Backlight lamp panel and manufacturing method therefor, and display apparatus

Abstract

Disclosed are a backlight lamp panel and a manufacturing method therefor, and a display apparatus. The backlight lamp panel comprises: a substrate; a plurality of light-emitting devices and a plurality of bonding pads for connecting to a flexible printed circuit board, the light-emitting devices and the bonding pads being respectively located on two opposite sides of the substrate in the thickness direction thereof, and the light-emitting devices being electrically connected to the bonding pads; a protective adhesive layer, covering the plurality of light-emitting devices; and a plurality of transflective dots, arranged on the side of the protective adhesive layer away from the substrate, wherein the orthographic projection of the light-emitting surface of each light-emitting device on the substrate is within the orthographic projection of each transflective dot on the substrate, and the transflective dots are used for reflecting part of light rays emitted by the light-emitting devices and transmitting the other part of the light rays.

Description

Backlight plate, manufacturing method thereof and display device TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of display, in particular to a backlight plate, a manufacturing method thereof and a display device. BACKGROUND

[0002] In the backlight module of small-size display products such as notebook computers and tablet computers, LEDs (light-emitting diodes) can be used as backlight sources, and the LEDs can be packaged by using a glue layer. However, the surface of the glue layer is not flat at present, which affects the display effect. SUMMARY

[0003] The present disclosure aims to at least solve one of the technical problems existing in the prior art, and proposes a backlight plate, a manufacturing method thereof and a display device.

[0004] To achieve the above-mentioned purpose, the present disclosure provides a backlight plate, comprising:

[0005] a substrate;

[0006] a plurality of light-emitting devices and a plurality of binding pads for connecting a flexible circuit board, the light-emitting devices and the binding pads are respectively located on opposite sides of the substrate along the thickness direction of the substrate, and the light-emitting devices are electrically connected to the binding pads;

[0007] a protective glue layer covering the plurality of light-emitting devices, and the protective glue layer and the binding pads have an overlap on the orthographic projection of the substrate;

[0008] a plurality of transreflective dots arranged on a side of the protective glue layer away from the substrate;

[0009] wherein the orthographic projection of the light-emitting surface of the light-emitting devices on the substrate is located within the orthographic projection range of the transreflective dots on the substrate, and the transreflective dots are used for reflecting part of the light emitted by the light-emitting devices and transmitting another part of the light.

[0010] In some embodiments, the transreflective dots comprise a main body part and a plurality of antenna parts, and the plurality of antenna parts are arranged around the main body part and connected to the main body part.

[0011] wherein the orthographic projection of the light-emitting surface of the light-emitting devices on the substrate is located within the orthographic projection range of the main body part on the substrate.

[0012] In some embodiments, the orthographic projection of the light-emitting surface of the light-emitting devices on the substrate covers the orthographic projection of the center of the main body part on the substrate.

[0013] In some embodiments, the plurality of antenna portions are evenly arranged along the circumference of the body portion; and a width of the antenna portion gradually decreases in a direction away from the body portion.

[0014] In some embodiments, a diameter of the transmissive-reflection dot is greater than a center-to-center distance between two adjacent light emitting devices.

[0015] In some embodiments, an area of a normal projection of the body portion on the substrate is at least 10 times of the area of the light emitting surface.

[0016] In some embodiments, a maximum height difference between positions on a surface of the protective layer away from the substrate is less than 50 microns.

[0017] In some embodiments, the light emitting device is electrically connected to the bonding pad through a connecting line, and a portion of the connecting line is located in a via hole penetrating through the substrate.

[0018] In some embodiments, a normal projection of the protective layer and the substrate on a reference surface coincides, and the reference surface is a plane perpendicular to a thickness direction of the substrate.

[0019] In some embodiments, a hardness of the protective layer is greater than 50D.

[0020] In some embodiments, the protective layer comprises a transparent matrix and a diffusion powder doped in the transparent matrix, and a mass percentage of the diffusion powder in the protective layer is greater than or equal to 5%.

[0021] In some embodiments, a material of the transmissive-reflection dot comprises silica gel and an anti-settling powder doped in the silica gel, and a mass percentage of the anti-settling powder in the transmissive-reflection dot is between 8% and 8.5%.

[0022] In some embodiments, the backlight plate further comprises a reflective layer arranged between the protective layer and the substrate, and the reflective layer has a plurality of avoiding holes, and the light emitting device is located in the avoiding hole.

[0023] Embodiments of the present disclosure further provide a display device, comprising a backlight module and a display panel arranged on a light emitting side of the backlight module, and the backlight module comprises the above backlight plate and a flexible circuit board electrically connected to the plurality of bonding pads.

[0024] In some embodiments, the backlight module further comprises an optical film arranged on a side of the plurality of transmissive-reflection dots away from the substrate.

[0025] Embodiments of the present disclosure further provide a manufacturing method of a backlight plate, comprising:

[0026] A substrate is provided, the substrate having a first surface and a second surface oppositely arranged along a thickness direction thereof;

[0027] A plurality of light emitting devices are formed on the first surface, and a plurality of bonding pads are formed on the second surface, the light emitting devices being electrically connected to the bonding pads;

[0028] An initial glue layer covering the plurality of light emitting devices is formed, the initial glue layer including an active portion covering the plurality of light emitting devices and a redundant portion surrounding the active portion;

[0029] A plurality of transmissive and reflective dots are formed on a side of the initial glue layer away from the substrate, a normal projection of a light emitting surface of the light emitting devices on the substrate being within a normal projection range of the transmissive and reflective dots on the substrate, the transmissive and reflective dots being configured to reflect a portion of light emitted by the light emitting devices and transmit another portion of the light;

[0030] The redundant portion of the initial glue layer is removed to form a protective glue layer covering the plurality of light emitting devices, the protective glue layer overlapping a normal projection of the bonding pads on the substrate.

[0031] In some embodiments, the step of removing the redundant portion of the initial glue layer includes:

[0032] The initial glue layer and the substrate are cut along an interface between the redundant portion and the active portion.

[0033] In some embodiments, the redundant portion has a width greater than or equal to 2.5 mm.

[0034] In some embodiments, the step of forming a plurality of transmissive and reflective dots on a side of the initial glue layer away from the substrate includes:

[0035] A dot material having a viscosity between 25,000 and 40,000 mPas is provided;

[0036] The dot material is printed on a surface of the initial glue layer away from the substrate using a printing process to form a plurality of dot patterns;

[0037] The plurality of dot patterns are cured to form a plurality of transmissive and reflective dots.

[0038] In some embodiments, the dot material includes silica gel and anti-settling powder doped in the silica gel, the anti-settling powder having a mass ratio in the dot material between 8% and 8.5%. BRIEF DESCRIPTION OF DRAWINGS

[0039] The accompanying drawings are included to provide a further understanding of the present disclosure and constitute a part of the specification, illustrate the present disclosure and are used to explain the present disclosure together with the specific embodiments described below. In the drawings:

[0040] FIG. 1 is a schematic diagram of the connection between the backlight plate and the flexible circuit board in some embodiments.

[0041] FIG. 2 is a schematic diagram of the initial adhesive layer and the substrate before and after cutting in some embodiments.

[0042] FIG. 3 is a schematic diagram of the connection between the backlight plate and the flexible circuit board in other embodiments.

[0043] FIG. 4 is a plan view of the backlight plate in other embodiments.

[0044] FIG. 5 is a schematic diagram of the light path of the backlight plate in other embodiments.

[0045] FIG. 6 is a schematic diagram of the backlight plate in some embodiments of the present disclosure.

[0046] FIG. 7 is a schematic diagram of the initial adhesive layer and the substrate before and after cutting in embodiments of the present disclosure.

[0047] FIG. 8 is a schematic diagram of the binding between the backlight plate and the flexible circuit board.

[0048] FIG. 9 is a plan view of the transmissive and reflective dot in some embodiments of the present disclosure.

[0049] FIG. 10 is a schematic diagram of the comparison between the irregular dot and the circular transmissive and reflective dot.

[0050] FIG. 11 is a schematic diagram of the comparison between two irregular dots and two circular transmissive and reflective dots.

[0051] FIG. 12 is a plan view of the transmissive and reflective dot in other embodiments of the present disclosure.

[0052] FIG. 13 is a schematic diagram of two arrangements of the transmissive and reflective dot in embodiments of the present disclosure.

[0053] FIG. 14 is a schematic diagram of the connection between the light emitting device and the binding pad in some embodiments of the present disclosure.

[0054] FIG. 15 is a schematic diagram of the manufacturing process of the backlight plate in one specific example of the present disclosure.

[0055] FIG. 16 is a schematic diagram of the backlight module in some embodiments of the present disclosure. DETAILED DESCRIPTION

[0056] The specific embodiments of the present disclosure will be described in detail below with reference to the drawings. It should be understood that the specific embodiments described herein are merely illustrative and explanatory, and are not intended to limit the present disclosure.

[0057] To make the objects, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments of the present disclosure. Based on the described embodiments of the present disclosure, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present disclosure.

[0058] Unless otherwise defined, technical terms or scientific terms used in the embodiments of the present disclosure should be understood as having the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. The terms “first”, “second”, and similar terms used in the present disclosure do not denote any order, quantity, or importance, but are used to distinguish different components. Similarly, the terms “include”, “contain”, and similar terms mean that the elements or objects before the terms encompass the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects. The terms “connect” or “connected” or similar terms do not mean physical or mechanical connection, but can include electrical connection, whether direct or indirect. The terms “upper”, “lower”, “left”, “right”, and the like only represent relative positional relationships, which can change when the absolute positions of the described objects change.

[0059] As used herein, “parallel”, “perpendicular” includes the stated case and the approximately similar case to the stated case, the range of which is within an acceptable deviation range, wherein the acceptable deviation range is determined by a person of ordinary skill in the art considering the measurement being discussed and the error related to the measurement of a specific quantity (i.e., the limitation of the measurement system). For example, “parallel” includes absolute parallel and approximately parallel, wherein the acceptable deviation range of approximately parallel can be, for example, within 5° deviation; “perpendicular” includes absolute perpendicular and approximately perpendicular, wherein the acceptable deviation range of approximately perpendicular can also be, for example, within 5° deviation.

[0060] It should be understood that when a layer or element is referred to as being on another layer or substrate, it can be directly on the other layer or substrate, or there can be an intermediate layer between the layer or element and the other layer or substrate.

[0061] Exemplary embodiments are described herein with reference to cross-sectional and / or plan view illustrations that are schematic illustrations of idealized embodiments. Variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and / or tolerances, are to be expected. Thus, embodiments should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. The regions illustrated in the figures are schematic and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of exemplary embodiments.

[0062] FIG. 1 is a schematic diagram of the connection between a backlight plate and a flexible circuit board provided in some embodiments. As shown in FIG. 1, the backlight plate includes a substrate 11 and a plurality of light emitting devices 12 disposed on the substrate 11, which can be Mini-LED devices. The first surface of the substrate 11 includes a device region and a bonding region located on one side of the device region. The light emitting devices 12 are disposed in the device region, and the bonding region is provided with bonding pads 14. The light emitting devices 12 are electrically connected to the bonding pads 14, and the bonding pads 14 are bonded to one end of the flexible circuit board 20. The other end of the flexible circuit board 20 is used to connect a driving circuit board, so that the driving signal on the driving circuit board is transmitted to the light emitting devices 12 through the bonding pads 14.

[0063] In small and medium-sized display products such as notebooks, tablets and the like, the spacing between the light emitting devices 12 in the backlight plate is small, for example, less than or equal to 5 mm. In this case, a protective glue layer 13 (i.e., flat glue) is usually used to encapsulate multiple light emitting devices 12. Since the protective glue layer 13 is formed after the curing of the glue material, when the protective glue layer 13 is used for encapsulation, the upper surface of the protective glue layer 13 is prone to unevenness. Specifically, as shown in FIG. 1, the distance from the edge region of the upper surface of the protective glue layer 13 to the substrate 11 (i.e., the maximum thickness of the edge region of the protective glue layer 13) is D2, and the distance from the middle region of the upper surface of the protective glue layer 13 to the substrate 11 (i.e., the maximum thickness of the middle region of the protective glue layer 13) is D1, where D2 is less than D1. In some embodiments, a process edge can be added to the sides other than the side close to the binding area, and then the process edge is removed by cutting the protective glue layer 13 and the substrate 11, thereby improving the flatness of the surface of the protective glue layer 13. Specifically, as shown in FIG. 2, a large-area initial glue layer 131 can be formed first, where the initial glue layer 131 includes an effective part and a redundant part, and the redundant part is the above-mentioned process edge. In addition to the side close to the binding area, the effective part is provided with a redundant part on the remaining sides. Then, the initial glue layer 131 and the substrate 11 are cut along the cutting line CL to remove the redundant part around the initial glue layer 131, thereby obtaining the final protective glue layer 13, so that the thickness of the protective glue layer 13 on the sides other than the side close to the binding area is the same as or close to D1. However, the binding area is provided with a binding pad 14, and the initial glue layer 131 cannot cover the binding pad 14, i.e., the process edge cannot be added to the side close to the binding area, thereby causing the thickness of the protective glue layer 13 close to the binding area to still have a certain gap with the thickness of the middle region, which in turn can cause display defects.

[0064] For example, FIG. 3 is a schematic diagram of the connection between the backlight plate and the flexible circuit board according to some embodiments, FIG. 4 is a plan view of the backlight plate according to some embodiments, and FIG. 5 is a schematic diagram of the light path of the backlight plate according to some embodiments. As shown in FIGS. 3-5, the structure shown in FIG. 3 is based on the structure shown in FIG. 1, and further includes a plurality of transreflective dots 15 located on the side of the protective layer 13 away from the substrate 11. Each of the transreflective dots 15 is arranged opposite to one of the light emitting devices 12. The transreflective dots 15 are configured to transmit a portion of the light emitted by the light emitting devices 12 and reflect another portion of the light. The light reflected by the transreflective dots 15 is reflected by a reflective layer (not shown) on the surface of the substrate 11 and then exits the protective layer 13. The arrangement of the transreflective dots 15 can improve the light uniformity of the backlight plate. However, as described above, the surface of the protective layer 13 is not flat, which can affect the thickness accuracy of the transreflective dots 15. For example, the thickness accuracy of the transreflective dots 15 can be ±20 microns. As a result, the thickness of different transreflective dots 15 can be uneven. For example, the transreflective dots 15 with a larger thickness can have a higher reflectivity and transmit less light, which can result in dark lines above the transreflective dots 15. The transreflective dots 15 with a smaller thickness can have a lower reflectivity and transmit more light, which can result in bright lines above the transreflective dots 15. In summary, the uneven surface of the protective layer 13 can result in bright and dark lines in the display image.

[0065] To solve the above problems, the backlight plate according to some embodiments of the present disclosure is shown in FIG. 6. As shown in FIG. 6, the backlight plate includes a substrate 11, a plurality of light emitting devices 12, a plurality of bonding pads 14, a protective layer 13, and a plurality of transreflective dots 15. The light emitting devices 12 and the bonding pads 14 are arranged on the substrate 11 and located on opposite sides of the substrate 11 along the thickness direction of the substrate 11. The bonding pads 14 are configured to connect to the flexible circuit board 20, and the light emitting devices 12 are electrically connected to the bonding pads 14. The light emitting devices 12 can emit light of the same color. The protective layer 13 covers the light emitting devices 12, and the orthogonal projection of the protective layer 13 on the substrate 11 overlaps with the orthogonal projection of the bonding pads 14 on the substrate 11. The transreflective dots 15 are arranged on the side of the protective layer 13 away from the substrate 11. The orthogonal projection of the light emitting surface of the light emitting devices 12 on the substrate 11 is located within the range of the orthogonal projection of the transreflective dots 15 on the substrate 11. The transreflective dots 15 are configured to reflect a portion of the light emitted by the light emitting devices 12 and transmit another portion of the light.

[0066] In the embodiments of the present disclosure, the light emitting device 12 and the binding pad 14 are respectively located on opposite sides of the substrate 11, thus the binding pad 14 does not affect the forming and cutting process of the protective layer 13. As shown in FIG. 7, a large-area initial layer 131 can be formed first, and the thin part (i.e., the process edge) of the initial layer 131 around the edges is cut off, so that the protective layer 13 with a flat surface can be formed, ensuring the thickness uniformity of the transmissive and reflective dots 15.

[0067] In some embodiments, as shown in FIG. 6, the orthographic projection of the binding pad 14 on the substrate 11 is located within the orthographic projection range of the protective layer 13 on the substrate 11. When the backlight plate is used in a display device, the flexible circuit board 20 is electrically connected to the driving circuit board, and the flexible circuit board 20 is bent so that the driving circuit board is located on the side of the backlight plate away from the display panel. In the embodiments of the present disclosure, the binding pad 14 is located on the side of the substrate 11 away from the protective layer 13 and the light emitting device 12, thus the binding pad 14 does not affect the cutting process of the protective layer 13, and therefore the binding pad 14 can be arranged closer to the middle of the backlight plate, so that the flexible circuit board 20 is closer to the middle of the backlight plate, reducing the occupation of the display device frame by the flexible circuit board 20, and thus facilitating the realization of a narrow frame.

[0068] In some embodiments, the edges of the protective layer 13 and the substrate 11 are flush, that is, the orthographic projection of the protective layer 13 on the reference surface perpendicular to the thickness direction of the substrate 11 coincides with the orthographic projection of the substrate 11 on the reference surface. That is, when the process edge of the protective layer 13 is removed, the protective layer 13 and the substrate 11 can be cut synchronously from the four sides of the protective layer 13.

[0069] In the embodiments of the present disclosure, by arranging the binding pad 14 on the side of the substrate 11 away from the light emitting device 12, the surface flatness of the protective layer 13 is improved. For example, in some embodiments, the maximum height difference between any two positions on the surface of the protective layer 13 away from the substrate 11 is less than 50 microns, for example, the maximum height difference is less than 50 microns and greater than 30 microns; or the maximum height difference is less than 30 microns; or the maximum height difference is less than or equal to 20 microns; or less than or equal to 15 microns; or less than or equal to 10 microns. Wherein, the height of any position on the surface of the protective layer 13 away from the substrate 11 refers to the vertical distance from the position to the surface of the substrate 11 facing the light emitting device 12.

[0070] In some embodiments, the maximum thickness of the protective glue layer 13 is between 0.2 mm and 0.4 mm. The transmittance of the protective glue layer 13 is in a range from 50% to 95%, for example, between 70% and 80%, or between 80% and 90%, or between 90% and 95%. The protective glue layer 13 can be made of transparent silicone or dry film. The transparent silicone can be made in two ways, one is a molding process, and the other is a dispensing process. Since the flatness of the surface of the protective glue layer 13 is required to be high for the transmissive and reflective dots 15, the protective glue layer 13 can be made by using a molding process with higher precision.

[0071] In some embodiments, the shape of the transmissive and reflective dots 15 can be circular, polygonal, or irregular. The transmissive and reflective dots 15 can correspond one-to-one to the light emitting devices 12, or the number of the transmissive and reflective dots 15 is greater than the number of the light emitting devices 12, and each light emitting device 12 is provided with one transmissive and reflective dot 15 on the light emitting side.

[0072] In some embodiments, the thickness of the transmissive and reflective dots 15 can be between 0.02 mm and 0.06 mm. The material of the transmissive and reflective dots 15 (hereinafter referred to as dot material) can be ink with a certain reflectivity or white silicone, and the reflectivity of the dot material is between 60% and 95% (the reflectivity is tested at a material thickness of 50 microns for a light of 450 nm wavelength).

[0073] In some embodiments, the transmissive and reflective dots 15 can be made by using a screen printing process, a steel screen printing process, a mask + spraying process, a pre-prepared layer + laser engraving process, etc. Among them, the printing process has the highest efficiency and the lowest process difficulty, so in the actual manufacturing process, a printing process with high efficiency and low cost can be used. Since the surface flatness of the protective glue layer 13 in the embodiments of the present disclosure is improved, the thickness accuracy of the transmissive and reflective dots 15 formed on the surface of the protective glue layer 13 is improved from ± 20 microns to ± 8 microns.

[0074] The inventor found that the printing process is prone to glue overflow defects, which affects the size accuracy of the transmissive and reflective dots 15, so in the embodiments of the present disclosure, when forming the transmissive and reflective dots 15, the formula of the dot material is adjusted to have a large viscosity, which can effectively improve the size deviation problem of the transmissive and reflective dots 15 caused by glue overflow.

[0075] In one example, the screen dot material includes white silica gel and anti-settling powder, and the mass percentage of the anti-settling powder in the screen dot material is between 8% and 8.5%, so as to effectively increase the viscosity of the silica gel. When the addition ratio of the anti-settling powder is small, the viscosity of the screen dot material is low, and there is a problem of glue overflow. When the addition ratio of the anti-settling powder is high, the printing is prone to the problem of sticking to the screen, and stable printing cannot be performed. Therefore, in the embodiments of the present disclosure, the addition ratio of the anti-settling powder in the silica gel is between 8% and 8.5%, so that the material viscosity of the transmissive and reflective screen dot 15 is between 25000 and 40000 mPas, thereby reducing or preventing the problem of glue overflow and achieving a better printing effect. Compared with not adding anti-settling powder, when the material viscosity of the transmissive and reflective screen dot 15 reaches 25000-40000 mPas by adding anti-settling powder, the dot diameter tolerance of the transmissive and reflective screen dot 15 can be improved from ±0.2 mm to ±0.1 mm.

[0076] Fig. 8 is a schematic diagram of the binding of the backlight plate and the flexible circuit board. As shown in Fig. 8, when the backlight plate and the flexible circuit board 20 are bound and connected, the protective glue layer 13 is abutted against the base 40, one end of the flexible circuit board 20 is pressed on the binding pad 14 by using the pressure head 50, and the binding pad 14 and the flexible circuit board 20 are electrically connected by using the piezoelectric glue. When the hardness of the protective glue layer 13 is insufficient, the pressure between the base 40 and the protective glue layer 13 can cause indentation on the surface of the protective glue layer 13. When the indentation is close to the transmissive and reflective screen dot 15, it can even affect the transmissive and reflective effect of the transmissive and reflective screen dot 15 on light.

[0077] In order to solve this problem, the protective glue layer 13 with high hardness is used in the embodiments of the present disclosure. Specifically, the protective glue layer 13 includes a transparent matrix and diffusion powder doped in the transparent matrix, and the mass percentage of the diffusion powder in the protective glue layer 13 is greater than or equal to 5%, so that the hardness of the protective glue layer 13 reaches more than 50D, thereby reducing or preventing the above indentation problem. For example, the mass percentage of the diffusion powder in the protective glue layer 13 is between 5% and 8%, or between 8% and 10%. In one example, the protective glue layer 13 further includes anti-settling powder doped in the transparent matrix, and the mass percentage of the anti-settling powder in the protective glue layer 13 is between 2% and 4%, for example, 2%, or 3%, or 4%.

[0078] Fig. 9 is a schematic diagram of the transmissive and reflective screen dot provided in some embodiments of the present disclosure. As shown in Fig. 9, the transmissive and reflective screen dot 15 is a special-shaped screen dot, which includes a main body part 151 and a plurality of antenna parts 152, and the plurality of antenna parts 152 are arranged around the main body part 151 and connected with the main body part 151. For example, the main body part 151 and the antenna part 152 are an integral structure. The orthographic projection of the light emitting surface of the light emitting device 12 on the substrate 11 is located in the orthographic projection range of the main body part 151 on the substrate 11.

[0079] For the circular transmissive and reflective dot 15, if the diameter of the transmissive and reflective dot 15 is too small and the thickness is thin, the reflected light between the light emitting devices 12 is small, and the positions between the light emitting devices 12 are prone to form dark stripes compared with the positions above the light emitting devices 12. If the diameter of the transmissive and reflective dot 15 is too large and the thickness is thick, the reflected light between the light emitting devices 12 is large, and the positions between the light emitting devices 12 are prone to form bright stripes compared with the positions above the light emitting devices 12, and the larger the diameter of the transmissive and reflective dot 15, the more the light efficiency loss. In order to improve the brightness uniformity, it is necessary to adjust the thickness or diameter of the transmissive and reflective dot 15. For the circular transmissive and reflective dot 15, the light uniformity effect is not obviously improved by adjusting the diameter of the transmissive and reflective dot 15, and the brightness loss is caused. Compared with the circular transmissive and reflective dot 15, the special-shaped dot used in the embodiment of the present disclosure has the following effects:

[0080] Firstly, the special-shaped dot has higher shape freedom, and the light uniformity effect can be improved. The boundary of the special-shaped dot is more complex, and it is not easy to form regular bright and dark stripes.

[0081] Secondly, as shown in FIG. 10, taking the same outer diameter as an example, compared with the circular transmissive and reflective dot 15, the reflective light area of the special-shaped dot can be reduced by 50%, thereby reducing the brightness loss of the secondary reflection, and achieving the purpose of improving the light efficiency.

[0082] Thirdly, as shown in FIG. 11, when the outer diameter P2 of the transmissive and reflective dot 15 is greater than the center distance P1 of the light emitting devices 12, the circular transmissive and reflective dot 15 will overlap, and the special-shaped dot in the present disclosure can prevent the transmissive and reflective dot 15 from overlapping by mutual avoidance between the antennal parts 152.

[0083] In some embodiments, the orthographic projection of the light emitting surface of the light emitting device 12 on the substrate 11 covers the orthographic projection of the center of the main body part 151 on the substrate 11, thereby facilitating the uniform distribution of light above and around the light emitting device 12. For example, the center of the light emitting surface is located on the central axis of the main body part 151.

[0084] In some embodiments, the orthographic projection area of the main body part 151 on the substrate 11 is at least 10 times the area of the light emitting surface of the light emitting device 12, so as to ensure that the transmissive and reflective dot 15 can reflect sufficient light to the interval region between the light emitting devices 12, and improve the light uniformity of the entire backlight panel. For example, the orthographic projection area of the main body part 151 on the substrate 11 is 10-15 times, or 15-20 times, or 20-30 times the area of the light emitting surface.

[0085] In some embodiments, the main body part 151 of the transmissive and reflective dot 15 can be an axisymmetric figure, thereby improving the uniformity of the light distribution above and around the light emitting device 12. For example, the main body part 151 is circular, rectangular, hexagonal, octagonal, etc.

[0086] In some embodiments, the plurality of antenna portions 152 in the same trans-reflective dot 15 are evenly arranged along the circumference of the body portion 151, so as to evenly distribute the light above and around the light emitting device 12.

[0087] In some embodiments, the diameter of the trans-reflective dot 15 is greater than the center-to-center distance between two adjacent light emitting devices 12, so as to improve the light uniformity of the backlight panel as a whole. Moreover, since the body portion 151 of the trans-reflective dot 15 is surrounded by the plurality of antenna portions 152, even if the center-to-center distance between two adjacent light emitting devices 12 and the center-to-center distance between two adjacent trans-reflective dots 15 are small, the antenna portions 152 can avoid each other, so as to prevent the trans-reflective dots 15 from overlapping. The diameter of the trans-reflective dot 15 refers to the outer diameter of the overall structure formed by the body portion 151 and the plurality of antenna portions 152, as shown by d2 in FIG. 9 and P2 in FIG. 11. The center-to-center distance between two adjacent light emitting devices 12 refers to the distance between the centers of the light emitting surfaces of two adjacent light emitting devices 12, as shown by PI in FIG. 11.

[0088] In some embodiments, the width of the antenna portion 152 gradually decreases along the direction away from the center of the body portion 151, so as to more facilitate the mutual avoidance of the antenna portions 152 of two adjacent trans-reflective dots 15 when the distance between the two adjacent trans-reflective dots 15 is small. The direction away from the center of the body portion 151 refers to the direction in which the antenna portion 152 extends, for example, when the body portion 151 is circular, the direction of extension of the antenna portion 152 is the radial direction of the body portion 151; when the body portion 151 is of other shapes, the direction of extension of the antenna portion 152 is the direction of extension of the line connecting the geometric center of the antenna portion 152 and the geometric center of the body portion 151. The width of the antenna portion 152 refers to the dimension perpendicular to the direction of extension thereof.

[0089] In one example, the antenna portion 152 can be an axisymmetric figure, so as to improve the uniformity of the light distribution above and around the light emitting device 12. The axis of symmetry of the antenna portion 152 is the straight line on which the line connecting the geometric center of the antenna portion 152 and the geometric center of the body portion 151 lies.

[0090] In one example, as shown in FIG. 9, the main body 151 of the transmissive and reflective dot 15 is circular, and the tentacle 152 is approximately triangular, which includes a first edge and a second edge, a first end of the first edge and a first end of the second edge are directly connected to the main body 151, and a second end of the first edge and a second end of the second edge are directly connected. The outer diameter of the transmissive and reflective dot 15 is d2, the inner diameter (i.e., the diameter of the main body 151) is d1, the length of the tentacle 152 is d3, the corresponding central angle of the tentacle 152 (i.e., the included angle between the line connecting the first end of the first edge to the center of the main body 151 and the line connecting the second end of the second edge to the center of the main body 151) is A1, the corresponding central angle of the position where the edge of the main body 151 is not provided with the tentacle 152 is A2, the plurality of tentacles 152 are uniformly arranged, and the number n of the tentacles 152 is 360 / (A1+A2). For example, d1=3.5mm, d2=1.8mm, A1=16°, and A2=6.5°, and then the number n of the tentacles 152 is 360 / (16+6.5)=16. In this design scheme, the ratio of the area of the special-shaped transmissive and reflective dot 15 to the area of the circular transmissive and reflective dot 15 is about 48%, thereby effectively reducing the light efficiency loss of secondary reflection.

[0091] It should be noted that the shape of the transmissive and reflective dot 15 described above is only an example, and the shape of the main body 151, the shape, size and distribution mode of the tentacle 152, and the number of the tentacles 152 are not specifically limited in the embodiments of the present disclosure. In other embodiments, the tentacles 152 can be arranged at equal intervals or at unequal intervals, and the lengths of the tentacles 152 in the same transmissive and reflective dot 15 can be the same or different. As shown in FIG. 12, the transmissive and reflective dot 15 in some other embodiments of the present disclosure can have a shape of a trapezoid, and the lengths of the plurality of tentacles 152 are the same, as shown in FIG. 12(A); or the transmissive and reflective dot 15 can have a shape of a trapezoid, and the shapes of the plurality of tentacles 152 are different, for example, the lengths of the tentacles 152 are alternately arranged at equal intervals in the circumferential direction of the main body 151, as shown in FIG. 12(B).

[0092] It should be further noted that the first edge and the second edge of the tentacle 152 are straight lines in the above examples, and in other examples, the first edge and the second edge can be arc-shaped or polyline-shaped.

[0093] FIG. 13 is a schematic diagram of two arrangements of the transmissive and reflective dots 15 provided in the embodiments of the present disclosure. The arrangement of the transmissive and reflective dots 15 is consistent with the arrangement of the light emitting devices 12. For example, as shown in FIG. 13(A), the transmissive and reflective dots 15 are arranged in an array. For another example, as shown in FIG. 13(B), the transmissive and reflective dots 15 are arranged in multiple columns, and adjacent two columns of the transmissive and reflective dots 15 are staggered. For another example, the transmissive and reflective dots 15 are arranged in multiple rows, and adjacent two rows of the transmissive and reflective dots 15 are staggered.

[0094] In some embodiments, the backlight plate can further include a reflective layer (not shown) disposed on the surface of the substrate 11 facing the light emitting devices 12, and the protective layer 13 is located on the side of the reflective layer away from the substrate 11. The reflective layer has a plurality of avoiding holes, and the light emitting devices 12 are located in the avoiding holes. Through the arrangement of the reflective layer, the light reflected by the transmissive and reflective dots 15 can be more reflected to the light emitting side of the backlight plate, further improving the light emitting brightness of the backlight plate and reducing the power consumption.

[0095] FIG. 14 is a schematic diagram of the connection between the light emitting devices 12 and the bonding pads 14 provided in some embodiments of the present disclosure. As shown in FIG. 14, the electrodes of the light emitting devices 12 are electrically connected to the bonding pads 14 through the connection lines 16. Part of the connection lines 16 is located in the via holes penetrating through the substrate 11. This way of punching holes on the substrate 11 and arranging part of the connection lines 16 in the via holes is conducive to reducing the process difficulty. Of course, the connection lines 16 can also pass through the side surface of the substrate 11 through side surface wiring and be electrically connected to the light emitting devices 12 and the bonding pads 14.

[0096] The embodiments of the present disclosure also provide a manufacturing method of the above backlight plate. In combination with FIGS. 6 and 7, the manufacturing method of the backlight plate includes the following steps.

[0097] S1, providing a substrate 11.

[0098] In one example, the material of the substrate 11 can be glass-based, FR4-based or BT-based.

[0099] S2, forming a plurality of light emitting devices 12 and a plurality of bonding pads 14 on the substrate 11, the light emitting devices 12 being electrically connected to the bonding pads 14; and the light emitting devices 12 and the bonding pads 14 being respectively located on opposite sides of the substrate 11 along the thickness direction thereof.

[0100] In the above embodiment, the light emitting devices 12 can be Mini-LED devices, and the light emitting devices 12 are formed on the substrate 11 through a die bonding process.

[0101] S3, forming an initial glue layer 131 covering the plurality of light emitting devices 12, the initial glue layer 131 covering the orthographic projection of the plurality of bonding pads 14 on the substrate 11; the initial glue layer 131 includes an effective part covering the plurality of light emitting devices 12 and a redundant part surrounding the effective part. The redundant part is the process edge described above.

[0102] In one example, the initial glue layer 131 can be formed by a molding process to improve the surface flatness.

[0103] In one example, the material of the initial glue layer 131 includes a silica gel material, and anti-settling powder and diffusion powder. The mass percentage of the anti-settling powder in the initial glue layer 131 is 3%, and the mass percentage of the diffusion powder in the initial glue layer 131 is greater than or equal to 5%, so that the hardness of the initial glue layer 131 reaches 50D or more to prevent indentation when the flexible circuit board 20 is connected to the bonding pads 14 later.

[0104] S4, forming a plurality of transmissive and reflective dots 15 on the side of the initial glue layer 131 away from the substrate 11, wherein the orthographic projection of the light emitting surface of the light emitting device 12 on the substrate 11 is located within the orthographic projection range of the transmissive and reflective dots 15 on the substrate 11, and the transmissive and reflective dots 15 are used to reflect part of the light emitted by the light emitting device 12 and transmit another part of the light.

[0105] In one example, the transmissive and reflective dots 15 can be formed by a printing process to improve production efficiency and reduce costs. Specifically, the step of forming a plurality of transmissive and reflective dots 15 includes: providing a dot material; printing the dot material on the surface of the initial glue layer 131 away from the substrate 11 by a printing process to form a plurality of dot patterns; and curing the plurality of dot patterns to form a plurality of transmissive and reflective dots. For example, the transmissive and reflective dots 15 are formed by a silk screen printing process.

[0106] In order to prevent poor overflow caused by the printing process, the present disclosure adjusts the formula of the dot material to make the dot material have a large viscosity, which can effectively improve the size deviation problem of the transmissive and reflective dots 15 caused by overflow.

[0107] In one example, the dot material includes silica gel and anti-settling powder doped in the silica gel, and the mass percentage of the anti-settling powder in the dot material is between 8% and 8.5%, so that the viscosity of the dot material is between 25000 and 40000 mPas, effectively improving the viscosity of the silica gel to reduce or prevent overflow problems and achieve better printing effect. Compared with not doping anti-settling powder, when the viscosity of the material of the transmissive and reflective dots 15 reaches 25000-40000 mPas by doping anti-settling powder, the point diameter tolerance of the transmissive and reflective dots 15 can be improved from ±0.2mm to ±0.1mm.

[0108] S5, removing the redundant part of the initial glue layer 131 to form a protective glue layer 13 covering the plurality of light emitting devices 12. The protective glue layer 13 overlaps with the orthographic projection of the bonding pads 14 on the substrate 11. In some embodiments, the width of the redundant part is greater than or equal to 2.5 mm, so that a sufficient process margin can be reserved to improve the flatness of the protective glue layer 13.

[0109] In some embodiments, step S5 can specifically include cutting the initial glue layer 131 and the substrate 11 along the junction line between the redundant part and the effective part, so as to remove the redundant part.

[0110] In one example, the maximum height difference between positions on the surface of the protective glue layer 13 away from the substrate 11 is less than 30 microns.

[0111] It should be noted that the sequence of the steps is not necessarily completely in the above order. FIG. 15 is a schematic diagram of a backlight panel manufacturing process in one specific example of the present disclosure. In combination with FIGS. 6, 7 and 15, the backlight panel manufacturing process can include: S11, forming a plurality of bonding pads 14 and a plurality of light emitting devices 12 on a substrate 11; S12, forming a reflective layer on the substrate 11; S13, forming an initial glue layer 131 by molding or dispensing; S14, pre-curing the initial glue layer 131; S15, forming a transmissive and reflective dot 15 on the initial glue layer 131; S16, detecting the formation result of the transmissive and reflective dot 15 by using an automatic optical inspection (AOI) system; S17, final curing the initial glue layer 131; S18, cutting the initial glue layer 131 to remove the edge part thereof; S19, bonding a flexible circuit board 20 with the bonding pads 14; and S20, detecting the bonding result. The formation sequence of the plurality of bonding pads 14, the plurality of light emitting devices 12 and the reflective layer is not limited, which can be forming the plurality of bonding pads 14 and the plurality of light emitting devices 12 first, and then forming the reflective layer; or forming the reflective layer first, and then forming the plurality of bonding pads 14 and the plurality of light emitting devices 12; or of course, forming the reflective layer between the step of forming the bonding pads 14 and the step of forming the light emitting devices 12.

[0112] The backlight module provided by some embodiments of the present disclosure is shown in FIG. 16. As shown in FIG. 16, the backlight module includes the backlight plate in the above embodiments, and further includes an optical film 30 and a flexible circuit board 20 (not shown in FIG. 16), wherein the flexible circuit board 20 is electrically connected with the plurality of bonding pads 14. The optical film 30 is arranged on the light-emitting side of the backlight plate, i.e., on the side of the plurality of transmissive and reflective dots 15 away from the substrate 11. The number of the optical film 30 can be one or more. For example, the one or more optical films 30 can include a diffusion sheet for diffusing light to improve the light-emitting uniformity of the backlight module. For another example, the one or more optical films 30 can include a prism sheet to improve the light-emitting brightness of the backlight module.

[0113] The display device provided by some embodiments of the present disclosure includes the backlight module and a display panel arranged on the light-emitting side of the backlight module.

[0114] The display panel can be a liquid crystal display panel, which includes an array substrate and a color film substrate arranged oppositely, and a liquid crystal layer between the array substrate and the color film substrate. The color film substrate includes a color film layer, which includes a plurality of color filter portions in one example, each of which corresponds to a sub-pixel region of the display panel. In this case, the light-emitting device of the backlight plate is configured to emit white light. In another example, the color film layer can include a plurality of color conversion portions and a plurality of light-transmitting portions, each of which corresponds to a sub-pixel region, and the color conversion portions and the light-transmitting portions correspond to different sub-pixel regions. The color conversion portions are configured to convert the color of light, such as converting blue light into red light or green light. The material of the plurality of color conversion portions includes quantum dot material in this case. In this case, the light-emitting device of the backlight plate can emit blue light.

[0115] The display device can include any device or product having a display function. For example, the display device can be a smart phone, a mobile phone, an e-book reader, a desktop PC (personal computer), a laptop PC, a netbook PC, a PDA (personal digital assistant), a PMP (portable multimedia player), a digital audio player, a mobile medical device, a camera, a wearable device (such as a head-mounted device, electronic clothing, an electronic bracelet, an electronic necklace, electronic accessories, an electronic tattoo, or a smart watch), a television, etc.

[0116] It can be understood that the above embodiments are only exemplary embodiments adopted for illustrating the principles of the present disclosure, and the present disclosure is not limited thereto. Various modifications and improvements can be made by those of ordinary skill in the art without departing from the spirit and essence of the present disclosure, and these modifications and improvements are also considered to be within the protection scope of the present disclosure.

Claims

1. A backlight panel, comprising: substrate; Multiple light-emitting devices and multiple bonding pads for connecting flexible circuit boards are provided, wherein the light-emitting devices and the bonding pads are located on opposite sides of the substrate along its thickness direction, and the light-emitting devices are electrically connected to the bonding pads. A protective adhesive layer covers the plurality of light-emitting devices, and the protective adhesive layer overlaps with the orthographic projection of the bonding pads on the substrate. Multiple reflective dots are disposed on the side of the protective adhesive layer away from the substrate; Wherein, the orthographic projection of the light-emitting surface of the light-emitting device on the substrate is located within the orthographic projection range of the transflective dots on the substrate, and the transflective dots are used to reflect part of the light emitted by the light-emitting device and transmit the other part of the light.

2. The backlight panel according to claim 1, wherein, The translucent and reflective dotted pattern includes: a main body and multiple tentacle-like parts, wherein the multiple tentacle-like parts are arranged around the main body and connected to the main body; Wherein, the orthographic projection of the light-emitting surface of the light-emitting device onto the substrate is located within the orthographic projection range of the main body onto the substrate.

3. The backlight panel according to claim 2, wherein, The orthographic projection of the light-emitting surface of the light-emitting device onto the substrate covers the orthographic projection of the center of the main body onto the substrate.

4. The backlight panel according to claim 2, wherein, The plurality of tentacles are evenly arranged circumferentially along the main body; the width of the tentacles gradually decreases in the direction away from the main body.

5. The backlight panel according to claim 2, wherein, The diameter of the reflective dots is greater than the center-to-center distance between two adjacent light-emitting devices.

6. The backlight panel according to claim 2, wherein, The projected area of ​​the main body on the substrate is at least 10 times the area of ​​the light-emitting surface.

7. The backlight panel according to any one of claims 1 to 6, wherein, The maximum height difference between various locations on the surface of the protective adhesive layer away from the substrate is less than 50 micrometers.

8. The backlight panel according to any one of claims 1 to 6, wherein, The light-emitting device is electrically connected to the bonding pad via a connecting line, a portion of which is located in a via penetrating the substrate.

9. The backlight panel according to any one of claims 1 to 6, wherein, The protective adhesive layer coincides with the orthographic projection of the substrate onto a reference plane, which is a plane perpendicular to the thickness direction of the substrate.

10. The backlight panel according to any one of claims 1 to 6, wherein, The hardness of the protective adhesive layer is greater than 50D.

11. The backlight panel according to claim 10, wherein, The protective adhesive layer comprises: a transparent matrix and a diffusion powder doped within the transparent matrix, wherein the mass percentage of the diffusion powder in the protective adhesive layer is greater than or equal to 5%.

12. The backlight panel according to any one of claims 1 to 6, wherein, The material of the transflective dots includes silica gel and anti-precipitation powder doped in the silica gel, wherein the anti-precipitation powder accounts for 8% to 8.5% of the mass of the transflective dots.

13. The backlight panel according to any one of claims 1 to 6, wherein, The backlight panel also includes a reflective layer, which is disposed between the protective adhesive layer and the substrate. The reflective layer has multiple clearance holes, and the light-emitting device is located in the clearance holes.

14. A display device, wherein, The backlight module includes a backlight module and a display panel disposed on the light-emitting side of the backlight module. The backlight module includes: Backlight panel as described in any one of claims 1 to 13; A flexible circuit board electrically connected to the plurality of bonding pads.

15. The display device according to claim 14, wherein, The backlight module also includes an optical film disposed on the side of the plurality of reflective dots away from the substrate.

16. A method for manufacturing a backlight panel, wherein, include: A substrate is provided, the substrate having a first surface and a second surface disposed opposite to each other along its thickness direction; A plurality of light-emitting devices are formed on the first surface, and a plurality of bonding pads are formed on the second surface, wherein the light-emitting devices are electrically connected to the bonding pads; An initial adhesive layer is formed to cover the plurality of light-emitting devices, the initial adhesive layer comprising: an effective portion covering the plurality of light-emitting devices and a redundant portion surrounding the effective portion; Multiple reflective dots are formed on the side of the initial adhesive layer away from the substrate. The orthographic projection of the light-emitting surface of the light-emitting device on the substrate is located within the orthographic projection range of the reflective dots on the substrate. The reflective dots are used to reflect part of the light emitted by the light-emitting device and transmit the other part of the light. The redundant portion of the initial adhesive layer is removed to form a protective adhesive layer covering the plurality of light-emitting devices. The protective adhesive layer overlaps with the orthographic projection of the bonding pads on the substrate.

17. The manufacturing method according to claim 16, wherein, The step of removing the redundant portions of the initial adhesive layer includes: The initial adhesive layer and the substrate are cut along the boundary line between the redundant portion and the effective portion.

18. The manufacturing method according to claim 16, wherein, The width of the redundant portion is greater than or equal to 2.5 mm.

19. The manufacturing method according to claim 16, wherein, The step of forming a plurality of reflective dots on the side of the initial adhesive layer away from the substrate includes: Provides dot materials with viscosities between 25,000 and 40,000 mPas; The halftone material is printed onto the surface of the initial adhesive layer away from the substrate using a printing process to form multiple halftone patterns. The multiple halftone dots are solidified to form multiple reflective halftone dots.

20. The manufacturing method according to claim 19, wherein, The dot material includes silica gel and anti-precipitation powder doped in the silica gel, wherein the anti-precipitation powder accounts for 8% to 8.5% of the mass of the dot material.

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