KR20210038512A - Light source module, display panel and display apparatus including the same - Google Patents

Abstract

A display panel disclosed in an embodiment of the present invention comprises: a circuit board having a transparent support member and a thin film transistor unit on the support member; a plurality of first pads and a plurality of second pads disposed on an upper surface of the circuit board and electrically connected to the thin film transistor; and a plurality of LED chips having a first electrode on the first pad and a second electrode on the second pad, and including a light emitting structure. Each of the plurality of LED chips is individually driven by the thin film transistor unit to form a subpixel. The plurality of first and second pads includes a plurality of metal layers disposed on the circuit board. The uppermost layer of the plurality of metal layers may be made of a metal material and bonded to the first and second electrodes.

Description

Light source module, display panel, and display device having the same {LIGHT SOURCE MODULE, DISPLAY PANEL AND DISPLAY APPARATUS INCLUDING THE SAME}

Embodiments of the invention relate to a light source module, a display panel, and a display device having a micro LED.

A conventional display device is mainly composed of a display panel composed of a liquid crystal display (LCD) and a backlight, but recently, a semiconductor device such as a light emitting diode (LED) is used as one pixel as it is. Display devices using such LEDs are being developed in a form that does not require a separate backlight. In addition, a display device using such an LED can be compact, and a high-brightness display having superior light efficiency compared to conventional LCDs can be implemented. In addition, since the aspect ratio of the display screen can be freely changed and implemented in a large area, it can be provided as a large display of various types.

In advertising and screen display in public places, demand for large screens is increasing, and LEDs are used as a display means for large screens. This is because it is easier to increase in size, consumes less electrical energy, and has a long life with low maintenance cost compared to a display means using a conventional liquid crystal light emitting panel. Recently, large-sized display means using LEDs are used in various places such as TVs, monitors, electronic billboards for stadiums, outdoor advertisements, indoor advertisements, public signs, and information display boards, and the construction method thereof is also various.

An embodiment of the invention may provide a light source module, a display panel, and a display device capable of reducing the surface resistance of a junction portion between a light emitting diode chip and a pad of a circuit board.

An embodiment of the present invention may provide a light source module, a display panel, and a display device capable of reducing surface resistance with an electrode of a chip of a light emitting diode and improving electrical connection by disposing a metal layer on a pad of a circuit board. .

A display panel according to an embodiment of the present invention includes: a circuit board having a transparent support member and a thin film transistor portion on the support member; A plurality of first pads and a plurality of second pads disposed on the upper surface of the circuit board and electrically connected to the thin film transistor unit; And a plurality of LED chips having a first electrode on the first pad and a second electrode on the second pad, and including a light emitting structure, wherein each of the plurality of LED chips is individually driven by the thin film transistor unit. A sub-pixel is formed, wherein the plurality of first and second pads include a plurality of metal layers disposed on the circuit board, and an uppermost layer of the plurality of metal layers is a metal material and is bonded to the first and second electrodes. Can be.

In addition, the display panel according to an embodiment of the present invention,

A circuit board having a transparent support member including glass and a thin film transistor portion on the transparent support member;

At least one first pad and a plurality of second pads disposed on the upper surface of the circuit board and electrically connected to the thin film transistor unit; And

A plurality of LED chips having a first electrode on the first pad and a second electrode on the second pad, and including a light emitting structure may be included.

The plurality of LED chips may include a first LED chip emitting a first wavelength, a second LED chip emitting a second wavelength greater than the first wavelength, and a third emitting device having a third wavelength greater than the second wavelength. Including an LED chip, each of the plurality of LED chips may be individually driven by the thin film transistor unit to form a sub-pixel of the display.

The plurality of second pads include a plurality of metal layers disposed on the circuit board, and an uppermost layer of the plurality of metal layers is made of a metal material and is bonded to the second electrode,

Each of the plurality of second pads may include a first metal layer, a second metal layer on the first metal layer, a third metal layer on the second metal layer, and a fourth metal layer that is an uppermost layer on the third metal layer.

The second electrode vertically overlapping the light emitting structure in each of the plurality of LED chips has a first horizontal width, and the fourth metal layer on the transparent support member has a second horizontal width greater than the first horizontal width. The third metal layer may include an exposed upper surface that is not covered by the fourth metal layer by having a third horizontal width greater than the horizontal width of the fourth metal layer.

Light emitted from the light emitting structure of each of the plurality of LED chips may be reflected from the exposed upper surface of the third metal layer.

According to an embodiment of the present invention, the uppermost layers of the first and second pads may include at least one of Ag, Au, and Cu. The uppermost layers of the first and second pads may have a surface resistance of 100 mΩ or less. The uppermost layers of the first and second pads may have a surface resistance of 50 mΩ or less. Each of the first and second pads is bonded to the first and second electrodes of the LED chip by a bonding layer, and the bonding layer may be a metal composite such as AgSn or AuSn based on Au, Ag, and Cu. .

According to an embodiment of the present invention, each of the first and second pads includes a first metal layer, a second metal layer on the first metal layer, a third metal layer on the second metal layer, and a fourth metal layer on the third metal layer, The first metal layer may be at least one of Ti or MO, the second metal layer may be Al, the third metal layer may be at least one of Ti or MO, and the fourth metal layer may be an uppermost layer of the first and second pads. have.

According to an embodiment of the present invention, the thickness of the fourth metal layer may be in the range of 10 nm to 2 μm. For example, the thickness of the fourth metal layer may range from 50 nm to 100 nm. A first insulating layer covering the thin film transistor may be disposed around the first and second pads on which the plurality of LED chips are respectively disposed.

In addition, the display panel according to the embodiment includes a circuit board having a transparent support member and a thin film transistor part on the transparent support member, at least one pad disposed on an upper surface of the circuit board and electrically connected to the thin film transistor part, and a second circuit board. 1 It includes at least one electrode having a horizontal width and a light emitting structure, and may include a plurality of LED chips disposed on the pad.

The pad includes a plurality of metal layers disposed on the circuit board, and an uppermost metal layer among the plurality of metal layers is made of a metal material and may contact the electrode.

The plurality of metal layers of the pad may include a first lower metal layer disposed under the uppermost metal layer.

The first lower metal layer may have an area larger than an area of the uppermost metal layer.

The uppermost metal layer on the transparent support member may have a second horizontal width equal to or greater than the first horizontal width.

The first lower metal layer may have a third horizontal width greater than the second horizontal width.

The first lower metal layer may include an exposed upper surface that is not covered by the uppermost metal layer.

Light emitted from the light emitting structure may be reflected from the exposed upper surface of the first lower metal layer.

The uppermost metal layer may include at least one of Ag, Au, Cu, and Ni.

The uppermost metal layer may have a sheet resistance of 100 mΩ or less.

The plurality of metal layers may include a second lower metal layer and a third lower metal layer sequentially disposed under the first lower metal layer.

The first lower metal layer may be at least one of Ti and MO, and the second lower metal layer may be at least one of Al (Aluminum), Cu, and W, or an alloy thereof. The third lower metal layer may be at least one of Ti and MO.

A first insulating layer covering the thin film transistor may be disposed around the pad on which the plurality of LED chips are respectively disposed.

The first insulating layer may be disposed on an exposed upper surface of the first lower metal layer that is not covered by the uppermost metal layer.

In an embodiment of the present invention, there is a technical effect of removing the ITO layer and the anisotropic conductive film disposed on the circuit board by metal bonding between the electrode of the LED chip and the pad of the circuit board.

In an embodiment of the present invention, since the electrode of the LED chip and the pad of the circuit board are metal-bonded, there is a technical effect of lowering the surface resistance of the pad on which the LED chip is mounted and reducing the heat generation problem.

In an embodiment of the present invention, there is a technical effect of improving the electrical efficiency between the electrode of the LED chip and the pad of the circuit board by metal bonding between the electrode of the LED chip and the pad of the circuit board.

In an embodiment of the present invention, since the electrode of the LED chip and the pad of the circuit board are metal-bonded, there is a technical effect of connecting the electrode of the LED chip and the pad of the circuit board by solder bonding without bumps.

By removing the ITO layer and the anisotropic conductive film in the embodiment of the present invention, there is a technical effect that it is easy to repair or replace the light emitting diode chip.

There is a technical effect that can improve the reliability of a light source module, a display panel, and a display device according to an embodiment of the present invention.

1 is a diagram illustrating a display device in which a display panel having a plurality of LED chips is combined according to an exemplary embodiment of the present invention.
2 is a front view showing an example of a light source module according to an embodiment of the present invention.
3 is a diagram illustrating an example of a side cross-section of the light source module of FIG. 2.
4 is a view for explaining an example of an LED chip and a TFT of a circuit board in FIG. 3.
5 is a diagram illustrating an example of a rear surface of the circuit board of the light source module of FIG. 2.
6 is an example of LED chips arranged in each pixel on the circuit board of FIG. 2.
7 is another example of LED chips arranged in each pixel on the circuit board of FIG. 2.
8 is a detailed configuration diagram of an electrode of an LED chip and a pad of a circuit board in FIG. 6 or 7.
9 is a diagram illustrating an example of bonding an electrode of an LED chip and a pad of a circuit board in FIG. 8.
10 is another example of metal layers of a pad of a circuit board in FIG. 8.
11 is an example of a light source module in which a plurality of LED chips are mounted on a circuit board according to an embodiment of the present invention.
12 is another example of an LED chip in each pixel of FIG. 11.
13 is a diagram illustrating an example in which the LED chips of FIG. 12 are mounted on a circuit board.
14 and 15 are views showing another example of LED chips of each pixel of a display panel according to an embodiment of the present invention.
16 is a diagram illustrating an example in which an ITO layer is discolored or peeled off a pad of a conventional circuit board.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, and only these embodiments make the disclosure of the present invention complete, and the general knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to the possessor, and the 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 exemplary, and thus the present invention is not limited to the illustrated matters. The same reference numerals refer to the same elements throughout the specification. In addition, in describing the present invention, when it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. When'include','have', and'consist of' mentioned in the present specification are used, other parts may be added unless'only' is used. In the case of expressing the constituent elements in the singular, it includes the case of including the plural unless specifically stated otherwise. In interpreting the constituent elements, it is interpreted as including an error range even if there is no explicit description. In the case of a description of the positional relationship, for example, if the positional relationship of two parts is described as'upper','upper of','lower of','next to','right' Or, unless'direct' 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 predecessor relationship is described as'after','following','after','before', etc.,'right' or'direct' It may also include cases that are not continuous unless this is used. First, second, etc. are used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one component from another component. Accordingly, the first component mentioned below may be a second component within the technical idea of the present invention.

Each of the features 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 of the embodiments may be independently implemented with respect to each other or can be implemented together in an association relationship. May be.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing a display device in which a display panel having a plurality of LED chips according to an embodiment of the invention is combined, FIG. 2 is a front view showing an example of a light source module according to an embodiment of the invention, and FIG. 3 is 2 is a view showing an example of a side cross-section of the light source module of FIG. 2, FIG. 4 is a view illustrating an example of the LED chip and the TFT of the circuit board in FIG. 3, and FIG. 5 is a diagram showing a rear example of the circuit board of the light source module of FIG. 6 is an example of LED chips arranged in each pixel on the circuit board of FIG. 2, FIG. 7 is another example of LED chips arranged in each pixel on the circuit board of FIG. 2, and FIG. 8 is 6 or 7 is a detailed configuration diagram of the electrode of the LED chip and the pad of the circuit board, and FIG. 9 is a view showing an example of bonding the electrode of the LED chip and the pad of the circuit board in FIG. 8.

1㎛, 10㎛ 등)의 범위일 수도 있다. 예를 들어, 상기 LED칩(2A,2B,2C)의 사이즈는 1㎛ 내지 50㎛ × 1㎛ 내지 50㎛의 범위일 수 있으나 이에 한정되는 것은 아니다1 to 3, the display device may include one or more display panels 11, 12, 13, and 14. The display panels 11, 12, 13, and 14 may be arranged on the same plane, and at least one of the panels 11, 12, 13, and 14 may be arranged or tilted on another plane. In the display panels 11, 12, 13, and 14, unit pixels having a plurality of LED chips 2A, 2B, and 2C may be arranged in a matrix form. LED chips 2A, 2B, and 2C may be disposed in each sub-pixel of the unit pixels. The unit pixel may be implemented with LED chips 2A, 2B, and 2C emitting different colors, for example, at least three colors, or a combination of an LED chip emitting the same color and a phosphor layer. The unit pixel may emit red, green, and blue light. For example, the LED chips 2A, 2B, 2C may include red (R), green (G), and blue (B) LED chips. . The size (X3×Y3) of each of the display panels 11, 12, 13, 14 is a size suitable for various application fields such as a wrist watch, a mobile phone terminal, or a tiling type monitor or TV, or a large TV, a single panel of a billboard Can be implemented as For example, the size (X3×Y3) of each of the display panels 11, 12, 13, and 14 may be 2 inches or more, but is not limited thereto. The LED chips 2A, 2B, 2C are chips having a micro size for sub-pixels, and, for example, the length of one side may range from 10 μm to 100 μm. The size of the LED chips (2A, 2B, 2C) is a fine size (

1 μm, 10 μm, etc.). For example, the size of the LED chips 2A, 2B, 2C may range from 1 μm to 50 μm × 1 μm to 50 μm, but is not limited thereto.

The boundary portions to which the display panels 2A, 2B, and 2C are coupled may be closely coupled so that they are not distinguished from the outside. That is, the display panels 2A, 2B, and 2C may have an arrangement structure or a combination structure in which dark lines do not occur at the boundary portion. The size of the display device including the display panels 2A, 2B, 2C may vary depending on the number of combinations of the display panels 2A, 2B, and 2C and the size of each panel. In addition, in the display device, each panel can be combined, separated or removed.

2 and 3, the circuit board 20 of the display panel uses a TFT array board capable of driving a plurality of LED chips 2A, 2B, and 2C. That is, the circuit board 20 includes a thin film transistor (TFT) unit 50 and various wires for driving a plurality of LED chips 2A, 2B, 2C, and when the thin film transistor is turned on, The driving signal input from the outside is applied to the LED chips 2A, 2B, 2C, and each LED chip emits light to realize an image. The circuit board 20 may include a circuit, eg, a thin film transistor, configured to independently drive sub-pixels, eg, LED chips 2A, 2B, and 2C, disposed in each pixel region 2.

Each pixel area 2 of the circuit board 20 includes at least three LED chips 2A, 2B, and 2C that emit red, green, and blue monochromatic light. Red, green, and blue colored light is emitted from the chip, so that an image can be displayed.

The plurality of LED chips 2A, 2B, 2C may be mounted in a process separate from the TFT array process of the circuit board 20. That is, the thin film transistor and various wirings disposed on the circuit board 20 are formed by a photo process, but the LED chips 2A, 2B, and 2C may be mounted through a separate bonding process or a reflow process.

Here, the configuration of the circuit board 20 having the thin film transistor and the plurality of LED chips 2A, 2B, and 2C disposed on the circuit board 20 may be defined as a light source module. The circuit board 20 may include a thin film transistor part 50 connected to the LED chips 2A, 2B, and 2C. The circuit board 20 may be formed of a transparent support member 1 such as glass, and the thin film transistor part 50 may be disposed on the front surface of the support member 1. The LED chips 2A, 2B, 2C may include a light emitting structure (102-104 of FIG. 8) that generates light, and first and second electrodes 105 and 106.

As shown in FIG. 4, a light-transmitting cover 7 may be disposed on the circuit board 20 on which the LED chips 2A, 2B, 2C are disposed, and the light-transmitting cover 7 includes the LED chips 2A, The light emitted from 2B, 2C) may be emitted. The transparent cover 7 may be a glass material or a soft or rigid plastic material, and may be a protective layer or a protective cover. A transparent layer 7A may be disposed between the LED chips 2A, 2B, 2C and the light-transmitting cover 7, and the transparent layer 7A may be formed of a transparent resin material such as silicone or epoxy, or air. It can be a gap.

In the circuit board 20, the thin film transistor unit 50 includes a gate electrode 51, a semiconductor layer 53, a source electrode 55, and a drain electrode 57. A gate electrode 51 is formed on the circuit board 20, a gate insulating layer 49 is formed over the entire area of the circuit board 110 to cover the gate electrode 51, and the semiconductor layer 53 is a gate It is formed on the insulating layer 49, and the source electrode 55 and the drain electrode 57 are formed on the semiconductor layer 53.

The gate electrode 51 may be formed of a metal such as Cr, Mo, Ta, Cu, Ti, Al, or an Al alloy, or an alloy thereof, and the gate insulating layer 49 is made of an inorganic insulating material such as SiOx or SiNx. It may be made of a single layer made of or a plurality of layers made of SiOx and SiNx. The semiconductor layer 53 may be composed of an amorphous semiconductor such as amorphous silicon, or may be composed of an oxide semiconductor such as _{Indium Gallium Zinc Oxide (IGZO), TiO2, ZnO, WO 3} , and SnO _2. When the semiconductor layer 53 is formed of an oxide semiconductor, the size of the thin film transistor (TFT) can be reduced, driving power can be reduced, and electric mobility can be improved. Of course, in the present invention, the semiconductor layer of the thin film transistor is not limited to a specific material, and all kinds of semiconductor materials currently used in the thin film transistor may be used.

The source electrode 55 and the drain electrode 57 may be made of a metal such as Cr, Mo, Ta, Cu, Ti, Al, or an Al alloy, or an alloy thereof. In this case, the drain electrode 57 may be used as a first connection electrode for applying a signal to the LED chips 2A, 2B, and 2C. Meanwhile, in the drawings, the thin film transistor unit 50 is a bottom gate type thin film transistor, but the present invention is not limited to such a specific structure thin film transistor, but has various structures such as a top gate type thin film transistor. Thin film transistors could be applied.

As shown in FIG. 4, a second connection electrode 59 is formed on the first insulating layer 41 in the display area A1. At this time, the second connection electrode 59 may be formed of a metal such as Cr, Mo, Ta, Cu, Ti, Al, or an Al alloy, or an alloy thereof, and the second connection electrode 59 (ie, a thin film transistor ( TFT) can be formed by the same process as the drain electrode 57).

The first insulating layer 41 is formed on the circuit board 20 on which the thin film transistor unit 50 is formed, and the LED chips 2A, 2B, and 2C are disposed on the first insulating layer 41 in the display area. In this case, in the drawing, a part of the first insulating layer 114 is removed, and the LED chips 2A, 2B, and 2C may be arranged on the removed region. The first insulating layer 41 may be composed of an organic layer such as a polyimide (PI) film or photoacrylic, or may be composed of a multilayer structure such as an inorganic layer/organic layer or an inorganic layer/organic layer/inorganic layer.

First and second pads 61 and 63 may be disposed in an area in which the first insulating layer 41 is opened. The first pad 61 may be disposed on the first connection electrode 57 or may be a part of the first connection electrode 57. The second pad 63 may be disposed on the second connection electrode 59 or may be a part of the second connection electrode 59.

3 and 5, a driver IC 19 and a lower pad connected thereto may be disposed on the rear surface of the circuit board 20. An edge pattern 31 is disposed in an edge area or a non-display area A2 on the front and rear surfaces of the circuit board 20, so that wirings such as an upper pad on the front side and a lower pad on the bottom surface may be connected to each other. The edge pattern 31 may be protected by the protective layer 33. The upper pad and the lower pad are connected to each other through an edge pattern 31 made of a conductive material around the outer periphery of the circuit board 20, so that holes penetrating the circuit board 20 do not need to be formed.

The first electrode 105 of the LED chips 2A, 2B, 2C is disposed on the first pad 61 of the circuit board, and the second electrode 106 is disposed on the second pad 63 Can be. The first and second pads 61 and 63 are electrically connected to the thin film transistor through the first and second connection electrodes 57 and 59, and the first and second pads of the LED chips 2A, 2B and 2C It may be electrically connected to the second electrodes 105 and 106. Here, the first and second pads 61 and 63 may not include a non-metallic material. The first and second pads 61 and 63 may include at least two or more of Ti, Ni, Pt, TiN, Mo, Al, W, Cu, Ag, and Au. The first and second pads 61 and 63 may be formed in multiple layers.

As shown in FIG. 6, in the pixel area 2, each of the LED chips 2A, 2B, and 2C may be disposed on the first and second pads 61 and 63, respectively. The LED chips 2A, 2B, 2C constituting the pixel area 2 may be arranged in a triangular shape, for example, a right-angled triangle shape or a regular triangle shape. At this time, each of the first pads 61 may be electrically connected to the common electrode 69 through the connection pattern 65. The first and second pads 61 and 63 are provided with a size larger than the size of the first and second electrodes 105 and 106 of each of the LED chips 2A, 2B, and 2C, so that the LED chips can be easily mounted. I can.

As shown in FIG. 7, in the pixel area 2, respective LED chips 2A, 2B, and 2C may be arranged in a row or column direction. In the direction in which the LED chips 2A, 2B, 2C are arranged, second pads 63A, 63B, 63C and a first pad 61 are disposed, respectively, and the first pad 61 includes a plurality of second pads. A single dog may be disposed in the area facing the pads 63A, 63B, and 63C. The first pad 61 may function as a common electrode.

In an embodiment of the present invention, a material of the pads 61 and 63 electrically connected to the LED chips 2A, 2B, 2C under the LED chips 2A, 2B, 2C is made of a metal material or a material having low surface resistance. Can provide. The material of the pads 61 and 63 bonded to each of the electrodes 105 and 106 of the LED chips 2A, 2B, 2C provides metal bonding, so that the surface of the layer connected to the LED chips 2A, 2B, 2C The resistance value is lowered and the heat generation problem can be improved.

Conventionally, a circuit board has a transparent glass material such as glass, and a transparent conductive layer such as ITO is used for each pad of the circuit board. Such a circuit board has a function of transmitting light emitted through a backlight unit in the same configuration as a liquid crystal display device. The pad or transparent conductive layer disposed on the circuit board is used as an electrode for opening and closing the liquid crystal. The conventional transparent conductive layer was used as an electrode for transmitting light and opening and closing liquid crystals rather than lowering surface resistance or reducing heat generation. When the transparent conductive layer of the circuit board is disposed on the pad and bonded to the LED chip, the surface resistance value of the transparent conductive layer increases, and there is a limit in dissipating heat conducted from the LED chip. That is, in the case of using the transparent conductive layer, the surface resistance is high in the range of 150 Ω or more, for example, 200 Ω to 300 Ω, and may cause heat generation of the LED chip. As a result, there may be a problem that the LED chip is damaged or the wiring is opened due to heat generation of the LED chip. In addition, as shown in (B) of FIG. 16, a problem in that the ITO layer is partially discolored or oxidized (TiOx) to the lower metal layer may occur.

In addition, conventionally, an anisotropic conductive film (ACF) is used between the LED chip and the circuit board for adhesion and conduction. At this time, the anisotropic conductive layer is attached by thermal compression on the pad, and may connect the LED chip and the pad. However, when the anisotropic conductive layer is attached by heat, a problem of melting a solder ball for connecting an LED chip may occur. In addition, when used for a long time, there may be a problem that the transparent conductive layer disposed on the circuit board and the anisotropic conductive film are separated, and the lower metal layer (Ti) of the pad may also be peeled off together with the film (Fig. (A) see). When attaching the anisotropic conductive film, it may be difficult to repair the LED chip. In addition, in the process of manufacturing a panel, it may cause defects in many LED chips due to the generation of static electricity by ACF and ITO.

Accordingly, in the embodiment of the present invention, the pads 61 and 63 of the circuit board 20 may be provided with a metal material as the uppermost layer bonded to the LED chips 2A, 2B and 2C. The uppermost layer of the metal material may bond the pads 61 and 63 to the respective electrodes 105 and 106 of the LED chips 2A, 2B, and 2C. Accordingly, the surface resistance of the bonding surface between the pad and the electrode connected to the LED chips 2A, 2B, 2C can be lowered, and electrical conduction and thermal conduction may be improved. In addition, the uppermost layer of the metal material may perform a wiring function compared to ITO. In addition, the uppermost layer of the metal material may be connected to the LED chips 2A, 2B, and 2C through a soldering process without bumps. By providing the uppermost layer of the metal material, the anisotropic conductive film can be removed. In addition, when repairing the LED chips 2A, 2B, 2C, the metal layer may be separated to separate or remove the LED chips 2A, 2B, 2C.

The first and second pads 61 and 63 of the circuit board 20 may have at least two or three or more layers. The first and second pads 61 and 63 of the circuit board 20 include a first metal layer L1 on the support member 1, a second metal layer L2 on the first metal layer L1, and A third metal layer L3 on the second metal layer L2 and a fourth metal layer L4 on the third metal layer L3 may be included. The first metal layer L1 is an adhesive layer adhered to the surface of the support member 1 and may include at least one of Ti, Ni, TiN, Mo, and Pt, or an alloy having the metal. The second metal layer (L2) is disposed between the first metal layer (L1) and the third metal layer (L3) and may be formed of a material for heat conduction and electrical conduction, for example, at least one of Al, Cu, W Or it may be formed of an alloy having a selected metal. The third metal layer L3 may be a layer for bonding the second metal layer L2 and the fourth metal layer L4 to each other. The third metal layer L3 may be formed of the same material as the first metal layer L1 or at least one of Ti, Ni, TiN, Mo, and Pt.

The fourth metal layer L4 is a bonding layer, and may be a bonding material, for example, a material bonded with solder. The fourth metal layer L4 may be selected from at least one of Ag, Au, or an alloy having the metal. The fourth metal layer L4 may be a layer for preventing oxidation.

The fourth metal layer L4 is a layer that is bonded to the first electrode 105 and the second electrode 106 of the LED chips 2A, 2B, 2C, and the surface resistance can be lowered by a metal material. It can improve the thermal conductivity. The surface resistance value of the fourth metal layer L4 is 1Ω or less, and may be 50mΩ or less, or in the range of 10mΩ to 30mΩ. That is, the fourth metal layer L4 is bonded to each electrode of the LED chip 2A, 2B, and 2C, and has a lower surface resistance compared to the existing ITO layer and can provide high thermal and electrical conduction characteristics. . The thickness of the fourth metal layer L4 may range from 10 nm to 2 μm. For example, the thickness of the fourth metal layer L4 may be provided in a range of 50 nm or more, for example, 50 to 100 nm. When the thickness of the fourth metal layer L4 is lower than the above range, heat conduction and electrical conduction characteristics may be low. The pads 61 and 63 having the fourth metal layer L4 may function as wiring compared to the low electrical conduction of the ITO layer. In addition, the first to fourth metal layers L1-L4 may be deposited by a sputtering method.

A first insulating layer 41 may be disposed outside the first to fourth metal layers L1-L4. That is, pads 61 and 63 having the first to fourth metal layers L1-L4 may be disposed in the open area of the first insulating layer 41, respectively.

As shown in FIG. 9, the electrodes 105 and 106 of the LED chips 2A, 2B and 2C and the pads 61 and 63 may be bonded to each other by bonding layers B1 and B2. The first electrode 105 and the first pad 61 may be bonded to each other by a first bonding layer B1. The second electrode 106 and the second pad 63 may be bonded to each other by a second bonding layer B2. The first and second bonding layers B1 and B2 may include Sn, and may include, for example, an intermetallic compound having AgSn or AuSn.

The first to fourth metal layers L1-L4 may be pads disposed separately from the connection electrode, or a layer included in the connection electrode. As another example, as shown in FIG. 10, of the first to fourth metal layers L1 to L4, the first to third metal layers L1 to L3 have a larger area or a longer length than the fourth metal layer L4. It may be a connection electrode having, and the fourth metal layer L4 may be a pad layer. As shown in FIG. 10, the first insulating layer 41 may be disposed on the upper surface of the third metal layer L3 and may be disposed outside the fourth metal layer L4. The first to third metal layers L1-L3 are lower pads and may be the connection electrodes.

8 and 10, the LED chips 2A, 2B, 2C may include a light-transmitting substrate 101 on the light emitting structures 102-104. The light-transmitting substrate 101 may be a growth substrate or a transparent layer, and may be formed of an insulating material or a semiconductor material. The light-transmitting substrate 101 may be selected from a group including, for example, a sapphire substrate (Al ₂ O ₃ ), SiC, GaAs, GaN, ZnO, Si, GaP, InP, and Ge.

The light emitting structures 102-104 may be provided with a compound semiconductor. The light-emitting structures 102-104 may be provided as a group 2-6 or 3-5 compound semiconductor, for example. For example, the light emitting structures 102-104 include at least two or more elements selected from aluminum (Al), gallium (Ga), indium (In), phosphorus (P), arsenic (As), and nitrogen (N). Can be provided.

The light emitting structure 102-104 includes a first conductivity type semiconductor layer 102 connected to the first electrode 105, an active layer 103, and a second conductivity type semiconductor layer 104 connected to the second electrode 106. Can include. The first and second conductivity-type semiconductor layers 102 and 104 may be implemented with at least one of a group 3-5 or a group 2-6 compound semiconductor. The first and second conductivity type semiconductor layers 102 and 104 include at least one selected from the group including, for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP, AlGaInP, etc. can do. The first conductivity-type semiconductor layer 102 may be an n-type semiconductor layer doped with an n-type dopant such as Si, Ge, Sn, Se, and Te. The second conductivity-type semiconductor layer 104 may be a p-type semiconductor layer doped with a p-type dopant such as Mg, Zn, Ca, Sr, or Ba. As another example, the first and second conductive type semiconductor layers 102 and 104 may be p-type and n-type semiconductor layers.

The active layer 103 may be implemented as a compound semiconductor. The active layer 103 may be implemented as at least one of a group 3-5 or a group 2-6 compound semiconductor. When the active layer 103 is implemented in a multi-well structure, the active layer 103 may include a plurality of well layers and a plurality of barrier layers alternately disposed, InGaN/GaN, GaN/AlGaN, AlGaN/AlGaN , InGaN/AlGaN, InGaN/InGaN, AlGaAs/GaAs, InGaAs/GaAs, InGaP/GaP, AlInGaP/InGaP, and InP/GaAs.

A layer of a reflective material (not shown) for reflecting light may be disposed under the light emitting structures 102-104. The reflective material layer may be formed of a metal or non-metal material, and may include a single layer or multiple layers.

The first and second electrodes 105 and 106 of the LED chips 2A, 2B and 2C may be disposed under the LED chips 2A, 2B and 2C, disposed opposite to each other, or disposed horizontally to each other. have. The LED chips 2A, 2B, 2C may be provided as flip chips, vertical chips, or horizontal chips depending on the positions of the first and second electrodes 105 and 106. The first and second electrodes 105 and 106 are Ti, Al, In, Ir, Ta, Pd, Co, Cr, Mg, Zn, Ni, Si, Ge, Ag, Ag alloy, Au, Hf, Pt, Ru, It includes at least one or two or more of Rh, and may be formed as a single layer or multiple layers.

The light-transmitting substrate 101 may be removed or separated from the top of the LED chips 2A, 2B, 2C. On top of each of the LED chips 2A, 2B, 2C, a layer or film having a wavelength converting material such as a phosphor may be disposed. The phosphor disposed on the layer or film disposed on each of the LED chips 2A, 2B, 2C may include at least one of yellow, green, red, and blue. For example, the phosphor may wavelength convert light emitted from the LED chips 2A, 2B, 2C into red, green, yellow, and blue light.

Referring to FIG. 11, each of the first to third LED chips 2A, 2B, and 2C disposed in the unit pixel area may be defined as an individual light emitting unit. The first to third LED chips 2A, 2B, 2C are formed on the first conductive type semiconductor layer 102, the active layer 103, the second conductive type semiconductor layer 104, and the first conductive type semiconductor layer 102. It may include a connected first electrode 105 and a second electrode 106 connected to the second conductive semiconductor layer 104. The insulating layer 107 electrically insulates between the first electrode 105, the second electrode 106, the first conductive semiconductor layer 102, the active layer 103 and the second conductive semiconductor layer 104 I can let you do it.

A light-transmitting substrate 101 may be disposed on each of the LED chips 2A, 2B, and 2C, and a wavelength converter 150 emitting a different color may be disposed on each of the light-transmitting substrates 101, respectively. have. For example, a first wavelength conversion unit 150a on the first LED chip 2A, a second wavelength conversion unit 150b on the second LED chip 2B, and a third wavelength conversion unit 150c on the third LED chip 2c. Can be placed. The LED chips 2A, 2B, 2C may be ultraviolet light or blue light. Light emitted through the first to third wavelength converters 150a, 150b, and 150c may be red, green, or blue. When the third LED chip 2C emits blue light, the third wavelength converter 150c may be removed or may be a transparent layer or may emit blue wavelengths having different peak wavelengths. The first to third LED chips 2A, 2B, and 2C are spaced apart from each other, and two adjacent LED chips may have the same distance from each other in one pixel area.

As shown in FIG. 12, the LED chip 110 is divided into a plurality of light emitting structures 102-104, and may be disposed under a single light-transmitting substrate 101. In this case, the plurality of light emitting structures 102 to 104 may emit the same blue light or ultraviolet light. In this case, the wavelength converter may be selectively disposed on the light-transmitting substrate 101 to emit light for the sub-pixel. The light emitting structures of the LED chip 110 may be separated from each other by the separation unit 108. As shown in FIG. 13, each of the electrodes 105 and 106 of the LED chip 110 may be metal bonded to each of the pads 61 and 63 in the pixel area of the circuit board 20.

As shown in FIG. 14, on the light-transmitting substrate 101 of the LED chip 110, a wavelength conversion unit 150 having first to third wavelength conversion units 150a, 150b, 150c is formed on each light emitting structure 102-104. And the light blocking part Pb may be disposed on the separating part 108. The first to third wavelength converters 150a, 150b, and 150c may emit red, green, and blue light. The light blocking part Pb may prevent the light emitted through different light emitting structures from being mixed. The light blocking part Pb may be formed separately, and may be a resin layer to which impurities such as _{TiO 2} and Sio _{2 are added.}

As shown in FIG. 15, a light blocking part 120 is disposed in the separating part 108 to support adjacent light emitting structures. The light blocking unit 120 may prevent the light emitted through different light emitting structures from being mixed, and may be a resin layer to which impurities such as _{TiO 2} and Sio _{2 are added.}

Therefore, it is possible to perform a TFT function by integrally installing a switching element in a pixel having a plurality of LED chips, and it is possible to reduce the surface resistance in the bonding layer bonded to the LED chip and improve electrical conduction and heat conduction.

As described above, although it has been described with reference to a preferred embodiment of the present invention, those skilled in the art will variously modify and change the present invention within the scope not departing from the spirit and scope of the present invention described in the following claims. You will understand that you can do it.

In addition, reference numerals in the claims of the present invention are provided for clarity and convenience of description, and are not limited thereto. In the process of describing the embodiments, the thickness of the lines shown in the drawings, the size of components, etc. May be exaggerated for clarity and convenience of description, and the above-described terms are terms defined in consideration of functions in the present invention and may vary according to the intention or custom of users and operators. Should be made based on the contents throughout this specification.

1: support member
2: pixel area
2A,2B,2C: LED chip
11,12,13,14: display panel
20: circuit board
41: first insulating layer
50: thin film transistor unit
61,63: pad
101: light-transmitting substrate
102: first conductive type semiconductor layer
103: active layer
104: second conductive type semiconductor layer
105,106: electrode
L1: first metal layer
L2: second metal layer
L3: third metal layer
L4: fourth metal layer

Claims (10)

A circuit board having a transparent support member and a thin film transistor portion on the transparent support member;
At least one pad disposed on an upper surface of the circuit board and electrically connected to the thin film transistor; And
Includes at least one electrode and a light emitting structure having a first horizontal width, a plurality of LED chips disposed on the pad; and,
The pad includes a plurality of metal layers disposed on the circuit board, and an uppermost metal layer of the plurality of metal layers is made of a metal material and contacts the electrode,
The plurality of metal layers of the pad includes a first lower metal layer disposed under the uppermost metal layer,
The display panel, wherein the first lower metal layer has an area larger than an area of the uppermost metal layer. The method of claim 1,
The uppermost metal layer on the transparent support member has a second horizontal width equal to or greater than the first horizontal width,
The display panel, wherein the first lower metal layer has a third horizontal width greater than the second horizontal width. The method of claim 2,
The first lower metal layer includes an exposed upper surface not covered by the uppermost metal layer,
The display panel, characterized in that the light emitted from the light emitting structure is reflected from the exposed upper surface of the first lower metal layer. The method of claim 1,
The plurality of LED chips may include a first LED chip emitting a first wavelength, a second LED chip emitting a second wavelength greater than the first wavelength, and a third emitting device having a third wavelength greater than the second wavelength. A display panel comprising an LED chip, wherein each of the plurality of LED chips is individually driven by the thin film transistor unit and forms subpixels of the display. The method of claim 1,
The uppermost metal layer is a display panel including at least one of Ag, Au, Cu, and Ni. The method of claim 5,
The uppermost metal layer is a display panel having a surface resistance of 100mΩ or less. The method of claim 1,
The pad is bonded to the electrode of the LED chip with a bonding layer,
The bonding layer is a display panel including any one or more of AgSn, AgCu, or AuSn. The method of claim 1,
The plurality of metal layers,
A second lower metal layer and a third lower metal layer sequentially disposed under the first lower metal layer,
The first lower metal layer is at least one of Ti or MO,
The second lower metal layer is at least one of Al (Aluminum), Cu, and W, or an alloy thereof,
The third lower metal layer is at least one of Ti or MO,
Display panel. The method of claim 3,
A display panel in which a first insulating layer covering the thin film transistor is disposed around the pads on which the plurality of LED chips are respectively disposed. The method of claim 9,
The first insulating layer,
The display panel, which is disposed on an exposed upper surface of the first lower metal layer that is not covered by the uppermost metal layer.

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