to an embodiment of the present invention may include only a process of mounting a micro light emitting device of a first color on each of the subpixels. In this case, the substrate 110 includes a wavelength conversion layer and a color filter layer overlapping each sub-pixel. The wavelength conversion layer emits light of a second color based on some of the light of the first color incident from the micro light emitting device. The color filter layer transmits only light having a wavelength of a color corresponding to a corresponding sub-pixel among white light generated by mixing light of a first color and light of a second color. Here, the first color may be blue, and the second color may be yellow. Also, the wavelength conversion layer may include phosphors or quantum dot particles that emit light of a second color based on some of the light of the first color.

5A and 5B are schematic diagrams for explaining arrangement of power lines to uniformly supply power. As described above, in the light emitting display device 100 using the LED element 150 as a light emitting element, since the LED element 150 consumes low power, there may be a difference in the amount of light emitted by a slight difference in current. As described in the above technical configuration for emitting light of the LED element 150, the wiring electrodes including the driving power supply line (DPL) and the common power supply line (CPL) have electrical resistance depending on their length and the thickness and material of the wiring electrodes. The characteristics of may appear differently for each location. For example, the plurality of LED elements 150 on the board 110 on which the driving power line DPL and the power supply line CPL described above from an external power source are disposed differ in the current supplied according to the length of the wiring electrode. There may be, which may affect the amount of light emitted from the LED element 150. In order to minimize the characteristics of the electrical resistance of the wiring electrode that can affect the amount of light emitted, the power supply line CPL disposed on the upper surface 110a of the substrate 110 and surrounding the periphery of the substrate 110 is ) is connected to the pad part PP disposed on the back surface 110b of the ? and the plurality of routing electrodes 160, and the plurality of routing electrodes 160 are low-resistance wiring so that a uniform current flows in the power supply line CPL. 170 to minimize the difference in the amount of current supplied to the power supply line (CPL) depending on the electrical resistance of the wiring electrode.

The routing electrode 160 electrically connects the power line CPL on the front surface 110a of the substrate 110 and the pad part PP on the rear surface 110b of the substrate 110 through the side surface of the substrate 110. make this happen The routing electrode 160 may be a mixture containing silver (Ag) and may be a wiring electrode having a width of less than 10 μm.

The low resistance wire 170 is electrically connected to the pad part PP, and the pad part PP is connected to the signal transmission cable STC.

Meanwhile, each of the plurality of routing wires 160 connected to the power line CPL on the upper surface 110a of the substrate 110 has a pad portion PP to which current is supplied due to the low electrical resistance of the low resistance wire 170. It may be configured to have a uniform wire electrical resistance regardless of the distance to the wire.

The low-resistance wiring 170 may be disposed on the second substrate, that is, the rear surface 110b of the substrate 110, and the power line CPL disposed on the routing electrode 160 or the front surface 110a of the substrate 110. ), but may be disposed of substantially the same material, more preferably, may be disposed of a material having an electrical resistance value of 1.68 * 10 (-0) ohm * meter or less, silver (Ag), copper (Cu) or carbon It can be arranged with graphene composed of.

In addition, the low-resistance wiring 170 may be disposed as one or more conductive electrodes depending on the number and arrangement of the pad parts PP, and artificially electrical resistance in consideration of the distance between the pad part PP and the routing electrode 160. A material that lowers the value or increases the electrical resistance value may be mixed and disposed so that a uniform current is applied to the entire routing electrode 160 .

The shape of the low-resistance wire 170 considering the electrical resistance value can be designed in various forms by considering the contact point of each routing electrode 160, and the shown form is only one example.

6 is a schematic diagram for explaining the arrangement of low-resistance wires in consideration of electrical resistance of power lines, and FIG. 7 is a schematic diagram for explaining various arrangements of low-resistance wires.

Various arrangements of the low-resistance wiring will be described with reference to FIGS. 6 and 7 , but will be described with reference to the previous drawings.

Since the light emitting display device 100 using the LED element 150 as a light emitting element does not require a separate encapsulation layer and has high luminous efficiency, a multi-display display device can be implemented by connecting a plurality of light emitting display devices 100. There are advantages to being

In particular, since the width of the non-display areas IA and BA can be made smaller than the distance between pixels, there is a further advantage in implementing a multi-display display device.

In this way, in order to implement a multi-display display device, it is preferable that the connection with the control board 180 is made on the rear surface 110b of the board 100, which has an effect of further minimizing the non-display areas IA and BA. there is.

The pad part PP is disposed on the rear surface 110b of the substrate 110, and electrical connection is made with the control board 180 through the signal transmission cable STC. The pad part PP is electrically connected to the routing electrode 160 through the connecting electrode CL, and through the routing electrode 160, the power wiring such as the power line CPL on the upper surface 110a of the substrate 110 It is electrically connected to (PL).

At this time, the pad part PP disposed on the rear surface 110b of the substrate 110 in order to supply a uniform current to the display area AA is connected to the routing electrode 1s60 relatively far from among the plurality of routing electrodes 160. Electrically connected through the low-resistance wiring 170, current is supplied, and as a result, the current supplied to the plurality of routing electrodes 160 is supplied with substantially the same current, and thus disposed in the display area AA. The light emission luminance of the LED element 150 is maintained substantially the same.

Referring to FIG. 7 , the substrate 110 constituting the light emitting display device 110 may include at least one substrate. When the substrate 110 is composed of a plurality of substrates, the substrate 110-1 on which the LED element 150 is disposed and the substrate 110 on which a pad portion (PP) having an electrical connection with the control board 180 is disposed. -2) can be configured separately and then the manufacturing process can be simplified through the method of bonding the two substrates together.

In this case, the low-resistance wiring 170 may be disposed on a selected side of each substrate, and the routing electrode 160 may have various electrical connection types.

More specifically, the display area AA where the LED element 150 is located is defined on the first substrate 110-1, and the first routing electrode 160a is disposed on the side of the first substrate 110-1. It can be. A second routing electrode 160b may be disposed on a side surface of the second substrate 110-2, and the low-resistance wiring 170 is interposed between the first substrate 110-1 and the second substrate 110-2. disposed and electrically connected to the aforementioned first routing electrode 160a and the second routing electrode 160b.

The aforementioned low-resistance wiring 170 may be disposed on a selected surface among the rear surface 110-1b of the first substrate 110-1 and the upper surface 110-2a of the second substrate 110-2.

A light emitting display device according to an embodiment of the present invention can be described as follows.

A light emitting display device according to an embodiment of the present invention includes a plurality of driving elements on the front surface of a substrate, a plurality of wiring electrodes connected to the plurality of light emitting elements, at least one pad part on the rear surface of the substrate, and a side surface of the substrate. It includes a plurality of routing electrodes electrically connecting the pad part and the wiring electrode through the substrate, and a low-resistance wiring for connecting at least one routing electrode among the plurality of routing electrodes and the pad part on the rear surface of the substrate.

The routing electrode may be a mixture containing silver (Ag), and the width of the routing electrode may be less than 10 μm.

Low-resistance wiring may have a resistance value of 1.68 * 10 (-8) ohm * meter or less.

The plurality of wiring electrodes may include a data electrode for transmitting a driving signal and a power electrode for supplying power, and the power electrode may be a wiring electrode connected to a low-resistance wiring among the plurality of wiring electrodes.

The low-resistance wiring may have uniform electrical resistance in consideration of a distance between the routing electrode and the pad portion connected to the routing electrode.

A light emitting display device according to another embodiment of the present invention includes a substrate including a first surface and a second surface opposite to the first surface and having at least one sub-region, a plurality of driving elements on the first surface, and a plurality of driving elements. of the plurality of wiring electrodes connected to the light emitting element, at least one pad portion on the second surface, electrically connected to the plurality of wiring electrodes, and connected to the pad portion on the second surface to be connected to the first surface and the second surface. A plurality of routing electrodes and at least one sub-region extending to a partial region of the second surface through a third surface between surfaces, and electrically connecting the plurality of routing electrodes and the pad part. It includes low-resistance wiring that

The wiring electrode may include a power electrode for supplying power to the light emitting element and a data electrode for transmitting a driving signal to the driving element.

A wiring electrode connected to the resistance wiring may be the power supply electrode.

Although the embodiments of the present invention have been described in more detail with reference to the accompanying drawings, the present invention is not necessarily limited to these embodiments, and may be variously modified and implemented without departing from the technical spirit of the present invention. . Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain, and the scope of the technical idea of the present invention is not limited by these embodiments. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The protection scope of the present invention should be construed according to the claims, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

100: light emitting display device
110: substrate
150: LED element
160: routing electrode
170: low resistance wiring
310: wiring electrode

Claims (15)

a plurality of driving elements on the front surface, which is the light emitting surface of the substrate;
a plurality of LED elements on the front surface of the substrate;
a pixel electrode connected to the driving element on the front surface of the substrate;
a power line connected to the LED element on the front surface of the board;
at least one pad part on the rear surface of the substrate;
a plurality of routing electrodes electrically connecting the pad part and the power line through a side surface of the substrate; and
It is on the rear surface of the substrate and includes a low resistance wiring for connecting at least one routing electrode of the plurality of routing electrodes and the pad portion,
A width of the low-resistance wire is wider than a width of the routing electrode. According to claim 1,
Wherein the routing electrode is a mixture containing silver (Ag). According to claim 2,
The light emitting display device, wherein the routing electrode has a width of less than 10 μm. According to claim 1,
The low-resistance wire has a resistance value of 1.68 * 10 (-8) ohm * meter or less, the light emitting display device. According to claim 1,
The light emitting display device of claim 1 , wherein the power line surrounds an outer periphery of the substrate. According to claim 1,
The light emitting display device of claim 1 , wherein the low resistance wires are two or more conductive electrodes. According to claim 1,
The low-resistance wire has a uniform electrical resistance considering a distance between the routing electrode and the pad portion connected to the routing electrode. According to claim 1,
The LED element,
a first semiconductor layer on the substrate;
a light emitting layer on a part of the first semiconductor layer;
a second semiconductor layer on the light emitting layer;
a first electrode on the second semiconductor layer; and
and a second electrode on the first semiconductor layer and parallel to the light emitting layer. According to claim 1,
wherein the driving element includes a gate electrode, a semiconductor layer, a source electrode, and a drain electrode. According to claim 9,
The light emitting display device further comprises a reflective layer disposed on the substrate and under the LED element to overlap with the LED element. According to claim 9,
The driving element is a driving thin film transistor. According to claim 10,
The reflective layer is formed of the same material as the same layer as the gate electrode. According to claim 9,
The light emitting display device of claim 1 , wherein the power line is disposed on the same layer as the gate electrode. According to claim 1,
The light emitting display device further comprises a protective layer formed of an organic material on the entire surface of the substrate to cover the driving element on the driving element. According to claim 14,
and an adhesive member disposed on the protective layer to adhere the LED element to the substrate.

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