Backlight assembly and manufacturing process thereof

Abstract

The invention discloses a backlight assembly and a manufacturing process thereof, which are used for solving the technical problem that in the existing backlight assembly, displacement can be generated between an optical film and a light guide plate as well as between the light guide plate and a reflector plate, so that the optical film or the reflector plate or the light guide plate is easily damaged, and the visual effect is further influenced. The backlight assembly comprises a light guide plate, an optical film layer fixed to the first surface of the light guide plate and a reflecting film layer fixed to the second surface of the light guide plate. Wherein the light guide plate, the optical film layer and the reflecting film layer are formed into an integrated structure through in-mold injection molding.

Description

Technical Field

[0001] This invention relates to the field of display device design technology, and in particular to a backlight component and its manufacturing process. Background Technology

[0002] Currently, the backlight assembly is one of the key components of LCD devices, providing a certain level of brightness. Existing backlight assemblies generally include optical films, light guide plates, and reflective sheets. When the backlight is illuminated, the light emitted by the light source is refracted through the light guide plate. Part of the light enters the optical films, while the other part is reflected by the reflective sheet before entering the optical films again. Finally, the light passes directly through the effective light-emitting surface of the LCD panel.

[0003] Because the optical film, light guide plate, and reflector in the backlight assembly are not effectively fixed together, displacement of the optical film, light guide plate, and reflector may occur during application, testing, or transportation. This can cause the surfaces of the reflector, light guide plate, and optical film to rub against other parts inside the LCD device (such as the frame, housing, and other hard objects), resulting in scratches. Consequently, light leakage and other defects may occur in the backlight assembly, ultimately severely affecting the visual effect and failing to provide users with a better experience.

[0004] Therefore, finding a technical solution that can solve the above-mentioned technical problems has become an important research topic for those skilled in the art. Summary of the Invention

[0005] This invention discloses a backlight assembly and its manufacturing process, which solves the technical problem that displacement occurs between the optical film and the light guide plate, and between the light guide plate and the reflective sheet in existing backlight assemblies, which can easily lead to damage to the optical film, reflective sheet or light guide plate, and thus affect the visual effect.

[0006] The present invention provides a backlight assembly, comprising a light guide plate, an optical film layer fixed to a first surface of the light guide plate, and a reflective film layer fixed to a second surface of the light guide plate;

[0007] The light guide plate, the optical film layer, and the reflective film layer are integrally formed by in-mold injection molding.

[0008] Optionally, the optical film layer includes a first protective layer, an optical film layer, and a first ink layer;

[0009] The optical film layer has the first ink layer fixed on the surface facing the light guide plate, and the optical film layer has the first protective layer fixed on the surface away from the light guide plate.

[0010] Optionally, the optical film layer has at least one optical film;

[0011] When the optical film layer has multiple optical films, the optical film layer also includes an adhesive layer, and adjacent optical films are bonded and fixed together by the adhesive layer.

[0012] Optionally, the reflective film layer includes a second ink layer, a reflective sheet, and a second protective layer;

[0013] The second ink layer is fixed to the surface of the reflective sheet facing the light guide plate, and the second protective layer is fixed to the surface of the reflective sheet away from the light guide plate.

[0014] Optionally, the light guide plate has a light-diffusing structure on its light-incoming side.

[0015] Optionally, the light-scattering structure is a continuous concave-convex structure formed on the light-incoming side of the light guide plate;

[0016] The continuous concave-convex structure includes a protruding portion protruding outward from the light-incoming side of the light guide plate and a recessed portion recessed inward from the light-incoming side of the light guide plate. The protruding portion and the recessed portion are arranged alternately in a straight line on the light-incoming side of the light guide plate.

[0017] Optionally, the light guide plate is provided with a support portion on the outer side other than the light-incoming side.

[0018] This invention provides a manufacturing process for a backlight assembly, the manufacturing process being used to manufacture the aforementioned backlight assembly, the manufacturing process comprising the following steps:

[0019] Fabrication of optical and reflective coatings;

[0020] The prepared optical film and reflective film are placed in the male mold and female mold of the injection mold, respectively.

[0021] The male mold and the female mold are closed together, and the injection molding material is injected into the space between the optical film layer and the reflective film layer through the material flow channel of the injection mold.

[0022] The injection mold is cooled to allow the injection molding material to cool and solidify into a light guide plate, and the optical film layer and the reflective film layer are combined into an integral structure through the light guide plate to form the aforementioned backlight assembly;

[0023] Open the injection mold and remove the completed backlight assembly.

[0024] Optionally, the steps of fabricating the optical film and the reflective film include the following steps:

[0025] Confirm the number of optical films in the optical film layer and cut the optical films according to the size requirements;

[0026] When there are multiple optical films, an adhesive is coated on the surface of one of the optical films to form an adhesive layer. Then, another optical film is pressed onto the adhesive layer to fix the two adjacent optical films. This process is repeated until all the optical films are composited and fixed to form the optical film layer.

[0027] A protective film is laminated onto one surface of the optical film layer to form a first protective layer, and ink is screen-printed on the other surface of the optical film layer to form a first ink layer, thereby producing the optical film layer.

[0028] Optionally, the steps of fabricating the optical film layer and the reflective film layer, specifically the steps of fabricating the reflective film layer, include:

[0029] Cut the reflective sheet according to the size requirements;

[0030] A protective film is laminated onto one surface of the reflective sheet to form a second protective layer, and ink is screen-printed on the other surface of the reflective sheet to form a second ink layer, thereby producing the reflective film layer.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] In the backlight assembly of the present invention, the light guide plate, the optical film layer, and the reflective film layer are integrally molded into a single structure through in-mold injection molding. The light guide plate, the reflective film layer, and the optical film layer are fixed and will not be displaced to each other. This effectively ensures that the optical film layer, the reflective film layer, and the light guide plate in the backlight assembly will not be scratched due to displacement, thus ensuring the optical performance stability of the backlight assembly and avoiding defects such as light leakage and white spots. This allows users to obtain a stable and good visual effect. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 A cross-sectional structural diagram of a backlight assembly provided by the present invention;

[0035] Figure 2 A cross-sectional view of a light guide plate in a backlight assembly provided by the present invention, wherein the light-incoming side has a light-diffusing structure;

[0036] Figure 3 A flowchart of the injection mold process in the manufacturing process of a backlight assembly provided by the present invention;

[0037] Figure 4 A schematic flowchart illustrating the manufacturing process of a backlight assembly provided by the present invention;

[0038] Illustration: Light guide plate 1; light diffusion structure 101; optical film layer 2; optical film 201; first ink layer 202; first protective layer 203; adhesive layer 204; reflective film layer 3; reflective sheet 301; second ink layer 302; second protective layer 303; male mold 4; female mold 5; adhesive flow channel 6. Detailed Implementation

[0039] This invention discloses a backlight assembly and its manufacturing process, which solves the technical problem that displacement occurs between the optical film and the light guide plate, and between the light guide plate and the reflective sheet in existing backlight assemblies, which can easily lead to damage to the optical film, reflective sheet or light guide plate, and thus affect the visual effect.

[0040] To enable those skilled in the art to better understand the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Please see Figures 1 to 2 An embodiment of the present invention provides a backlight assembly, including a light guide plate 1, an optical film layer 2 fixed to a first surface of the light guide plate 1, and a reflective film layer 3 fixed to a second surface of the light guide plate 1;

[0042] The light guide plate 1, the optical film layer 2, and the reflective film layer 3 are integrally formed by in-mold injection molding.

[0043] In this embodiment, the light guide plate 1, the optical film layer 2, and the reflective film layer 3 are integrally molded into a single structure through in-mold injection molding. The light guide plate 1, the reflective film layer 3, and the optical film layer 2 are fixed and will not shift relative to each other. This effectively ensures that the optical film layer 2, the reflective film layer 3, and the light guide plate 1 within the backlight assembly will not be scratched due to displacement, thus ensuring the optical performance stability of the backlight assembly and avoiding defects such as light leakage and white spots. This allows users to obtain a stable and good visual effect.

[0044] Furthermore, in this embodiment, the optical film layer 2 specifically includes a first protective layer 203, an optical film layer, and a first ink layer 202;

[0045] The optical film layer has the first ink layer 202 fixed on the surface facing the light guide plate 1, and the optical film layer has the first protective layer 203 fixed on the surface away from the light guide plate 1.

[0046] It should be noted that the aforementioned first protective layer 203 is specifically a protective film, which can be made of scratch-resistant PET (polyethylene terephthalate) film with good mechanical properties. The design of this first protective layer 203 forms a protective layer on the surface of the optical film layer, effectively preventing damage caused by friction between the optical film layer and other internal components of the liquid crystal display device. Furthermore, the design of the first protective layer 203 makes the entire optical film layer scratch-resistant, corrosion-resistant, extends its service life, provides dust and moisture protection, and enhances its resistance to deformation.

[0047] The first ink layer 202 described above can be specifically selected from functional inks containing diffusing agents or dark inks (such as black or gray) according to actual needs. When the backlight assembly exhibits localized darkness or insufficient uniformity of light brightness, functional inks containing diffusing agents can be screen-printed onto the optical film layer to cause multiple refractions and scattering of light, thereby achieving effects such as light source concealment, light uniformity, and glare elimination. When the backlight assembly exhibits high edge brightness, dark inks can be screen-printed on the sides of the optical film layer to reduce the light brightness at those locations, thereby reducing the brightness of the screen sides. Based on the above, this embodiment does not impose specific limitations on the first ink layer 202; designers can select appropriate types of inks as the first ink layer 202 according to actual conditions. Furthermore, the optical film layer in this embodiment has at least one optical film 201.

[0048] When there is only one optical film 201, the first ink layer 202 and the first protective layer 203 are respectively fixed on the opposite two side surfaces of the optical film 201;

[0049] When the optical film layer has multiple optical films 201, the optical film layer also includes an adhesive layer 204, and adjacent optical films 201 are bonded and fixed together by the adhesive layer 204.

[0050] It should be noted that when the optical film layer has multiple optical films 201, the above design can prevent relative displacement between two adjacent optical films 201, and can further avoid scratches caused by relative displacement of the optical films 201.

[0051] In addition, the optical film 201 mentioned above can be selected as a brightness enhancement film, a diffusion film, etc. Designers can select a brightness enhancement film, a diffusion film, or a combination of the two according to the actual situation. This embodiment does not limit this.

[0052] Furthermore, in this embodiment, the reflective film layer 3 specifically includes a second ink layer 302, a reflective sheet 301, and a second protective layer 303;

[0053] The second ink layer 302 is fixed on the surface of the reflective sheet 301 facing the light guide plate 1, and the second protective layer 303 is fixed on the surface of the reflective sheet 301 away from the light guide plate 1.

[0054] It should be noted that the aforementioned second protective layer 303 is specifically a protective film, which can be made of scratch-resistant PET (polyethylene terephthalate) film with good mechanical properties. This second protective layer 303 is designed to provide protection on the surface of the reflective sheet 301, effectively preventing damage caused by friction between the reflective sheet 301 and other internal components of the liquid crystal display device. Furthermore, the design of the second protective layer 303 makes the entire reflective film layer scratch-resistant, corrosion-resistant, extends its service life, provides dust and moisture protection, and enhances its resistance to deformation.

[0055] The second ink layer 302 is specifically formed by screen printing a highly reflective and non-light-absorbing ink onto the surface of the reflective sheet 301. The screen printing process mainly forms a second ink layer 302 of a preset shape on the surface of the reflective sheet 301. This shape can be circular or square diffusion dots (i.e., ink dots) arranged in a matrix on the reflective sheet 301. The size of the diffusion dots can be adaptively adjusted according to the uniformity of optical reflection, and this embodiment does not limit this.

[0056] Additionally, it should be noted that the second ink layer 302 primarily enhances the reflectivity of the reflective sheet 301, ensuring that the light refracted by the light guide plate 1 onto the reflective sheet 301 is completely reflected onto the optical film layer 2. When the backlight assembly exhibits locally high brightness, the shape of the ink dots at that location can be reduced, and the density of the ink dots can be decreased to reduce light reflection at that location, thereby lowering the brightness of the light at that location and improving the uniformity of light brightness.

[0057] Furthermore, in this embodiment, the light guide plate 1 has a light-diffusing structure 101 on its light-incoming side.

[0058] It should be noted that in liquid crystal display devices, the light source is generally located on the side of the light guide plate 1, and the side of the light guide plate 1 corresponding to the light source is called the light-inlet side. The aforementioned light-diffusing structure 101 can effectively disperse the light emitted by the light source, so that the light can be evenly dispersed and enter the light guide plate 1 from the light-inlet side.

[0059] Specifically, in one embodiment, the light-scattering structure 101 is a continuous concave-convex structure formed on the light-incoming side of the light guide plate 1.

[0060] The continuous concave-convex structure includes a protruding portion that protrudes outward from the light-incoming side of the light guide plate 1 and a recessed portion that is recessed into the light-incoming side of the light guide plate 1. The protruding portion and the recessed portion are arranged alternately in a straight line on the light-incoming side of the light guide plate 1.

[0061] It should be noted that the above-mentioned concave-convex structure is specifically similar to a sawtooth structure or a wave-like structure. The light emitted by the light source enters the protrusions and concave parts and undergoes multiple reflections and refractions, so that the light can be evenly dispersed and enter the light guide plate 1 from the light-inlet side.

[0062] Furthermore, in this embodiment, the light guide plate 1 has support portions on its outer surfaces other than the light-incoming side.

[0063] It should be noted that, through the above design, when the backlight assembly is installed inside the liquid crystal display device, the light guide plate 1 can abut against the housing or frame inside the liquid crystal display device through the above-mentioned support part, which can effectively increase the support area and increase the support stability of the light guide plate 1.

[0064] Specifically, the aforementioned support portion can be a support rib protruding outward from the light guide plate 1, etc. The specific shape of the aforementioned support portion needs to be designed according to the shape of the housing or frame and other parts inside the liquid crystal display device. This embodiment does not impose any restrictions on this.

[0065] Please see Figures 1 to 4 This invention provides a manufacturing process for a backlight assembly, the manufacturing process being used to manufacture the aforementioned backlight assembly, the manufacturing process comprising the following steps:

[0066] S1. Fabricate optical film layer 2 and reflective film layer 3;

[0067] S2. Place the prepared optical film layer 2 and reflective film layer 3 into the male mold 4 and female mold 5 of the injection mold, respectively.

[0068] S3. The male mold 4 and the female mold 5 are closed, and the injection molding material is injected into the space between the optical film layer 2 and the reflective film layer 3 through the material flow channel 6 of the injection mold.

[0069] S4. Cool the injection mold to cool and form the injection molding material into a light guide plate 1, and combine the optical film layer 2 and the reflective film layer 3 into an integral structure through the light guide plate 1 to form the above-mentioned backlight assembly.

[0070] S5. Open the injection mold and take out the completed backlight assembly.

[0071] It should be noted that the above-mentioned injection mold is specifically an IML injection mold. During the operation of a mature IML injection mold with correct parameter settings, the optical film layer 2 and the reflective film layer 3 will not be burned, curled, warped or deformed due to the high temperature of the molten rubber.

[0072] The reason is that the time the injection molding compound, in its molten state at high temperature, comes into contact with the optical film layer 2 and the reflective film layer 3 is very short. In such a short time, the heat doesn't have enough time to be conducted into the interior of the optical film layer 2 and the reflective film layer 3, causing their overall temperature to rise to the deformation point. The cooling system of the IML injection mold already begins to function. The IML injection mold has an internal cooling water system. During injection, the temperature of the IML injection mold is controlled at 60-80℃. When the high-temperature injection molding compound enters the injection mold, the mold is rapidly cooled by the cooling water system. When the high-temperature injection molding compound comes into contact with the surface of the injection mold and the aforementioned optical film layer 2 and reflective film layer 3, the mold absorbs a large amount of heat instantly, like a "cold iron," causing the molten injection molding compound at the contact surface to cool rapidly and form a thin shell (freezing layer). This thin shell protects the relevant films inside the optical film layer 2 and the reflective film layer 3 from continuous thermal shock.

[0073] In the backlight assembly manufacturing process of this embodiment, the light guide plate 1, the optical film layer 2, and the reflective film layer 3 are integrally molded into a single structure through in-mold injection molding. The light guide plate 1, the reflective film layer 3, and the optical film layer 2 are fixed and will not shift relative to each other. This effectively ensures that the optical film layer 2, the reflective film layer 3, and the light guide plate 1 within the backlight assembly will not be scratched due to displacement, thus ensuring the optical performance stability of the backlight assembly and avoiding defects such as light leakage and white spots. This allows users to obtain a stable and good visual effect.

[0074] Furthermore, in the above manufacturing process, the specific shape of the light guide plate 1 can be determined according to the shape of the injection mold. For example, by designing an injection mold with a curved cavity, the light guide plate 1 can automatically form a curved structure after injection molding.

[0075] Compared to the traditional design method, which requires the light guide plate 1 to be bent before assembly, the above manufacturing process can directly form the bent light guide plate 1 before installation. This can effectively eliminate the bending rebound force of the light guide plate 1, minimize the stress in the backlight assembly, effectively improve the visual effect, and enhance the uniformity of the display image.

[0076] Furthermore, the step of opening the injection mold and removing the completed backlight assembly in this embodiment specifically includes:

[0077] Products can be directly gripped from injection molds using a multi-axis robotic arm (equipped with a vacuum suction cup or pneumatic gripper);

[0078] Alternatively, a vacuum adsorption hole can be designed in the cavity of the injection mold. A negative pressure is generated by an external vacuum pump, and the product is adsorbed onto the male mold 4 or female mold 5 when the injection mold is opened. The backlight component can then be removed by a robotic arm or manually.

[0079] In addition, after removing the backlight assembly from the injection mold, the sprue on the light guide plate 1 in the backlight assembly needs to be removed, for example by cutting it off using CNC machining.

[0080] Furthermore, in the steps of fabricating the optical film layer 2 and the reflective film layer 3 in this embodiment, fabricating the optical film layer 2 specifically includes the following steps:

[0081] Confirm the number of optical films 201 in the optical film layer 2, and cut the optical films 201 according to the size requirements;

[0082] When there are multiple optical films 201, an adhesive is coated on the surface of one of the optical films 201 to form an adhesive layer 204. Then, another optical film 201 is pressed onto the adhesive layer 204 to fix the two adjacent optical films 201. This process is repeated until all the optical films 201 are composited and fixed to form the optical film layer.

[0083] A protective film is laminated onto one surface of the optical film layer to form a first protective layer 203, and ink is screen-printed on the other surface of the optical film layer to form a first ink layer 202, thereby producing the optical film layer 2.

[0084] It should be noted that in the above specific steps, OCA adhesive (optical adhesive) can be used to ensure that the optical performance is not affected;

[0085] In addition, in the above specific steps, two adjacent optical films 201 are pressed and fixed by the pressure roller through the adhesive layer 204. After the pressing and fixing is completed, the air between the two is removed by vacuuming to avoid the formation of air bubbles in the subsequent optical film layer 2, which would affect the optical performance.

[0086] Furthermore, in the steps of fabricating the optical film layer 2 and the reflective film layer 3 in this embodiment, the fabrication of the reflective film layer 3 specifically includes the following steps:

[0087] The reflective sheet 301 is cut according to the size requirements;

[0088] A protective film is attached to one surface of the reflective sheet 301 to form a second protective layer 303, and ink is screen-printed on the other surface of the reflective sheet 301 to form a second ink layer 302, thereby producing the reflective film layer 3.

[0089] The foregoing has provided a detailed description of a backlight assembly and its manufacturing process provided by the present invention. For those skilled in the art, based on the ideas of the embodiments of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A backlight assembly, characterized in that, It includes a light guide plate (1), an optical film layer (2) fixed to a first surface of the light guide plate (1), and a reflective film layer (3) fixed to a second surface of the light guide plate (1). The light guide plate (1), the optical film layer (2) and the reflective film layer (3) are integrally formed by in-mold injection molding.

2. The backlight assembly according to claim 1, characterized in that, The optical film layer (2) includes a first protective layer (203), an optical film layer, and a first ink layer (202); The optical film layer has the first ink layer (202) fixed on the surface facing the light guide plate (1), and the optical film layer has the first protective layer (203) fixed on the surface away from the light guide plate (1).

3. The backlight assembly according to claim 2, characterized in that, The optical film layer has at least one optical film (201). When the optical film layer has multiple optical films (201), the optical film layer also includes an adhesive layer (204), and two adjacent optical films (201) are bonded and fixed together by the adhesive layer (204).

4. The backlight assembly according to claim 1, characterized in that, The reflective film layer (3) includes a second ink layer (302), a reflective sheet (301), and a second protective layer (303). The second ink layer (302) is fixed on the surface of the reflective sheet (301) facing the light guide plate (1), and the second protective layer (303) is fixed on the surface of the reflective sheet (301) away from the light guide plate (1).

5. The backlight assembly according to claim 1, characterized in that, The light guide plate (1) has a light-diffusing structure (101) on its light-incoming side.

6. The backlight assembly according to claim 5, characterized in that, The light-scattering structure (101) is a continuous concave-convex structure formed on the light-incoming side of the light guide plate (1); The continuous concave-convex structure includes a protruding part that protrudes outward from the light-inlet side of the light guide plate (1) and a recessed part that is recessed into the light-inlet side of the light guide plate (1). The protruding part and the recessed part are arranged alternately in a straight line on the light-inlet side of the light guide plate (1).

7. The backlight assembly according to claim 1, characterized in that, The light guide plate (1) has a support portion on its outer surface, except for the light-incoming side.

8. A manufacturing process for a backlight component, characterized in that, The manufacturing process is used to manufacture the backlight assembly as described in any one of claims 1 to 7, and the manufacturing process includes the following steps: Fabricate optical film (2) and reflective film (3); The prepared optical film layer (2) and reflective film layer (3) are placed in the male mold (4) and female mold (5) of the injection mold, respectively. The male mold (4) and the female mold (5) are closed together, and the injection molding material is injected into the space between the optical film layer (2) and the reflective film layer (3) through the material flow channel (6) of the injection mold. The injection mold is cooled to cool and form the injection molding material into a light guide plate (1), and the optical film layer (2) and the reflective film layer (3) are combined into an integral structure through the light guide plate (1) to form the backlight assembly according to any one of claims 1 to 7; Open the injection mold and remove the completed backlight assembly.

9. The manufacturing process of the backlight assembly according to claim 8, characterized in that, The steps of fabricating the optical film layer (2) and the reflective film layer (3) include the following steps: Confirm the number of optical films (201) in the optical film layer of the optical film layer (2), and cut the optical films (201) according to the size requirements; When there are multiple optical films (201), an adhesive is coated on the surface of one of the optical films (201) to form an adhesive layer (204), and then another optical film (201) is pressed onto the adhesive layer (204) to fix the two adjacent optical films (201). This process is repeated until all the optical films (201) are composited and fixed to form the optical film layer. A protective film is attached to one surface of the optical film layer to form a first protective layer (203), and ink is screen-printed on the other surface of the optical film layer to form a first ink layer (202), thereby producing the optical film layer (2).

10. The manufacturing process of the backlight assembly according to claim 8, characterized in that, The steps of fabricating the optical film layer (2) and the reflective film layer (3) include the following steps: The reflective sheet (301) is cut according to the size requirements; A protective film is attached to one surface of the reflective sheet (301) to form a second protective layer (303), and ink is screen-printed on the other surface of the reflective sheet (301) to form a second ink layer (302), thereby producing the reflective film layer (3).

Images