Circuit board and light strip

Abstract

Embodiments of the present application provide a circuit board and a light strip. The circuit board comprises a first insulating layer, a first conductor layer, a second insulating layer, a second conductor layer, and a third insulating layer which are stacked. The first conductor layer is provided with a first main power line and a second main power line extending in the length direction of the circuit board. The second conductor layer is provided with a plurality of branch power line groups sequentially distributed in the length direction of the circuit board. Each branch power line group comprises a plurality of branch power lines, and the branch power lines at two ends of each branch power line group are a first branch power line and a second branch power line, respectively. The circuit board is provided with a plurality of groups of filler holes penetrating from a top surface of the circuit board to the first conductor layer. The filler holes comprise first sub-holes and a second sub-holes. The first sub-holes penetrate through the first branch power lines and extend to the first main power line. The second sub-holes penetrate through the second branch power lines and extend to the second main power line.

Description

Circuit boards and LED strips

[0001] Cross-references

[0002] This application claims priority to Chinese Patent Application No. 202520274748.4, filed on February 20, 2025, entitled "Circuit Board and Light Strip", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of lighting device technology, and more particularly to a circuit board and a light strip. Background Technology

[0004] A typical LED strip consists of a circuit board and light-emitting devices. The circuit board has a first main power line, a second main power line, and a branch power line group distributed on the same layer. The branch power line group is sandwiched between the first and second main power lines along the width of the circuit board. Because the first main power line, the branch power line group, and the second main power line are distributed along the width of the circuit board, it is difficult to reduce the width of the circuit board. This difficulty in reducing the width of the circuit board, in turn, makes it difficult to reduce the width of the area containing the circuit board. Summary of the Invention

[0005] This application provides a circuit board and a light strip.

[0006] In a first aspect, embodiments of this application provide a circuit board.

[0007] The circuit board provided in this application embodiment includes: a first insulating layer, a first conductor layer, a second insulating layer, a second conductor layer, and a third insulating layer stacked together; the first conductor layer is provided with a first main power line and a second main power line extending along the length direction of the circuit board; the second conductor layer is provided with a plurality of branch power line groups distributed sequentially along the length direction of the circuit board, each branch power line group including a plurality of branch power lines, the branch power lines at both ends of the branch power line group being a first branch power line and a second branch power line, respectively; the circuit board is provided with a plurality of sets of filler holes penetrating from the top surface of the circuit board to the first conductor layer, each filler hole including a first sub-hole and a second sub-hole, the first sub-hole penetrating the first branch power line and penetrating to the first main power line, the second sub-hole penetrating the second branch power line and penetrating to the second main power line.

[0008] In one embodiment, the circuit board is provided with multiple sets of exposed power line windows extending from the top surface of the circuit board to the first conductor layer, and each set of exposed power line windows is distributed at intervals along the length direction of the circuit board; the exposed power line windows include a first sub-exposed window and a second sub-exposed window, and in the thickness direction of the circuit board, the first sub-exposed window is opposite to the first main power line, and the second sub-exposed window is opposite to the second main power line.

[0009] In one embodiment, the surface of the first main power line in the area enclosed by the first sub-exposed window is provided with a first tin layer, and the surface of the second main power line in the area enclosed by the second sub-exposed window is provided with a second tin layer.

[0010] In one embodiment, the circuit board is a flexible circuit board, the thickness of the first tin layer is less than or equal to 0.1 mm, and the thickness of the second tin layer is less than or equal to 0.1 mm.

[0011] In one embodiment, along the length of the circuit board, each of the power line exposure windows is located at the boundary area of ​​adjacent branch power line groups.

[0012] Secondly, embodiments of this application provide a light strip.

[0013] The light strip provided in this application embodiment includes: light-emitting devices and any type of circuit board provided in this application embodiment; each of the light-emitting devices is sequentially disposed on the circuit board along the length direction of the circuit board, and each light-emitting device is electrically connected to the branch power line group in a one-to-one correspondence, so that the branch power line group and the corresponding light-emitting device form a light-emitting circuit.

[0014] In one embodiment, the first sub-hole is filled with a first conductive element that electrically connects the first branch power line and the first main power line; the second sub-hole is filled with a second conductive element that electrically connects the second branch power line and the second main power line, and the orthographic projection of the light-emitting device on the circuit board is offset from the filler hole.

[0015] In one embodiment, the first conductive element is formed by solidifying liquid metal filling the first sub-hole, and the second conductive element is formed by solidifying liquid metal filling the second sub-hole.

[0016] In one embodiment, the light strip further includes a double-sided adhesive layer, one side of which is adhered to the bottom surface of the circuit board. The circuit board includes a first side and a second side along its width direction, and the double-sided adhesive layer includes a third side and a fourth side along its width direction. The first side and the third side are located on the same side of the light strip, and the third side and the fourth side are located on the same side of the light strip. The first side and the third side are flush, and / or the third side and the fourth side are flush.

[0017] In one embodiment, the light strip further includes a first dam and a second dam extending along the length of the circuit board. The first dam and the second dam are disposed on opposite sides of the light-emitting device along the width of the circuit board, and a light-transmitting adhesive is disposed between the first dam and the second dam. The height of the first dam is greater than the height of the light-emitting device, and the height of the second dam is greater than the height of the light-emitting device. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 is a schematic diagram of a circuit board provided in an embodiment of this application;

[0020] Figure 2 is an exploded view of a single-segment circuit board provided in an embodiment of this application;

[0021] Figure 3 is a schematic diagram of a light strip provided in an embodiment of this application;

[0022] Figure 4 is a partial schematic diagram of a light strip provided in an embodiment of this application;

[0023] Figure 5 is a left view of a light strip provided in an embodiment of this application;

[0024] Figure 6 is a schematic diagram of a light strip provided in an embodiment of this application, which shows a case in which the first damming adhesive, the second damming adhesive, and the light-transmitting adhesive are omitted from the light strip shown in Figure 3.

[0025] Figure 7 is a schematic diagram of a first conductor layer provided in an embodiment of this application;

[0026] Figure 8 is a schematic diagram of a second conductor layer and a light-emitting device provided in an embodiment of this application;

[0027] Figure 9 is a schematic diagram of a single-segment light strip provided in an embodiment of this application;

[0028] Figure 10 is a schematic diagram of a single-segment light strip provided in an embodiment of this application, which shows the case where the first damming adhesive, the second damming adhesive, and the light-transmitting adhesive are omitted from the light strip shown in Figure 9.

[0029] Figure 11 is a schematic diagram of a single-segment light strip provided in an embodiment of this application, which shows the case in which the first conductive element and the second conductive element are omitted from the light strip shown in Figure 10.

[0030] Figure 12 is an exploded view of the single-segment light strip shown in Figure 10;

[0031] Figure 13 is a schematic diagram of the first conductor layer, the second conductor layer, and the light-emitting device of a single-segment light strip provided in an embodiment of this application;

[0032] Figure 14 is a schematic diagram of a semi-finished LED strip before cutting, provided in an embodiment of this application;

[0033] Figure 15 is a schematic diagram of a circuit board, a light-emitting device, and a glue-drawing needle provided in an embodiment of this application.

[0034] Explanation of reference numerals in the attached diagram: 1-LED strip; 100-Circuit board; 111-First insulating layer; 112-Second insulating layer; 113-Third insulating layer; 120-First conductor layer; 121-First main power line; 122-Second main power line; 130-Second conductor layer; 131-Branch power line group; 1310-Branch power line; 1311-First branch power line; 1312-Second branch power line; 141-Filling hole; 1411-First sub-hole; 1412-Second sub-hole; 142-Exposed power line Window; 1421-First exposed window; 1422-Second exposed window; 1431-First tin layer; 1432-Second tin layer; 1441-First conductive element; 1442-Second conductive element; 151-First side; 152-Second side; 200-Light-emitting device; 210-LED bead; 220-Resistor; 300-Double-sided adhesive layer; 310-Third side; 320-Fourth side; 410-First damming adhesive; 420-Second damming adhesive; 430-Light-transmitting adhesive; 2-Adhesive-pulling needle. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0037] Furthermore, although the terminology used in this application is selected from commonly known and used terms, some terms mentioned in this application specification may have been selected by the applicant at his or her own discretion, and their detailed meanings are explained in the relevant sections of this description.

[0038] Furthermore, this application is required to be understood not only through the actual terms used, but also through the meaning implied by each term.

[0039] The technical solutions provided by the various embodiments of this application are described in detail below with reference to the accompanying drawings.

[0040] This application provides a circuit board. Referring to Figures 1 to 13, the circuit board 100 provided in this application includes a first insulating layer 111, a first conductor layer 120, a second insulating layer 112, a second conductor layer 130, and a third insulating layer 113 stacked together.

[0041] Referring to Figure 7, the first conductor layer 120 has a first main power line 121 and a second main power line 122 extending along the length of the circuit board 100. Referring to Figures 8, 12, and 13, the second conductor layer 130 has a plurality of branch power line groups 131 sequentially distributed along the length of the circuit board 100. Each branch power line group 131 includes a plurality of branch power lines 1310. The branch power lines 1310 at both ends of the branch power line group 131 are a first branch power line 1311 and a second branch power line 1312, respectively.

[0042] In this way, when the circuit board 100 is used to carry the light-emitting device 200, the light-emitting device 200 can be electrically connected to the branch power line group 131 in a one-to-one correspondence, so that the branch power line group 131 and the corresponding light-emitting device 200 form a light-emitting circuit.

[0043] For example, both the first conductor layer 120 and the second conductor layer 130 are made of copper or copper alloys. Furthermore, the first main power line 121, the second main power line 122, and the branch power line group 131 are also made of copper or copper alloys. This allows the first conductor layer 120 and the second conductor layer 130 to possess both good conductivity and low cost. Of course, it is understood that the first conductor layer 120 and the second conductor layer 130 can also be made of any other conductive material, which will not be listed here.

[0044] Further, referring to Figures 6, 10 to 12, the circuit board 100 is provided with multiple sets of filler holes 141 extending from the top surface of the circuit board 100 to the first conductor layer 120. The filler holes 141 include a first sub-hole 1411 and a second sub-hole 1412. The first sub-hole 1411 passes through a first branch power line 1311 and extends to a first main power line 121. The second sub-hole 1412 passes through a second branch power line 1312 and extends to a second main power line 122.

[0045] In this way, by filling the first sub-hole 1411 with a first conductive element 1441 for electrically connecting the first branch power line 1311 and the first main power line 121, and by filling the second sub-hole 1412 with a second conductive element 1442 for electrically connecting the second branch power line 1312 and the second main power line 122, the light-emitting circuit can be connected to the first main power line 121 and the second main power line 122 respectively. Furthermore, by connecting the live wire and neutral wire of the external power line to the first main power line 121 and the second main power line 122 respectively, power can be supplied to the light-emitting circuit through the first main power line 121 and the second main power line 122, thereby enabling the light-emitting device 200 to emit light.

[0046] In this way, in the embodiments of this application, the width of the circuit board 100 can be reduced by making the first conductor layer 120 for forming the first main power line 121 and the second main power line 122 and the second conductor layer 130 for forming the branch power line group 131 spaced apart in the thickness direction of the circuit board 100.

[0047] Since the circuit board 100 can be used to carry the light-emitting device 200, to facilitate those skilled in the art to understand the solution provided by the embodiments of this application, the following mainly uses the circuit board 100 carrying the light-emitting device 200 and combining them into a light strip 1 as an example to explain in detail the solution provided by the embodiments of this application. It should be noted that in other embodiments, the circuit board 100 can also carry other components, which will not be described in detail here.

[0048] Referring to Figures 3 and 4, in some embodiments, the circuit board 100 is provided with multiple sets of power line exposed windows 142 extending from the top surface of the circuit board 100 to the first conductor layer 120, and the sets of power line exposed windows 142 are distributed sequentially at intervals along the length direction of the circuit board 100.

[0049] The power line exposure window 142 includes a first sub-exposed window 1421 and a second sub-exposed window 1422. In the thickness direction of the circuit board 100, the first sub-exposed window 1421 is opposite to the first main power line 121, and the second sub-exposed window 1422 is opposite to the second main power line 122. Exemplarily, the first main power line 121 forms the live wire of the circuit board 100, and the second main power line 122 forms the neutral wire of the circuit board 100. The first main power line 121 is used to connect to the live wire of an external power source, and the second main power line 122 is used to connect to the neutral wire of an external power source.

[0050] Thus, by adopting the solution provided in this application embodiment, the first main power line 121 can be exposed on the outer surface of the light strip 1 through the first sub-exposed window 1421, and the second main power line 122 can be exposed on the outer surface of the light strip 1 through the second sub-exposed window 1422; thereby, the external power line can be soldered to the part of the first main power line 121 exposed outside the light strip 1 and the part of the second main power line 122 exposed outside the light strip 1, thereby using the external power line to supply power to the light strip 1.

[0051] Referring to Figures 4, 3, and 4, in some embodiments, a first tin layer 1431 is provided on the surface of the first main power line 121 in the area enclosed by the first exposed window 1421. This first tin layer 1431 prevents the exposed portion of the first main power line 121 from being oxidized, thus preventing problems such as difficulty in soldering or weak soldering during subsequent soldering with external power lines.

[0052] Similarly, a second tin layer 1432 is provided on the surface of the second main power line 122 in the area enclosed by the second exposed window 1422. In this way, the second tin layer 1432 can be used to prevent the exposed part of the second main power line 122 from being oxidized, which would make it difficult to solder or cause problems with weak soldering when soldering to the external power line later.

[0053] In some embodiments, the circuit board 100 is a flexible circuit board 100, the thickness of the first tin layer 1431 is less than or equal to 0.1 mm, and the thickness of the second tin layer 1432 is less than or equal to 0.1 mm. This avoids the problem that, due to the relatively large thickness of the first tin layer 1431 and the second tin layer 1432, the first tin layer 1431 easily separates from the first main power line 121, and the second tin layer 1432 easily separates from the second main power line 122 during the winding of the LED strip 1.

[0054] It should be noted that in other embodiments, the circuit board 100 may also be a rigid circuit board.

[0055] Referring to Figures 6 and 8, in some embodiments, along the length of the circuit board 100, each power line exposure window 142 is located at the boundary area of ​​adjacent branch power line groups 131. This facilitates the cutting of the LED strip 1 with the circuit board 100 mounted on it from the power line exposure window 142 as needed, so that the length of the cut LED strip meets the user's requirements.

[0056] This application provides a light strip. Referring to Figures 3 to 13, the light strip 1 provided in this application includes a light-emitting device 200 and any type of circuit board 100 provided in this application. Exemplarily, the light-emitting device 200 may include at least one of a light-emitting diode (LED) and a light bulb.

[0057] Each light-emitting device 200 is sequentially arranged on the circuit board 100 along its length. Each light-emitting device 200 is electrically connected to a branch power line group 131, forming a light-emitting circuit. Furthermore, the light-emitting circuit can be powered by an external power supply by connecting the light-emitting circuit to the first main power line 121 and the second main power line 122, with the first and second main power lines 121 and 122 respectively connected to the live and neutral wires of an external power supply. This allows the light-emitting devices 200 to emit light.

[0058] In some embodiments, the first sub-hole 1411 is filled with a first conductive element 1441 that electrically connects the first branch power line 1311 and the first main power line 121. Thus, the first conductive element 1441 can be used to electrically connect the first branch power line 1311 and the first main power line 121. The second sub-hole 1412 is filled with a second conductive element 1442 that electrically connects the second branch power line 1312 and the second main power line 122. Thus, the second conductive element 1442 can be used to electrically connect the second branch power line 1312 and the second main power line 122.

[0059] Furthermore, the orthographic projections of the light-emitting devices 200 on the circuit board 100 are all staggered with the filler holes 141. This ensures that the light-emitting devices 200 do not obstruct the first sub-hole 1411 and the second sub-hole 1412. Consequently, by visually inspecting whether the first conductive element 1441 is filled in the first sub-hole 1411 and whether the second conductive element 1442 is filled in the second sub-hole 1412, it can be determined whether the branch power lines 1310 at both ends of the light-emitting circuit are respectively connected to the first main power line 121 and the second main power line 122. Therefore, it is relatively convenient to determine whether the light-emitting circuit is connected to the first main power line 121 and the second main power line 122.

[0060] Since visual inspection is a relatively easy method to implement, the solution provided in this application can be used to conveniently determine whether the branch power lines 1310 at both ends of the light-emitting circuit are connected to the first main power line 121 and the second main power line 122, respectively.

[0061] In some embodiments, the first conductive element 1441 is formed by solidifying liquid metal filling the first sub-hole 1411, and the second conductive element 1442 is formed by solidifying liquid metal filling the second sub-hole 1412.

[0062] For example, the first conductive element 1441 is formed by the solidification of molten solder filling the first sub-hole 1411, and the second conductive element 1442 is formed by the solidification of molten solder filling the second sub-hole 1412. For example, when 1 ml of molten solder is filled into the first sub-hole 1411, the molten solder will not overflow from the opening of the first sub-hole 1411, and the top surface of the solidified solder block is slightly lower than the height of the opening of the first sub-hole 1411. Therefore, by observing whether there is solder dross around the opening of the first sub-hole 1411 and by observing the height difference between the solidified solder block inside the first sub-hole 1411 and the opening of the first sub-hole 1411, it can be determined more accurately whether the first branch power line 1311 and the first main power line 121 are connected by the solder block inside the first sub-hole 1411. Similarly, it can be determined more accurately whether the second branch power line 1312 and the second main power line 122 are connected by the solder block inside the second sub-hole 1412.

[0063] Referring to Figures 8, 12, and 13, in some embodiments, the light-emitting device 200 includes a plurality of LEDs 210, and a branch power line 1310 is electrically connected to each LED 210 in sequence, so that the LEDs 210 of each light-emitting circuit are connected in series. For example, a single group of light-emitting devices 200 includes seven LEDs 210 with a rated voltage of 24 volts. In addition, a resistor 220 is connected in series in the light-emitting circuit. The resistor 220 serves to limit current.

[0064] In some embodiments, the light strip further includes a double-sided adhesive layer 300, one side of which is adhered to the bottom surface of the circuit board 100. Thus, during the use of the light strip 1, the backing paper on the back of the double-sided adhesive layer 300 can be removed, thereby adhering the light strip 1 to the location where it needs to be installed.

[0065] Referring to Figure 5, in some embodiments, the circuit board 100 includes a first side surface 151 and a second side surface 152 along its width direction, and the double-sided adhesive layer 300 includes a third side surface 310 and a fourth side surface 320 along its width direction. The first side surface 151 and the third side surface 310 are located on the same side of the light strip, and the third side surface 310 and the fourth side surface 320 are located on the same side of the light strip. The first side surface 151 is flush with the third side surface 310, and / or the third side surface 310 is flush with the fourth side surface 320.

[0066] It should be noted that, referring to Figure 14, during the production of LED strips, semi-finished LED strips are connected side-by-side. Double-sided tape, approximately the same width as the semi-finished LED strips, can be applied to the back of the connected strips. Then, the semi-finished LED strips with the double-sided tape can be cut to form individual strips. Because the double-sided tape is adhered to the back of the semi-finished LED strips, it can be cut to the appropriate width during the cutting process. This improves production efficiency compared to related technologies where double-sided tape is applied to individual LED strips after they have been cut.

[0067] Understandably, since a single LED strip is obtained by cutting a semi-finished LED strip with double-sided adhesive attached, the LED strips located on either side of the parallel semi-finished LED strips, after being cut, only have one side as the cut surface, thus the double-sided adhesive layer 300 and the LED strip 1 are flush on the side of the cut surface. The LED strip located between the two parallel semi-finished LED strips, after being cut, has both sides as the cut surface, thus the double-sided adhesive layer 300 and the two sides of the LED strip 1 are correspondingly flush.

[0068] In some embodiments, the light strip further includes a first dammed adhesive 410 and a second dammed adhesive 420 extending along the length direction of the circuit board 100. The first dammed adhesive 410 and the second dammed adhesive 420 are disposed on opposite sides of the light-emitting device 200 along the width direction of the circuit board 100, and a light-transmitting adhesive 430 is disposed between the first dammed adhesive 410 and the second dammed adhesive 420.

[0069] It should be noted that the first damming adhesive 410 and the second damming adhesive 420 can be formed by solidifying an adhesive liquid with slightly poorer fluidity. Therefore, the first damming adhesive 410 and the second damming adhesive 420 can be processed using an adhesive liquid with slightly poorer fluidity. After the first damming adhesive 410 and the second damming adhesive 420 solidify, an adhesive liquid that meets the requirements for light transmittance and light scattering can be placed between the first damming adhesive 410 and the second damming adhesive 420. The solidification of the adhesive liquid between the first damming adhesive 410 and the second damming adhesive 420 forms the light-transmitting adhesive 430.

[0070] In some embodiments, the height of the first dammed adhesive 410 is greater than the height of the light-emitting device 200, and the height of the second dammed adhesive 420 is greater than the height of the light-emitting device 200.

[0071] It should be noted that, referring to Figure 15, during the process of forming the first dammed adhesive 410 and the second dammed adhesive 420 using an adhesive with slightly poorer fluidity, the adhesive-drawing needle 2 of the adhesive-drawing device can be positioned slightly higher than the light-emitting device 200. This avoids collisions between the adhesive-drawing needle 2 and the light-emitting device 200, especially when there is a positional error in the width direction of the light strip, due to the lower position of the adhesive-drawing needle 2. Because the adhesive-drawing needle 2 of the adhesive-drawing device is slightly higher than the light-emitting device 200, the height of the first dammed adhesive 410 will be greater than the height of the light-emitting device 200, and the height of the second dammed adhesive 420 will also be greater than the height of the light-emitting device 200.

[0072] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0073] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the embodiments of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A circuit board, comprising: A first insulating layer (111), a first conductor layer (120), a second insulating layer (112), a second conductor layer (130), and a third insulating layer (113) are stacked together; The first conductor layer (120) is provided with a first main power line (121) and a second main power line (122) extending along the length direction of the circuit board; The second conductor layer (130) is provided with a plurality of branch power line groups (131) arranged sequentially along the length direction of the circuit board. The branch power line group (131) includes a plurality of branch power lines (1310). The branch power lines (1310) at both ends of the branch power line group (131) are respectively the first branch power line (1311) and the second branch power line (1312). The circuit board is provided with multiple sets of filler holes (141) extending from the top surface of the circuit board to the first conductor layer (120). The filler holes (141) include a first sub-hole (1411) and a second sub-hole (1412). The first sub-hole (1411) extends through the first branch power line (1311) and through the first main power line (121). The second sub-hole (1412) extends through the second branch power line (1312) and through the second main power line (122).

2. The circuit board according to claim 1, wherein, The circuit board is provided with multiple sets of power line exposed windows (142) extending from the top surface of the circuit board to the first conductor layer (120), and each set of power line exposed windows (142) is distributed at intervals along the length of the circuit board. The power line exposed window (142) includes a first sub-exposed window (1421) and a second sub-exposed window (1422). In the thickness direction of the circuit board, the first sub-exposed window (1421) is opposite to the first main power line (121), and the second sub-exposed window (1422) is opposite to the second main power line (122).

3. The circuit board according to claim 2, wherein, The surface of the first main power line (121) in the area enclosed by the first sub-exposed window (1421) is provided with a first tin layer (1431), and the surface of the second main power line (122) in the area enclosed by the second sub-exposed window (1422) is provided with a second tin layer (1432).

4. The circuit board according to claim 3, wherein, The circuit board is a flexible circuit board, the thickness of the first tin layer (1431) is less than or equal to 0.1 mm, and the thickness of the second tin layer (1432) is less than or equal to 0.1 mm.

5. The circuit board according to claim 2, wherein, Along the length of the circuit board, each of the power line exposed windows (142) is located in the boundary area of ​​adjacent branch power line groups (131).

6. A light strip, comprising: The light-emitting device (200) and the circuit board according to any one of claims 1 to 5; Each of the light-emitting devices (200) is sequentially disposed on the circuit board along the length of the circuit board, and each of the light-emitting devices (200) is electrically connected to the branch power line group (131) in a corresponding manner, so that the branch power line group (131) and the corresponding light-emitting device (200) form a light-emitting circuit.

7. The light strip according to claim 6, wherein, The first sub-hole (1411) is filled with a first conductive element (1441) that electrically connects the first branch power line (1311) and the first main power line (121); the second sub-hole (1412) is filled with a second conductive element (1442) that electrically connects the second branch power line (1312) and the second main power line (122), and the orthographic projection of the light-emitting device (200) on the circuit board is offset from the filler hole (141).

8. The light strip according to claim 7, wherein, The first conductive element (1441) is formed by solidifying liquid metal filling the first sub-hole (1411), and the second conductive element (1442) is formed by solidifying liquid metal filling the second sub-hole (1412).

9. The light strip according to claim 6, wherein, The light strip also includes a double-sided adhesive layer (300), one side of which is bonded to the bottom surface of the circuit board. The circuit board includes a first side (151) and a second side (152) along the width direction of the circuit board. The double-sided adhesive layer (300) includes a third side (310) and a fourth side (320) along the width direction of the circuit board. The first side (151) and the third side (310) are located on the same side of the light strip. The third side (310) and the fourth side (320) are located on the same side of the light strip. The first side (151) is flush with the third side (310), and / or the third side (310) is flush with the fourth side (320).

10. The light strip according to claim 6, wherein, The light strip also includes a first dammed adhesive (410) and a second dammed adhesive (420) extending along the length direction of the circuit board. The first dammed adhesive (410) and the second dammed adhesive (420) are disposed on opposite sides of the light-emitting device (200) along the width direction of the circuit board. A light-transmitting adhesive (430) is disposed between the first dammed adhesive (410) and the second dammed adhesive (420). The height of the first dammed adhesive (410) is greater than the height of the light-emitting device (200), and the height of the second dammed adhesive (420) is greater than the height of the light-emitting device (200).

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