Backlight module

Abstract

A backlight module includes a circuit board, a light-guiding plate, and a film. The circuit board includes a first light-emitting element and a second light-emitting element. The light-guiding plate is disposed on the circuit board. The film is disposed on the light-guiding plate, and includes a first single-key light transmitting region, a second single-key light transmitting region, and a first light shielding region located between the first and second single-key light transmitting regions. The second single-key light transmitting region is located between the first light-emitting element and the second light-emitting element. There is no light-emitting element between the first light-emitting element and the second light-emitting element. The first and second single-key light transmitting regions have a first width in a direction parallel to a long side of the film. The first light shielding region has a second width in the direction. A distance between a center of the first light-emitting element and a center of the second light-emitting element is greater than or equal to a sum of the first width and the second width, and less than or equal to twice the sum of the first width and the second width.

Description

Technical Field

[0001] This invention relates to a backlight module, and more particularly to a backlight module suitable for a keyboard. Prior Technology

[0002] There are three existing designs for keyboard backlight modules. The first design places at least one light-emitting diode (LED) under each keycap. This design requires a large number of LEDs, resulting in higher costs. The second design uses LED strips and a light guide plate. The LED strip is perpendicular to the long side of the backlight module and located in the center. The light emitted by the LED strip is conducted through the light guide plate to the left and right sides of the backlight module. Since the length of the LED strip is approximately the width of the backlight module, this design requires only about 10-16 LEDs, reducing costs. However, because the light emitted by the LED strip has a limited transmission distance within the light guide plate, the larger the backlight module, the lower the brightness on the left and right sides. The third design places the LED strip along one long side of the backlight module, and the light emitted by the LED strip is conducted through the light guide plate to the other long side of the backlight module. This design solves the uneven brightness problem of the second design. However, since the length of the LED strip is approximately the length of the backlight module, this design requires about 20-30 LEDs, increasing costs. Furthermore, if the backlight module requires heat dissipation, the light guide plate needs to have more heat dissipation holes. The more heat dissipation holes there are, the more obstructed the light transmission will be, and the lower the brightness of the other long side of the backlight module will be.

[0003] Therefore, how to reduce the number of LEDs while maintaining brightness uniformity is a technical problem that existing keyboard backlight modules need to solve. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention provides a backlight module comprising a circuit board, a light guide plate, and a thin film. The circuit board has a first light-emitting element and a second light-emitting element. The light guide plate is disposed on the circuit board and has a first through-hole and a second through-hole. The first light-emitting element is housed in the first through-hole, and the second light-emitting element is housed in the second through-hole. The thin film is disposed on the light guide plate and has a first single-bond light-transmitting area, a second single-bond light-transmitting area, and a first light-shielding area. The first light-shielding area is located between the first single-bond light-transmitting area and the second single-bond light-transmitting area. The second single-bond light-transmitting area is located between the first light-emitting element and the second light-emitting element. There is no light-emitting element between the first light-emitting element and the second light-emitting element. The first single-bond light-transmitting area and the second single-bond light-transmitting area have a first width in a direction parallel to one of the long sides of the thin film. The first light-shielding area has a second width in that direction. The distance between a center of the first light-emitting element and a center of the second light-emitting element is greater than or equal to the sum of the first width and the second width, and less than or equal to twice the sum of the first width and the second width.

[0005] In some embodiments, the film further includes a second light-shielding region. The second single-bond light-transmitting region is located between the first light-shielding region and the second light-shielding region. The first light-emitting element is disposed corresponding to the first single-bond light-transmitting region. The second light-emitting element is disposed corresponding to the second light-shielding region.

[0006] In some embodiments, the film further includes a third single-bond transparent region. The second light-shielding region is located between the second and third single-bond transparent regions. The light guide plate has a first light guide region, a second light guide region, and a third light guide region, respectively corresponding to the first, second, and third single-bond transparent regions. The microstructure density of the third light guide region is greater than that of the second light guide region. The microstructure density of the second light guide region is greater than that of the first light guide region.

[0007] In some embodiments, the film further includes a second light-shielding region. The second single-bond light-transmitting region is located between the first light-shielding region and the second light-shielding region. The first light-emitting element is disposed corresponding to the first light-shielding region. The second light-emitting element is disposed corresponding to the second light-shielding region.

[0008] In some embodiments, the film further includes a third single-bond transparent region. The second light-shielding region is located between the second and third single-bond transparent regions. The light guide plate has a first light guide region, a second light guide region, and a third light guide region, respectively corresponding to the first, second, and third single-bond transparent regions. The microstructure density of the second light guide region is less than that of the first and third light guide regions. The microstructure density of the first light guide region is substantially equal to that of the third light guide region.

[0009] In some embodiments, the film further includes a second light-shielding region and a third single-bond light-transmitting region. The second single-bond light-transmitting region is located between the first light-shielding region and the third single-bond light-transmitting region. The first light-emitting element is disposed corresponding to the first single-bond light-transmitting region. The second light-emitting element is disposed corresponding to the third single-bond light-transmitting region.

[0010] In some embodiments, the light guide plate has a first light guide region, a second light guide region, and a third light guide region corresponding to the first single-bond light-transmitting region, the second single-bond light-transmitting region, and the third single-bond light-transmitting region, respectively. The microstructure density of the second light guide region is greater than the microstructure density of the first light guide region and the microstructure density of the third light guide region. The microstructure density of the first light guide region is substantially equal to the microstructure density of the third light guide region.

[0011] In some embodiments, a reflective portion is provided on one surface of the film facing the light guide plate, the reflective portion corresponding to the first light-emitting element.

[0012] In some embodiments, when the projection of the first light-emitting element on the film is located within the first single-bond light-transmitting area, the film is further provided with a light-shielding portion, which is located between the reflective portion and the film and corresponds to the first light-emitting element.

[0013] In some embodiments, a long side of the first light-emitting element is perpendicular to a long side of the circuit board. Simple Explanation of the Diagram

[0014] Figure 1 is a top view of the backlight module of the present invention. Figure 2 is an exploded view of the backlight module of the present invention. Figure 3 is a partial enlarged view of the backlight module of the present invention. Figure 4 is another enlarged view of the backlight module of the present invention. Figure 5 is another enlarged view of the backlight module of the present invention. Figure 6 is another enlarged view of the backlight module of the present invention. Figure 7 is another enlarged view of the backlight module of the present invention. Implementation

[0015] The various embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. The elements in the drawings are not drawn to scale and are only used to illustrate the various embodiments of the present invention. The terms "first," "second," etc., used below do not represent any order, quantity, or importance, but are only used to distinguish different parts.

[0016] Referring to Figures 1 and 2, the present invention provides a backlight module 1, which includes a circuit board 2, a light guide plate 3, and a thin film 4. The circuit board 2 has a plurality of light-emitting elements 20. The circuit board 2 can be, but is not limited to, a flexible circuit board. The light-emitting elements 20 can be light-emitting diodes. More specifically, the light-emitting elements 20 can be sub-millimeter light-emitting diodes, but are not limited thereto. The light guide plate 3 is disposed on the circuit board 2 and has a plurality of through holes 30. Each through hole 30 is used to accommodate one light-emitting element 20. The thin film 4 is disposed on the light guide plate 3 and has a plurality of single-bond light-transmitting areas 40 and a light-shielding area 41 surrounding the plurality of single-bond light-transmitting areas 40. That is, the plurality of single-bond light-transmitting areas 40 are a plurality of independent regions separated by the light-shielding area 41.

[0017] Please refer to Figures 1 to 5. The plurality of light-emitting elements 20 includes a first light-emitting element 21 and a second light-emitting element 22. The plurality of through holes 30 includes a first through hole 301 and a second through hole 302. The first light-emitting element 21 is housed in the first through hole 301, and the second light-emitting element 22 is housed in the second through hole 302. The plurality of single-bond light-transmitting areas 40 includes a first single-bond light-transmitting area 401, a second single-bond light-transmitting area 402, and a third single-bond light-transmitting area 403. The light-shielding area 41 includes a first light-shielding area 411 and a second light-shielding area 412. The first light-shielding area 411 is located between the first single-bond light-transmitting area 401 and the second single-bond light-transmitting area 402. The second single-bond light-transmitting area 402 is located between the first light-shielding area 411 and the second light-shielding area 412. The second light-shielding area 412 is located between the second single-bond light-transmitting area 402 and the third single-bond light-transmitting area 403. That is, the first single-bond light-transmitting area 401, the first light-shielding area 411, the second single-bond light-transmitting area 402, the second light-shielding area 412, and the third single-bond light-transmitting area 403 are arranged sequentially in the direction LD. The second single-bond light-transmitting area 402 is located between the first light-emitting element 21 and the second light-emitting element 22, and no other light-emitting element is disposed between the first light-emitting element 21 and the second light-emitting element 22. That is, no light-emitting element needs to be disposed in the second single-bond light-transmitting area 402. The first single-bond light-transmitting area 401, the second single-bond light-transmitting area 402, and the third single-bond light-transmitting area 403 have a first width W1 in the direction LD parallel to the long side FL of the film 4. The first light-shielding area 411 and the second light-shielding area 412 have a second width W2 in the direction LD. The distance D between the center of the first light-emitting element 21 and the center of the second light-emitting element 22 is greater than or equal to the sum of the first width W1 and the second width W2, and less than or equal to twice the sum of the first width W1 and the second width W2. That is, (W1+W2)≦D≦(W1+W2) 2. As long as at least one area of ​​the backlight module 1 contains one or more of the various light-emitting element distribution methods that satisfy the aforementioned conditions, the number of LEDs can be reduced while maintaining brightness uniformity; and the larger the area, the greater the reduction in the number of LEDs.

[0018] To enable those skilled in the art to fully understand this invention, Figures 3 to 5 illustrate three light-emitting element distribution schemes that satisfy the aforementioned conditions. Figure 1 illustrates that most of the central area of ​​the backlight module 1 includes the aforementioned three light-emitting element distribution schemes, while each single-bond light-transmitting area in most of the peripheral area of ​​the backlight module 1 contains one light-emitting element. However, Figures 1, 3 to 5 are not intended to limit the invention. Those skilled in the art can design various light-emitting element distribution schemes in the backlight module under the aforementioned conditions, and these all fall within the scope of protection of this invention.

[0019] The first distribution of light-emitting elements in this invention is shown in Figure 3. The first light-emitting element 21 corresponds to the first single-bond light-transmitting area 401, and the second light-emitting element 22 corresponds to the second light-shielding area 412. The distance D between the center of the first light-emitting element 21 and the center of the second light-emitting element 22 is approximately 1.5 times the sum of the first width W1 and the second width W2. The light guide plate 3 has a first light guide area 31, a second light guide area 32, and a third light guide area 33, respectively corresponding to the first single-bond light-transmitting area 401, the second single-bond light-transmitting area 402, and the third single-bond light-transmitting area 403. The first light guide area 31, the second light guide area 32, and the third light guide area 33 all have microstructures. A first through-hole 301 is located within the first light guide area 31. The first light-emitting element 21 is located within the first through-hole 301, that is, within the first light guide area 31. In this embodiment, the first through-hole 301 and the first light-emitting element 21 are located at the center of the first light guide area 31, but this is not a limitation. The second through-hole 302 is located between the second light-guiding area 32 and the third light-guiding area 33. The second light-emitting element 22 is located within the second through-hole 302, that is, between the second light-guiding area 32 and the third light-guiding area 33. In this embodiment, the distance between the center of the second through-hole 302 and the second light-guiding area 32 is equal to the distance between the center of the second through-hole 302 and the third light-guiding area 33, and the distance between the center of the second light-emitting element 22 and the second light-guiding area 32 is equal to the distance between the center of the second light-emitting element 22 and the third light-guiding area 33, but is not limited thereto. The first light-guiding area 31 is located in the middle region of the illumination range C1 of the first light-emitting element 21. The third light-guiding area 33 is located in the right region of the illumination range C2 of the second light-emitting element 22. The second light-guiding area 32 is located in the left region of the illumination range C2 of the second light-emitting element 22, and a portion of the second light-guiding area 32 is located in the right region of the illumination range C1 of the first light-emitting element 21. That is, the overlapping portion of the illumination range C1 and the illumination range C2 covers a part of the second light guide area 32. Furthermore, the brightness of the illumination range C1 gradually decreases from the center of the illumination range C1 (i.e., where the first light-emitting element 21 is located) outwards, and the brightness of the illumination range C2 gradually decreases from the center of the second light-emitting element 22 outwards. Taking all the above factors into consideration, the microstructure density of the third light guide area 33 can be designed to be greater than the microstructure density of the second light guide area 32, and the microstructure density of the second light guide area 32 can be designed to be greater than the microstructure density of the first light guide area 31, so that the brightness of the first light guide area 31, the second light guide area 32, and the third light guide area 33 is substantially the same. In addition, considering that the brightness of the illumination range C1 gradually decreases from the center of the illumination range C1 outwards, the microstructure within the first light guide area 31 can be designed to gradually become denser from the center of the first light guide area 31 outwards (not shown in the figure), so that the brightness of each part of the first light guide area 31 is substantially the same.Furthermore, considering that the brightness of the illumination range C2 gradually decreases from the center outwards, the microstructure within the third light guide region 33 can be designed to gradually increase in density from the left to the right (not shown in the figure) to ensure that the brightness of each part of the third light guide region 33 is substantially consistent. Also, the microstructure density of each part of the second light guide region 32 can be designed based on whether it is covered by illumination ranges C1 and / or C2, and its position within illumination ranges C1 and / or C2 (not shown in the figure), to ensure that the brightness of each part of the second light guide region 32 is substantially consistent.

[0020] The second distribution of light-emitting elements in this invention is shown in Figure 4. A first light-emitting element 21 is disposed corresponding to a first light-shielding area 411, and a second light-emitting element 22 is disposed corresponding to a second light-shielding area 412. The distance D between the center of the first light-emitting element 21 and the center of the second light-emitting element 22 is approximately the sum of the first width W1 and the second width W2. The light guide plate 3 has a first light guide area 31, a second light guide area 32, and a third light guide area 33, respectively corresponding to the first single-bond light-transmitting area 401, the second single-bond light-transmitting area 402, and the third single-bond light-transmitting area 403. A first through-hole 301 is located between the first light guide area 31 and the second light guide area 32. The first light-emitting element 21 is located within the first through-hole 301, that is, between the first light guide area 31 and the second light guide area 32. In this embodiment, the distance between the center of the first through-hole 301 and the first light-guiding area 31 is equal to the distance between the center of the first through-hole 301 and the second light-guiding area 32, and the distance between the center of the first light-emitting element 21 and the first light-guiding area 31 is equal to the distance between the center of the first light-emitting element 21 and the second light-guiding area 32, but is not limited thereto. The second through-hole 302 is located between the second light-guiding area 32 and the third light-guiding area 33. The second light-emitting element 22 is located within the second through-hole 302, that is, between the second light-guiding area 32 and the third light-guiding area 33. In this embodiment, the distance between the center of the second through-hole 302 and the second light-guiding area 32 is equal to the distance between the center of the second through-hole 302 and the third light-guiding area 33, and the distance between the center of the second light-emitting element 22 and the second light-guiding area 32 is equal to the distance between the center of the second light-emitting element 22 and the third light-guiding area 33, but is not limited thereto. The first light-guiding area 31 is located in the left-hand region of the illumination range C1 of the first light-emitting element 21. The third light guide area 33 is located in the right-hand region of the illumination range C2 of the second light-emitting element 22. The second light guide area 32 is located simultaneously in the right-hand region of the illumination range C1 and the left-hand region of the illumination range C2. To ensure that the brightness of the first light guide area 31, the second light guide area 32, and the third light guide area 33 is substantially consistent, the microstructure density of the second light guide area 32 can be designed to be less than the microstructure density of the first light guide area 31 and the third light guide area 33, and the microstructure density of the first light guide area 31 can be designed to be substantially equal to the microstructure density of the third light guide area 33. Furthermore, the microstructure within the first light guide area 31 can be designed to gradually increase in density from the right side to the left side (not shown in the figure) to ensure that the brightness of each part of the first light guide area 31 is substantially consistent. Similarly, the microstructure within the third light guide area 33 can be designed to gradually increase in density from the left side to the right side (not shown in the figure) to ensure that the brightness of each part of the third light guide area 33 is substantially consistent. Furthermore, the position of each part of the second light guide area 32 within the illumination ranges C1 and C2 can be considered to design the microstructure density of each part of the second light guide area 32 (not shown in the figure) so that the brightness of each part of the second light guide area 32 is substantially consistent.

[0021] The third distribution of light-emitting elements in this invention is shown in Figure 5. The first light-emitting element 21 is disposed corresponding to the first single-bond light-transmitting area 401, and the second light-emitting element 22 is disposed corresponding to the third single-bond light-transmitting area 403. The distance D between the center of the first light-emitting element 21 and the center of the second light-emitting element 22 is approximately twice the sum of the first width W1 and the second width W2. The light guide plate 3 has a first light guide area 31, a second light guide area 32, and a third light guide area 33, respectively corresponding to the first single-bond light-transmitting area 401, the second single-bond light-transmitting area 402, and the third single-bond light-transmitting area 403. The first through-hole 301 is located within the first light guide area 31. The first light-emitting element 21 is located within the first through-hole 301, i.e., within the first light guide area 31. In this embodiment, the first through-hole 301 and the first light-emitting element 21 are located at the center of the first light guide area 31, but this is not a limitation. The second through-hole 302 is located within the third light guide area 33. The second light-emitting element 22 is located within the second through-hole 302, i.e., within the third light guide area 33. In this embodiment, the second through-hole 302 and the second light-emitting element 22 are located at the center of the third light-guiding area 33, but are not limited thereto. The first light-guiding area 31 is located in the middle region of the illumination range C1 of the first light-emitting element 21. The third light-guiding area 33 is located in the middle region of the illumination range C2 of the second light-emitting element 22. The second light-guiding area 32 is partially located in the right region of the illumination range C1 of the first light-emitting element 21, and partially located in the left region of the illumination range C2 of the second light-emitting element 22. The overlapping portion of the illumination range C1 and the illumination range C2 covers a portion of the second light-guiding area 32. In order to make the brightness of the first light-guiding area 31, the second light-guiding area 32 and the third light-guiding area 33 substantially the same, the microstructure density of the second light-guiding area 32 can be designed to be greater than the microstructure density of the first light-guiding area 31 and the microstructure density of the third light-guiding area 33, and the microstructure density of the first light-guiding area 31 can be designed to be substantially equal to the microstructure density of the third light-guiding area 33. Furthermore, the microstructure within the first light guide region 31 can be designed to gradually increase in density from the center outwards (not shown in the figure) to ensure that the brightness of each part of the first light guide region 31 is substantially consistent. Similarly, the microstructure within the third light guide region 33 can be designed to gradually increase in density from the center outwards (not shown in the figure) to ensure that the brightness of each part of the third light guide region 33 is substantially consistent. Additionally, the microstructure density of each part of the second light guide region 32 can be designed (not shown in the figure) considering the position of each part within the illumination ranges C1 and C2 to ensure that the brightness of each part of the second light guide region 32 is substantially consistent.

[0022] In any of the light-emitting element distribution methods of the present invention, any part of the second single-bond light-transmitting area 402 is covered by the illumination range C1 of the first light-emitting element 21 and / or the illumination range C2 of the second light-emitting element 22. Therefore, no light-emitting element needs to be provided in the second single-bond light-transmitting area 402. Therefore, compared with the prior art that at least one LED is provided for each single bond, by adopting any of the light-emitting element distribution methods of the present invention in any region of the backlight module 1 containing three single-bond light-transmitting areas 40, at least one LED can be reduced to reduce costs without changing the brightness uniformity of the backlight module 1.

[0023] In Figures 3 to 5, the illumination range C1 of the first light-emitting element 21 and the illumination range C2 of the second light-emitting element 22 are represented by dashed circles. However, these dashed circles are not the actual boundaries of the illumination ranges C1 and C2. They are only used to roughly represent the range that the light emitted by the first light-emitting element 21 and the second light-emitting element 22 can reach. Furthermore, depending on the type and shape of the first light-emitting element 21 and the second light-emitting element 22, the illumination ranges C1 and C2 can also be other shapes. Referring to Figure 6, in some embodiments, when the light-emitting element 20 is rectangular, the illumination range C of the light-emitting element 20 is slightly elliptical. Referring to Figure 1, the number of single-bond transparent areas 40 in a row of single-bond transparent areas 40 parallel to the long side FL of the thin film 4 is greater than the number of single-bond transparent areas 40 in a column of single-bond transparent areas 40. Therefore, compared to the long side LL of the light-emitting element 20 being parallel to the long side CL of the circuit board 2, the long side LL of the light-emitting element 20 being perpendicular to the long side CL of the circuit board 2 allows the illumination range C to cover more of the single-bond light-transmitting area 40 on the left and right sides of the light-emitting element 20, thereby improving the light utilization rate of the light-emitting element 20 (see Figures 2 and 6).

[0024] Referring to Figure 7, in some embodiments, the thin film 4 has a reflective portion 46 on the surface of the light guide plate 3. The reflective portion 46 corresponds to the light-emitting element 20 and is used to reflect the light emitted upward from the light-emitting element 20 to the light guide plate 3, thereby increasing light utilization and preventing bright spots from being generated at the light-emitting element 20. In some embodiments, when the projection of the light-emitting element 20 on the thin film 4 is located within the single-bond light-transmitting area 40, the thin film further has a light-shielding portion 47. The light-shielding portion 47 is located between the reflective portion 46 and the thin film 4 and corresponds to the light-emitting element 20, to further prevent bright spots from being generated at the light-emitting element 20. The area of ​​the reflective portion 46 may be greater than or equal to the area of ​​the light-shielding portion 47. The light-emitting element 20 may be a first light-emitting element 21 or a second light-emitting element 22.

[0025] Several embodiments have been detailed above to enable those skilled in the art to fully understand the concept of the present invention. The foregoing embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. That is, the foregoing embodiments are not intended to limit the present invention. Those skilled in the art can modify the technical solutions in the foregoing embodiments or make equivalent substitutions for one or more technical features, and such modifications or equivalent substitutions should all be included within the scope of protection of the present invention. The scope of protection of the present invention should be determined by the appended claims.

[0026] 1: Backlight Module 2: Circuit board 20: Illuminating components 21: First light-emitting element 22: Second light-emitting element 3: Light guide plate 30: Through hole 301: First through hole 302: Second through hole 31: First light guide area 32: Second light guide area 33: Third light guide area 4: Film 40: Single-bond light-transmitting area 401: First single-bond light-transmitting area 402: Second single-bond light-transmitting area 403: Third single bond light-transmitting area 41: Shading area 411: First shaded area 412: Second shading zone 46: Reflective section 47:Light shielding part C, C1, C2: Illumination range D: Distance FL, CL, LL: Long side LD: Direction W1: First width W2: Second width

Claims

1. A backlight module, comprising: a circuit board having a first light-emitting element and a second light-emitting element; a light guide plate disposed on the circuit board and having a first through-hole and a second through-hole, wherein the first light-emitting element is accommodated in the first through-hole, and the second light-emitting element is accommodated in the second through-hole; and a thin film disposed on the light guide plate and having a first single-bond light-transmitting area, a second single-bond light-transmitting area, and a first light-shielding area, wherein the first light-shielding area is located between the first single-bond light-transmitting area and the second single-bond light-transmitting area, the second single-bond light-transmitting area is located between the first light-emitting element and the second light-emitting element, and there is no light-emitting element between the first light-emitting element and the second light-emitting element; wherein... The first single-bond light-transmitting area and the second single-bond light-transmitting area have a first width in a direction parallel to one of the long sides of the film, and the first light-blocking area has a second width in the same direction. The distance between a center of the first light-emitting element and a center of the second light-emitting element is greater than or equal to the sum of the first width and the second width and less than or equal to twice the sum of the first width and the second width.

2. The backlight module of claim 1, wherein the film further comprises a second light-shielding area, the second single-bond light-transmitting area is located between the first light-shielding area and the second light-shielding area, the first light-emitting element is disposed corresponding to the first single-bond light-transmitting area, and the second light-emitting element is disposed corresponding to the second light-shielding area.

3. The backlight module of claim 2, wherein the thin film further comprises a third single-bond light-transmitting region, the second light-shielding region is located between the second single-bond light-transmitting region and the third single-bond light-transmitting region, the light guide plate has a first light guide region, a second light guide region and a third light guide region respectively corresponding to the first single-bond light-transmitting region, the second single-bond light-transmitting region and the third single-bond light-transmitting region, the microstructure density of the third light guide region is greater than the microstructure density of the second light guide region, and the microstructure density of the second light guide region is greater than the microstructure density of the first light guide region.

4. The backlight module of claim 1, wherein the film further comprises a second light-shielding area, the second single-bond light-transmitting area is located between the first light-shielding area and the second light-shielding area, the first light-emitting element is disposed corresponding to the first light-shielding area, and the second light-emitting element is disposed corresponding to the second light-shielding area.

5. The backlight module of claim 4, wherein the thin film further comprises a third single-bond light-transmitting region, and the light guide plate has a first light guide region, a second light guide region, and a third light guide region corresponding to the first single-bond light-transmitting region, the second single-bond light-transmitting region, and the third single-bond light-transmitting region, respectively, wherein the microstructure density of the second light guide region is less than the microstructure density of the first light guide region and the microstructure density of the third light guide region, and the microstructure density of the first light guide region is substantially equal to the microstructure density of the third light guide region.

6. The backlight module of claim 1, wherein the film further comprises a second light-shielding area and a third single-bond light-transmitting area, the second single-bond light-transmitting area being located between the first light-shielding area and the second light-shielding area, the second light-shielding area being located between the second single-bond light-transmitting area and the third single-bond light-transmitting area, the first light-emitting element being disposed corresponding to the first single-bond light-transmitting area, and the second light-emitting element being disposed corresponding to the third single-bond light-transmitting area.

7. The backlight module of claim 6, wherein the light guide plate has a first light guide area, a second light guide area, and a third light guide area corresponding to the first single-bond light-transmitting area, the second single-bond light-transmitting area, and the third single-bond light-transmitting area, respectively, wherein the microstructure density of the second light guide area is greater than the microstructure density of the first light guide area and the microstructure density of the third light guide area, and the microstructure density of the first light guide area is substantially equal to the microstructure density of the third light guide area.

8. The backlight module of claim 1, wherein a reflective portion is provided on a surface of the thin film facing the light guide plate, the reflective portion corresponding to the first light-emitting element.

9. The backlight module of claim 8, wherein when the projection of the first light-emitting element on the film is located within the first single-bond light-transmitting area, the film is further provided with a light-shielding portion, the light-shielding portion being located between the reflective portion and the film and corresponding to the first light-emitting element.

10. The backlight module of claim 1, wherein a long side of the first light-emitting element is perpendicular to a long side of the circuit board.

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