Display device

Abstract

A display device includes a circuit substrate, a plurality of contact pad groups, and a plurality of light emitting elements. The plurality of contact pad groups are disposed on the circuit substrate, and each contact pad group includes a first contact pad, a second contact pad, and a third contact pad, wherein the first contact pad, the second contact pad, and the third contact pad are separated from each other, and the third contact pad surrounds the first contact pad. The plurality of light emitting elements are disposed on the circuit substrate, and each light emitting element includes a first electrode, a second electrode, and a light emitting stack between the first electrode and the second electrode, wherein the first electrode is electrically connected to the first contact pad, and the second electrode is electrically connected to the second contact pad and / or the third contact pad.

Description

Technical Field

[0001] This invention relates to a display device. Background Technology

[0002] Micro-LED displays offer advantages such as power saving, high efficiency, high brightness, and fast response time. Due to the extremely small size of micro-LEDs, current manufacturing methods employ mass transfer technology, utilizing microelectromechanical arrays (MEMS) to handle the placement and loading of micro-LED dies, transferring a large number of dies onto a circuit board in a single operation. However, during mass transfer, micro-LED dies often tip over, resulting in poor production yields and difficulties in reprocessing. Summary of the Invention

[0003] The present invention provides a display device with improved production yield.

[0004] An embodiment of the present invention provides a display device, comprising: a circuit board; a plurality of pad groups disposed on the circuit board, each pad group including a first pad, a second pad and a third pad, wherein the first pad, the second pad and the third pad are separated from each other, and the third pad surrounds the first pad; and a plurality of light-emitting elements disposed on the circuit board, each light-emitting element including a first electrode, a second electrode and a light-emitting stack located between the first electrode and the second electrode, wherein the first electrode is electrically connected to the first pad, and the second electrode is electrically connected to the second pad and / or the third pad.

[0005] In one embodiment of the present invention, the first pad and the second pad described above have different potentials.

[0006] In one embodiment of the present invention, the second pad and the third pad described above have the same potential.

[0007] In one embodiment of the invention, the third pad described above has an annular profile.

[0008] In one embodiment of the present invention, the ring width of the third pad is between 1 μm and 3 μm.

[0009] In one embodiment of the present invention, the portion of the third pad is located between the first pad and the second pad.

[0010] In one embodiment of the present invention, the distance between the center of the first pad and the center of any part of the third pad is equal.

[0011] In one embodiment of the present invention, the aforementioned spacing is approximately equal to the height of the light-emitting element.

[0012] In one embodiment of the present invention, the second electrode of the first light-emitting element among the plurality of light-emitting elements is electrically connected to the second pad, and the second electrode of the second light-emitting element among the plurality of light-emitting elements is electrically connected to the third pad.

[0013] In one embodiment of the present invention, the second electrode of the second light-emitting element and the third pad have mutually matching surface profiles.

[0014] In one embodiment of the present invention, the surface of the second electrode of the second light-emitting element is in solid contact with the third pad.

[0015] In one embodiment of the present invention, the distance between the second electrode of the first light-emitting element and the circuit board is greater than the distance between the second electrode of the second light-emitting element and the circuit board.

[0016] In one embodiment of the present invention, the second electrode of the first light-emitting element among the plurality of light-emitting elements is electrically connected to the second pad, and the second electrode of the third light-emitting element among the plurality of light-emitting elements is electrically connected to the second pad and the third pad.

[0017] In one embodiment of the present invention, the distance between the second electrode of the first light-emitting element and the circuit board is greater than the distance between the second electrode of the third light-emitting element and the circuit board.

[0018] To make the above features and advantages of the present invention more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings. Attached Figure Description

[0019] Figure 1A This is a top view schematic diagram of a display device 10 according to an embodiment of the present invention;

[0020] Figure 1B yes Figure 1A An enlarged top view of the pad assembly 120 of the display device 10;

[0021] Figure 1C It is along Figure 1A A schematic diagram of the cross section drawn by section line A-A';

[0022] Figure 2 This is a partial cross-sectional schematic diagram of a display device 20 according to an embodiment of the present invention.

[0023] Symbol Explanation

[0024] 10,20: Display device

[0025] 110:Substrate

[0026] 112: Base Plate

[0027] 114: Driver Circuit Layer

[0028] 116: Active (Powered) Components

[0029] 118: Wiring Layer

[0030] 120: Connector assembly

[0031] 121: First receiving pad

[0032] 122: Second pad

[0033] 123: Third connecting pad

[0034] 130, 130A, 130B, 130C: Light-emitting elements

[0035] 131: First electrode

[0036] 132: Second electrode

[0037] 133: Light-emitting stack

[0038] 140, 141, 142: Overlay layer

[0039] 150, 151, 152: Conductor Layer

[0040] 151a: Part

[0041] A-A': Section line

[0042] AB: lower part

[0043] AL: Left side

[0044] AR:right

[0045] AT: Upper part

[0046] CE: Center

[0047] CH: Semiconductor layer

[0048] CL: Conductor Layer

[0049] DC: Driving element

[0050] DE: Drain

[0051] GE: Gate

[0052] HD: Height

[0053] IL: Insulation layer

[0054] O1, O2, OP: Opening

[0055] PS: Connector assembly

[0056] PXs: Subpixels

[0057] RW: Ring width

[0058] S1~S3,SA,SB,SL,SR,ST: Spacing

[0059] SE: Source

[0060] TE: Thickness Detailed Implementation

[0061] In the accompanying drawings, the thicknesses of layers, films, panels, regions, etc., are enlarged for clarity. Throughout the specification, the same reference numerals denote the same elements. It should be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "connected" to another element, it may be directly on or connected to the other element, or intermediate elements may also be present. Conversely, when an element is referred to as being "directly on" or "directly connected" to another element, no intermediate elements are present. As used herein, "connection" can refer to a physical and / or electrical connection. Furthermore, "electrical connection" or "coupling" may refer to the presence of other elements between two elements.

[0062] It should be understood that although the terms "first," "second," "third," etc., may be used herein to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or part from another. Therefore, the first "element," "component," "region," "layer," or "part" discussed below may be referred to as a second element, component, region, layer, or part without departing from the teachings of this document.

[0063] The terminology used herein is for the purpose of describing particular embodiments only and is not restrictive. As used herein, unless the content clearly indicates otherwise, the singular forms "a," "an," and "the" are intended to include the plural forms, including "at least one" or indicating "and / or." As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It should also be understood that, when used in this specification, the terms "comprising" and / or "including" specify the presence of the stated features, areas, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, areas, integrals, steps, operations, elements, components, and / or combinations thereof.

[0064] Furthermore, relative terms such as "down" or "bottom" and "up" or "top" may be used herein to describe the relationship between one element and another, as illustrated in the figures. It should be understood that relative terms are intended to include different orientations of the device beyond those shown in the figures. For example, if a device in one figure is flipped, an element described as being "down" of another element will be oriented "up" of that element. Thus, the exemplary term "down" can include both "down" and "up" orientations, depending on the specific orientation of the figure. Similarly, if a device in one figure is flipped, an element described as being "down" or "below" of another element will be oriented "above" that element. Thus, the exemplary terms "down" or "below" can include both "up" and "down" orientations.

[0065] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant technology and this invention, and will not be interpreted as having idealized or overly formal meanings unless expressly defined herein.

[0066] This document describes exemplary embodiments with reference to cross-sectional views, which are schematic diagrams of idealized embodiments. Therefore, variations in shape as a result of, for example, manufacturing techniques and / or tolerances, are expected in the illustrations. Consequently, the embodiments described herein should not be construed as limited to the specific shapes of the regions shown herein, but rather include, for example, shape deviations caused by manufacturing processes. For example, regions shown or described as flat may generally have rough and / or non-linear characteristics. Furthermore, the acute angles shown may be rounded. Therefore, the regions shown in the figures are schematic in nature, and their shapes are not intended to show the precise shapes of the regions, nor are they intended to limit the scope of the claims.

[0067] Figure 1A This is a top view of a display device 10 according to an embodiment of the present invention. Figure 1B yes Figure 1A An enlarged top view of the pad assembly 120 of the display device 10. Figure 1C It is along Figure 1A A schematic cross-sectional view along section line A-A'. To make the accompanying drawing more concise, Figure 1A The substrate 110, light-emitting element 130, sub-pixels PXs and driving element DC of the display device 10 are schematically illustrated, and other components are omitted.

[0068] Please refer to Figures 1A to 1CThe display device 10 includes: a circuit board 110; a plurality of pad groups 120 disposed on the circuit board 110, and each pad group 120 includes a first pad 121, a second pad 122 and a third pad 123, wherein the first pad 121, the second pad 122 and the third pad 123 are separated from each other, and the third pad 123 surrounds the first pad 121; and a plurality of light-emitting elements 130 disposed on the circuit board 110, each light-emitting element 130 including a first electrode 131, a second electrode 132 and a light-emitting stack 133 located between the first electrode 131 and the second electrode 132, wherein the first electrode 131 is electrically connected to the first pad 121, and the second electrode 132 is electrically connected to the second pad 122 or the third pad 123.

[0069] In a display device 10 according to an embodiment of the present invention, by providing a third pad 123 surrounding the first pad 121, the tilted light-emitting element 130 can operate normally, thereby improving the production yield of the display device 10. Hereinafter, in conjunction with... Figures 1A to 1C The embodiments of the various components of the display device 10 will be described further, but the present invention is not limited thereto.

[0070] Specifically, the display device 10 may include a plurality of sub-pixels PXs, and the plurality of sub-pixels PXs may be arranged in an array, but the present invention is not limited thereto. In some embodiments, the display device 10 may further include a driving element DC, and the driving element DC may be electrically connected to the sub-pixels PXs to transmit signals to the light-emitting element 130. For example, the light-emitting element 130 is electrically connected to a first pad 121 and a second pad 122, and the driving element DC may be electrically connected to the first pad 121 and the second pad 122 respectively. In some embodiments, the first pads 121 of the plurality of sub-pixels PXs are separated from each other and independently receive signals provided by the driving element DC. In some embodiments, the second pads 122 of the plurality of sub-pixels PXs may be electrically connected to each other or be subjected to the same common voltage during operation. In some embodiments, the driving element DC may be a chip bonded to the circuit board 110 or a circuit element (including active elements, passive elements, or combinations thereof) directly formed in the circuit board 110.

[0071] Each sub-pixel PXs of the display device 10 includes, for example, a circuit board 110, a first pad 121, a second pad 122, a third pad 123, and a light-emitting element 130. The first pad 121, the second pad 122, and the third pad 123 are disposed on the surface of the circuit board 110, and the first electrode 131 of the light-emitting element 130 is electrically connected to the first pad 121, and the second electrode 132 of the light-emitting element 130 is electrically connected to the second pad 122 and / or the third pad 123.

[0072] In some embodiments, the circuit board 110 may include a base plate 112 and a driving circuit layer 114. The base plate 112 of the circuit board 110 may be a transparent substrate or a non-transparent substrate, and its material may be a quartz substrate, a glass substrate, a polymer substrate, or other suitable materials, but the present invention is not limited thereto. The driving circuit layer 114 may include components or lines required by the display device 10, such as driving elements, switching elements, storage capacitors, power lines, driving signal lines, timing signal lines, current compensation lines, detection signal lines, etc.

[0073] In some embodiments, a driving circuit layer 114 may be formed on a substrate 112 using a thin film deposition process, a photomask fabrication process, and an etching process. The driving circuit layer 114 may include an active element array, wherein the active element array includes a plurality of active elements arranged in an array, such as thin film transistors.

[0074] In some embodiments, the driving circuit layer 114 includes a plurality of active elements 116 and a wiring layer 118. In other embodiments, the driving circuit layer 114 may also include other elements, such as passive elements, as needed.

[0075] The active element 116 may be composed of a semiconductor layer CH, a gate GE, a source SE, and a drain DE. The region of the semiconductor layer CH overlapping the gate GE can be considered as the channel region of the active element 116. The gate GE, source SE, and drain DE are electrically separate from each other, and the source SE and drain DE can be electrically connected to the two ends of the semiconductor layer CH, respectively. The gate GE and source SE can receive signals from, for example, a driving element DC. The material of the semiconductor layer CH may include silicon semiconductor materials (e.g., polycrystalline silicon, amorphous silicon, etc.), oxide semiconductor materials, organic semiconductor materials, but the present invention is not limited thereto. The materials of the gate GE, source SE, and drain DE may include metals with good conductivity, such as aluminum, molybdenum, titanium, copper, etc.

[0076] The wiring layer 118 may be located above multiple active elements 116. In some embodiments, the wiring layer 118 may include multiple insulating layers IL and multiple conductive layers CL, wherein the multiple conductive layers CL form multiple conductive lines separated by the multiple insulating layers IL, enabling each active element 116 to be electrically connected to, for example, a corresponding light-emitting element 130. In this way, the driving element DC can control the operation of the light-emitting element 130 by controlling the signals sent to the active elements 116.

[0077] In some embodiments, each sub-pixel PXs may include a set of pad groups 120, but the invention is not limited thereto. In some embodiments, each sub-pixel PXs may include two or more sets of pad groups 120. Figure 1BAs shown, the first pad 121, second pad 122, and third pad 123 of each pad group 120 can be disposed on the wiring layer 118 and electrically connected to the corresponding conductor layer CL or conductive line in the wiring layer 118. In some embodiments, the first pad 121, second pad 122, and third pad 123 may belong to the same film layer or be located on the same plane, and the patterns of the first pad 121, second pad 122, and third pad 123 are separated from each other. In some embodiments, the first pads 121, second pads 122, and third pads 123 with the same potential can be electrically connected to each other through the corresponding conductor layer CL or conductive line in the wiring layer 118. In some embodiments, the first pad 121 and the second pad 122 may have different potentials. In some embodiments, the second pad 122 and the third pad 123 may have the same potential. In some embodiments, the third pad 123 can be electrically connected to the second pad 122 through the corresponding conductor layer CL or conductive line in the wiring layer 118.

[0078] In some embodiments, the third pad 123 includes multiple parts, such as an upper part AT, a lower part AB, a left part AL, and a right part AR, and the distance ST between the center CE of the first pad 121 and the center of the upper part AT, the distance SB between the center CE of the first pad 121 and the center of the lower part AB, the distance SL between the center CE of the first pad 121 and the center of the left part AL, and the distance SR between the center CE of the first pad 121 and the center of the right part AR are all equal.

[0079] In some embodiments, the third pad 123 has an annular profile surrounding the first pad 121, and the aforementioned upper portion AT, lower portion AB, left portion AL, and right portion AR are all located within the annular profile. In some embodiments, the first pad 121 may overlap the center of the annular profile. In some embodiments, the annular width RW of the third pad 123 is between 1 μm and 3 μm. In some embodiments, a portion of the third pad 123 (e.g., the left portion AL) is located between the first pad 121 and the second pad 122.

[0080] In some embodiments, the first pad 121, the second pad 122, and the third pad 123 may have a single-layer structure or a structure with multiple or more conductive layers stacked together. For example, the first pad 121, the second pad 122, and the third pad 123 may each have a structure in which metals such as aluminum, molybdenum, titanium, and copper are stacked with indium tin oxide (ITO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), or other suitable conductive oxides, but the present invention is not limited thereto.

[0081] In some embodiments, the first pad 121 is electrically connected to the drain DE of the active element 116 via a corresponding conductor layer CL or conductive line in the wiring layer 118, but the invention is not limited thereto. In other embodiments, the second pad 122 or the third pad 123 may also be electrically connected to the drain DE of the active element 116.

[0082] In some embodiments, the first electrode 131 and the second electrode 132 of the light-emitting element 130 are electrically connected to different layers in the light-emitting stack 133. For example, the light-emitting stack 133 may include two semiconductor layers and a light-emitting layer sandwiched between the two semiconductor layers, and the first electrode 131 may be electrically connected to one of the two semiconductor layers, while the second electrode 132 may be electrically connected to the other of the two semiconductor layers. In some embodiments, the first electrode 131 and the second electrode 132 of the light-emitting element 130 are located on opposite sides of the light-emitting stack 133, and the first electrode 131, the second electrode 132, and the light-emitting stack 133 are arranged and stacked in a vertical direction. In some embodiments, the light-emitting element 130 is a vertical micro light-emitting diode. In some embodiments, the materials of the first electrode 131 and the second electrode 132 may include metal, alloy, nitride of metal material, oxide of metal material, oxynitride of metal material, or other suitable materials, or a stack of metal material and other conductive materials, or other low-resistance materials.

[0083] In some embodiments, the plurality of light-emitting elements 130 may all be blue light-emitting diodes (LEDs), and the display device 10 may further include a color conversion layer (not shown) disposed on the plurality of light-emitting elements 130. The color conversion layer may include phosphor or a similar wavelength conversion material to convert the blue light emitted by the blue LEDs into light of different colors to achieve a full-color display effect. In other embodiments, the plurality of light-emitting elements 130 may include a plurality of red LEDs, a plurality of green LEDs, and a plurality of blue LEDs to achieve a full-color display effect. When the emission colors of the plurality of light-emitting elements 130 are different, the aforementioned color conversion layer may be selectively omitted or retained in the display device 10. In other embodiments, the plurality of light-emitting elements 130 may all be white LEDs, and the color conversion layer may be a color filter layer to achieve a full-color display effect.

[0084] In some embodiments, the plurality of light-emitting elements 130 of the display device 10 include light-emitting element 130A and light-emitting element 130B, wherein the second electrode 132 of light-emitting element 130A is electrically connected to the second pad 122, and the second electrode 132 of light-emitting element 130B is electrically connected to the third pad 123.

[0085] For example, the light-emitting element 130A is a light-emitting element that is manufactured on a growth substrate and then transferred to the circuit board 110 through a mass transfer process without being tilted, and the first electrode 131 of the light-emitting element 130A can be transferred to the first pad 121. In some embodiments, the first electrode 131 can be electrically connected to the first pad 121 through metal, conductive adhesive or other conductive materials.

[0086] In some embodiments, the display device 10 further includes a cover layer 140 having a plurality of openings OP. The cover layer 140 covers the third pads 123 of the plurality of pad groups 120, the first electrode 131 of the light-emitting element 130A, and the light-emitting stack 133. The cover layer 140 exposes the second electrode 132 of the light-emitting element 130A, and the plurality of openings OP of the cover layer 140 expose the second pads 122 of the plurality of pad groups 120. The material of the cover layer 140 may include a transparent insulating material, such as organic materials, acrylic materials, siloxane materials, polyimide materials, epoxy resin materials, etc., but the present invention is not limited thereto.

[0087] In some embodiments, the display device 10 may further include a conductor layer 150 located on the cover layer 140, and the conductor layer 150 electrically connects the second pad 122 exposed by the opening OP to the corresponding second electrode 132 exposed by the cover layer 140.

[0088] In some embodiments, the light-emitting element 130B is a light-emitting element tilted during a mass transfer fabrication process, and the second electrode 132 of the light-emitting element 130B rests on the third pad 123. In some embodiments, the second electrode 132 of the light-emitting element 130B and the third pad 123 have matching surface profiles, so that the surface of the second electrode 132 can physically contact the third pad 123, or connect the third pad 123 through other conductive materials, so that the second electrode 132 can electrically connect to the third pad 123. Therefore, the tilted light-emitting element 130B can operate normally, and the production yield of the display device 10 can be improved without the need for a repair fabrication process on the light-emitting element 130B. In some embodiments, the surface of the second electrode 132 of the light-emitting element 130B has a stepped profile, and the surface of the third pad 123 also has a stepped profile that matches the surface of the second electrode 132, in order to improve the conductivity between the second electrode 132 and the third pad 123.

[0089] In some embodiments, in order for the surface of the second electrode 132 to make solid contact with the third pad 123, the distance SA from the center of the first pad 121 to the center of any portion of the third pad 123 is approximately the height HD of the light-emitting element 130B. In some embodiments, the annular width RW of the third pad 123 is approximately the thickness TE of the second electrode 132 of the light-emitting element 130B. In some embodiments, the distance S1 between the second electrode 132 of the light-emitting element 130A and the circuit board 110 is greater than the distance S2 between the second electrode 132 of the light-emitting element 130B and the circuit board 110.

[0090] The following uses Figure 2 Further embodiments of the present invention will be described, and the following will be used... Figures 1A to 1C The component designations and related content of the embodiments are as follows: the same designations are used to represent the same or similar components, and descriptions of identical technical content are omitted. For explanations of the omitted parts, please refer to... Figures 1A to 1B The embodiments described below will not be repeated.

[0091] Figure 2 This is a partial cross-sectional schematic diagram of a display device 20 according to an embodiment of the present invention. The display device 20 includes: a circuit board 110, a plurality of pad groups 120 and a plurality of light-emitting elements 130, and each light-emitting element 130 includes a first electrode 131, a second electrode 132 and a light-emitting stack 133.

[0092] With Figures 1A to 1C Compared to the display device 10 shown, Figure 2 The main difference of the display device 20 shown is that the multiple light-emitting elements 130 of the display device 20 include light-emitting element 130A and light-emitting element 130C, wherein the second electrode 132 of light-emitting element 130A is electrically connected to the second pad 122, and the second electrode 132 of light-emitting element 130C is electrically connected to the second pad 122 and the third pad 123.

[0093] For example, the display device 20 may also include a cover layer 141 located between the light-emitting element 130 and the third pad 123, wherein the light-emitting element 130A is a light-emitting element that is not tilted during the formation of the cover layer 141, and the light-emitting element 130C is a light-emitting element that is tilted during the formation of the cover layer 141.

[0094] In some embodiments, the cover layer 141 has an opening O1 exposing the second pad 122, and the display device 20 may further include a conductive layer 151 located on the cover layer 141. The conductive layer 151 can electrically connect the second electrode 132 of the light-emitting element 130C and the third pad 123 to the second pad 122 exposed by the opening O1 through the opening O1, such that the second electrode 132 of the light-emitting element 130C is simultaneously electrically connected to both the second pad 122 and the third pad 123. In some embodiments, a portion 151a of the conductive layer 151 is located on the second electrode 132 of the light-emitting element 130A.

[0095] In some embodiments, the display device 20 may further include a cover layer 142 and a conductive layer 152, wherein the cover layer 142 is located on the conductive layer 151, and the conductive layer 152 is located on a portion 151a of the cover layer 142 and the conductive layer 151. The cover layer 142 may have an opening O2 overlapping the opening O1, and the conductive layer 152 can electrically connect the second electrode 132 of the light-emitting element 130A to the conductive layer 151 on the second pad 122 through the opening O2. Due to the tilting of the light-emitting element 130C, the distance S1 between the second electrode 132 of the light-emitting element 130A and the circuit board 110 will be greater than the distance S3 between the second electrode 132 of the light-emitting element 130C and the circuit board 110. In addition, the stacking of the double-layer cover layers 141, 142 and the conductive layers 151, 152 can also enhance the stability of the light-emitting elements 130A, 130C.

[0096] In summary, the display device of the present invention, by providing a third pad surrounding the first pad, enables the tilted light-emitting element to operate normally, thereby improving the production yield of the display device. Furthermore, the display device of the present invention can also enhance the stability of the light-emitting element by providing a double-layer cover layer and a conductive layer.

[0097] Although the present invention has been disclosed in conjunction with the above embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A display device, comprising: Circuit board; Multiple pad groups are disposed on the circuit board, and each pad group includes a first pad, a second pad and a third pad, wherein the first pad, the second pad and the third pad are separated from each other, and the third pad surrounds the first pad. as well as Multiple light-emitting elements are disposed on the circuit substrate, and each light-emitting element includes a first electrode, a second electrode, and a light-emitting stack located between the first electrode and the second electrode. The first electrode is electrically connected to the first pad, and the second electrode is electrically connected to the second pad and / or the third pad. The second electrode of the light-emitting element and the third pad have mutually matching surface profiles, such that the surface of the second electrode of the light-emitting element can physically contact the third pad, or be connected to the third pad through other conductive materials.

2. The display device of claim 1, wherein the first pad and the second pad have different potentials.

3. The display device of claim 1, wherein the second pad and the third pad have the same potential.

4. The display device of claim 1, wherein the third pad has an annular profile.

5. The display device of claim 4, wherein the ring width of the third pad is between 1 μm and 3 μm.

6. The display device of claim 1, wherein a portion of the third pad is located between the first pad and the second pad.

7. The display device of claim 1, wherein the distance between the center of the first pad and the center of any portion of the third pad is equal.

8. The display device of claim 7, wherein the spacing approximates the height of the light-emitting element, such that the surface of the second electrode of the light-emitting element can substantially contact the third pad.

9. The display device of claim 1, wherein the second electrode of the first light-emitting element of the plurality of light-emitting elements is electrically connected to the second pad, and the second electrode of the second light-emitting element of the plurality of light-emitting elements is electrically connected to the third pad.

10. The display device of claim 9, wherein the second electrode of the second light-emitting element and the third pad have mutually matching surface profiles.

11. The display device of claim 10, wherein the surface of the second electrode of the second light-emitting element contacts the third pad.

12. The display device of claim 9, wherein the distance between the second electrode of the first light-emitting element and the circuit board is greater than the distance between the second electrode of the second light-emitting element and the circuit board.

13. The display device of claim 1, wherein the second electrode of the first light-emitting element of the plurality of light-emitting elements is electrically connected to the second pad, and the second electrode of the third light-emitting element of the plurality of light-emitting elements is electrically connected to the second pad and the third pad.

14. The display device of claim 13, wherein the distance between the second electrode of the first light-emitting element and the circuit board is greater than the distance between the second electrode of the third light-emitting element and the circuit board.

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