KR20230073938A - Manufacturing method of display panel - Google Patents

Abstract

A manufacturing method of a display panel is disclosed. The manufacturing method comprises the following steps of: inputting a first substrate into liquid; inputting a plurality of light emitting diodes into the liquid into which the first substrate is inputted; fluidly self-assembling the plurality of light emitting diodes with the first substrate; transferring the plurality of light emitting diodes arranged on the first substrate to a second substrate; and thermally compressing the plurality of light emitting diodes transferred to the second substrate to the second substrate.

Description

Manufacturing method of display panel {MANUFACTURING METHOD OF DISPLAY PANEL}

The present disclosure relates to a method of manufacturing a display panel.

The self-luminous display device displays an image without a color filter and a backlight, and may use an inorganic light emitting diode that emits light by itself.

The display panel expresses various colors while being operated in units of pixels or sub-pixels. The operation of each pixel or sub-pixel is controlled by a plurality of thin film transistors (TFTs). A plurality of TFTs are provided on one surface, and a plurality of light emitting diodes are electrically connected to the plurality of TFTs.

A plurality of light emitting diodes arranged on a wafer may be transferred to a target substrate by a pick and place method utilizing adhesive force of a stamp or transferred to a target substrate by a laser transfer method.

However, the pick-and-place method has a problem in that the wavelength distribution on the wafer is recognized by the target substrate as the wavelength distribution of the wafer is directly reflected on the target substrate. In order to prevent the wavelength distribution from being visible on the target substrate, a process of making the positions of the plurality of light emitting diodes transferred to the target substrate irregular is required. Such fixing has a problem of increasing manufacturing time and thus increasing manufacturing cost.

In the case of the laser transfer method, a laser beam is irradiated onto the wafer to remove an adhesive layer between the wafer and the light emitting diode, so that the light emitting diode attached to the wafer falls to the target substrate. Such a laser transfer method also has disadvantages in that a high cost is required to completely remove the wavelength distribution on the wafer, and a complicated process is required to transfer the light emitting diode onto a target substrate without damaging the light emitting diode during laser transfer.

An object of the present disclosure is to provide a method of manufacturing a display panel in which a plurality of light emitting diodes are arranged on a target substrate so that a specific wavelength distribution does not appear on the target substrate.

An object of the present disclosure is to provide a manufacturing method of a display panel capable of reducing manufacturing time and stably connecting a plurality of light emitting diodes to a target substrate.

According to an embodiment of the present disclosure, injecting the first substrate into the liquid; injecting a plurality of light emitting diodes into the liquid into which the first substrate is injected; fluid self-assembling the plurality of light emitting diodes to the first substrate; transferring the plurality of light emitting diodes arranged on the first substrate to a second substrate; and thermally compressing the plurality of light emitting diodes transferred to the second substrate to the second substrate.

The method of manufacturing the display panel may further include subjecting a portion of the first substrate and a portion of the plurality of light emitting diodes to a hydrophilic surface treatment before injecting the first substrate and the plurality of light emitting diodes into the liquid. .

Any one of the first electrode pad and the second electrode pad arranged in pairs on the first substrate may be treated with a hydrophilic surface, and one of the first electrode terminal and the second electrode terminal of the plurality of light emitting diodes may be treated with a hydrophilic surface. can do.

The liquid may be circulated so that the plurality of light emitting diodes may flow in the liquid and be inserted into a plurality of guide grooves provided in the first substrate.

The first substrate may be withdrawn from the liquid after the fluid self-assembly is completed.

The plurality of light emitting diodes arranged on the first substrate may be transferred to the second substrate in a pick and place method.

The plurality of light emitting diodes arranged on the first substrate may be transferred to the second substrate by a plurality of adhesive heads of the stamper.

In the thermal compression step, the light emitting diode may be fixed to the second substrate by an adhesive layer provided on one surface of the second substrate.

The manufacturing method of the display panel may further include curing the adhesive layer of the second substrate after the thermal compression step.

The adhesive layer may use an anisotropic conductive film or a non-conductive film.

1 is a block diagram illustrating a display device according to an exemplary embodiment of the present disclosure.
2 is a plan view illustrating a display panel included in a display device according to an exemplary embodiment of the present disclosure.
FIG. 3 is an enlarged view of pixels of portion A shown in FIG. 2 .
4 is a flowchart illustrating a manufacturing process of a display panel according to an embodiment of the present disclosure.
5 is a view showing an example of injecting a plurality of light emitting diodes into the liquid stored in the tank.
FIG. 6 is an enlarged view of portion B shown in FIG. 5 .
7 is a diagram illustrating an example in which a plurality of light emitting diodes are self-assembled to a relay substrate in a liquid stored in a tank.
FIG. 8 is an enlarged view of portion C shown in FIG. 7 .
9 is a diagram illustrating an example of picking a plurality of light emitting diodes arranged on a relay board with a stamper.
10 is a diagram illustrating an example of transferring a plurality of light emitting diodes to a target substrate by a stamper.
FIG. 11 is an enlarged view of portion D shown in FIG. 10 .
12 is a view showing an example of placing a plurality of light emitting diodes on a target substrate with a stamper.
FIG. 13 is an enlarged view of portion E indicated in FIG. 12 .
14 is a diagram illustrating an example of thermal compression to stably connect a plurality of light emitting diodes to a substrate.
FIG. 15 is an enlarged view of portion F shown in FIG. 14 .
16 is a diagram illustrating a display panel according to an embodiment of the present disclosure.

Hereinafter, various embodiments will be described in more detail with reference to the accompanying drawings. The embodiments described in this specification may be modified in various ways. Particular embodiments may be depicted in the drawings and described in detail in the detailed description. However, specific embodiments disclosed in the accompanying drawings are only intended to facilitate understanding of various embodiments. Therefore, the technical idea is not limited by the specific embodiments disclosed in the accompanying drawings, and it should be understood to include all equivalents or substitutes included in the spirit and technical scope of the invention.

In the present disclosure, terms including ordinal numbers such as first and second may be used to describe various elements, but these elements are not limited by the above-mentioned terms. The terminology described above is only used for the purpose of distinguishing one component from another.

In the present disclosure, terms such as “comprise” or “have” are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded. It is understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle. It should be. On the other hand, when an element is referred to as “directly connected” or “directly connected” to another element, it should be understood that no other element exists in the middle.

In the present disclosure, the expression 'same' means not only completely matching, but also including a degree of difference considering a processing error range.

In addition, in describing the present disclosure, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present disclosure, the detailed description thereof will be abbreviated or omitted.

In the present disclosure, the display module may include a display panel having an inorganic light emitting diode for displaying an image. Here, the display panel may be a flat panel display panel or a curved display panel, and a plurality of inorganic light emitting diodes (eg, micro LEDs or mini LEDs) of 100 μm or less are mounted, which provides better contrast compared to LCDs requiring a backlight. , response time and energy efficiency.

The inorganic light emitting diode applied to the present disclosure has higher brightness, luminous efficiency, and longer lifetime than organic light emitting diodes (OLEDs). The inorganic light emitting device may be a semiconductor chip capable of emitting light by itself when power is supplied. Micro LED, an inorganic light emitting diode, has fast response speed, low power, and high luminance. For example, microLEDs are more efficient at converting electricity into photons than LCDs or OLEDs. That is, they have higher "brightness per watt" compared to LCD or OLED displays. As a result, micro LEDs can produce the same brightness with about half the energy compared to LEDs or OLEDs that exceed 100 μm. In addition, micro LED can realize high resolution, excellent color, contrast and brightness, so it can accurately express a wide range of colors, and it can implement a clear screen even in bright sunlight outdoors. In addition, micro LED is resistant to burn-in and generates little heat, guaranteeing a long lifespan without deformation. The micro LED may have a flip chip structure in which an anode and a cathode electrode are formed on the same first surface and a light emitting surface is formed on a second surface opposite to the first surface on which the electrodes are formed.

In the present disclosure, a target substrate has a TFT layer having a thin film transistor (TFT) circuit formed thereon on the front surface, and a power supply circuit for supplying power to the TFT circuit, a data driving driver, and a gate on the rear surface. A driving driver and a timing controller controlling each driving driver may be disposed. A plurality of pixels arranged in a TFT layer can be driven by a TFT circuit.

In the present disclosure, the TFT provided in the display module may be a low-temperature polycrystalline silicon (LTPS) TFT, a low-temperature polycrystalline oxide (LTPO) TFT, or an oxide TFT.

In the present disclosure, the target substrate is a glass substrate, a synthetic resin series having a flexible material (eg, PI (polyimide), PET (polyethylene terephthalate), PES (polyethersulfone), PEN (polyethylene naphthalate), PC (polycarbonate) ), etc.) or a ceramic substrate can be used.

In the present disclosure, a TFT layer having a TFT circuit is disposed on the front surface of the target substrate, and the circuit may not be disposed on the rear surface of the target substrate. The TFT layer may be integrally formed on the target substrate or made in the form of a separate film and attached to one surface of the glass substrate.

In the present disclosure, the front surface of the target substrate may be divided into an active region and an inactive region. The active region may correspond to an area occupied by the TFT layer on the entire surface of the target substrate, and the inactive area may be an area other than the area occupied by the TFT layer on the entire surface of the target substrate.

In the present disclosure, the edge region of the target substrate may be the outermost region of the glass substrate. Also, the edge region of the target substrate may be an area other than the region where the circuit of the target substrate is formed. Also, the edge region of the target substrate may include a part of the front surface of the target substrate adjacent to the side surface of the target substrate and a part of the rear surface of the target substrate adjacent to the side surface of the target substrate. The target substrate may be formed in a quadrangle type. For example, the target substrate may be formed in a rectangle or square. The edge region of the target substrate may include at least one side of the four sides of the glass substrate.

In the present disclosure, the TFTs constituting the TFT layer (or backplane) are not limited to a specific structure or type. For example, the TFTs cited in the present disclosure include LTPS TFTs (Low-temperature polycrystalline silicon TFTs) and others. It can be implemented with oxide TFT, Si TFT (poly silicon, a-silicon), organic TFT, graphene TFT, etc., and only P-type (or N-type) MOSFET can be made and applied in the Si wafer CMOS process.

In the present disclosure, the target substrate included in the display module is not limited to the TFT substrate. For example, the target substrate may be a substrate without a TFT layer on which a TFT circuit is formed. In this case, the display module may include a substrate on which the micro IC is separately mounted and only the wiring is patterned.

In the present disclosure, the pixel driving method of the display module may be an active matrix (AM) driving method or a passive matrix (PM) driving method. The display module may form a wiring pattern to which each micro LED is electrically connected according to an AM driving method or a PM driving method.

In the present disclosure, the display module can be installed and applied to electronic products or electric vehicles that require wearable devices, portable devices, handheld devices, and various displays as a single unit, matrix type It can be applied to display devices such as monitors for personal computers (PCs), high-definition TVs and signage (or digital signage), electronic displays and the like through a plurality of assembling arrangements.

The display module of the present disclosure may include a plurality of inorganic light emitting devices for displaying an image arranged on a target substrate on which thin film transistors are formed. A plurality of inorganic light emitting devices may be sub-pixels constituting a single pixel. In the present disclosure, one 'light emitting element', one 'micro LED', and one 'sub-pixel' may be interchangeably used as the same meaning.

Hereinafter, with reference to the accompanying drawings, embodiments of the present disclosure will be described in detail so that those skilled in the art can easily carry out the present disclosure. However, the present disclosure may be implemented in many different forms and is not limited to the embodiments described herein. And in order to clearly describe the present disclosure in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Furthermore, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings and the contents described in the accompanying drawings, but the present disclosure is not limited or limited by the embodiments.

Hereinafter, a display device according to various embodiments of the present disclosure will be described with reference to drawings.

1 is a block diagram illustrating a display device according to an exemplary embodiment of the present disclosure.

Referring to FIG. 1 , a display device 1 according to an embodiment of the present disclosure may include a display module 3 and a processor 5.

The display module 3 according to an embodiment of the present disclosure may display various images. Here, the image is a concept including still images and/or moving images. The display module 3 can display various images such as broadcast content and multimedia content. Also, the display module 3 may display a user interface and icons.

The display module 3 may include a display panel 10 and a display driver IC (DDI) 7 for controlling the display panel 10 .

The display driver IC 7 may include an interface module 7a, a memory 7b (eg, a buffer memory), an image processing module 7c, or a mapping module 7d. The display driver IC 7 transmits image information including, for example, image data or image control signals corresponding to commands for controlling the image data to other parts of the display device 1 through the interface module 7a. can be received from the component. For example, according to an embodiment, image information may be received from a processor 5 (eg, a main processor (eg, an application processor) or an auxiliary processor (eg, a graphic processing unit) that operates independently of the function of the main processor). can

The display driver IC 7 may store at least a portion of the received image information in the memory 7b, for example, in units of frames. The image processing module 7c pre-processes or post-processes at least a portion of the image data based on the characteristics of the image data or the characteristics of the display panel 10 (eg, resolution, brightness, or size adjustment). can be performed. The mapping module 7d may generate a voltage value or current value corresponding to the image data pre-processed or post-processed through the image processing module 7c. According to an embodiment, the generation of the voltage value or the current value depends on, for example, the properties of the pixels of the display panel 10 (eg, the arrangement of pixels (RGB stripe or pentile structure) or the size of each sub-pixel). It can be performed based at least in part. At least some pixels of the display panel 10 are driven based, for example, at least in part on the voltage value or current value, so that visual information (eg text, image, or icon) corresponding to the image data is displayed on the display panel ( 10) can be displayed.

The display driver IC 7 may transmit a driving signal (eg, a driver driving signal, a gate driving signal, etc.) to the display based on image information received from the processor 5 .

The display driver IC 7 may display an image based on the image signal received from the processor 5 . For example, the display driver IC 7 generates a driving signal for a plurality of subpixels based on the image signal received from the processor 5, and displays an image by controlling light emission of the plurality of subpixels based on the driving signal. can do.

The display module 3 may further include a touch circuit (not shown). The touch circuit may include a touch sensor and a touch sensor IC for controlling the touch sensor. The touch sensor IC may control the touch sensor to detect, for example, a touch input or a hovering input to a designated position of the display panel 10 . For example, the touch sensor IC may detect a touch input or a hovering input by measuring a change in a signal (eg, voltage, light amount, resistance, or charge amount) for a designated position of the display panel 10 . The touch sensor IC may provide information (eg, location, area, pressure, or time) on the sensed touch input or hovering input to the processor 5 . According to an embodiment, at least a part of the touch circuit (eg, touch sensor IC) is a display driver IC 7, a part of the display panel 10, or another component disposed outside the display module 3 ( eg as part of a co-processor).

The processor 5 includes a digital signal processor (DSP), a microprocessor, a graphics processing unit (GPU), an artificial intelligence (AI) processor, a neural processing unit (NPU), and a TCON for processing digital image signals. (time controller), but is not limited to, central processing unit (CPU), micro controller unit (MCU), micro processing unit (MPU), controller, application It may include, or be defined in terms of, one or more of a processor (application processor (AP)), communication processor (communication processor (CP)), or ARM processor. In addition, the processor 50 has a built-in processing algorithm. It may be implemented in the form of a system on chip (SoC), large scale integration (LSI), application specific integrated circuit (ASIC), or field programmable gate array (FPGA).

The processor 5 may control hardware or software components connected to the processor 5 by driving an operating system or an application program, and may perform various data processing and operations. In addition, the processor 5 may load and process commands or data received from at least one of the other components into a volatile memory, and store various data in a non-volatile memory.

FIG. 2 is a plan view illustrating a display panel included in a display device according to an exemplary embodiment of the present disclosure, and FIG. 3 is an enlarged view of pixels of portion A shown in FIG. 2 .

Referring to FIGS. 2 and 3 , the display panel 10 may include a plurality of pixels P arranged on a target substrate 20 .

The display panel 10 may include a plurality of pixel areas 40 arranged in a matrix form. One pixel P may be disposed in each pixel area 40, and one pixel P includes a first sub-pixel 31 emitting light of a red wavelength band and a light emitting light of a green wavelength band. It may include a second sub-pixel 33 and a third sub-pixel 35 emitting light in a blue wavelength band. In the present disclosure, a sub-pixel represents a light emitting diode.

In one pixel area 40, the first to third subpixels 31, 33, and 35 are provided in areas not occupied by the first subpixel 31, the second subpixel 33, and the third subpixel 35. ) may be disposed.

The first to third sub-pixels 31, 33, and 35 may be arranged in a row at regular intervals, but are not limited thereto. For example, the first to third subpixels 31, 33, and 35 may be arranged in an L shape or in a pentile RGBG method. The pentile RGBG method is a method of arranging the number of red, green, and blue sub-pixels in a ratio of 1:1:2 (RGBG) by using the characteristic that humans discriminate blue less and green the most. The pen tile RGBG method is effective because it can increase yield, lower unit cost, and implement high resolution on a small screen.

The first to third subpixels 31 , 33 , and 35 may be inorganic light emitting diodes, such as micro LEDs or mini LEDs, having a size of less than 100 μm.

The display module 3 may be a touch screen combined with a touch sensor, a flexible display, a rollable display, and/or a 3D display. Also, according to an embodiment, a plurality of display modules of the present disclosure may be provided and the modules may be physically connected to implement a large format display (eg, LFD, large format display).

The display panel 10 includes an amorphous silicon (a-Si) TFT, a low temperature polycrystalline silicon (LTPS) TFT, a low temperature polycrystalline oxide (LTPO) TFT, a hybrid oxide and polycrystalline silicon (HOP) TFT, and a liquid crystalline polymer (LCP) TFT. , or a target substrate that can be implemented in the form of an organic TFT (OTFT) or the like.

In the method of manufacturing a display panel according to an embodiment of the present disclosure, a plurality of light emitting diodes are relayed at high speed while randomly making a plurality of light emitting diodes without maintaining a wavelength distribution of a wafer through a fluidic self-assembly method. It can be arranged on the substrate 60. The plurality of light emitting diodes arranged on the relay board may be transferred to the target substrate 20 by the stamper 80 and then firmly connected to the target substrate 20 by a thermal compression method.

Hereinafter, a manufacturing process of a display panel according to an embodiment of the present disclosure will be sequentially described with reference to the drawings.

4 is a flowchart illustrating a manufacturing process of a display panel according to an embodiment of the present disclosure. 5 is a view showing an example of injecting a plurality of light emitting diodes into the liquid stored in the tank. FIG. 6 is an enlarged view of portion B shown in FIG. 5 . 7 is a diagram illustrating an example in which a plurality of light emitting diodes are self-assembled to a relay substrate in a liquid stored in a tank. FIG. 8 is an enlarged view of portion C shown in FIG. 7 .

Referring to FIGS. 5 and 6 , a plurality of guide grooves 61 into which a plurality of light emitting diodes 30 are inserted are provided on one surface of the relay substrate 60 . A pair of electrode pads, for example, a first electrode pad 63 and a second electrode pad 65 may be disposed in each guide groove 61 . The first electrode pad 63 corresponds to the first electrode terminal 30a (see FIG. 8) of the light emitting diode 30, and the second electrode pad 65 corresponds to the second electrode terminal 30b of the light emitting diode 30 (see FIG. 8). 8). The relay board 60 may use a dummy substrate that does not include wires and circuits.

First, before injecting the relay substrate 60 and the plurality of light emitting diodes 30 into the liquid 51 stored in the tank 50, hydrophilic surface treatment is applied to the relay substrate 60 and the plurality of light emitting diodes 30, respectively. do.

For example, a hydrophilic surface treatment is performed along the rows where the plurality of first electrode pads 63 of the relay substrate 60 are located. In addition, a hydrophilic surface treatment is applied to one of the first electrode terminals 30a and the second electrode terminals 30b of each light emitting diode 30, for example, the first electrode terminal 30a. The first electrode terminal 30a may be an anode electrode terminal and the second electrode terminal 30b may be a cathode electrode terminal. In this case, the first electrode terminal 30a subjected to hydrophilic treatment may be a terminal corresponding to the hydrophilic treated first electrode pad 63 of the relay substrate 60 .

The hydrophilic surface treatment for modifying the relay substrate 60 and each light emitting diode 30 to be hydrophilic may be, for example, a chemical treatment method, an ultraviolet irradiation method, an oxygen plasma treatment method, or the like.

Referring to FIG. 5, when hydrophilic treatment is completed on the relay substrate 60 and the plurality of light emitting diodes 30, the relay substrate 60 is put into the liquid 51 stored in the tank 50 (401, FIG. 4). reference). In this case, the relay substrate 60 is disposed so that the plurality of first and second electrode pads 63 and 65 (see FIG. 6) face the upper surface (the opening side of the tank 50).

Subsequently, a plurality of light emitting diodes 30 are put into the tank 51 (402, see FIG. 4). The plurality of light emitting diodes 30 may be mixed while flowing in the liquid 71 stored in the container 70 .

Referring to FIG. 7 , after putting a plurality of light emitting diodes 50 into the liquid 51 in the tank 50, the liquid 51 is circulated. Accordingly, the plurality of light emitting diodes 50 may be inserted into the guide groove 61 of the relay substrate 60 while flowing in the liquid 51 . An attractive force acts between the first electrode terminal 30a of the light emitting diode 30 treated with hydrophilicity and the first electrode pad 63 of the relay substrate 60 treated with hydrophilicity.

Referring to FIG. 8 , the first electrode terminal 30a of the diode 30 may adhere to the first electrode pad 63 of the relay board 60 . In this case, while the light emitting diode 30 is guided by the guide groove 61 of the relay board 60, the second electrode terminal 30b of the light emitting diode 30 is connected to the second electrode pad 65 of the relay board 60. ) will correspond to Accordingly, the plurality of light emitting diodes 30 may be aligned while being inserted into the plurality of guide grooves 61 of the relay substrate 60 .

The plurality of light emitting diodes 30 may be rapidly disposed on the relay substrate 60 by a fluid self-assembly method (403, see FIG. 4).

Meanwhile, in the above, a plurality of light emitting diodes 30 are fluidly self-assembled in a state in which the relay substrate 60 is poured into the liquid 51 in the tank 50 as an example, but is not limited thereto. For example, hydrophobic surface treatment is performed along a row where one electrode pad (eg, the first electrode pad 63) is located among the plurality of first and second electrode pads 63 and 65 of the relay substrate 60, and , A hydrophobic surface treatment is applied to the first electrode terminal 30a of each light emitting diode 30 . After the hydrophobic surface treatment, a predetermined amount of water is sprayed onto the upper surface of the relay substrate 60 . In this state, in a state where the plurality of light emitting diodes 30 are scattered on the upper surface of the relay substrate 60, a plurality of light emitting diodes 30 are worked by using a device (not shown) equipped with a plurality of brushes like a predetermined broom. direction and vice versa. In this case, the plurality of light emitting diodes 30 may be naturally inserted into the guide groove 61 while moving while being pushed on the upper surface of the relay substrate 60 by the device.

When the light emitting diodes 30 are inserted into all the guide grooves 61 of the relay board 60, the relay board 60 is taken out of the tank 50.

Through such a fluid self-assembly process, the plurality of light emitting diodes 30 may be randomly disposed on the relay substrate 60 . Accordingly, the plurality of light emitting diodes 30 do not maintain a wavelength distribution on the wafer.

9 is a diagram illustrating an example of picking a plurality of light emitting diodes arranged on a relay board with a stamper.

Referring to FIG. 9 , the stamper 80 positioned above the relay substrate 60 may include a plurality of adhesive heads 81 . Each adhesive head 81 picks up a plurality of light emitting diodes 30 arranged on the relay substrate 60 .

In this case, each light emitting diode 30 is separated from the relay substrate 60 while the light emitting surface 30c (see Fig. 8) is attached to each adhesive head 81. Subsequently, the stamper 80 moves to a preset position, for example, a position to transfer the plurality of light emitting diodes 30 to the target substrate 20 .

10 is a diagram illustrating an example of transferring a plurality of light emitting diodes to a target substrate by a stamper. FIG. 11 is an enlarged view of portion D shown in FIG. 10 .

Referring to FIGS. 10 and 11 , an adhesive layer 21 may be formed on one surface of a target substrate 20 on which a plurality of light emitting diodes 30 are to be disposed. The adhesive layer 21 may include a resin 21a and a plurality of conductive balls 21b. As the resin 21a, for example, an epoxy resin, a polyurethane resin, an acrylic resin or the like can be used. The plurality of conductive balls 21b may have a fine diameter (eg, 3 to 15 μm) and may be conductive. The plurality of conductive balls 21b may include, for example, polymer particles and a conductive film such as gold (Au), nickel (Ni), or lead (Pd) coated on the surface of the polymer particles. In this case, as the plurality of conductive balls 21b are distributed in the resin 21a, the adhesive layer 21 may have conductivity in a compression direction and insulation in a direction perpendicular to the compression direction. The adhesive layer 21 may be an anisotropic conductive film.

The adhesive layer 21 is not limited to an anisotropic conductive film and may be a non-conductive film. In this case, the adhesive layer does not contain conductive balls. Therefore, in the thermal compression process to be described later, the first electrode terminal 30a and the second electrode terminal 30b of the light emitting diode 30 correspond to the first substrate electrode pad 23 and the second substrate of the target substrate 20 It can directly contact the electrode pad 25.

The stamper 80 descends to transfer the plurality of light emitting diodes 30 to the target substrate 20 (404, see FIG. 4). In this case, the first electrode terminal 30a of the light emitting diode 30 corresponds to the first substrate electrode pad 23 of the target substrate 20, and the second electrode terminal 30a of the light emitting diode 30 corresponds to the target substrate 20. It may correspond to the second substrate electrode pad 25 of the substrate 20 .

12 is a view showing an example in which a plurality of light emitting diodes are placed on a target substrate with a stamper. FIG. 13 is an enlarged view of portion E indicated in FIG. 12 .

Referring to FIG. 12 , the stamper 80 moves up after transferring the plurality of light emitting diodes 30 to the target substrate 20 . At this time, since the adhesive force between the plurality of light emitting diodes 30 and the adhesive layer 21 is greater than the adhesive force between the plurality of light emitting diodes 30 and the adhesive head 81, the plurality of adhesive heads 81 may have a plurality of light emitting diodes (30) can be separated.

Referring to FIG. 13, the plurality of light emitting diodes 30 attached to the adhesive layer 21 have first and second electrode terminals 30a and 30b corresponding to the first and second substrate electrode pads 23, 25) and may be spaced apart at predetermined intervals.

14 is a diagram illustrating an example of thermal compression to stably connect a plurality of light emitting diodes to a target substrate. FIG. 15 is an enlarged view of portion F shown in FIG. 14 . 16 is a diagram illustrating a display panel according to an embodiment of the present disclosure.

Referring to FIG. 14 , a plurality of light emitting diodes 30 are pressed by a pressing member 90 and thermally compressed to the target substrate 20 (405, see FIG. 4).

A heater (eg, a sheath heater) may be disposed inside the pressing member 90 and inside a stage (not shown) on which the target substrate 20 is seated. In this case, the pressing member 90 and the stage may be made of a material with high heat transfer efficiency.

Referring to FIG. 15 , the adhesive layer 21 may be heated by heat transmitted from the pressure member 90 and the stage. At this time, each light emitting diode 30 pressed by the pressing member 90 has first and second electrode terminals 30a and 30b of the target substrate 20 corresponding to the first and second substrate electrode pads 23, 25) can be adhered to.

In this case, a plurality of conductive balls 21b are positioned between the first electrode terminal 30a and the first substrate electrode pad 23 and between the second electrode terminal 30b and the second substrate electrode pad 25. . Accordingly, the first electrode terminal 30a and the first substrate electrode pad 23 are electrically connected by the plurality of conductive balls 21b, and the second electrode terminal 30b and the second substrate electrode pad 25 are electrically connected by a plurality of conductive balls 21b.

Referring to FIG. 16 , the display panel 10 manufactured through the thermal compression process may be cured. Accordingly, the plurality of light emitting diodes 30 arranged on the target substrate 20 may be physically firmly fixed to the target substrate 20 while the resin 21a of the adhesive layer 21 is cured.

As described above, in the method of manufacturing a display panel according to an embodiment of the present disclosure, the plurality of light emitting diodes 30 may be randomly distributed on the relay substrate 60 by a fluid self-assembly method. Accordingly, when the plurality of light emitting diodes 30 are transferred from the relay substrate 60 to the target substrate 20, the wavelength distribution of the target substrate 20 may be randomly arranged without maintaining the wavelength distribution of the wafer. Therefore, in the display panel 10 including the target substrate 20 of the present disclosure, a specific wavelength distribution (eg, a wavelength distribution on a wafer) is not recognized.

In addition, the plurality of light emitting diodes 30 transferred from the relay substrate 60 to the target substrate 20 may be physically and firmly fixed to the target substrate 20 through a thermal compression process. In this case, in the plurality of light emitting diodes 30, first and second electrode terminals 30a and 30b are electrically connected to corresponding first and second substrate electrode pads 23 and 25 of the target substrate 20, respectively. can

Although the above has been shown and described with respect to preferred embodiments of the present disclosure, the present disclosure is not limited to the specific embodiments described above, and is commonly used in the technical field belonging to the present disclosure without departing from the gist of the present disclosure claimed in the claims. Of course, various modifications and implementations are possible by those with knowledge of, and these modifications should not be individually understood from the technical spirit or perspective of the present disclosure.

1: display device
3: display module
10: display panel
20: substrate
21: adhesive layer
30: light emitting diode
60: relay board

Claims (10)

In the manufacturing method of the display panel,
putting the first substrate into the liquid;
injecting a plurality of light emitting diodes into the liquid into which the first substrate is injected;
fluid self-assembling the plurality of light emitting diodes to the first substrate;
transferring the plurality of light emitting diodes arranged on the first substrate to a second substrate; and
and thermally compressing the plurality of light emitting diodes transferred to the second substrate to the second substrate. According to claim 1,
and subjecting a portion of the first substrate and a portion of the plurality of light emitting diodes to a hydrophilic surface treatment before injecting the first substrate and the plurality of light emitting diodes into the liquid. According to claim 2,
A hydrophilic surface treatment is performed on any one of the first electrode pad and the second electrode pad arranged in pairs on the first substrate;
A method of manufacturing a display panel by subjecting one of the first electrode terminals and the second electrode terminals of the plurality of light emitting diodes to a hydrophilic surface treatment. According to claim 1,
A method of manufacturing a display panel in which the liquid is circulated so that the plurality of light emitting diodes flow in the liquid and are inserted into the plurality of guide grooves provided in the first substrate. According to claim 1,
A method of manufacturing a display panel in which the first substrate is withdrawn from the liquid after the fluid self-assembly is completed. According to claim 1,
A method of manufacturing a display panel in which the plurality of light emitting diodes arranged on the first substrate are transferred to the second substrate in a pick and place manner. According to claim 6,
A method of manufacturing a display panel in which a plurality of light emitting diodes arranged on the first substrate are transferred to the second substrate by a plurality of adhesive heads of a stamper. According to claim 1,
In the thermal compression step, the light emitting diode is fixed to the second substrate by an adhesive layer provided on one surface of the second substrate. According to claim 8,
After the thermal compression step, the manufacturing method of the display panel further comprising the step of curing the adhesive layer of the second substrate. According to claim 8,
The adhesive layer is a method of manufacturing a display panel using an anisotropic conductive film or a non-conductive film.

Images