Direct-type light source module and display device

Abstract

The present invention provides a direct - type light source module and a display device. The direct - type light source module includes an N - stage light source and an optical film. The optical film is disposed above the N - stage light source, wherein the mixing light distance between the i - th stage light source and the optical film is less than the mixing light distance between the (i + 1) - th stage light source and the optical film, where 1 ≤ i < N, and N is a positive integer greater than 1.

Description

Technical Field

[0001] The present invention relates to a light source module and an electronic device, and particularly to a direct - type light source module and a display device. Background Art

[0002] Currently, the direct - type light source modules on the market mainly arrange multiple light - emitting diodes with the same light - mixing distance evenly on the backplane, and an optical film is disposed above these light - emitting diodes to provide uniform surface light. However, the larger the size of the direct - type light source module, the more light - emitting diodes are required, resulting in an increase in the cost and weight of the direct - type light source module. Summary of the Invention

[0003] The present invention provides a direct - type light source module and a display device, which helps to reduce the number of required light - emitting elements.

[0004] According to an embodiment of the present invention, the direct - type light source module includes an N - order light source and an optical film. The optical film is disposed above the N - order light source, wherein the light - mixing distance between the i - th order light source and the optical film is less than the light - mixing distance between the (i + 1)-th order light source and the optical film, where 1 ≤ i < N, and N is a positive integer greater than 1.

[0005] According to another embodiment of the present invention, the display device includes a direct - type light source module and a display panel. The direct - type light source module includes an N - order light source and an optical film. The optical film is disposed above the N - order light source, wherein the light - mixing distance between the i - th order light source and the optical film is less than the light - mixing distance between the (i + 1)-th order light source and the optical film, where 1 ≤ i < N, and N is a positive integer greater than 1. The display panel is disposed on the direct - type light source module.

[0006] The beneficial effects of the present invention are that through the design of different light - mixing distances, it is possible to reduce the number of required light - emitting elements, reduce the cost and / or weight of the direct - type light source module and the display device, or provide a thin visual effect. In addition, the larger the size of the direct - type light source module or the display device, the more the usage amount of the light - emitting elements can be reduced.

[0007] To make the above - mentioned features and advantages of the present invention more obvious and understandable, specific embodiments are hereinafter given and detailed descriptions are made in conjunction with the accompanying drawings as follows. Brief Description of the Drawings

[0008] Figure 1 and Figure 2 are respectively an exploded schematic view and a cross - sectional schematic view of a display device according to an embodiment of the present invention.

[0009] Figure 3 is Figure 2 an enlarged schematic view of region R in

[0010] Figures 4 to 6 They are cross-sectional schematic diagrams of display devices according to other embodiments of the present invention.

[0011] The reference numerals are as follows:

[0012] 1, 1A, 1B, 1C: Display device

[0013] 10, 10A, 10B, 10C: Direct-lit light source modules

[0014] 12: Display Panel

[0015] 100, 100A, 100B, 100C: N-order light source

[0016] 100-1: 1st order light source

[0017] 100-2: 2nd order light source

[0018] 100-3: 3rd order light source

[0019] 100-4: 4th order light source

[0020] 100-5: 5th order light source

[0021] 102: Optical film

[0022] 102-1: Reflective sheet

[0023] 102-2: Diffuser

[0024] 102-3: Color conversion film

[0025] 102-4: Prism

[0026] 104: Back panel

[0027] 106: Middle frame

[0028] A, B, C, D, E: Mixed light distance

[0029] C1: First circuit board

[0030] C2: Second circuit board

[0031] C3: The third circuit board

[0032] C4: Fourth circuit board

[0033] C5: Fifth circuit board

[0034] D1: First direction

[0035] D2: Second direction

[0036] D3: Third direction

[0037] L1: first light emitting element

[0038] L2: second light emitting element

[0039] L3: third light emitting element

[0040] L4: fourth light emitting element

[0041] L5: fifth light emitting element

[0042] P1, P2, P3, P4, P5, PT: Pitch

[0043] R: Region

[0044] S2, S3, S4, S5: Secondary optical elements

[0045] TH:Through hole DETAILED DESCRIPTION

[0046] The directional terms mentioned herein, such as "up," "down," "front," "back," "left," "right," etc., are merely references to the directions in the accompanying drawings. Therefore, the directional terms used are for illustrative purposes only and are not intended to limit the present invention.

[0047] In the accompanying drawings, each figure illustrates the general characteristics of the methods, structures, or materials used in a particular embodiment. However, these figures should not be interpreted as defining or limiting the scope or nature of the embodiments. For example, the relative size, thickness, and position of various layers, regions, or structures may be reduced or exaggerated for clarity.

[0048] In the following embodiments, identical or similar elements will be denoted by identical or similar reference numerals, and redundant descriptions will be omitted. Furthermore, features from different embodiments may be combined unless there is a conflict, and simple equivalent variations and modifications made according to this specification or claims are still within the scope of this patent.

[0049] The terms "first," "second," and the like mentioned in this specification or claims are used only to name different elements or to distinguish different embodiments or scopes, and are not intended to limit the upper or lower limit on the number of elements, nor to define the order in which the elements are manufactured or disposed. Furthermore, "one element / film layer disposed on (or over) another element / film layer" may encompass situations where the element / film layer is directly disposed on (or over) the other element / film layer, with the two elements / film layers in direct contact; and situations where the element / film layer is indirectly disposed on (or over) the other element / film layer, with one or more elements / film layers interposed between the two elements / film layers.

[0050] Figure 1 and Figure 2Explosion schematic diagram and cross-sectional schematic diagram of a display device according to an embodiment of the present invention, respectively. Figure 3 is Figure 2 an enlarged schematic diagram of area R in

[0051] Please refer to Figures 1 to 3 , the display device 1 includes a direct-lit light source module 10 and a display panel 12, but is not limited thereto. The display device 1 can be increased or decreased by one or more components or film layers according to requirements.

[0052] The direct-lit light source module 10 can be used to provide illumination light beams to the display panel 12. The display panel 12 is disposed on the direct-lit light source module 10 and can be used to convert the illumination light beams into display light beams with display information (such as grayscale and / or color). For example, the display panel 12 can include a non-self-emitting display panel, such as a liquid crystal display panel, but is not limited thereto.

[0053] The direct-lit light source module 10 can include an N-stage light source 100 and an optical film 102, but is not limited thereto. The direct-lit light source module 10 can be increased or decreased by one or more components or film layers according to requirements. For example, the direct-lit light source module 10 can further include a backplane 104 and a middle frame 106, but is not limited thereto.

[0054] N in the N-stage light source 100 is a positive integer greater than 1. The N-stage light source 100 satisfies: the mixing distance between the i-th stage light source and the optical film 102 is less than the mixing distance between the (i + 1)-th stage light source and the optical film 102, where 1 ≤ i < N. In other words, the N-stage light source 100 can have N mixing distances, and the N mixing distances are different from each other (the larger i is, the larger the mixing distance is). The mixing distance between the i-th stage light source and the optical film 102 can be defined as the shortest distance between the circuit board in the i-th stage light source and the optical film 102 in the thickness direction (such as the third direction D3) of the direct-lit light source module 10. When the optical film 102 includes multiple films, the mixing distance between the i-th stage light source and the optical film 102 can be defined as the shortest distance between the circuit board in the i-th stage light source and the film closest to the i-th stage light source (i.e., the bottommost film) in the optical film 102 in the thickness direction (such as the third direction D3) of the direct-lit light source module 10. [[ID=二十]]

[0055] In this embodiment, as Figure 1 and Figure 2 shown, N is, for example, 2, that is, the N-stage light source 100 is a two-stage light source, and the N-stage light source 100 includes a first-stage light source 100-1 and a second-stage light source 100-2, where the mixing distance A between the first-stage light source 100-1 and the optical film 102 is less than the mixing distance B between the second-stage light source 100-2 and the optical film 102.

[0056] Specifically, the first-order light source 100 - 1 may include a first circuit board C1 and a plurality of first light-emitting elements L1 . The first circuit board C1 may include a printed circuit board, but is not limited thereto.

[0057] A plurality of first light emitting elements L1 are disposed on the first circuit board C1 and may be arranged in an array along a first direction D1 and a second direction D2. The first direction D1 and the second direction D2 intersect with each other and are both perpendicular to the thickness direction (e.g., the third direction D3) of the direct-lit light source module 10. In some embodiments, the first direction D1 and the second direction D2 may be perpendicular to each other, but are not limited thereto. For ease of illustration, Figure 2 The number of the first light emitting elements L1 is less than Figure 1 The number of the first light emitting elements L1 is not limited to , but it should be understood that Figure 1 and Figure 2 The number of the first light emitting elements L1 arranged in the first direction D1 is the same. Figure 1 It is schematically shown that a plurality of first light-emitting elements L1 are arranged on opposite sides of the second-order light source 100-2 in the first direction D1, but the present invention is not limited thereto. In other embodiments not shown, a plurality of first light-emitting elements L1 may be arranged on opposite sides of the second-order light source 100-2 in the second direction D2, or a plurality of first light-emitting elements L1 may be arranged on three sides or all four sides of the second-order light source 100-2. The plurality of first light-emitting elements L1 may include a plurality of sub-millimeter light-emitting diodes (mini LEDs), and the plurality of first light-emitting elements L1 may have the same light mixing distance A. The light mixing distance A may be defined as the shortest distance between the first circuit board C1 and the optical film 102 (e.g., the diffuser 102-2) in the thickness direction (e.g., the third direction D3) of the direct-type light source module 10.

[0058] The second-order light source 100 - 2 may include a second circuit board C2 , a plurality of second light-emitting elements L2 , and a plurality of secondary optical elements S2 . The second circuit board C2 may include a printed circuit board, but is not limited thereto.

[0059] A plurality of second light emitting elements L2 are disposed on the second circuit board C2 and can be arranged in an array along the first direction D1 and the second direction D2. Figure 2 The number of the second light emitting elements L2 is less than Figure 1 The number of the second light emitting elements L2, but it should be understood that Figure 1 and Figure 2The number of second light-emitting elements L2 arranged in the first direction D1 is the same. The multiple second light-emitting elements L2 may include multiple light-emitting diodes (LEDs), and the multiple second light-emitting elements L2 may have the same light mixing distance B. The light mixing distance B can be defined as the shortest distance between the second circuit board C2 and the optical film 102 (e.g., the diffuser 102-2) in the thickness direction (e.g., the third direction D3) of the direct-lit light source module 10. However, this is not a limitation.

[0060] Multiple secondary optical elements S2 are disposed on the second circuit board C2, with the multiple second light-emitting elements L2 positioned between the multiple secondary optical elements S2 and the second circuit board C2. The multiple secondary optical elements S2 may include multiple secondary lenses, and each secondary optical element S2 may be disposed above one or more second light-emitting elements L2 to modify the light shape of the one or more second light-emitting elements L2, such as, for example, increasing the light output angle, but this is not limited to this.

[0061] In the second-order light source 100-2, light-emitting diodes are used instead of sub-millimeter light-emitting diodes as the second light-emitting elements L2. Therefore, the pitch P2 of the multiple second light-emitting elements L2 in the second-order light source 100-2 can be greater than the pitch P1 of the multiple first light-emitting elements L1 in the first-order light source 100-1, thereby helping to reduce the number of light-emitting elements required (such as the total number of sub-millimeter light-emitting diodes and light-emitting diodes), and reduce the cost and / or weight of the direct-type light source module 10 and the display device 1. In addition, by designing a secondary optical element with a light-emitting diode, the light output angle of the light-emitting diode can be magnified, so the pitch P2 can be further increased, which helps to further reduce the number of light-emitting elements required, and reduce the cost and / or weight of the direct-type light source module 10 and the display device 1.

[0062] Taking a 27-inch display device as an example, the light mixing distance A and light mixing distance B of the second-order light source can be 5mm and 15mm respectively, the pitch P1 and pitch P2 can be 10mm and 52mm respectively, and the total number of sub-millimeter LEDs and LEDs is approximately 1062. On the other hand, a direct-lit light source module using only sub-millimeter LEDs as light-emitting elements requires approximately 2040 sub-millimeter LEDs, 978 more than a direct-lit light source module using both LEDs and sub-millimeter LEDs as light-emitting elements.

[0063] Furthermore, in the direct-lit light source module 10 and the display device 1, the N light mixing distances (including the light mixing distance A and the light mixing distance B) between the N-order light source 100 and the optical film 102 can all fall within the range of 5 mm to 30 mm, i.e., 5 mm ≤ A (or B) ≤ 30 mm. Therefore, the direct-lit light source module 10 and the display device 1 can provide a slim visual effect or have a slim appearance.

[0064] It should be understood that although Figure 1 as well as Figure 2 The N-order light source 100 is schematically shown as a 2-order light source, but N can be increased as needed. For example, N can increase as the size of the display device 1 increases. In some embodiments, N falls within the range of 2 to 5 (i.e., 2 ≤ N ≤ 5), which can reduce the number of light-emitting elements required, reduce the cost and / or weight of the direct-lit light source module 10 and the display device 1, or provide a slimmer visual effect. Furthermore, the larger the direct-lit light source module 10 or the display device 1, the more the number of light-emitting elements can be reduced.

[0065] The use of multiple light-emitting diodes and multiple secondary optical elements helps to reduce the number of light-emitting elements required and reduce the cost and / or weight of the direct-lit light source module 10 and the display device 1. On the other hand, the use of multiple sub-millimeter light-emitting diodes helps to reduce the driving current and realize the design of local dimming. In an embodiment where N falls within the range of 2 to 5, the light source (such as the second-order light source 100-2) with a light mixing distance (such as the light mixing distance B) greater than or equal to 15 mm among the N-order light sources can include or use multiple light-emitting diodes and multiple secondary optical elements, and the light source (such as the first-order light source 100-1) with a light mixing distance (such as the light mixing distance A) less than 15 mm among the N-order light sources can include or use multiple sub-millimeter light-emitting diodes.

[0066] In an architecture with multiple light mixing distances, the light mixing distance A, for example, falls within the range of 5mm to 13mm (i.e., 5mm≤A≤13mm), and the light mixing distance B, for example, falls within the range of 15mm to 30mm (i.e., 15mm≤B≤30mm). Based on image performance considerations, the direct-lit light source module 10 can satisfy the following requirements: the pitch PT between the first light-emitting element L1 adjacent to the second light-emitting element 100-2 in the first-order light source 100-1 and the second light-emitting element L2 adjacent to the first-order light source 100-1 in the second-order light source 100-2 falls between S1 and S2, where S1 = -1.6A + 2B and S2 = A + 0.47B. S1 and S2 are the boundary values ​​of the pitch PT, respectively. When the pitch PT falls within the range of S1 and S2, the image between the first-order light source 100-1 and the second-order light source 100-2 appears uniform, and no obvious dark bands are visible when using a 2% neutral density filter.

[0067] Table 1 shows 10 examples. Taking Example 10 as an example, when A = 5 mm and B = 15 mm, the pitch PT can fall within the range of 12 mm (rounded to the nearest decimal point) to 22 mm (i.e., 12 mm ≤ PT ≤ 22 mm). Thus, the image between the first-order light source 100 - 1 and the second-order light source 100 - 2 appears uniform. The remaining examples are similar and are not further detailed.

[0068]

[0069] Table 1

[0070] Please refer to Figure 1 and Figure 2 , the optical film 102 is arranged above the N-order light source 100. Figure 1 and Figure 2 For example, the optical film 102 may include a reflective sheet 102-1 (not shown) stacked in sequence along the third direction D3. Figure 2 , please refer to Figure 1 ), the diffusion sheet 102-2, the color conversion sheet 102-3 and the prism sheet 102-4, but not limited thereto. The optical film 102 can be increased or decreased by one or more sheets as required.

[0071] The reflective sheet 102-1 can be used to reflect the light beam transmitted toward the bottom of the direct-lit light source module 10, redirecting the light beam and transmitting it toward the display panel 12. For example, the reflective sheet 102-1 can be a metal sheet or a white reflective sheet, but is not limited thereto. The reflective sheet 102-1 can have a plurality of through holes TH. The plurality of through holes TH respectively expose the plurality of light-emitting elements in the N-stage light source 100, such as the plurality of first light-emitting elements L1 and the plurality of second light-emitting elements L2.

[0072] The diffuser 102 - 2 can be used to make the light beam uniform. For example, the diffuser can be a transparent film with a rough surface or diffuser particles, but is not limited thereto.

[0073] The color conversion plate 102-3 can be used to change the color of the light beam. For example, the color conversion plate 102-3 may include, but is not limited to, phosphors, quantum dots, or a combination thereof. In some embodiments, the multiple light-emitting elements (e.g., the multiple first light-emitting elements L1 and the multiple second light-emitting elements L2) in the N-stage light source 100 may be light-emitting elements that emit blue light. Correspondingly, the color conversion plate 102-3 may be a color conversion element that converts blue light into red and green light, thereby mixing them to produce white light.

[0074] In some embodiments not shown, the optical film 102 may further include a blue light-transmitting film. The blue light-transmitting film allows blue light to penetrate and reflects red light and green light, and the blue light-transmitting film may be disposed between the diffuser 102-2 and the color conversion plate 102-3 to improve the color shift problem. Specifically, after the blue light passes through the color conversion plate 102-3, the red light and green light excited by the blue light will scatter in all directions, of which part of the red light and green light will return to the optical cavity (i.e., the accommodation space between the optical film 102 and the back plate 104) and then be reflected by the reflective plate 102-1. Under different light mixing distances, the distances traveled by the red light and the green light in the optical cavity will be different, thereby causing the color shift phenomenon. By disposing a blue light transmitting film between the diffuser 102 - 2 and the color conversion film 102 - 3 , the red and green light transmitted toward the optical cavity can be reflected. In addition to reducing the light loss of the red and green light, the probability of the red and green light entering the optical cavity can also be reduced, thereby improving the color shift problem.

[0075] Tables 1 and 2 below demonstrate the effectiveness of using a blue light-transmitting film to improve color shift. In these tables, the experimental light sources are all LEDs equipped with secondary optical lenses, and the LED pitch is 15mm. In these tables, OD5, OD10, and OD15 represent light mixing distances of 5mm, 10mm, and 15mm, respectively. The x and y values ​​are color coordinates.

[0076]

[0077] Table 1

[0078]

[0079] Table 2

[0080] According to Tables 1 and 2, at different light mixing distances, without the blue light-transmitting film, the maximum color coordinate differences of white light are: Δx = 0.0215, Δy = 0.0308. On the other hand, at different light mixing distances, with the blue light-transmitting film, the maximum color coordinate differences of white light are: Δx = 0.0002, Δy = 0.002. This shows that placing a blue light-transmitting film between the diffuser 102-2 and the color conversion film 102-3 can improve the color shift problem.

[0081] In other embodiments, the plurality of light-emitting elements (e.g., the plurality of first light-emitting elements L1 and the plurality of second light-emitting elements L2) in the N-order light source 100 may be light-emitting elements that emit white light, such as LED chips encapsulated with a color conversion layer or sub-millimeter LED chips encapsulated with a color conversion layer. In this case, the color conversion plate 102-3 may be omitted.

[0082] The prism sheet 102 - 4 can be used to provide an effect of concentrating and brightening the light beams. For example, the prism sheet 102 - 4 can include a plurality of prism columns extending along the first direction D1 or the second direction D2 , but is not limited thereto.

[0083] The back plate 104 is disposed at the bottom of the direct-lit light source module 10 and can be used to provide support or loading. In some embodiments, the back plate 104 can be made of metal, alloy, or a combination thereof to further improve heat dissipation.

[0084] Middle frame 106 (not shown) Figure 2 , please refer to Figure 1 ) can be used to support the display panel 12 and fix or press the optical film 102 thereunder.

[0085] Figures 4 to 6 are schematic cross-sectional views of display devices according to other embodiments of the present invention. Figures 4 to 6 Some elements are also omitted, such as Figure 1 The reflector 102-1 and the middle frame 106 are provided. Figures 4 to 6 In the embodiment, although not shown, the optical film 102 may further include a blue light transmitting film disposed between the diffusion film 102 - 2 and the color conversion film 102 - 3 to improve the color shift problem.

[0086] Please refer to Figure 4 , the display device 1A and Figure 2 The main differences of the display device 1 are described as follows. In the display device 1A, the N-order light source 100A of the direct-lit light source module 10A is a 3-order light source, and the N-order light source 100A includes a 1st-order light source 100-1, a 2nd-order light source 100-2, and a 3rd-order light source 100-3, wherein the light mixing distance A between the 1st-order light source 100-1 and the optical film 102 (such as the diffuser 102-2) is smaller than the light mixing distance B between the 2nd-order light source 100-2 and the optical film 102 (such as the diffuser 102-2), and the light mixing distance B between the 2nd-order light source 100-2 and the optical film 102 is smaller than the light mixing distance C between the 3rd-order light source 100-3 and the optical film 102 (such as the diffuser 102-2).

[0087] In addition, the first-order light source 100-1 may include a first circuit board C1 and a plurality of first light-emitting elements L1. The second-order light source 100-2 may include a second circuit board C2 and a plurality of second light-emitting elements L2. The third-order light source 100-3 may include a third circuit board C3, a plurality of third light-emitting elements L3, and a plurality of secondary optical elements S3. The relative arrangement relationship between the plurality of elements in the third-order light source 100-3 may refer to Figure 3The first light emitting elements L1 and the second light emitting elements L2 may include sub-millimeter light emitting diodes, and the third light emitting elements L3 may include light emitting diodes.

[0088] In addition, the pitch P2 of the multiple second light-emitting elements L2 in the second-order light source 100-2 is greater than the pitch P1 of the multiple first light-emitting elements L1 in the first-order light source 100-1, and the pitch P3 of the multiple third light-emitting elements L3 in the third-order light source 100-3 is greater than the pitch P2 of the multiple second light-emitting elements L2 in the second-order light source 100-2.

[0089] Taking a 50-inch display device as an example, the light mixing distances A, B, and C of the three-order light source can be 5mm, 12mm, and 20mm, respectively. The pitches P1, P2, and P3 can be 10mm, 24mm, and 76mm, respectively. The total number of sub-millimeter LEDs and LEDs is approximately 3176. On the other hand, a direct-lit light source module using only sub-millimeter LEDs as light-emitting elements requires approximately 6882 sub-millimeter LEDs, 3706 more than the direct-lit light source module 10A using both LEDs and sub-millimeter LEDs as light-emitting elements.

[0090] Please refer to Figure 5 , the display device 1B and Figure 2 The main differences of the display device 1 are described as follows. In the display device 1B, the N-order light source 100B of the direct-type light source module 10B is a 4-order light source, and the N-order light source 100B includes a 1st-order light source 100-1, a 2nd-order light source 100-2, a 3rd-order light source 100-3 and a 4th-order light source 100-4, wherein the light mixing distance A between the 1st-order light source 100-1 and the optical film 102 (such as the diffuser 102-2) is smaller than the light mixing distance A between the 2nd-order light source 100-2 and the optical film 102 (such as the diffuser 102-2). The light mixing distance B between the second-order light source 100-2 and the optical film 102 is smaller than the light mixing distance C between the third-order light source 100-3 and the optical film 102 (such as the diffuser 102-2), and the light mixing distance C between the third-order light source 100-3 and the optical film 102 is smaller than the light mixing distance D between the fourth-order light source 100-4 and the optical film 102 (such as the diffuser 102-2).

[0091] In addition, the first-order light source 100-1 may include a first circuit board C1 and a plurality of first light-emitting elements L1. The second-order light source 100-2 may include a second circuit board C2 and a plurality of second light-emitting elements L2. The third-order light source 100-3 may include a third circuit board C3, a plurality of third light-emitting elements L3, and a plurality of secondary optical elements S3. The fourth-order light source 100-4 may include a fourth circuit board C4, a plurality of fourth light-emitting elements L4, and a plurality of secondary optical elements S4. The relative arrangement relationship between the plurality of elements in the third-order light source 100-3 and the fourth-order light source 100-4 can be referred to. Figure 3 The first light emitting elements L1 and the second light emitting elements L2 may include sub-millimeter light emitting diodes, and the third light emitting elements L3 and the fourth light emitting elements L4 may include light emitting diodes.

[0092] In addition, the pitch P2 of the multiple second light-emitting elements L2 in the second-order light source 100-2 is greater than the pitch P1 of the multiple first light-emitting elements L1 in the first-order light source 100-1, the pitch P3 of the multiple third light-emitting elements L3 in the third-order light source 100-3 is greater than the pitch P2 of the multiple second light-emitting elements L2 in the second-order light source 100-2, and the pitch P4 of the multiple fourth light-emitting elements L4 in the fourth-order light source 100-4 is greater than the pitch P3 of the multiple third light-emitting elements L3 in the third-order light source 100-3.

[0093] Taking a 75-inch display device as an example, the mixing distances A, B, C, and D of the 4-order light source can be 5mm, 12mm, 18mm, and 25mm, respectively. The pitches P1, P2, P3, and P4 can be 10mm, 24mm, 73mm, and 90mm, respectively. The total number of sub-millimeter LEDs and LEDs is approximately 4783. On the other hand, a direct-lit light source module using only sub-millimeter LEDs as light-emitting elements requires approximately 15,604 sub-millimeter LEDs, 10,821 more than the direct-lit light source module 10A using both LEDs and sub-millimeter LEDs as light-emitting elements.

[0094] Please refer to Figure 6 , the display device 1C and Figure 2The main differences of the display device 1 are described as follows. In the display device 1C, the N-order light source 100C of the direct-type light source module 10C is a 5-order light source, and the N-order light source 100C includes a 1st-order light source 100-1, a 2nd-order light source 100-2, a 3rd-order light source 100-3, a 4th-order light source 100-4 and a 5th-order light source 100-5, wherein the light mixing distance A between the 1st-order light source 100-1 and the optical film 102 (such as the diffuser 102-2) is smaller than the light mixing distance B between the 2nd-order light source 100-2 and the optical film 102 (such as the diffuser 102-2), and the 2nd-order light source 100- 2 and the optical film 102 is smaller than the light mixing distance C between the third-order light source 100-3 and the optical film 102 (such as the diffuser 102-2), the light mixing distance C between the third-order light source 100-3 and the optical film 102 is smaller than the light mixing distance D between the fourth-order light source 100-4 and the optical film 102 (such as the diffuser 102-2), and the light mixing distance D between the fourth-order light source 100-4 and the optical film 102 is smaller than the light mixing distance E between the fifth-order light source 100-5 and the optical film 102 (such as the diffuser 102-2).

[0095] In addition, the 1st-order light source 100-1 may include a first circuit board C1 and a plurality of first light-emitting elements L1. The 2nd-order light source 100-2 may include a second circuit board C2 and a plurality of second light-emitting elements L2. The 3rd-order light source 100-3 may include a third circuit board C3, a plurality of third light-emitting elements L3 and a plurality of secondary optical elements S3. The 4th-order light source 100-4 may include a fourth circuit board C4, a plurality of fourth light-emitting elements L4 and a plurality of secondary optical elements S4. The 5th-order light source 100-5 may include a fifth circuit board C5, a plurality of fifth light-emitting elements L5 and a plurality of secondary optical elements S5. The relative arrangement relationship between the multiple elements in the 3rd-order light source 100-3, the 4th-order light source 100-4 and the 5th-order light source 100-5 can be referred to Figure 3 The first light emitting elements L1 and the second light emitting elements L2 may include sub-millimeter light emitting diodes, and the third light emitting elements L3, the fourth light emitting elements L4 and the fifth light emitting elements L5 may include light emitting diodes.

[0096] In addition, the pitch P2 of the multiple second light-emitting elements L2 in the 2nd-order light source 100-2 is greater than the pitch P1 of the multiple first light-emitting elements L1 in the 1st-order light source 100-1, the pitch P3 of the multiple third light-emitting elements L3 in the 3rd-order light source 100-3 is greater than the pitch P2 of the multiple second light-emitting elements L2 in the 2nd-order light source 100-2, the pitch P4 of the multiple fourth light-emitting elements L4 in the 4th-order light source 100-4 is greater than the pitch P3 of the multiple third light-emitting elements L3 in the 3rd-order light source 100-3, and the pitch P5 of the multiple fifth light-emitting elements L5 in the 5th-order light source 100-5 is greater than the pitch P4 of the multiple fourth light-emitting elements L4 in the 4th-order light source 100-4.

[0097] Taking a 75-inch display device as an example, the mixing distances A, B, C, D, and E of the 5-step light source can be 5mm, 12mm, 18mm, 24mm, and 30mm, respectively. The pitches P1, P2, P3, P4, and P5 can be 10mm, 24mm, 73mm, 86mm, and 100mm, respectively. The total number of sub-millimeter LEDs and LEDs is approximately 3,891. On the other hand, a direct-lit light source module using only sub-millimeter LEDs as light-emitting elements requires approximately 15,604 sub-millimeter LEDs, 11,713 more than the direct-lit light source module 10A using both LEDs and sub-millimeter LEDs as light-emitting elements.

[0098] In summary, in the embodiments of the present invention, the design of different light mixing distances can reduce the number of light-emitting elements required, lower the cost and / or weight of the direct-lit light source module and display device, or achieve a slimmer visual effect. Furthermore, the larger the direct-lit light source module or display device, the more the number of light-emitting elements can be reduced.

[0099] Although the present invention has been disclosed above with reference to the embodiments, they are not intended to limit the present invention. Those skilled in the art may make slight changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A direct - type light source module, comprising: An N - stage light source; And An optical film disposed above the N - stage light source, wherein the mixing light distance between the i - th stage light source and the optical film is less than the mixing light distance between the (i + 1) - th stage light source and the optical film, where 1 ≤ i < N, and N is a positive integer greater than 1; Wherein the 1st - stage light source includes: A first circuit board; and A plurality of first light - emitting elements disposed on the first circuit board; The 2nd - stage light source includes: A second circuit board; A plurality of second light - emitting elements disposed on the second circuit board; Wherein the mixing light distance between the 1st - stage light source and the optical film is A, and the mixing light distance between the 2nd - stage light source and the optical film is B; Wherein the pitch from the first light - emitting element adjacent to the 2nd - stage light source in the 1st - stage light source to the second light - emitting element adjacent to the 1st - stage light source in the 2nd - stage light source falls between S1 and S2, where S1 = - 1.6A+2B, and S2 = A + 0.47B; Wherein the light sources in the N - stage light source with a mixing light distance greater than or equal to 15 mm include a plurality of light - emitting diodes and a plurality of secondary optical elements, and the light sources in the N - stage light source with a mixing light distance less than 15 mm include a plurality of sub - millimeter light - emitting diodes.

2. The direct - type light source module according to claim 1, wherein the N mixing light distances between the N - stage light source and the optical film all fall within the range of 5 mm to 30 mm.

3. The direct - type light source module according to claim 1, wherein the pitch of the plurality of light - emitting elements in the (i + 1) - th stage light source is greater than the pitch of the plurality of light - emitting elements in the i - th stage light source.

4. The direct - type light source module according to claim 1, wherein N falls within the range of 2 to 5.

5. The direct - type light source module according to claim 1, wherein the 2nd - stage light source further includes: A plurality of secondary optical elements disposed on the second circuit board, wherein the plurality of second light - emitting elements are located between the plurality of secondary optical elements and the second circuit board.

6. The direct - type light source module according to claim 5, wherein the plurality of first light - emitting elements include a plurality of sub - millimeter light - emitting diodes, and the plurality of second light - emitting elements include a plurality of light - emitting diodes.

7. The direct - type light source module according to claim 5, wherein A falls within the range of 5 mm to 13 mm, and B falls within the range of 15 mm to 30 mm.

8. A display device, comprising: A direct - type light source module, comprising: An N - stage light source; and An optical film disposed above the N - stage light source, wherein the mixing light distance between the i - th stage light source and the optical film is less than the mixing light distance between the (i + 1) - th stage light source and the optical film, where 1 ≤ i < N, and N is a positive integer greater than 1; and A display panel disposed on the direct - type light source module; Wherein the 1st - stage light source includes: A first circuit board; and A plurality of first light - emitting elements disposed on the first circuit board; and The 2nd - stage light source includes: A second circuit board; A plurality of second light - emitting elements disposed on the second circuit board; The light mixing distance between the first-order light source and the optical film is A, and the light mixing distance between the second-order light source and the optical film is B; wherein a pitch between a first light emitting element adjacent to the second light emitting element in the first-order light source and a second light emitting element adjacent to the first-order light source in the second-order light source falls between S1 and S2, wherein S1 = -1.6A + 2B, and S2 = A + 0.47B; The light source with a mixing distance greater than or equal to 15 mm in the N-order light source includes multiple light emitting diodes and multiple secondary optical elements, and the light source with a mixing distance less than 15 mm in the N-order light source includes multiple sub-millimeter light emitting diodes. 9 . The display device according to claim 8 , wherein N light mixing distances between the N-order light source and the optical film are all within a range of 5 mm to 30 mm. 10 . The display device of claim 8 , wherein a pitch of the plurality of light emitting elements in the (i+1)th order light source is greater than a pitch of the plurality of light emitting elements in the (i)th order light source. The display device of claim 8 , wherein N falls within a range of 2 to 5.

12. The display device according to claim 8, wherein the second-order light source further comprises: A plurality of secondary optical elements are arranged on the second circuit board, wherein the plurality of second light-emitting elements are located between the plurality of secondary optical elements and the second circuit board. 13 . The display device of claim 12 , wherein the plurality of first light-emitting elements comprise a plurality of sub-millimeter light-emitting diodes, and the plurality of second light-emitting elements comprise a plurality of light-emitting diodes. 14 . The display device of claim 12 , wherein A falls within a range of 5 mm to 13 mm, and B falls within a range of 15 mm to 30 mm.

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