TWI860750B - Light-emitting module - Google Patents

Abstract

A light-emitting module includes a first power supply wire, a second power supply wire, and a light-emitting device. The light-emitting device includes M light-emitting elements arranged in a row, where M is an integer greater than 3. A first end of an N^th light-emitting element of the light-emitting device is connected to a first power supply node through the first power supply wire, and a second end of an (M-N+1)^th light-emitting element of the light-emitting device is connected to a second power supply node through the second power supply wire. N is an integer greater than 1 but not greater than M/2.

Description

Light emitting module

The present invention relates to a light-emitting module, in particular to a light-emitting module capable of making the light-emitting elements in the light-emitting module emit light uniformly.

With the popularity of personal computers, personal computers may be used in various environments, such as in places with insufficient light. In order to meet the use needs in places with insufficient light, self-luminous keyboards are widely used. A traditional light-emitting keyboard is provided with a plurality of light-emitting diodes therein, so that the keyboard glows with the help of the light emitted by the light-emitting diodes. Please refer to Figures 1 and 2, Figure 1 is an equivalent circuit diagram of a light-emitting module 10 applied to a traditional light-emitting keyboard, and Figure 2 is a layout diagram of the light-emitting module 10 of Figure 1. The light-emitting module 10 includes a light-emitting device 110, which is coupled between a first power node VCC and a second power node GND. The first power node VCC is used to provide a positive voltage, and the second power node GND is used to be grounded. The light-emitting device 110 includes a plurality of light-emitting elements D1 to D15, and the light-emitting elements D1 to D15 are arranged in a row along a first direction X. Each of the light-emitting elements D1 to D15 can be a light-emitting diode. The first terminal P1 and the second terminal P2 of the light-emitting device 110 are coupled to the first power node VCC and the second power node GND, respectively, wherein the first terminal P1 is the anode of the light-emitting element D1, the second terminal P2 is the cathode of the light-emitting element D15, and the resistance value between the anodes of two adjacent light-emitting elements and the resistance value between the cathodes of two adjacent light-emitting elements are both R. The light-emitting elements D1 to D15 are arranged on the film 21 of FIG. 2, and the film 21 has conductive lines 24, 25, 26 and 27 and contact pads 22 and 23 formed by printing technology. Among them, the contact pad 22 serves as the first power node VCC, and the contact pad 23 serves as the first power node GND. Among them, in order to save manufacturing costs, the contact pads 22 and 23 and the conductive lines 24, 25, 26 and 27 are not copper lines, but are formed by printing conductive paste (e.g., silver paste) on the film 21. The conductive lines 24, 25, 26 and 27 formed by the conductive paste all have resistance. Theoretically, if the resistance between the anodes of two adjacent light-emitting elements and the resistance between the cathodes of two adjacent light-emitting elements are both R, the current of each light-emitting element D1 to D15 will be equal. However, when the current of the light-emitting elements D1 to D15 is actually measured, the curve shown in Figure 3 will be obtained. Figure 3 is a relationship diagram between each light-emitting element D1 to D15 of the light-emitting module 10 of Figure 1 and the current flowing through each light-emitting element D1 to D15. Since the internal resistance of the light-emitting diode is not linear, the current flowing through each light-emitting element is different, which makes the brightness of each light-emitting diode different, and thus causes the keyboard to emit uneven light. Among them, the current flowing through the light-emitting elements D1 and D15 is the largest, while the current flowing through the light-emitting element D8 is the smallest, so the brightness of the light-emitting elements D1 and D15 is the largest, while the brightness of the light-emitting element D8 is the smallest.

An embodiment of the present invention provides a light-emitting module, which includes at least one first power wire, at least one second power wire and a plurality of light-emitting devices. At least one first power wire is connected to a first power node, and at least one second power wire is connected to a second power node. Each light-emitting device includes a first terminal, a second terminal, a third power wire, a fourth power wire and M light-emitting elements, where M is an integer greater than 3. The first terminal is connected to at least one first power wire, the second terminal is connected to at least one second power wire, the third power wire is connected to and passes through the first terminal, and the fourth power wire is connected to and passes through the second terminal. The M light-emitting elements are arranged in a row. The first end of each light-emitting element is connected to the third power wire, and the second end of each light-emitting element is connected to the fourth power wire. Wherein starting from the first end point, passing through any of the Nth to (M-N+1)th light-emitting elements in a row of M light-emitting elements to reach the second end point, the total length of the third power wire and the fourth power wire passed through are both equal to the first total length , N is an integer greater than 1 and not greater than M/2. Wherein starting from the first end point, passing through any of the first and Mth light-emitting elements in a row of M light-emitting elements to reach the second end point, the total length of the third power wire and the fourth power wire passed through are both greater than the first total length. Wherein starting from the first power node, passing through any single light-emitting device to reach the second power node, the total length of at least one first power wire and at least one second power wire passed through are equal.

Another embodiment of the present invention provides another light-emitting module, which includes a first power wire, a second power wire and a light-emitting device. The first end of the first power wire is connected to the first power node, and the first end of the second power wire is connected to the second power node. The light-emitting device includes a first terminal, a second terminal, a third power wire, a fourth power wire and M light-emitting elements, where M is an integer greater than 3. The first terminal of the light-emitting device is connected to the first power wire, the second terminal of the light-emitting device is connected to the second power wire, the third power wire is connected to and passes through the first terminal of the light-emitting device, and the fourth power wire is connected to and passes through the second terminal of the light-emitting device. The M light-emitting elements are arranged in a row. The first end of each light-emitting element is connected to the third power wire, and the second end of each light-emitting element is connected to the fourth power wire. Wherein, starting from the first end point, passing through any of the Nth to (M-N+1)th light-emitting elements in a row of M light-emitting elements to reach the second end point, the total length of the third power wire and the fourth power wire passed through are both equal to the first total length, and N is an integer greater than 1 and not greater than M/2. Wherein, starting from the first end point, passing through any of the first and Mth light-emitting elements in a row of M light-emitting elements to reach the second end point, the total length of the third power wire and the fourth power wire passed through are both greater than the first total length.

10, 20, 30, 40: light-emitting module

21: Film

22, 23: Contact pad

24, 25, 26, 27: Conductive lines

110, 210, 310: Light-emitting device

410: Solid line

420: Dashed line

52, 53, 62, 63: Curved structure

A, A1, A2, A3: First power conductor

B, B1, B2, B3: Second power conductor

C: The third power conductor

D: Fourth power conductor

D1 to D15: Light-emitting elements

GND: Second power node

_LA1 , _LA2 , _LB1 , _LB2 , _LC1 to _LC14 , _LD1 to _LD14 : Length

P1: First endpoint

P2: Second endpoint

R, _RA1 , _RA2 , _RB1 , _RB2 , _RC1 to _RC14 , _RD1 to _RD14 : Resistance value

VCC: first power node

X: First direction

Y: Second direction

Figure 1 is an equivalent circuit diagram of a light-emitting module used in a traditional light-emitting keyboard.

Figure 2 is the wiring diagram of the light-emitting module in Figure 1.

Figure 3 is a diagram showing the relationship between each light-emitting element of the light-emitting module in Figure 1 and the current flowing through each light-emitting element.

Figure 4 is an equivalent circuit diagram of the light-emitting module of an embodiment of the present invention.

Figure 5 is a diagram showing the relationship between each light-emitting element of the light-emitting module in Figure 4 and the current flowing through each light-emitting element.

Figure 6 is a schematic diagram of a light-emitting module of another embodiment of the present invention.

Figure 7 is the equivalent circuit diagram of the light-emitting module in Figure 6.

Figure 8 is a schematic diagram of a light-emitting module of another embodiment of the present invention.

Please refer to FIG. 4 and FIG. 5. FIG. 4 is an equivalent circuit diagram of a light-emitting module 20 of an embodiment of the present invention, and FIG. 5 is a relationship diagram between each light-emitting element D1 to D15 of the light-emitting module 20 of FIG. 4 and the current flowing through each light-emitting element D1 to D15. The light-emitting module 20 includes a light-emitting device 210, which is coupled between a first power node VCC and a second power node GND. The voltage of the first power node VCC is higher than the voltage of the second power node GND, for example: the first power node VCC is used to provide a positive voltage, and the second power node GND is used to be grounded, but the present invention is not limited thereto. The light-emitting device 210 includes a plurality of light-emitting elements D1 to D15, and the light-emitting elements D1 to D15 are arranged in a row along a first direction X. Each of the light-emitting elements D1 to D15 can be a light-emitting diode. The first terminal P1 and the second terminal P2 of the light-emitting device 210 are coupled to the first power node VCC and the second power node GND respectively, wherein the first terminal P1 is the anode of the light-emitting element D4, the second terminal P2 is the cathode of the light-emitting element D12, and the resistance value between the anodes of two adjacent light-emitting elements and the resistance value between the cathodes of two adjacent light-emitting elements are both R. Since the first end point P1 and the second end point P2 of the light-emitting device 210 are the anode of the light-emitting element D4 and the cathode of the light-emitting element D12, respectively, the current flowing through the light-emitting elements D4 and D12 is the largest, so that the current of the light-emitting elements D1 to D15 of the light-emitting device 210 is more average than the current of the light-emitting elements D1 to D15 of the light-emitting device 110. As shown in FIG. 5, the solid line 410 is used to represent the current flowing through each light-emitting element D1 to D15 of the light-emitting device 210, and the dotted line 420 is used to represent the current flowing through each light-emitting element D1 to D15 of the light-emitting device 110 of FIG. 1. Compared with the light-emitting device 110 of FIG. 1, the current of the light-emitting elements D1 to D15 of the light-emitting device 210 of FIG. 4 is more average. Therefore, compared with the light emitting device 110 in FIG. 1, the light generated by the light emitting device 210 is more uniform.

The first end point P1 of the light emitting device 210 may be the anode of the light emitting element D4 or the anode of the light emitting element D2, D3, D5, D6 or D7; and the second end point P2 of the light emitting device 210 may be the cathode of the light emitting element D12 or the cathode of the light emitting element D9, D10, D11, D13 or D14. In detail, the first end point P1 of the light emitting device 210 may be the anode of one of the light emitting elements D2 to D7, and the second end point P2 of the light emitting device 210 may be the cathode of one of the light emitting elements D9 to D14. When the positions of the first end point P1 and the second end point P2 meet the above conditions, the light generated by the light-emitting device 210 will be more uniform than the light generated by the light-emitting device 110 in FIG. 1. Therefore, by adjusting the positions of the first end point P1 and the second end point P2, the brightness difference between adjacent light-emitting elements can be reduced, and the brightness uniformity of the light-emitting device 210 of the light-emitting module 20 can be optimized.

Furthermore, if the light-emitting device of the light-emitting module of any embodiment of the present invention comprises M light-emitting elements arranged in a row, and the first terminal P1 of the light-emitting device is the first terminal of the Nth light-emitting element, the second terminal P2 of the light-emitting device is the second terminal of the (M-N+1)th light-emitting element, and M is an integer greater than 3, then as long as N is an integer greater than 1 but not greater than M/2, the light generated by the light-emitting device of the light-emitting module of the present invention can have a uniform effect. Among them, the first terminal P1 is a contact point of the light-emitting device connected to the first power node VCC through the power wire, and the second terminal P2 is a contact point of the light-emitting device connected to the second power node GND through the power wire. Therefore, M is at least 4, and N is at least 2. In other words, each light-emitting device of the light-emitting module of any embodiment of the present invention includes at least four light-emitting elements. When the light-emitting device includes four light-emitting elements, the first end point P1 may be the first end of the second light-emitting element (e.g., light-emitting element D2) of the light-emitting device, and the second end point P2 of the light-emitting device may be the second end of the third light-emitting element.

Please refer to FIG. 6 and FIG. 7. FIG. 6 is a schematic diagram of a light-emitting module 30 of another embodiment of the present invention, and FIG. 7 is an equivalent circuit diagram of the light-emitting module 30 of FIG. 6. The light-emitting module 30 includes a first power wire A, a second power wire B, a third power wire C, a fourth power wire D, and M light-emitting elements D1 to D15, and M is an integer greater than 3. For example, in this embodiment, M is equal to 15. The first power wire A is connected between the first power node VCC and the first terminal P1 of the light-emitting device 310, the second power wire B is connected between the second terminal P2 of the light-emitting device 310 and the second power node GND, the third power wire C is connected to and passes through the first terminal P1, and the fourth power wire D is connected to and passes through the second terminal P2. The light-emitting elements D1 to D15 are arranged in a row. Each light-emitting element D1 to D15 can be a light-emitting diode. The first end of each light-emitting element D1 to D15 is connected to the third power wire C, and the second end of each light-emitting element D1 to D15 is connected to the fourth power wire D. That is, in this embodiment, the anode of each light-emitting element D1 to D15 is connected to the third power wire C, and the cathode of each light-emitting element D1 to D15 is connected to the fourth power wire D. The third power wire C and the fourth power wire D have the same length and are made of the same material and have the same resistance value. In one embodiment of the present invention, the first power wire A, the second power wire B, the third power wire C and the fourth power wire D are conductive plasma printed circuits formed by printing a conductive paste (e.g., silver paste) on a film. The material of the above-mentioned film can be polyethylene terephthalate (PET), polyimide (PI) or polyethylene terephthalate (PEN).

For convenience of explanation, in this embodiment, the first power wire A and the second power wire B are arranged in a manner of extending along a first direction X and a second direction Y, and the second direction Y may be perpendicular to the first direction X. The lengths of the first power wire A extending along the first direction X and the second direction Y are L _A1 and L _A2 , respectively, and the lengths of the second power wire B extending along the first direction X and the second direction Y are L _B1 and L _B2 , respectively. The equivalent resistance of the portion of the first power wire A extending in the first direction X is R _A1 , and the equivalent resistance of the portion of the first power wire A extending in the second direction Y is R _A2 , and the equivalent resistance of the portion of the second power wire B extending in the first direction X is R _B1 , and the equivalent resistance of the portion of the second power wire B extending in the second direction Y is R _B2 . In addition, in the present embodiment, the portion of the third power lead C disposed between the first end points (i.e., the anodes of the light-emitting diodes) of any two adjacent light-emitting elements and the portion of the fourth power lead D disposed between the second end points (i.e., the cathodes of the light-emitting diodes) of any two adjacent light-emitting elements have equal lengths. Taking FIG. 6 as an example, the lengths _LC1 to _LC14 and the lengths _LD1 to _LD14 are equal to each other. In contrast, the portion of the third power lead C disposed between the first end points (i.e., the anodes of the light-emitting diodes) of any two adjacent light-emitting elements and the portion of the fourth power lead D disposed between the second end points (i.e., the cathodes of the light-emitting diodes) of any two adjacent light-emitting elements have equal resistance values. Taking Figure 7 as an example, the resistance values _RC1 to _RC14 and the resistance values _RD1 to _RD14 are all equal.

Assuming that starting from the first end point P1, passing through the fourth light-emitting element D4 of the light-emitting device 310 and reaching the second power node GND, the total length of the third power wire C and the fourth power wire D passed through is equal to the first total length, then the first total length will be equal to ( _LD4 + _LD5 + _LD6 + _LD7 + _LD8 + _LD9 + _LD10 + _LD11 ). Since the lengths _LC1 to _LC14 and the lengths _LD1 to _LD14 are equal, starting from the first end point P1, passing through any single light-emitting element among the fifth light-emitting element D5 to the twelfth light-emitting element D12 of the light-emitting device 310 and reaching the second end point P2, the total length of the third power wire C and the fourth power wire D passed through will be equal to the above-mentioned first total length. In addition, starting from the first end point P1, passing through the first light-emitting element D1 of the light-emitting device 310 to reach the second end point P2, the total length of the third power wire C and the fourth power wire D passed through is equal to (L _C3 +L _C2 +L _C1 +L _D1 +L _D2 +L _D3 +L _D4 +L _D5 +L _D6 +L _D7 +L _D8 +L _D9 +L _D10 +L _D11 ), which is 6L _C1 longer than the first total length mentioned above (L _C3 +L _C2 +L _C1 +L _D1 +L _D2 +L _D3 ). Similarly, starting from the first end point P1, passing through the second light emitting element D2 of the light emitting device 310 to reach the second end point P2, the total length of the third power wire C and the fourth power wire D passed through will be 4L _C1 (L _C3 +L _C2 +L _D2 +L _D3 ) greater than the first total length mentioned above; starting from the first end point P1, passing through the third light emitting element D3 of the light emitting device 310 to reach the second end point P2, the total length of the third power wire C and the fourth power wire D passed through will be 2L _C1 (L _C3 +L _D3 ) greater than the first total length mentioned above; starting from the first end point P1, passing through the thirteenth light emitting element D13 of the light emitting device 310 to reach the second end point P2, the total length of the third power wire C and the fourth power wire D passed through will be 2L _C1 (L C3 +L D3) greater than the first total length mentioned above. _C12 +L _D12 ); starting from the first end point P1, passing through the fourteenth light-emitting element D14 of the light-emitting device 310 to reach the second end point P2, the total length of the third power wire C and the fourth power wire D passed through is 4L _C1 (L _C12 +L _C13 +L _D12 +L _D13 ) greater than the above-mentioned first total length; starting from the first end point P1, passing through the fifteenth light-emitting element D15 of the light-emitting device 310 to reach the second end point P2, the total length of the third power wire C and the fourth power wire D passed through is 6L _C1 (L _C12 +L _C13 +L _C14 +L _D14 +L _D13 +L _D12 ) greater than the above-mentioned first total length. In short, starting from the first end point P1, passing through any single light-emitting element among the first light-emitting element D1 to the third light-emitting element D3 and the thirteenth light-emitting element D13 to the fifteenth light-emitting element D15 of the light-emitting device 310 to reach the second end point P2, the total length of the third power wire C and the fourth power wire D passed through are both greater than the first total length mentioned above.

In summary, the light-emitting device of the light-emitting module of any embodiment of the present invention includes M light-emitting elements arranged in a row, the first end P1 of the light-emitting device is the first end (e.g., anode) of the Nth light-emitting element, and the second end P2 of the light-emitting device is the second end (e.g., cathode) of the (M-N+1)th light-emitting element, M is an integer greater than 3, and N is an integer greater than 1 but not greater than M/2. Under this framework, assuming that starting from the first end P1, passing through the Nth light-emitting element of the light-emitting device and reaching the second power node GND, the total length of the third power wire C and the fourth power wire D passed through is equal to the first total length. Then, starting from the first end point P1, passing through any light-emitting element from the (N+1)th to the (M-N+1)th light-emitting element of the light-emitting device to reach the second end point P2, the total length of the third power wire C and the fourth power wire D passed through will be equal to the first total length. In other words, starting from the first end point P1, passing through any light-emitting element from the Nth to the (M-N+1)th light-emitting element of the light-emitting device to reach the second end point P2, the total length of the third power wire C and the fourth power wire D passed through will be equal to the first total length. In addition, starting from the first end point P1, passing through any single light-emitting element of the first and Mth light-emitting elements (such as the light-emitting elements D1 and D15 in FIG. 6) of the light-emitting device to reach the second end point P2, the total length of the third power wire C and the fourth power wire D passed through is greater than the first total length mentioned above.

In addition, if N is an integer greater than 2 but not greater than M/2 (for example, N is equal to 3 and M is equal to 9), then starting from the first end point P1, passing through any single light-emitting element from the first to (N-1)th and (M-N+2)th to Mth light-emitting elements of the light-emitting device to reach the second end point P2, the total length of the third power wire C and the fourth power wire D passed through will be greater than the first total length mentioned above.

Please refer to FIG. 8, which is a schematic diagram of a light-emitting module 40 of another embodiment of the present invention. The light-emitting module 40 includes a plurality of first power wires A1 to A3, a plurality of second power wires B1 to B3, and a plurality of light-emitting devices 310. The circuit of each light-emitting device 310 of the light-emitting module 40 is the same as the light-emitting device 310 in FIG. 6 and FIG. 7, so it will not be described in detail here. The first end points P1 of the plurality of light-emitting devices 310 are connected to the first power node VCC through the first power wires A1, A2, and A3, respectively, and the second end points P2 of the plurality of light-emitting devices 310 are connected to the second power node GND through the second power wires B1, B2, and B3, respectively. Among them, the first power wires A1, A2, and A3 have the same length, are made of the same material, and have the same resistance value. The second power wires B1, B2 and B3 also have the same length and are made of the same material and have the same resistance value. Therefore, starting from the first power node VCC, passing through any single light-emitting device 310 and reaching the second power node GND, the total length of the corresponding first power wire A1, A2 or A3 and the corresponding second power wire B1, B2 or B3 passed through is equal. In other words, the total length of the first power wire A1 and the second power wire B1 is equal to the total length of the first power wire A2 and the second power wire B2, and is also equal to the total length of the first power wire A3 and the second power wire B3. Since the distances between the first end points P1 of the three light-emitting devices 310 and the first power node VCC are different, the first power wires A2 and A3 connected to the light-emitting device 310 closer to the first power node VCC may have bending structures 52 and 53, respectively, so that the lengths of the first power wires A2 and A3 may be equal to the length of the first power wire A1. Similarly, since the distances between the second end points P2 of the three light-emitting devices 310 and the second power node GND are different, the second power wires B2 and B3 connected to the light-emitting device 310 closer to the second power node GND may have bending structures 62 and 63, respectively, so that the lengths of the second power wires B2 and B3 may be equal to the length of the second power wire B1.

In summary, the light-emitting device of the light-emitting module of any embodiment of the present invention includes M light-emitting elements arranged in a row, the first end point P1 of the light-emitting device is the first end of the Nth light-emitting element, and the second end point P2 of the light-emitting device is the second end of the (M-N+1)th light-emitting element. Wherein, N is an integer greater than 1 and not greater than M/2. By adjusting the positions of the first end point P1 and the second end point P2, the brightness difference between adjacent light-emitting elements can be reduced, and the brightness uniformity of the light-emitting device of the light-emitting module can be optimized.

The above is only the preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

30: Light-emitting module

310: Light-emitting device

D1 to D15: Light-emitting elements

GND: Second power node

P1: First endpoint

P2: Second endpoint

_RA1 , _RA2 , _RB1 , _RB2 , _RC1 to _RC14 , _RD1 to _RD14 : Resistance value

VCC: first power node

X: First direction

Y: Second direction

Claims (10)

A light-emitting module comprises: at least one first power wire connected to a first power node; at least one second power wire connected to a second power node; and a plurality of light-emitting devices, each of which comprises: a first terminal connected to the at least one first power wire; a second terminal connected to the at least one second power wire; a third power wire connected to and passing through the first terminal; a fourth power wire connected to and passing through the second terminal; and M light-emitting elements arranged in a row, a first terminal of each light-emitting element connected to the third power wire, and a second terminal of each light-emitting element connected to the fourth power wire, M being an integer greater than 3; wherein, starting from the first terminal, through the Nth to (M-N+1)th light-emitting elements in the row, Any light-emitting element to reach the second end point, the total length of the third power wire and the fourth power wire passed through is equal to a first total length, N is an integer greater than 1 and not greater than M/2; wherein, starting from the first end point, passing through any light-emitting element in the first and Mth light-emitting elements in the row to reach the second end point, the total length of the third power wire and the fourth power wire passed through is greater than the first total length; and wherein, starting from the first power node, passing through any single light-emitting device to reach the second power node, the total length of the at least one first power wire and the at least one second power wire passed through is equal, wherein the first power wire, the second power wire, the third power wire and the fourth power wire are conductive paste printed circuits. A light-emitting module as described in claim 1, wherein N is an integer greater than 2 but not greater than M/2, and starting from the first end point, passing through any single light-emitting element from the first to (N-1)th and (M-N+2)th to Mth light-emitting elements in the row to reach the second end point, the total length of the third power line and the fourth power line passed through is greater than the first total length. A light-emitting module as described in claim 1, wherein the portion of the third power lead disposed between the first end points of any two adjacent light-emitting elements in the same light-emitting device has an equal length, and the portion of the fourth power lead disposed between the second end points of any two adjacent light-emitting elements in the same light-emitting device has an equal length. A light-emitting module as described in claim 1, wherein the first power node provides a first voltage, the second power node provides a second voltage, and the first voltage is higher than the second voltage. As described in claim 4, the light-emitting module, wherein each light-emitting element is a light-emitting diode, the first end of each light-emitting element is the anode of the light-emitting diode, and the second end of each light-emitting element is the cathode of the light-emitting diode. The light-emitting module as described in claim 1, wherein the at least one first power wire is a plurality of first power wires, and the at least one second power wire is a plurality of second power wires. A light-emitting module as described in claim 6, wherein the first end of each light-emitting device is connected to a corresponding first power wire of the first power wires, and the second end of each light-emitting device is connected to a corresponding second power wire of the second power wires. A light-emitting module comprises: a first power wire, a first end of which is connected to a first power node; a second power wire, a first end of which is connected to a second power node; and a light-emitting device, comprising: a first end connected to the first power wire; a second end connected to the second power wire; a third power wire connected to and passing through the first end; a fourth power wire connected to and passing through the second end; and M light-emitting elements arranged in a row, a first end of each light-emitting element connected to the third power wire, and a second end of each light-emitting element connected to the fourth power wire, M being an integer greater than 3; wherein the first end of the light-emitting element is connected to the third power wire, and the second end of the light-emitting element is connected to the fourth power wire. Starting from the first end point, passing through any light-emitting element from the Nth to the (M-N+1)th light-emitting element in the row to reach the second end point, the total length of the third power wire and the fourth power wire passed through are both equal to a first total length, N is an integer greater than 1 and not greater than M/2; and wherein, starting from the first end point, passing through any light-emitting element from the first to the Mth light-emitting element in the row to reach the second end point, the total length of the third power wire and the fourth power wire passed through are both greater than the first total length, wherein the first power wire, the second power wire, the third power wire and the fourth power wire are conductive paste printed circuits. A light-emitting module as described in claim 8, wherein N is an integer greater than 2 but not greater than M/2, and starting from the first end point, passing through any single light-emitting element from the first to (N-1)th and (M-N+2)th to Mth light-emitting elements in the row to reach the second end point, the total length of the third power line and the fourth power line passed through are both greater than the first total length. A light-emitting module as described in claim 8, wherein the portion of the third power line disposed between the first end points of any two adjacent light-emitting elements has an equal length, and the portion of the fourth power line disposed between the second end points of any two adjacent light-emitting elements has an equal length.

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