COB structure

Abstract

The utility model relates to the technical field of photoelectricity, and provides a COB (chip on board) structure, which comprises a substrate provided with a light-emitting area. The light-emitting elements are arranged on the substrate and distributed in the light-emitting area at intervals, and the light-emitting elements are connected with one another through bonding wires to form series-parallel connection; the bridging wafer is arranged in the light-emitting area and is electrically connected with at least one light-emitting element through a bonding wire; the bonding pad comprises a positive electrode bonding pad and a negative electrode bonding pad, and the bonding pad is arranged on the substrate in the circumferential direction of the periphery of the light-emitting area. The COB structure provided by the utility model is provided with the bridging wafer, so that the processing of two adjacent light-emitting elements with a larger distance is facilitated, the electrical connection between the light-emitting elements can be better adjusted, and the stability between the elements is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of optoelectronics and provides a COB structure. Background Art

[0002] The current state of the art shows that in COB (Chip on Board) welding wire design, there are the following defects when the length of the welding wire is too long: First, the increase in the length of the welding wire will cause the resistance to rise, resulting in the obstruction of the current flow, thus affecting the performance of the circuit. Secondly, the excessively long welding wire may introduce additional inductance, hindering the transmission of high-frequency signals and damaging the signal integrity. In addition, the excessively long welding wire may also cause thermal problems, because when the current passes through the welding wire, heat is generated. Long welding wires may not be able to effectively dissipate heat, resulting in temperature rise, affecting the stability and life of the chip and surrounding components. Therefore, optimizing the length of the welding wires between COB chips is the key to ensuring circuit performance and reliability. Utility Model Content

[0003] In order to solve the problem of too long welding wire length in the COB process in the above-mentioned prior art, the utility model provides a COB structure, including:

[0004] A substrate, wherein a light emitting area is provided on the substrate;

[0005] A plurality of light-emitting elements are disposed on the substrate and are spaced apart in the light-emitting region, and the plurality of light-emitting elements are connected to each other through welding wires to form a series-parallel connection;

[0006] At least one bridge chip, the bridge chip is disposed in the light-emitting area and is electrically connected to at least one light-emitting element through a bonding wire;

[0007] The pads include a positive pad and a negative pad, and are arranged on the substrate along the periphery of the light emitting area.

[0008] In one embodiment, a transparent covering layer is further included, covering the light emitting area on the substrate.

[0009] In one embodiment, the light emitting element includes a single-color temperature light source and / or a multi-color temperature light source.

[0010] In one embodiment, the bridge chip includes a conductive layer, and the conductive layer is electrically connected to the light-emitting element through a bonding wire; the material of the conductive layer includes a conductive metal material and / or a conductive non-metal material.

[0011] In one embodiment, the light emitting elements are distributed in the light emitting area in an array, and the light emitting elements in the same row or column form a lamp group, the spacing between two adjacent lamp groups is 0.1mm to 5mm, and the spacing between two adjacent light emitting elements in the lamp group is greater than or equal to 0.2mm.

[0012] In one embodiment, the length of the welding wire is 0.1 mm to 1.5 mm.

[0013] In one embodiment, when two adjacent light emitting elements with a spacing greater than 0.6 mm are electrically connected to each other, at least one bridge chip is provided between the two adjacent light emitting elements, and the bridge chip is electrically connected to the two adjacent light emitting elements through a bonding wire.

[0014] In one embodiment, the positive electrode pad is used to electrically connect the positive electrode of the light emitting element; and the negative electrode pad is used to electrically connect the negative electrode of the light emitting element.

[0015] In one embodiment, when the distance between the positive electrode pad and the light-emitting element connected thereto is greater than 0.6 mm, at least one bridge chip is provided between the positive electrode pad and the light-emitting element connected thereto, and the bridge chip is electrically connected to the positive electrode pad and the light-emitting element respectively through bonding wires;

[0016] And / or, when the distance between the negative electrode pad and the light-emitting element connected thereto is greater than 0.6 mm, at least one bridge chip is provided between the negative electrode pad and the light-emitting element connected thereto, and the bridge chip is electrically connected to the negative electrode pad and the light-emitting element respectively through welding wires.

[0017] In one embodiment, a dam is further included, wherein the dam is disposed on the substrate, and the width of the dam is greater than 0.2 mm.

[0018] Based on the above, compared with the prior art, the COB structure provided by the utility model controls the length of the welding wire and the distance between two adjacent light-emitting elements. In particular, when the distance between two adjacent light-emitting elements electrically connected to each other is too large, a bridge chip is provided as a conductor to better adjust the electrical connection between the light-emitting elements and improve the stability between the elements.

[0019] Other features and beneficial effects of the utility model will be described in the subsequent description, and partly become apparent from the description, or understood by practicing the utility model. The purpose and other beneficial effects of the utility model can be achieved and obtained by the structures specifically pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. The positional relationships described in the drawings in the following description are based on the directions of the components shown in the diagrams unless otherwise specified.

[0021] Figure 1 A front view of a COB structure provided by an embodiment of the utility model;

[0022] Figure 2 This is a front view of a COB structure provided in another embodiment of the utility model.

[0023] Reference numerals:

[0024] 1-substrate 2-light emitting element 3-bridge chip

[0025] 4- positive electrode pad 5- negative electrode pad 6- welding wire DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the utility model clearer, the technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all of the embodiments; the technical features designed in different implementation modes of the utility model described below can be combined with each other as long as they do not conflict with each other; based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0027] In the description of the present invention, it should be noted that all terms (including technical terms and scientific terms) used in the present invention have the same meanings as those generally understood by ordinary technicians in the field to which the present invention belongs, and cannot be understood as limitations on the present invention; it should be further understood that the terms used in the present invention should be understood to have meanings consistent with the meanings of these terms in the context of this specification and in the relevant fields, and should not be understood in an idealized or overly formal sense, unless explicitly defined in this utility model.

[0028] The utility model provides a COB structure, including a substrate 1, on which a light-emitting area is provided; a plurality of light-emitting elements 2, which are arranged on the substrate 1 and are distributed in the light-emitting area at intervals, and the plurality of light-emitting elements 2 are connected to each other through welding wires 6 to form a series-parallel connection; at least one bridge chip 3, which is arranged in the light-emitting area and is electrically connected to at least one light-emitting element 2 through the welding wire 6; and pads, which include a positive pad 4 and a negative pad 5, and are circumferentially arranged on the substrate 1 along the outer periphery of the light-emitting area.

[0029] When implementing it, Figure 1 As shown, the COB structure includes a substrate 1, a plurality of light-emitting elements 2, at least one bridge chip 3, a positive electrode pad 4, and a negative electrode pad 5.

[0030] The substrate 1 carries a plurality of light-emitting elements 2, at least one bridge chip 3 and a pad. Preferably, the material of the substrate 1 can be an aluminum substrate, a ceramic substrate, a glass substrate or other structures with sufficient mechanical strength to support the COB light source, all of which fall within the scope of protection of the present utility model. A light-emitting area is provided on the substrate 1. Preferably, the shape of the light-emitting area can be circular, triangular, rectangular or any other shape. In this embodiment, the light-emitting area is preferably circular. A high degree of integration is achieved by arranging a plurality of light-emitting elements 2 at intervals in the light-emitting area. It should be noted that the substrate 1 and the shape of the light-emitting area on the substrate 1 are not limited to the following. Figure 1 The shape structure shown may also be other shapes that can adapt to specific application scenarios and lamp designs, which are not limited here.

[0031] The light-emitting element 2 is arranged on the substrate 1. The light-emitting element 2 used in this embodiment is an LED lamp bead or LED chip that emits light on both its circumference and top surface. Preferably, the light-emitting element 2 includes a single-color temperature light source and / or a multi-color temperature light source, which provides the possibility of including light sources of different color temperatures in the same COB structure, thereby enhancing the flexibility of the lamp. The plurality of light-emitting elements 2 are connected in series and parallel to each other through welding wires 6, which helps to improve the overall energy efficiency. By reasonably designing the connection method between the elements, the luminous efficiency of each light-emitting element 2 can be maximized and energy waste can be reduced.

[0032] The bridge chip 3 is arranged in the light-emitting area on the substrate 1. The shape and size of the bridge chip 3 can be designed according to the actual circuit distribution and the number of bridge chips 3, and are not limited here. The bridge chip 3 includes a conductive layer, and the conductive layer is electrically connected to the light-emitting element through a welding wire. When the length of the welding wire 6 used for electrical connection in the circuit is too long, the conductive layer of the bridge chip 3 is connected to at least one light-emitting element 2 to shorten the length of the welding wire 6 in the circuit and maintain electrical connection. Preferably, the material of the conductive layer includes conductive metal materials and / or conductive non-metallic materials, all of which fall within the protection scope of the present utility model.

[0033] Specifically, when the spacing between the adjacent light-emitting elements 2 electrically connected to each other is greater than the preset spacing, at least one bridge chip 3 is provided between the adjacent light-emitting elements 2, and the bridge chip 3 is electrically connected to the two adjacent light-emitting elements 2 through a welding wire. And / or, when the spacing between the soldering pad and the light-emitting element 2 connected thereto is greater than the preset spacing, at least one bridge chip 3 is provided between the soldering pad and the light-emitting element 2 connected thereto, and the bridge chip 3 is electrically connected to the soldering pad and the light-emitting element 2 respectively through a welding wire.

[0034] Among them, the preset spacing can be reasonably set according to the length of the welding wire to be controlled in the actual product, and is not limited here. In this embodiment, the preset spacing is preferably between 0.6 and 1.8 mm, that is, the maximum length of the welding wire can be controlled between 0.6 and 1.8 mm. For example, in order to avoid the welding wire being too long, the required length of the welding wire can be controlled to be less than or equal to 0.6 mm, and the preset spacing is 0.6 mm. That is, when the spacing between the light-emitting element 2 and the welding pad or the adjacent light-emitting element is greater than 0.6 mm, it is necessary to introduce a bridge chip 3 in the middle to ensure that the length of the welding wire can be less than or equal to 0.6 mm. For another example, if the required length of the welding wire is to be controlled to be less than or equal to 1.5 mm, the preset spacing is 1.5 mm. That is, when the spacing between the light-emitting element 2 and the welding pad or the adjacent light-emitting element 2 is greater than 1.5 mm, it is necessary to introduce a bridge chip 3 in the middle to ensure that the length of the welding wire can be less than or equal to 1.5 mm.

[0035] The COB structure provided by the utility model introduces a bridge chip 3 to control the spacing between two adjacent light-emitting elements 2 and the length of the welding wire 6, which can better improve the stability between the elements. It can not only reduce the impact of the obstruction of current flow caused by the excessive length of the welding wire 6, but also avoid the introduction of additional inductance, which is beneficial to heat dissipation.

[0036] The positive electrode pad 4 and the negative electrode pad 5 are fixed on the substrate 1 and are arranged along the outer circumference of the plurality of light-emitting elements 2 and the bridge chip 3 in the light-emitting area. The plurality of light-emitting elements 2 are electrically connected to the positive electrode pad 4 and the negative electrode pad 5 in series, parallel or a combination of series and parallel. Preferably, the material of the positive electrode pad 4 and the negative electrode pad 5 includes a conductive metal material and / or a conductive non-metallic material. In this embodiment, a metal material is preferably used to meet the conductive requirements of the present invention. It should also be noted that the shapes of the positive electrode pad 4 and the negative electrode pad 5 are not limited to the following. Figure 1 The shape structure shown may also be other structures located on two opposite sides of the light-emitting area, which is not limited here.

[0037] Preferably, it further comprises a transparent covering layer, covering the light emitting area on the substrate.

[0038] In this embodiment, the transparent covering layer covers the multiple light-emitting elements 2, at least one bridge chip 3 and the pads on the substrate 1 to protect the circuit from corrosion or oxidation and not affect the light-emitting effect. The transparent covering layer can be made of high-strength, lightweight transparent materials such as glass, PC, PET or acrylic, but this embodiment is not limited to this.

[0039] Preferably, the light-emitting elements 2 are distributed in the light-emitting area in an array, and the light-emitting elements 2 in the same row or column form a lamp group. The spacing between two adjacent lamp groups is 0.1mm to 5mm, and the spacing between two adjacent light-emitting elements 2 in the lamp group is greater than or equal to 0.2mm, so as to facilitate wire bonding. The length of the welding wire 6 is 0.1mm to 1.5mm. When two adjacent light-emitting elements 2 with a spacing greater than or equal to 0.2mm and less than or equal to 0.6mm are electrically connected to each other, there is no need to design a bridge chip 3 between the two adjacent light-emitting elements 2. When two adjacent light-emitting elements 2 with a spacing greater than 0.6mm are electrically connected to each other, at least one bridge chip 3 is provided between the two adjacent light-emitting elements 2.

[0040] When implementing it, Figure 1As shown, a circular light-emitting area is provided on the substrate 1, and a plurality of light-emitting elements 2 are distributed in the light-emitting area in an array. The number of light-emitting elements 2 in each row or column decreases gradually from the axis of the circular light-emitting area to both sides. The number of light-emitting elements 2 at the axis can be 1, 2, 3, 4, 5, 6, etc. The light-emitting elements 2 in the same row form a lamp group. The light-emitting elements 2 in the same lamp group are connected to each other through welding wires 6 to form a series connection, and the light-emitting elements 2 in different lamp groups are connected in parallel. The spacing between two adjacent lamp groups is stipulated to be 0.1 mm to 5 mm, which helps to achieve accurate layout of components in the design and ensure the overall uniformity of the system. At the same time, it is stipulated that the spacing between two adjacent light-emitting elements 2 in the lamp group is greater than 0.6 mm, and the length of the welding wire 6 is 0.1 mm to 1.5 mm. Further, the length of the welding wire 6 is preferably 0.1 mm to 0.6 mm, which helps to avoid internal interference and improve the performance and reliability of the light-emitting element 2. Preferably, the material of the welding wire 6 can be gold wire, copper wire or other wire material for electrical connection, but this embodiment is not limited thereto.

[0041] In this embodiment, when two adjacent light-emitting elements 2 with a spacing greater than 0.6 mm are electrically connected to each other, at least one bridge chip 3 needs to be provided between the two adjacent light-emitting elements 2, and the conductive layer of the bridge chip 3 is electrically connected to the two light-emitting elements 2 through the welding wire 6, which helps to improve the efficiency of signal transmission. At this time, the length of the welding wire 6 can be controlled between 0.1 mm and 0.6 mm. The shorter welding wire is not only beneficial to avoid the increase of the welding wire resistance and the introduction of additional inductance, but also conducive to heat dissipation.

[0042] It should be noted that, in this embodiment, a preset spacing of 0.6 mm is used to limit whether a bridge chip 3 is provided between the electrical connections of adjacent light-emitting elements 2. Those skilled in the art can also design other reasonable preset spacings according to the size and structure of the actual light-emitting element 2 and the COB structure. For example, the preset spacing is 0.8 mm or 0.9 mm or 1 mm or 1.2 mm or 1.3 mm or 1.4 mm or 1.5 mm or 1.6 mm or 1.7 mm or 1.8 mm, etc., all of which fall within the protection scope of the present utility model.

[0043] In another optional embodiment, the light emitting element 2 is configured as a rectangular LED chip, and a plurality of light emitting elements 2 are arranged in a concentric circle array on at least one concentric circle with the geometric center of the circular light emitting area as the center, and the number of light emitting elements 2 on each concentric circle increases step by step from the inside to the outside. Figure 2As shown, the light-emitting elements 2 form four concentric circles, and the number of light-emitting elements 2 on each concentric circle from the inside to the outside is 3, 8, 11, and 18 respectively. The arrangement of the four concentric circles is as follows: the extension line of the short axis of the three light-emitting elements 2 in the innermost ring passes through the center of the circle, and the light-emitting elements 2 in two adjacent columns are evenly distributed in a staggered manner as much as possible. The spacing between two adjacent concentric circles is 0.1mm-5mm, the spacing between two adjacent light-emitting elements 2 is greater than 0.6mm, and at least one bridge chip 3 is provided between two adjacent light-emitting elements 2 that are electrically connected to each other with too large spacing. Such a setting makes the utilization rate of the light-emitting area higher, avoids mutual light blocking between the light-emitting elements 2, has a higher light output rate, and improves the light effect; the arrangement of the light-emitting elements 2 is more uniform, the light shape is more beautiful, and the light spot is improved, so that the light-emitting chip in the central area of ​​the substrate 1 can quickly conduct heat in a path shorter than the existing light-emitting element 2 distribution path when conducting heat, which is beneficial to the heat dissipation of the light-emitting element 2, prevents the light-emitting element 2 from failing due to heat accumulation, and ensures the quality of the light-emitting element 2 and the stability of use.

[0044] Preferably, the positive electrode pad 4 is used to electrically connect the positive electrode of the light emitting element 2 ; and the negative electrode pad 5 is used to electrically connect the negative electrode of the light emitting element 2 .

[0045] When implementing it, Figure 1 As shown, the positive electrode pad 4 and the negative electrode pad 5 are arranged as electrodes on opposite sides of the light-emitting area, enclosing the light-emitting area within a limited range, and the light-emitting elements 2 in the same row form a lamp group, and the positive electrode and the negative electrode of each lamp group are electrically connected to the positive electrode pad 4 and the negative electrode pad 5 on both sides thereof through welding wires 6. Such a setting allows multiple light-emitting elements 2 to contribute to the brightness together, which helps to achieve a more uniform light distribution and reduce obvious brightness differences.

[0046] Preferably, when the distance between the positive electrode pad 4 and the light-emitting element 2 connected thereto is greater than 0.6 mm, at least one bridge chip 3 is provided between the positive electrode pad 4 and the light-emitting element 2 connected thereto, and the bridge chip 3 is electrically connected to the positive electrode pad 4 and the light-emitting element 2 respectively through the bonding wire 6;

[0047] And / or, when the distance between the negative electrode pad 5 and the light-emitting element 2 connected thereto is greater than 0.6 mm, at least one bridge chip 3 is provided between the negative electrode pad 5 and the light-emitting element 2 connected thereto, and the bridge chip 3 is electrically connected to the negative electrode pad 5 and the light-emitting element 2 respectively through the welding wire 6.

[0048] When implementing it, Figure 1As shown, when the spacing between the positive electrode pad 4 and the light-emitting element 2 exceeds 0.6 mm, at least one bridge chip 3 is provided between the positive electrode pad 4 and the light-emitting element 2 connected thereto to make up for the spacing, so that the length of the welding wire 6 is controlled within the range of 0.1 mm to 0.6 mm; when the spacing between the negative electrode pad 5 and the light-emitting element 2 exceeds 0.6 mm, at least one bridge chip 3 is provided between the negative electrode pad 5 and the light-emitting element 2 connected thereto to make up for the spacing, so that the length of the welding wire 6 can be controlled within the range of 0.1 mm to 0.6 mm. By carefully controlling the layout of the welding wire 6 and the bridge chip 3, the electrical performance can be optimized and the loss and interference during signal transmission can be reduced.

[0049] Similarly, in this embodiment, a preset spacing of 0.6 mm is used to limit whether a bridge chip 3 is provided between the light-emitting element 2 and the electrical connection of the pad. Those skilled in the art can also design other reasonable preset spacings according to the size and structure of the actual light-emitting element 2 and the COB structure. For example, the preset spacing is 0.8 mm or 0.9 mm or 1 mm or 1.2 mm or 1.3 mm or 1.4 mm or 1.5 mm or 1.6 mm or 1.7 mm or 1.8 mm, etc., all of which fall within the protection scope of the present utility model.

[0050] Preferably, it further comprises a dam (not shown in the figure), wherein the dam is arranged on the substrate and the width of the dam is greater than 0.2 mm.

[0051] During specific implementation, the dam is arranged on the substrate 1 to form a receiving space, which provides protection for the light-emitting area on the substrate 1 and helps prevent the external environment from affecting the substrate 1 and the light-emitting element 2. The width of the dam is greater than 0.2 mm, which helps to provide sufficient insulation and isolation and reduce electromagnetic interference that may occur between adjacent components. Such width and spacing restrictions provide a certain manufacturing tolerance, making it easier to maintain design specifications during the actual manufacturing process and reducing potential risks caused by mechanical, electrical or thermal problems. Preferably, the cross-section of the inner wall of the dam is circular, elliptical or rectangular. It should be noted that the structure of the dam can be any enclosure structure that can accommodate the light-emitting area, and is not limited here.

[0052] In another optional embodiment, since the positive electrode pad 4 and the negative electrode pad 5 both include a welding line area and a non-welding line area, the dam is arranged on the substrate 1 and passes through the positive electrode pad 4 and the negative electrode pad 5, so that the parts of the positive electrode pad 4 and the negative electrode pad 5 connected to the light-emitting element are located on the inner side of the receiving space, and the other parts are located on the outer side of the receiving space, so that the welding line tolerance in the light-emitting area is limited within the receiving space enclosed by the dam to form protection.

[0053] In summary, compared with the prior art, the COB structure provided by the utility model has the following advantages:

[0054] 1. The light-emitting elements are distributed in an array, so that a highly dense configuration can be achieved in the light-emitting area, thereby improving the space utilization efficiency;

[0055] Second, by using bridge chips and bonding wires between adjacent light-emitting elements with large spacing, the reliability of electrical connections can be ensured and potential problems in signal transmission can be reduced;

[0056] 3. Limiting the length of the bonding wires and the use of bridge chips helps control manufacturing costs and simplifies the assembly process.

[0057] In addition, those skilled in the art should understand that, although there are many problems in the prior art, each embodiment or technical solution of the utility model can be improved in only one or several aspects, without having to solve all the technical problems listed in the prior art or background technology at the same time. Those skilled in the art should understand that the content not mentioned in a claim should not be used as a limitation on the claim.

[0058] Although the terms such as substrate, light-emitting area, light-emitting element, bonding wire, bridge chip, pad, etc. are used more frequently in this article, the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the utility model; interpreting them as any additional restrictions is contrary to the spirit of the utility model; the terms "positive" and "negative" (if any) in the description and claims of the embodiments of the utility model and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A COB structure, characterized in that: include: A substrate, wherein a light emitting area is provided on the substrate; A plurality of light-emitting elements are disposed on the substrate and are spaced apart in the light-emitting region, and the plurality of light-emitting elements are connected to each other through welding wires to form a series-parallel connection; At least one bridge chip, the bridge chip is disposed in the light-emitting area and is electrically connected to at least one light-emitting element through a bonding wire; The pads include a positive pad and a negative pad, and are arranged on the substrate along the periphery of the light emitting area.

2. The COB structure according to claim 1, characterized in that: A transparent covering layer is also included, covering the light emitting area on the substrate.

3. The COB structure according to claim 1, characterized in that: The plurality of light emitting elements include single-color temperature light sources and / or multi-color temperature light sources.

4. The COB structure according to claim 1, characterized in that: The bridge chip includes a conductive layer, and the conductive layer is electrically connected to the light-emitting element through a bonding wire; the material of the conductive layer includes a conductive metal material and / or a conductive non-metal material.

5. The COB structure according to claim 1, characterized in that: The light emitting elements are distributed in the light emitting area in an array, and the light emitting elements in the same row or column form a lamp group, the spacing between two adjacent lamp groups is 0.1 mm to 5 mm, and the spacing between two adjacent light emitting elements in the lamp group is greater than or equal to 0.2 mm.

6. The COB structure according to claim 1, characterized in that: The length of the welding wire is 0.1 mm to 1.5 mm.

7. The COB structure according to claim 5 or 6, characterized in that: When two adjacent light emitting elements with a spacing greater than 0.6 mm are electrically connected to each other, at least one bridge chip is provided between the two adjacent light emitting elements, and the bridge chip is electrically connected to the two adjacent light emitting elements through a welding wire.

8. The COB structure according to claim 1, characterized in that: The positive electrode pad is used to electrically connect the positive electrode of the light emitting element; the negative electrode pad is used to electrically connect the negative electrode of the light emitting element.

9. The COB structure according to claim 8, characterized in that: When the distance between the positive electrode pad and the light-emitting element connected thereto is greater than 0.6 mm, at least one bridge chip is provided between the positive electrode pad and the light-emitting element connected thereto, and the bridge chip is electrically connected to the positive electrode pad and the light-emitting element respectively through bonding wires; And / or, when the distance between the negative electrode pad and the light-emitting element connected thereto is greater than 0.6 mm, at least one bridge chip is provided between the negative electrode pad and the light-emitting element connected thereto, and the bridge chip is electrically connected to the negative electrode pad and the light-emitting element respectively through welding wires.

10. The COB structure according to claim 1, characterized in that: It also includes a dam, which is arranged on the substrate and has a width greater than 0.2 mm.

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