Display device including display module and method of manufacturing the same

Abstract

A display module includes: a substrate including a mounting surface and a pad electrode provided on the mounting surface; an inorganic light emitting element including a contact electrode provided to correspond to the pad electrode; a bump disposed between the pad electrode and the contact electrode so as to join the pad electrode and the contact electrode and electrically connect the contact electrode and the pad electrode; and a reflective member which underfills the inorganic light-emitting element so as to cover the side surfaces and the bottom surface of the inorganic light-emitting element, and which is configured so as to reflect light. And a cover member which is provided so as to cover the side surface of the reflection member and the mounting surface, and which is configured to have a black color.

Description

Technical Field

[0001] The present disclosure relates to a display module including an inorganic light-emitting element and a method for manufacturing the same. Background Art

[0002] A display device is an output device provided to visually display data information such as text and graphics, and images.

[0003] Micro LED display panels are constructed from multiple inorganic LEDs (inorganic LEDs). Each of these LEDs is smaller than 100 microns. Micro LED panels are self-luminous, requiring no backlight. Furthermore, they are resistant to burn-in and offer excellent brightness, resolution, power consumption, and durability.

[0004] Since the inorganic light-emitting elements included in the micro LED panel are very small, the electrical connection between the electrodes of the inorganic light-emitting elements and the electrodes of the substrate may be unstable, and the bonding between the inorganic light-emitting elements and the substrate may be unstable. Summary of the Invention

[0005] Technical issues One aspect of the present disclosure is to provide a display module having stable electrical connection between electrodes of an inorganic light-emitting element and electrodes of a substrate, and a method for manufacturing the same.

[0006] One aspect of the present disclosure is to provide a display module having enhanced bonding between an inorganic light-emitting element and a substrate, and a method for manufacturing the same.

[0007] An aspect of the present disclosure is to provide a display module including an inorganic light emitting element having improved light efficiency and a method of manufacturing the same.

[0008] An aspect of the present disclosure is to provide a display module with reduced material cost and a method of manufacturing the same.

[0009] The technical problems to be solved by the present disclosure are not limited to the technical problems mentioned above, and ordinary technicians in the technical field to which the present invention belongs can clearly understand other technical problems not mentioned from the following description.

[0010] Technical Solution A display module according to the concepts of the present disclosure includes: a substrate including a mounting surface and a pad electrode provided on the mounting surface; an inorganic light-emitting element including a contact electrode provided to correspond to the pad electrode; a bump provided between the pad electrode and the contact electrode to bond the pad electrode and electrically connect the contact electrode to the pad electrode; a reflective component that underfills the inorganic light-emitting element to cover the side and bottom surfaces of the inorganic light-emitting element and is configured to reflect light; and a cover component provided to cover the side surfaces of the reflective component and the mounting surface and configured to have a black color.

[0011] A method for manufacturing a display module according to the concepts of the present disclosure includes the following steps: transferring an inorganic light-emitting element onto a mounting surface of a substrate in a manner such that a pad electrode of the substrate corresponds to a contact electrode of the inorganic light-emitting element; subjecting the inorganic light-emitting element to a reflow process to melt a protrusion provided between the pad electrode and the contact electrode; applying glue to a reflective component in a liquid state on the mounting surface; curing the reflective component; applying glue to a cover component in a liquid state on the mounting surface; and curing the cover component. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a diagram illustrating a display device according to an embodiment.

[0013] Figure 2 It is decomposed to show Figure 1 The diagram shows the main structure of the display device.

[0014] Figure 3 It is enlarged to show Figure 1 A cross-sectional view of a portion of the display module is shown.

[0015] Figure 4 It is enlarged to show Figure 3 A cross-sectional view of the inorganic light-emitting element shown.

[0016] Figure 5 FIG. 1 is a cross-sectional view illustrating an inorganic light emitting element of a display module according to an embodiment.

[0017] Figure 6 FIG. 1 is a cross-sectional view illustrating an inorganic light emitting element of a display module according to an embodiment.

[0018] Figure 7 is a flowchart for illustrating a method for manufacturing a display module according to an embodiment.

[0019] Figure 8 is a cross-sectional view of a substrate of a display module according to an embodiment.

[0020] Figure 9FIG. 1 is a cross-sectional view of transferring an inorganic light-emitting element onto a substrate of a display module according to one embodiment.

[0021] Figure 10 FIG. 1 is a cross-sectional view schematically showing a state in which an inorganic light-emitting element transferred onto a substrate of a display module is subjected to a reflow process according to an embodiment.

[0022] Figure 11 is a cross-sectional view schematically illustrating a process of dispensing a reflective component on a substrate of a display module according to an embodiment.

[0023] Figure 12 FIG. 1 is a cross-sectional view schematically illustrating curing a reflective component dispensed on a substrate of a display module by ultraviolet (UV) light according to an embodiment.

[0024] Figure 13 FIG. 1 is a cross-sectional view schematically illustrating a process of dispensing a cover member on a substrate of a display module according to an embodiment.

[0025] Figure 14 FIG. 1 is a cross-sectional view schematically illustrating a state in which a cover member glued onto a substrate of a display module is cured by ultraviolet (UV) light according to an embodiment.

[0026] Figure 15 is a cross-sectional view schematically illustrating a state of thermally curing a cover member of a display module according to an embodiment. DETAILED DESCRIPTION

[0027] The various embodiments of this specification and the terms used therein are not intended to limit the technical features described in this specification to specific embodiments, but should be understood to include various modifications, equivalents, or substitutes of the corresponding embodiments.

[0028] Regarding the description of the drawings, like reference numerals may be used to designate like or related components.

[0029] Unless the context clearly dictates otherwise, a singular form of a noun corresponding to an item may include one or more of the item.

[0030] In this specification, each of the statements such as "A or B", "at least one of A and B", "at least one of A or B", "A, B or C", "at least one of A, B and C" and "at least one of A, B or C" may include one or all possible combinations of the items listed together in the corresponding statement.

[0031] The term "and / or" includes a combination of a plurality of related stated elements or a certain element among a plurality of related stated elements.

[0032] Terms such as “1st”, “2nd” or “first”, “second” may be used simply to distinguish a corresponding component from another corresponding component, and do not limit the corresponding component in other aspects (for example, importance or order).

[0033] When a certain component (for example, a first) is referred to as being “coupled” or “connected” to another component (for example, a second), whether or not the term “functionally” or “communicatively” is used, it means that the certain component may be connected to the other component directly (for example, by wire), wirelessly, or through a third component.

[0034] Terms such as "including" or "having" are used to specify the existence of features, numbers, steps, operations, constituent elements, parts or their combinations recorded in this specification, and do not preclude the existence or additional possibility of one or more other features or numbers, steps, operations, constituent elements, parts or their combinations.

[0035] When an element is referred to as being “connected,” “coupled,” “supported,” or “in contact with” another element, this includes not only the case where the elements are directly connected, coupled, supported, or in contact with each other, but also the case where the elements are indirectly connected, coupled, supported, or in contact with each other via a third element.

[0036] When a certain element is “on” another element, this includes not only a case where the certain element is in contact with the other element, but also a case where another element is present between the two elements.

[0037] Furthermore, terms such as "front", "rear", "left", "right", "up" and "down" used in the following description and related to directions are defined with reference to the accompanying drawings, and the shape and position of each structural element are not limited by these terms.

[0038] Figure 1 is a diagram illustrating a display device according to an embodiment. Figure 2 It is decomposed to show Figure 1 The diagram shows the main structure of the display device. Figure 3 It is enlarged to show Figure 1 A cross-sectional view of a portion of the display module is shown. Figure 4 It is enlarged to show Figure 3 A cross-sectional view of the inorganic light-emitting element shown.

[0039] In the drawings, a portion of the display device 1 including the plurality of inorganic light emitting elements 50 has a micrometer unit size ranging from several μm to several hundred μm, and the proportion of the portion (eg, the plurality of inorganic light emitting elements 50 ) is exaggerated for ease of explanation.

[0040] The display device 1 can display information, information, data, etc. in the form of text, graphics, charts, images, etc. The display device 1 can be implemented as a TV, a PC, a mobile phone, a digital signage, etc.

[0041] According to one embodiment, Figure 1 and Figure 2 As shown, the display device 1 includes: a display panel 20 that displays images; a power supply device that supplies power to the display panel 20; a main board 25 that controls the overall operation of the display panel 20; a frame 15 that supports the display panel 20; and a rear cover 10 that covers the rear surface of the frame 15.

[0042] The display panel 20 may include a plurality of display modules 30A- 30P, a driving board configured to drive each display module 30A- 30P, and a timing controller (TCON) board configured to generate timing signals required for controlling each display module 30A- 30P.

[0043] The rear cover 10 may support the display panel 20. The rear cover 10 may be placed on the floor via a bracket, or may be placed on a wall via a hanger or the like.

[0044] The multiple display modules 30A-30P can be arranged adjacent to each other vertically, horizontally, and horizontally. The multiple display modules 30A-30P can be arranged in an M*N matrix. In one embodiment, there are 16 display modules 30A-30P arranged in a 4*4 matrix, but the number and arrangement of the multiple display modules 30A-30P are not limited.

[0045] The plurality of display modules 30A-30P may be mounted on the frame 15. The plurality of display modules 30A-30P may be mounted on the frame 15 using various known methods, such as magnetic force of magnets or mechanical assembly structures. A rear cover 10 may be coupled to the rear of the frame 15, and the rear cover 10 may form the rear surface appearance of the display device 1.

[0046] The rear cover 10 may be made of metal, so that heat generated from the plurality of display modules 30A-30P and the frame 15 can be easily transferred to the rear cover 10 , thereby improving the heat dissipation efficiency of the display device 1 .

[0047] As described above, the display device 1 according to one embodiment can realize a large screen by tiling a plurality of display modules 30A- 30P.

[0048] According to one embodiment, each of the multiple display modules 30A-30P can be used as a single unit in a display device. Display modules 30A-30P can be arranged as a single unit and applied to wearable devices, portable devices, handheld devices, and various electronic products or devices requiring a display. Furthermore, as in the above-described embodiment, by arranging multiple modules in a matrix, they can be applied to display devices such as personal computer (PC) monitors, high-resolution TVs and signage, and electronic displays.

[0049] The plurality of display modules 30A-30P may have the same configuration as one another. Therefore, the description of a display module described below may be similarly applied to all other display modules.

[0050] Hereinafter, all of the plurality of display modules 30A- 30P are formed identically, and each of the plurality of display modules 30A- 30P will be described with reference to the first display module 30A.

[0051] To avoid duplication of description, the configuration of the plurality of display modules 30A- 30P will be described using the display module 30 and the substrate 40 as representatives.

[0052] Among the multiple display modules 30A-30P, the first display module 30A is used as an example. The first display module 30A can be formed in a quadrangle shape. The first display module 30A can be configured in a rectangular shape or a square shape. Therefore, the first display module 30A can include edges 31, 32, 33, and 34 formed in the upper, lower, left, and right directions with respect to the first direction X as the front.

[0053] Reference Figure 3 Each of the plurality of display modules 30A-30P may include a substrate 40 and a plurality of inorganic light emitting elements 50 mounted on the substrate 40. The plurality of inorganic light emitting elements 50 may be mounted on a mounting surface 41 of the substrate 40 facing the first direction X.

[0054] The substrate 40 may be formed in a quadrangle shape. In one embodiment, each of the plurality of display modules 30A-30P may be configured in a quadrangle shape, and the substrate 40 may be formed in a quadrangle shape to correspond thereto. The substrate 40 may be configured in a rectangular shape or a square shape.

[0055] The substrate 40 may include a substrate body 42 , a mounting surface 41 (one surface of the substrate body 42 ), and a rear surface 43 (the other surface of the substrate body 42 ) disposed on the opposite side to the mounting surface 41 .

[0056] In one embodiment, the substrate 40 may include a thin film transistor (TFT) layer 44 formed on a substrate body 42 to drive a plurality of inorganic light-emitting elements 50. The substrate body 42 may include a glass substrate. The substrate 40 may include a chip-on-glass (COG) substrate. The substrate 40 may include a first pad electrode 44 a and a second pad electrode 44 b configured to electrically or operatively connect the inorganic light-emitting elements 50 to the TFT layer 44.

[0057] The thin film transistors (TFTs) in the TFT layer 44 are not limited to a specific structure or type and can be formed using a variety of types. According to one embodiment, the TFTs in the TFT layer 44 can also be implemented as low-temperature polysilicon (LTPS) TFTs, oxide TFTs, silicon (polysilicon or amorphous silicon (a-silicon)) TFTs, organic TFTs, graphene TFTs, and the like.

[0058] Furthermore, when the substrate body 42 of the substrate 40 is formed of a silicon wafer, the TFT layer 44 may be replaced by a complementary metal-oxide semiconductor (CMOS) transistor, an n-type MOSFET, or a p-type MOSFET transistor.

[0059] The substrate 40 may further include a light absorbing layer 44 c that improves contrast by absorbing external light. The light absorbing layer 44 c may be formed on the entire mounting surface 41 of the substrate 40 . The light absorbing layer 44 c may be formed between the TFT layer 43 and the non-conductive film 100 .

[0060] The plurality of inorganic light-emitting elements 50 may be made of an inorganic material and may have dimensions ranging from several μm to several tens of μm in width, length, and height. The length of the shortest side of the inorganic light-emitting element in width, length, and height may be less than 100 μm. The inorganic light-emitting element 50 may be picked up from a sapphire or silicon wafer and directly transferred to the substrate 40. The plurality of inorganic light-emitting elements 50 may be picked up and transferred using an electrostatic method using an electrostatic head or a stamp method using a flexible polymer such as polydimethylsiloxane (PDMS) or silicon as a head.

[0061] Each of the plurality of inorganic light-emitting elements 50 may be a light-emitting structure including an n-type semiconductor 58a, an active layer 58c, a p-type semiconductor 58b, a first contact electrode 57a, and a second contact electrode 57b. The structure of one of the plurality of inorganic light-emitting elements 50 will be described below as an example.

[0062] In one embodiment, one of the first contact electrode 57 a and the second contact electrode 57 b may be configured to be electrically connected to the n-type semiconductor 58 a , and the other to be electrically connected to the p-type semiconductor 58 b .

[0063] exist Figure 3 In the embodiment, the first contact electrode 57 a and the second contact electrode 57 b may be arranged horizontally and in a flip chip configuration facing the same direction (the opposite direction to the light emitting direction).

[0064] The inorganic light emitting element 50 may include a protective layer 54. According to one embodiment, the protective layer 54 may be disposed above the n-type semiconductor 58a. The protective layer 54 may be disposed at the outermost side of the inorganic light emitting element 50 in the first direction X.

[0065] like Figure 3 As shown, when the inorganic light emitting element 50 is mounted on the mounting surface 41, it may have a light emitting surface 54a arranged in the first direction X, a side surface 55, and a bottom surface 56 arranged on the opposite side of the light emitting surface 54. A first contact electrode 57a and a second contact electrode 57b may be formed on the bottom surface 56 of the inorganic light emitting element 50. The contact electrodes 57a and 57b of the inorganic light emitting element 50 may be arranged on the opposite side of the light emitting surface 54 (i.e., the opposite side of the direction of light irradiation).

[0066] According to one embodiment, the inorganic light emitting element 50 may include a first bump 59 a formed on the first contact electrode 57 a and a second bump 59 a formed on the second contact electrode 57 b .

[0067] like Figure 3As shown, a first bump 59a can be plated on the first contact electrode 57a to cover the first contact electrode 57a. A second bump 59b can be plated on the second contact electrode 57b to cover the second contact electrode 57b. The first bump 59a and the second bump 59b can melt when heat and pressure are applied. When the first bump 59a melts, the first bump 59a can electrically connect the first contact electrode 57a to the first pad electrode 44a. When the second bump 59b melts, the second bump 59b can electrically connect the second contact electrode 57b to the second pad electrode 44b.

[0068] The first contact electrode 57a may be arranged facing the mounting surface 41 and may be configured to be electrically connected to the TFT layer 44. The first contact electrode 57a may be electrically connected to the first pad electrode 44a via the first bump 59a. The first contact electrode 57a may be electrically connected to the TFT layer 44 via the first pad electrode 44a.

[0069] The second contact electrode 57b may face the mounting surface 41 and may be configured to be electrically connected to the TFT layer 44. The second contact electrode 57b may be electrically connected to the second pad electrode 44b via the second bump 59b. The second contact electrode 57b may be electrically connected to the TFT layer 44 via the second pad electrode 44b.

[0070] In contrast, the first bump 59 can be provided to cover at least a portion of the first pad electrode 44a. The second bump 59b can also be provided to cover at least a portion of the second pad electrode 44b. The first bump 59 can be provided between the first contact electrode 57a and the first pad electrode 44a to electrically connect the first contact electrode 57a and the first pad electrode 44a. The second bump 59b can be provided between the second contact electrode 57b and the second pad electrode 44b to electrically connect the second contact electrode 57b and the second pad electrode 44b.

[0071] The light emitting surface 54 may radiate light in a direction opposite to the direction in which the contact electrodes 57 a and 57 b are arranged. The light emitting surface 54 a may be directed toward the upper surface of the protective layer 54 .

[0072] According to the above arrangement, when light generated from the active layer 58 c is irradiated in the first direction X through the light emitting surface 54 , the light may be irradiated in the first direction X without interference from the first contact electrode 57 a or the second contact electrode 57 b .

[0073] The plurality of inorganic light-emitting elements 50 may include a red light-emitting element 51, a green light-emitting element 52, and a blue light-emitting element 53. The light-emitting element 50 may be mounted on the mounting surface 41 of the substrate 40 as a unit, with the series of red light-emitting elements 51, green light-emitting elements 52, and blue light-emitting elements 53 being mounted as a unit. The series of red light-emitting elements 51, green light-emitting elements 52, and blue light-emitting elements 53 may form a pixel. In this case, the red light-emitting element 51, green light-emitting element 52, and blue light-emitting element 53 may each form a subpixel.

[0074] like Figure 3 As shown, the red light emitting elements 51, green light emitting elements 52, and blue light emitting elements 53 can be arranged in a row and spaced apart at predetermined intervals. In another embodiment, the red light emitting elements 51, green light emitting elements 52, and blue light emitting elements 53 can also be arranged in a triangular shape or other different shapes.

[0075] According to one embodiment, the inorganic light emitting element 50 may be coupled to the substrate 40 via the first bump 59 a and the second bump 59 b .

[0076] After the inorganic light-emitting element 50 is transferred onto the substrate 40 so that its first contact electrode 57a and second contact electrode 57b correspond to the first pad electrode 44a and second pad electrode 44b of the substrate 40, respectively, heat and pressure can be applied to the inorganic light-emitting element 50 to melt the first bump 59a and the second bump 59b. When the first bump 59a melts, it electrically connects the first contact electrode 57a to the first pad electrode 44a. When the second bump 59b melts, it electrically connects the second contact electrode 57b to the second pad electrode 44b. Furthermore, when the first bump 59a melts, it bonds the first contact electrode 57a to the first pad electrode 44a. When the second bump 59b melts, it bonds the second contact electrode 57b to the second pad electrode 44b.

[0077] As described above, the first bump 59 a can connect the first contact electrode 57 a and the first pad electrode 44 a , and the second bump 59 b can connect the second contact electrode 57 b and the second pad electrode 44 b , so that the inorganic light emitting element 50 can be bonded to the substrate 40 .

[0078] The bond between the inorganic light-emitting element 50 and the substrate 40 via the first and second bumps 59a and 59b may be relatively weak. According to the present disclosure, to strengthen the bond between the inorganic light-emitting element 50 and the substrate 40, the display module 30 may include a reflective member 100 formed by underfilling the inorganic light-emitting element 50. The reflective member 100 can reinforce the bond between the inorganic light-emitting element 50 and the substrate 40. In other words, the reflective member 100 can strengthen the adhesion of the inorganic light-emitting element 50 to the substrate 40.

[0079] The reflective member 100 can be formed by underfilling the inorganic light-emitting element 50 to cover the side surfaces 55 and bottom surface 56 of the inorganic light-emitting element 50. The reflective member 100 can be formed by dispensing or jetting a liquid around the inorganic light-emitting element 50. The reflective member 100 can fill the space between the substrate 40 and the bottom surface 56 of the inorganic light-emitting element 50 and underfill to cover all four side surfaces of the inorganic light-emitting element 50.

[0080] The reflective member 100 may be configured to reflect light. According to an embodiment, the reflective member 100 may include a resin 110 and a plurality of reflective beads 120 configured to reflect light. The reflective member 100 may reflect light incident to the reflective member 100 by including the plurality of reflective beads 120.

[0081] The resin 110 may be configured to have a gray color. The resin 110 may have a gray color that is brighter than black, so that the absorption rate of light incident from the inorganic light emitting element 50 to the resin 110 can be relatively reduced.

[0082] If the color of the resin 110 is represented by an RGB color code, R=G=B, and 0<R, G, B<20. The RGB color code represents a color by representing each of R, G, and B as an integer value from 0 to 255.

[0083] The reflective member 100 may include a plurality of reflective beads 120 distributed within the resin 110. The plurality of reflective beads 120 may be configured to reflect light. The plurality of reflective beads 120 may be configured in a spherical shape having a diameter of approximately 1 μm to 5 μm.

[0084] According to one embodiment, the plurality of reflective beads 120 may include spherical glass having a diameter of approximately 1 μm to 5 μm. Alternatively, the plurality of reflective beads 120 may be provided by coating spherical glass having a diameter of approximately 1 μm to 5 μm with titanium dioxide (TiO2), aluminum (Al), or silver (Ag). Alternatively, for example, the plurality of reflective beads 120 may include spherical titanium dioxide (TiO2) having a diameter of approximately 1 μm to 5 μm.

[0085] The plurality of reflective beads 120 can diffusely reflect light incident on an interface at an opposite interface and emit it through the interface. The plurality of reflective beads 120 can reflect light incident on the plurality of reflective beads 120. The light incident on the plurality of reflective beads 120 can be reflected as light parallel to the incident light and emit it.

[0086] According to one embodiment, for example, the reflective component 100 may be configured such that the reflective beads 120 have a composition ratio of 50% or greater. For example, the reflective component 100 may be configured such that the reflective beads 120 have a composition ratio of 80% or greater. The composition ratio of the reflective beads 120 in the reflective component 100 may represent the mass of the reflective beads 120 in the total mass of the reflective component 100.

[0087] The reflective component 100 can be formed by dispensing liquid adhesive around the inorganic light-emitting element 50 to fill the bottom of the inorganic light-emitting element 50, and then curing it. The liquid reflective component 100 can fill the space between the bottom surface 56 of the inorganic light-emitting element 50 and the substrate 40, and is dispensed or sprayed to cover all four sides of the inorganic light-emitting element 50. The liquid reflective component 100 can be cured by ultraviolet (UV) light.

[0088] The reflective member 100 may have the same height as the inorganic light emitting element 50. In other words, the upper surface of the reflective member 100 and the light emitting surface 54a of the inorganic light emitting element 50 may be arranged on the same plane. The reflective member 100 may not cover the light emitting surface 54a of the inorganic light emitting element 50. The reflective member 100 may not protrude further than the light emitting surface 54a of the inorganic light emitting element 50 in the first direction X.

[0089] The reflective member 100 may be configured to reflect light emitted from the inorganic light emitting element 50 and incident thereon. The reflective member 100 may reflect light emitted through the side surface 55 or bottom surface 56 of the inorganic light emitting element 50, thereby improving light efficiency of the display module 30.

[0090] The reflective component 100 can bottom-fill the inorganic light-emitting element 50 to cover the side surfaces 55 of the inorganic light-emitting element 50. The reflective component 100 can fill the area between the bottom surface 56 of the inorganic light-emitting element 50 and the mounting surface 41 of the substrate 40. The reflective component 100 can be dispensed on the mounting surface 41 of the substrate 40 in a liquid state and fill the area between the mounting surface 41 and the bottom surface 56 of the inorganic light-emitting element 50, and then cover the side surfaces 55 of the inorganic light-emitting element 50. The reflective component 100 can be cured by ultraviolet light after dispensing. The reflective component 100 is dispensed and cured in a manner that surrounds the bottom surface 56 and the side surfaces 55 of the inorganic light-emitting element 50, thereby strengthening the bonding between the inorganic light-emitting element 50 and the substrate 40. According to the present disclosure, the inorganic light-emitting element 50 can be stably electrically connected and bonded to the substrate 40 by means of the first bump 59a, the second bump 59b and the reflective component 100.

[0091] According to the present disclosure, the display module 30 may include a cover member 130 configured to cover the entire mounting surface 41 of the substrate 40 not provided with the reflective member 100 and having a black color. The cover member 130 may be configured to cover the side surface of the reflective member 100 and the entire mounting surface 41 of the substrate 40 outside the reflective member 100.

[0092] like Figure 3 As shown, according to one embodiment, the cover member 130 can have the same height as the inorganic light emitting element 50 and the reflective member 100. In other words, the upper surface of the cover member 130, the upper surface of the reflective member 100, and the light emitting surface 54a of the inorganic light emitting element 50 can be arranged on the same plane. The cover member 130 does not need to cover the upper surface of the reflective member 100. The cover member 130 may not protrude further than the light emitting surface 54a of the inorganic light emitting element 50 and the upper surface of the reflective member 100 in the first direction X.

[0093] In one embodiment, the cover member 130 may be provided with a black color. For example, the cover member 130 may be provided with a black color by using black ink. The cover member 130 may be provided with a resin containing black ink. However, this is not limited thereto, and the cover member 130 may be provided with a black color by various methods.

[0094] The cover member 130 is black to prevent light interference between sub-pixels when the inorganic light-emitting elements 50 emit light. In one embodiment, light emitted from a portion of the sub-pixels—the red, green, and blue light-emitting elements 51, 52, and 53—is reflected from the substrate 40, preventing interference with light emitted from the remaining sub-pixels. In other words, when the inorganic light-emitting elements 50 emit light, crosstalk is reduced or eliminated, thereby improving the optical properties of the display device 1.

[0095] The cover member 130 can be formed by dispensing or spraying a liquid onto the outside of the reflective member 100 and then curing it. The cover member 130 can be applied to the mounting surface 41 of the substrate 40 in a liquid state around the reflective member 100. The cover member 130, applied in a liquid state to the substrate 40, can be cured first using ultraviolet (UV) light and then cured secondarily by thermal curing. When thermally curing the cover member 130, heat can be applied to the inorganic light-emitting element 50, the reflective member 100, and the cover member 130, or heat and pressure can be applied simultaneously.

[0096] In related art, anisotropic conductive film (ACF) is used to bond an inorganic light-emitting element to a substrate. ACF consists of an anisotropic conductive adhesive attached to a protective film, with conductive spheres dispersed in an adhesive resin. These spheres are surrounded by a thin insulating film, and when the insulating film is ruptured by heat and pressure, they can electrically connect the conductors. A portion of these conductive spheres is positioned between the substrate's pad electrode and the inorganic light-emitting element's contact electrode, thereby electrically connecting the two.

[0097] In the case of the aforementioned anisotropic conductive film, the conductive balls cannot be arranged through patterning, resulting in the presence of conductive balls across the entire film area. This results in a greater number of unused conductive balls than those used to electrically connect the substrate and the inorganic light-emitting element, increasing material costs. Furthermore, the irregular distribution of conductive balls within the anisotropic conductive film may prevent the conductive balls from being adequately arranged between the substrate's pad electrodes and the inorganic light-emitting element's contact electrodes. In this case, electrical connection between the substrate and the inorganic light-emitting element may be lost. This results in an unstable electrical connection between the inorganic light-emitting element and the substrate.

[0098] Furthermore, in related art, after the inorganic light-emitting element is bonded to the substrate using an anisotropic conductive layer, a black matrix layer is additionally disposed on the substrate. The black matrix layer can be configured to completely cover the mounting surface of the substrate and may include multiple holes that penetrate the inorganic light-emitting element. The black matrix layer absorbs external light, making the substrate appear black, thereby improving the contrast of the screen.

[0099] When a black matrix layer covers an inorganic light-emitting element, light irradiated from the inorganic light-emitting element is absorbed by the black matrix layer. Therefore, the black matrix layer includes multiple holes corresponding to the size and position of the inorganic light-emitting element. The inorganic light-emitting element can only pass through the holes if each of the holes is larger than the size of the inorganic light-emitting element. Therefore, there are limitations in reducing the size of the holes provided in the black matrix layer. This is because, ideally, the size of the holes provided in the black matrix layer should be exactly the same as the size of the inorganic light-emitting element, but in reality, the size of the holes should be larger than the size of the inorganic light-emitting element.

[0100] The black matrix layer is used to reduce the aforementioned crosstalk. If the holes in the black matrix layer are larger than those in the inorganic light-emitting elements, a region without the black matrix layer is formed around the inorganic light-emitting elements. This region can cause light interference between sub-pixels, potentially leading to crosstalk.

[0101] According to one embodiment, the reflective member 100, which is configured in gray, can perform underfilling on the inorganic light-emitting element 50 and cover the bottom surface 56 and side surfaces 55 of the inorganic light-emitting element 50, and the cover member 130, which is configured in black, can be provided on the outer area of the reflective member 100. The inorganic light-emitting element 50 can be metal-bonded to the substrate 40 via the first and second bumps 59a, 59b. The inorganic light-emitting element 50 is metal-bonded via the first and second bumps 59a, 59b, thereby being stably bonded and electrically connected to the substrate 40.

[0102] Light emitted from the inorganic light emitting element 50 can be emitted through the light emitting surface 54 a. Light emitted toward the bottom surface 56 or the side surface 55 of the inorganic light emitting element 50 can be reflected by the reflective component 100 and emitted along the first direction X. The reflective component 100 can reflect the light emitted from the bottom surface 56 or the side surface 55 of the inorganic light emitting element 50 forward, thereby improving the light efficiency of the inorganic light emitting element 50.

[0103] A black cover member 130 can be provided on the outside of the reflective member 100 to function as the aforementioned black matrix layer. Unlike related art, the cover member 130 of the present disclosure is not provided in the form of a film including holes for the inorganic light-emitting element 50 and the reflective member 100 to pass through. Therefore, like the ideal black matrix layer, the cover member 130 can cover the entire mounting surface 41 of the substrate 40 without any area separated from the reflective member 100. The cover member 130 can cover the entire mounting surface 41 of the substrate 40, excluding the area where the inorganic light-emitting element 50 and the reflective member 100 are arranged. The cover member 130 can improve the contrast or clarity of the screen by removing or reducing light interference between the sub-pixels 51, 52, and 53. The cover member 130 can also supplement the light absorption layer 44c formed entirely on the mounting surface 41 side of the substrate 40. The cover member 130 can absorb external light, making the substrate 40 appear black, thereby improving the contrast of the screen.

[0104] Figure 5 FIG. 1 is a cross-sectional view illustrating an inorganic light emitting element of a display module according to an embodiment.

[0105] Reference Figure 5 The inorganic light emitting element 50 may include a first bump 59a and a second bump 59b. The first bump 59a and the second bump 59b may include a first bump 59a plated on the first contact electrode 57a and a second bump 59b plated on the second contact electrode 57b.

[0106] According to one embodiment, the first bump 59a and the second bump 59b may be formed by including indium, tin, or an alloy of indium and tin. For example, the first bump 59a and the second bump 59b may be formed by plating indium on the first contact electrode 57a and the second contact electrode 57b, respectively. For example, the first bump 59a and the second bump 59b may be formed by plating tin on the first contact electrode 57a and the second contact electrode 57b, respectively. For example, the first bump 59a and the second bump 59b may be formed by plating an alloy of indium and tin on the first contact electrode 57a and the second contact electrode 57b, respectively.

[0107] Figure 6 FIG. 1 is a cross-sectional view illustrating an inorganic light emitting element of a display module according to an embodiment.

[0108] Reference Figure 6 The inorganic light emitting element 50 may include a first bump 59a and a second bump 59b. The first bump 59a and the second bump 59b may include a first bump 59a plated on the first contact electrode 57a and a second bump 59b plated on the second contact electrode 57b.

[0109] According to one embodiment, the first bump 59a may include a first layer 59a1 configured to cover the first contact electrode 57a and a second layer 59a2 configured to cover the first layer 59a1. The second bump 59b may include a first layer 59b1 configured to cover the second contact electrode 57b and a second layer 59b2 configured to cover the first layer 59b1. In other words, the first bump 59a and the second bump 59b may include two or more layers.

[0110] According to one embodiment, the first layer 59a1 of the first bump 59a and the first layer 59b1 of the second bump 59b can be configured to include one of indium and tin, and the second layer 59a2 of the first bump 59a and the second layer 59b2 of the second bump 59b can be configured to include the other of indium and tin. For example, the first layer 59a1 of the first bump 59a and the first layer 59b1 of the second bump 59b can be configured to include indium, and the second layer 59a2 of the first bump 59a and the second layer 59b2 of the second bump 59b can be configured to include tin. For example, the first layer 59a1 of the first bump 59a and the first layer 59b1 of the second bump 59b can be configured to include tin, and the second layer 59a2 of the first bump 59a and the second layer 59b2 of the second bump 59b can be configured to include indium.

[0111] According to one embodiment, the first layer 59a1 of the first bump 59a and the first layer 59b1 of the second bump 59b may be formed by plating on the first contact electrode 57a and the second contact electrode 57b. The second layer 59a2 of the first bump 59a and the second layer 59b2 of the second bump 59b may be formed by plating on the first layer 59a1 of the first bump 59a and the first layer 59b1 of the second bump 59b.

[0112] Figure 7 is a flowchart for illustrating a method for manufacturing a display module according to an embodiment. Figure 8 is a cross-sectional view of a substrate of a display module according to an embodiment. Figure 9 FIG. 1 is a cross-sectional view of transferring an inorganic light-emitting element onto a substrate of a display module according to one embodiment. Figure 10 FIG. 1 is a cross-sectional view schematically showing a state in which an inorganic light-emitting element transferred onto a substrate of a display module is subjected to a reflow process according to an embodiment. Figure 11 is a cross-sectional view schematically illustrating a process of dispensing a reflective component on a substrate of a display module according to an embodiment. Figure 12 FIG. 1 is a cross-sectional view schematically illustrating a state in which a reflective component dispensed on a substrate of a display module is cured by ultraviolet (UV) light according to an embodiment. Figure 13 FIG. 1 is a cross-sectional view schematically illustrating a process of dispensing a cover member on a substrate of a display module according to an embodiment. Figure 14FIG. 1 is a cross-sectional view schematically illustrating a state in which a cover member glued onto a substrate of a display module is cured by ultraviolet (UV) light according to an embodiment. Figure 15 is a cross-sectional view schematically illustrating a state of thermally curing a cover member of a display module according to an embodiment.

[0113] In the following, reference will be made to Figures 7 to 15 A method for manufacturing a display module according to an embodiment is described.

[0114] Reference Figure 7 According to one embodiment, a method for manufacturing a display module may include the following steps: transferring the inorganic light-emitting element onto the mounting surface of the substrate in a manner such that the pad electrode of the substrate corresponds to the contact electrode of the inorganic light-emitting element (S210); subjecting the inorganic light-emitting element to a reflow process to melt a protrusion provided between the pad electrode and the contact electrode (S220); dispensing a liquid reflective component on the mounting surface (S230); curing the reflective component (S240); dispensing a liquid cover component on the mounting surface (S250); UV curing the cover component (S260); and thermal curing (S270).

[0115] Reference Figure 8 , pad electrodes 44 a and 44 b may be formed on the TFT layer 44 of the substrate 40 .

[0116] Reference Figure 9 The inorganic light emitting element 50 may be transferred onto the mounting surface 41 of the substrate 40 in such a manner that the pad electrodes 44 a and 44 b of the substrate 40 correspond to the contact electrodes 57 a and 57 b of the inorganic light emitting element 50 .

[0117] The inorganic light-emitting elements 50 can be picked up from a sapphire or silicon wafer and directly transferred onto the substrate 40. Multiple inorganic light-emitting elements 50 can be picked up and transferred using an electrostatic method using an electrostatic head or a stamp method using a flexible polymer such as PDMS or silicon as a head. In addition to the above methods, multiple inorganic light-emitting elements 50 can be transferred onto the substrate 40 using various other methods.

[0118] Reference Figure 10 By applying heat to the plurality of inorganic light-emitting elements 50 transferred onto the substrate 40, the first bumps 59a and the second bumps 59b disposed between the contact electrodes 57a, 57b and the pad electrodes 44a, 44b can be melted. In other words, by subjecting the plurality of inorganic light-emitting elements 50 to a reflow process, the first bumps 59a and the second bumps 59b can be melted.

[0119] When the first and second bumps 59a, 59b are melted, the first and second bumps 59a, 59b can electrically connect the contact electrodes 57a, 57b of the inorganic light emitting element 50 to the pad electrodes 44a, 44b of the substrate 40. When the first and second bumps 59a, 59b are melted, the first and second bumps 59a, 59b can metal-bond the contact electrodes 57a, 57b of the inorganic light emitting element 50 to the pad electrodes 44a, 44b of the substrate 40. When the first and second bumps 59a, 59b are melted, the first and second bumps 59a, 59b can stably electrically connect the contact electrodes 57a, 57b of the inorganic light emitting element 50 to the pad electrodes 44a, 44b of the substrate 40.

[0120] Reference Figure 11 , after the reflow process, the reflective member 100 may be dispensed on the substrate 40 in a liquid state.

[0121] The reflective component 100 can be dispensed in a liquid state around the inorganic light-emitting element 50 to underfill the inorganic light-emitting element 50. In other words, the reflective component 100 can be dispensed onto the substrate 40 so that the liquid reflective component 100 fills the space between the substrate 40 and the bottom surface of the inorganic light-emitting element 50. The reflective component 100 can be dispensed onto the substrate 40 so that the liquid reflective component 100 covers the side surfaces 55 of the inorganic light-emitting element 50.

[0122] Reference Figure 12 The reflective member 100, which is dispensed onto the substrate 40 in a liquid state, can be cured by ultraviolet (UV) light. The reflective member 100 can be cured by exposure to ultraviolet (UV) light. According to one embodiment, the reflective member 100, like the cover member 130 described later, can be cured for the first time by ultraviolet (UV) light.

[0123] Reference Figure 13 The cover member 130 can be dispensed in a liquid state around the reflective member 100. The cover member 130 can be dispensed so as to cover the entire area of the substrate 40 that is not provided with the inorganic light-emitting element 50 and the reflective member 100. The cover member 130 can be dispensed so as to cover the entire area outside the reflective member 100 on the substrate 40.

[0124] Reference Figure 14 The first curing may be performed by irradiating ultraviolet rays (UV) to the cover member 130 dispensed in a liquid state on the substrate 40. The cover member 130 exposed to the ultraviolet rays (UV) may be first cured.

[0125] Reference Figure 15, the second curing may be performed by applying heat to the cover member 130 that was first cured by ultraviolet (UV) rays.

[0126] According to an embodiment, by applying heat to the cover member 130 first cured by ultraviolet (UV), the cover member 130 may have a predetermined hardness, which may be greater than the hardness of the cover member 130 cured by UV.

[0127] According to one embodiment, the cover member 130 may be cured for a second time by heat and pressure. In this case, in order to cure the cover member 130 , heat and pressure may be applied to the cover member 130 together.

[0128] The second-cured cover member 130 may support the reflective member 100 so that the reflective member 100 is fixed at a predetermined position on the substrate 40. In other words, the cover member 130 may fix the position of the reflective member 100 by contacting the side surface of the reflective member 100.

[0129] A display module 30 according to one embodiment includes: a substrate 40 including a mounting surface 41 and pad electrodes 44 a and 44 b provided on the mounting surface 41; an inorganic light-emitting element 50 including contact electrodes 57 a and 57 b provided to correspond to the pad electrodes; a first bump 59 a and a second bump 59 b provided between the pad electrodes and the contact electrodes to bond and electrically connect the pad electrodes to the contact electrodes; a reflective component 100 that underfills the inorganic light-emitting element to cover side surfaces 55 and a bottom surface 56 of the inorganic light-emitting element and is configured to reflect light; and a cover component 130 provided to cover the side surfaces of the reflective component and the mounting surface and configured to have a black color.

[0130] The reflective member may be formed by dispensing a gray-colored resin 110 on the substrate.

[0131] The reflective member may include a plurality of reflective beads 120 distributed within the resin and configured to reflect light.

[0132] Each of the plurality of reflective beads may be provided in a spherical shape having a diameter of 1 μm to 5 μm.

[0133] The plurality of reflective beads may include at least one of titanium dioxide (TiO 2 ), glass (glass), aluminum (Al), and silver (Ag).

[0134] The cover member may be provided to cover the entire area outside the reflective member on the mounting surface.

[0135] The cover member may be formed by dispensing a resin including black ink on the substrate.

[0136] The upper surface of the inorganic light emitting element faces the first direction, and the upper surface of the reflective member 100 may be configured to be less protruding than the upper surface of the inorganic light emitting element in the first direction.

[0137] The upper surface of the inorganic light emitting element may face a first direction, and the upper surface of the cover member may be configured so as not to protrude more than the upper surface of the inorganic light emitting element in the first direction.

[0138] The upper surface of the inorganic light emitting element, the upper surface of the reflective member, and the upper surface of the cover member may be arranged on the same plane.

[0139] The bump may be plated on the contact electrode to cover the contact electrode.

[0140] The bump may be melted to electrically connect the contact electrode and the pad electrode.

[0141] The bumps may be formed to include indium, tin, or an alloy of indium and tin.

[0142] The bump may include: a first layer 59a1 of the first bump 59a, a first layer 59b1 of the second bump 59b, which are configured to cover the contact electrode and include one of indium and tin; and a second layer 59a2 of the first bump 59a, a second layer 59b2 of the second bump 59b, which are configured to cover the first layer and include the other of indium and tin.

[0143] The reflective member may strengthen bonding between the inorganic light emitting element and the substrate by performing underfilling on the inorganic light emitting element.

[0144] According to one embodiment, a method for manufacturing a display module includes the following steps: transferring an inorganic light-emitting element onto a mounting surface of a substrate in such a manner that a pad electrode of the substrate corresponds to a contact electrode of the inorganic light-emitting element (S210); subjecting the inorganic light-emitting element to a reflow process to melt a protrusion provided between the pad electrode and the contact electrode (S220); dispensing a liquid reflective component on the mounting surface (S230); curing the reflective component (S240); dispensing a liquid cover component on the mounting surface (S250); UV curing the cover component (S260); and thermal curing (S270).

[0145] The reflective component may be cured by ultraviolet rays.

[0146] The cover member may be cured first by ultraviolet light and second by heat.

[0147] The reflective member may underfill the inorganic light emitting element to cover the side surfaces and bottom surface of the inorganic light emitting element and be configured to reflect light.

[0148] The cover member may be provided to cover the side surfaces of the reflective member and the mounting surface, and may be configured to have a black color.

[0149] The reflective member may include a resin configured to have a gray color and a plurality of reflective beads distributed within the resin and configured to reflect light.

[0150] According to the concept of the present disclosure, a display module and a manufacturing method thereof can be provided in which the electrical connection between the electrodes of an inorganic light-emitting element and the electrodes of a substrate is stable.

[0151] According to the concept of the present disclosure, a display module having enhanced bonding between an inorganic light-emitting element and a substrate and a method for manufacturing the same can be provided.

[0152] According to the concept of the present disclosure, a display module including an inorganic light emitting element with improved light efficiency and a method of manufacturing the same can be provided.

[0153] According to the concept of the present disclosure, a display module with reduced material cost and a method of manufacturing the same may be provided.

[0154] While specific embodiments have been illustrated and described above, the present invention is not limited to the aforementioned embodiments, and a person skilled in the art can implement various modifications without departing from the spirit of the technical concept of the present invention as described in the claims.

Claims

1. A display module, comprising: A substrate comprising a mounting surface and pad electrodes provided on the mounting surface; an inorganic light-emitting element, comprising a contact electrode corresponding to the pad electrode; a bump provided between the pad electrode and the contact electrode to join the pad electrode and the contact electrode and electrically connect the contact electrode and the pad electrode; a reflective component that performs bottom filling on the inorganic light-emitting element to cover the side surfaces and the bottom surface of the inorganic light-emitting element and is configured to reflect light; as well as The cover member is provided to cover the side surface of the reflecting member and the mounting surface of the substrate and is configured to have a black color.

2. The display module according to claim 1, wherein The reflective component is formed by dispensing resin on the substrate. The resin is configured to have a gray color.

3. The display module according to claim 2, wherein: The reflective component comprises: A plurality of reflective beads are distributed within the resin and configured to reflect light.

4. The display module according to claim 3, wherein: Each of the plurality of reflective beads is provided in a spherical shape having a diameter of 1 μm to 5 μm.

5. The display module according to claim 3, wherein: The plurality of reflective beads include at least one of titanium dioxide, glass, aluminum, and silver. The display module according to claim 1 , wherein: The cover member is provided so as to cover the entire area outside the reflective member on the mounting surface of the substrate.

7. The display module according to claim 1, wherein: The cover member is formed by dispensing resin on the substrate. The resin composition includes black ink.

8. The display module according to claim 1, wherein: The upper surface of the inorganic light emitting element faces the first direction, The upper surface of the reflective member does not protrude further than the upper surface of the inorganic light emitting element in the first direction.

9. The display module according to claim 1, wherein: The upper surface of the inorganic light emitting element faces the first direction, The upper surface of the cover member does not protrude further than the upper surface of the inorganic light emitting element in the first direction.

10. The display module according to claim 1, wherein: The upper surface of the inorganic light emitting element, the upper surface of the reflective member, and the upper surface of the cover member are arranged on the same plane.

11. The display module according to claim 1, wherein: The bump is plated on the contact electrode to cover the contact electrode, The bump is melted to electrically connect the contact electrode and the pad electrode.

12. The display module according to claim 1, wherein: The bumps include indium, tin, or an alloy of indium and tin.

13. The display module according to claim 1, wherein: The convex block includes: a first layer configured to cover the contact electrode and comprising at least one of indium and tin; and The second layer is provided to cover the first layer and is configured to include at least one of indium and tin that is not included in the first layer.

14. The display module according to claim 1, wherein: The reflective member strengthens the bonding between the inorganic light emitting element and the substrate by underfilling the inorganic light emitting element.

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