Light guide plate mold structure for improving flow channel

Abstract

The application relates to the technical field of light guide plates, in particular to a light guide plate mold structure capable of improving a flow channel, which is characterized in that an irregular curved structure is adopted for a turnover flow channel, the irregular curved structure can change the flowing direction of a melt, the melt is subjected to more disturbance in the flowing process, the velocity gradient of the melt flowing is broken, stress concentration caused by flow rate difference is reduced, meanwhile, the inlet end of the turnover flow channel is wide, the sectional area of the melt flowing is increased, according to the fluid dynamics principle, under the condition that the flow rate is constant, the sectional area increase leads to flow rate reduction, the setting slows down the speed of the melt entering the turnover end and the outlet end, thereby reducing the shear stress generated by the melt when flowing at high speed, not only the possibility of the bending deformation of the light guide plate edge caused by excessive stress is reduced, but also the generation of cracks of the light guide plate caused by excessive stress is reduced, and the forming quality and production efficiency of the light guide plate are improved.

Description

Technical Field

[0001] This application relates to the field of light guide plate technology, and in particular to a light guide plate mold structure for improving flow channels. Background Technology

[0002] In the field of light guide plate manufacturing, mold forming technology is the core link in producing high-quality light guide plates. As an optical component of liquid crystal display devices, the light guide plate can convert the line light source and point light source emitted by LED or cold cathode lamp tube into a uniform surface light source, providing the display screen with background lighting with uniform brightness and extremely low color difference.

[0003] In related technologies, traditional light guide plate injection molding mold structures perform reasonably well when handling small-sized light guide plates and can meet basic production needs. Traditional light guide plate injection molds mostly adopt a single main runner combined with a linear branch runner design. After the melt is injected from the center gate, it diffuses to both sides along the radial straight runner. It is pushed to both sides of the cavity through the straight cylindrical main runner and the symmetrically distributed straight branch runners to achieve melt filling. The melt flow is controlled by adjusting the injection pressure and holding time. After cooling and solidification, it is injection molded.

[0004] However, in the production of small-sized light guide plates, existing technologies can ensure product stability and consistency, and there are generally no obvious internal stress problems. When facing the production of large-sized light guide plates, due to the low flow resistance in the central area, the melt preferentially fills the center of the cavity at high speed under the injection pressure, resulting in a significantly higher flow velocity in the center than on the sides. This can easily lead to greater stress or S-shaped bending of the light guide plate after demolding. Specifically, the presence of internal stress may also lead to a decrease in the optical performance of the light guide plate, such as uneven light distribution and reduced brightness. At the same time, the mechanical strength will also be affected, making it prone to cracking or damage. Utility Model Content

[0005] To address the aforementioned issues, this application provides a light guide plate mold structure that improves the flow channel.

[0006] The light guide plate mold structure for improving the flow channel provided in this application adopts the following technical solution:

[0007] A light guide plate mold structure for improving flow channels includes a front mold and a rear mold. The front mold includes a front mold flow channel block and a front mold core, and the rear mold includes a rear mold flow channel block and a rear mold core. The front mold flow channel block is fixedly connected to the front mold core, and the rear mold flow channel block is fixedly connected to the rear mold core. When the front mold core and the rear mold core are closed, the surfaces of the front mold core and the rear mold core abut against each other. The front mold flow channel block and the rear mold flow channel block are provided with opposing gaps to form a melt flow cavity. The melt flow cavity includes a flipping flow channel. The flipping flow channel has an irregular curved structure. The flipping flow channel is divided into an inlet end, a flipping end, and an outlet end along the melt flow direction. The inlet end and the outlet end are distributed on both sides of the flipping end. The inlet end, the flipping end, and the outlet end are connected. The flow channel width at the inlet end is greater than the flow channel width at the outlet end.

[0008] By adopting the above technical solution, the irregular curved structure of the flipping channel can change the flow direction of the melt, causing more disturbance to the melt during the flow process. This disturbance helps to break the velocity gradient in the melt, reduce stress concentration caused by velocity differences, and the wider channel at the inlet end increases the cross-sectional area of ​​the melt flow. According to the principle of fluid dynamics, with a constant flow rate, an increase in cross-sectional area will correspondingly reduce the flow velocity. Therefore, the flow velocity of the melt will be relatively low when entering the inlet end, which helps to slow down the speed of the melt entering the flipping end and the outlet end. A higher flow velocity may cause the melt to generate greater shear stress during the flow process. A lower flow velocity reduces the shear stress of the melt during the flow process, reduces the occurrence of bending deformation at the edge of the light guide plate, and reduces the probability of cracks in the light guide plate, thereby improving the forming quality of the light guide plate and increasing production efficiency.

[0009] Preferably, the front mold runner block is provided with a front mold runner insert, the rear mold runner block is provided with a rear mold runner insert, the front mold runner block is fixedly connected to the front mold runner insert, the rear mold runner is fixedly connected to the rear mold runner insert, and when the front mold core and the rear mold core are closed, the opposing gap between the front mold runner insert and the rear mold runner insert forms the flip-over runner.

[0010] By adopting the above technical solution, the tumbling flow is formed by the opposing gap between the front mold runner insert and the rear mold runner insert. This can guide the melt to flow along a predetermined path. When the melt flows through the tumbling area, the flow direction of the melt can be changed, causing the melt to be subjected to more disturbances during the flow process. This disturbance helps to break the velocity gradient in the melt and reduce stress concentration caused by the difference in flow velocity.

[0011] Preferably, both the front mold runner insert and the rear mold runner insert are provided with a plurality of trapezoidal protrusions, and the rear mold runner insert is also provided with a plurality of first grooves. When the front mold runner insert and the rear mold runner insert are arranged opposite to each other, the plurality of first grooves and the plurality of trapezoidal protrusions are fitted together with a gap to form the flipping runner.

[0012] By adopting the above technical solution, the trapezoidal protrusion edge of the front mold runner insert and the irregular curved structure of the first groove edge are gap-fitted to form a flipping runner with an irregular curved structure. During the process of melt flow flipping the runner, the irregular curved structure breaks the velocity gradient distribution in the melt, so that the shear stress originally caused by the flow velocity difference tends to be uniform, thereby reducing the stress concentration phenomenon caused by the flow velocity difference.

[0013] Preferably, the melt flow cavity is further provided with an inlet flow channel and an outlet flow channel, both of which are connected to the inverting flow channel. The inlet flow channel and the outlet flow channel are formed by the front mold flow channel block and the rear mold flow channel block facing each other.

[0014] By adopting the above technical solution, the inlet flow channel and the outlet flow channel are connected to the reversing flow channel. The inlet flow channel is responsible for guiding the melt into the reversing flow channel, while the outlet flow channel guides the melt to flow out of the reversing flow channel, thus realizing the stable flow of the melt in the mold.

[0015] Preferably, the rear mold runner block is provided with a first recess, and the rear mold runner insert is provided with a second recess. The depths of the first recess and the second recess match. When the front mold core and the rear mold core are closed, the front mold core and the rear mold core abut against each other. The first recess is in clearance fit with the surface of the front mold runner block, and the second recess is in clearance fit with the surface of the front mold runner insert.

[0016] By adopting the above technical solution, the second recess and the surface clearance of the front mold runner insert form an irregularly curved overturning runner, while the first recess and the front mold runner block form an inlet runner and an outlet runner.

[0017] Preferably, both the front mold core and the rear mold core are provided with a second groove, which is located on both sides of the melt flow cavity. When the front mold core and the rear mold core are closed, the second groove of the front mold core and the rear mold core form a cavity, which is connected to the melt flow cavity.

[0018] By adopting the above technical solution, the mold cavity and the melt flow cavity are directly connected, thereby realizing that the melt flows from the melt flow cavity into the mold cavity and forms a light guide plate after cooling and solidification.

[0019] Preferably, a gate is provided on the side of the front mold core away from the moving mold core, the gate passes through the front mold core, and the front mold core is connected to the melt flow cavity.

[0020] By adopting the above technical solution, the gate guides the melt to flow smoothly from the gate into the melt flow cavity, ensuring that the melt can be uniformly filled during the molding process.

[0021] Preferably, the rear mold core is provided with a plurality of ejector pin holes, the ejector pin holes penetrating the rear mold core.

[0022] By adopting the above technical solution, the ejector pin hole provides a guide for the ejector pin, so that after the light guide plate is injection molded, the ejector pin can smoothly and steadily eject the light guide plate from the rear mold core, reducing the deformation or damage of the light guide plate and ensuring the integrity and quality of the light guide plate.

[0023] In summary, this application includes at least one of the following beneficial technical effects:

[0024] 1. A melt flow cavity is formed by the opposing gap between the flow channel blocks of the front mold and the rear mold. The flipping flow channel adopts an irregular curved structure and is divided into an inlet end, a flipping end and an outlet end along the flow direction. The width of the flow channel at the inlet end is greater than that at the outlet end. The irregular curved structure forces the melt to continuously change direction during flow, generating dynamic disturbance to break the velocity gradient of the melt and reduce the shear stress caused by the difference in flow velocity. The wider flow channel cross section at the inlet end reduces the inlet flow velocity according to the principle of fluid dynamics, so that the melt enters the flipping end and the outlet end in a more stable state, reducing the stress concentration caused by high-speed flow, reducing the risk of bending deformation and crack tendency of the light guide plate edge caused by stress concentration, improving the molding quality of the light guide plate and increasing production efficiency.

[0025] 2. An irregularly curved overturning flow channel is formed by the gap fit between the edge of the trapezoidal protrusion and the edge of the first groove. The irregular curved structure is used to disturb and break the melt velocity gradient and homogenize the shear stress and pressure distribution, thereby significantly reducing stress concentration caused by flow velocity differences.

[0026] 3. The inlet and outlet flow channels formed by the opposing gap between the front mold flow channel block and the rear mold flow channel block are connected to the flip flow channel to achieve a stable flow path for melt introduction and export, ensuring that the melt is evenly distributed in the mold and efficiently fills the melt flow cavity. Attached Figure Description

[0027] Figure 1 This is a cross-sectional view of an embodiment of this application.

[0028] Figure 2 This is a structural schematic diagram of an embodiment of this application.

[0029] Figure 3This is a schematic diagram of the front mold core structure according to an embodiment of this application.

[0030] Figure 4 This is a schematic diagram of the rear mold core structure according to an embodiment of this application.

[0031] Explanation of reference numerals in the attached drawings: 1. Front mold; 11. Front mold core; 111. Gate; 12. Front mold runner block; 13. Front mold runner insert; 2. Rear mold; 21. Rear mold core; 211. Ejector pin hole; 22. Rear mold runner block; 221. First recess; 23. Rear mold runner insert; 231. Second recess; 3. Melt flow cavity; 31. Tilting runner; 311. Inlet end; 312. Tilting end; 313. Outlet end; 32. Inlet runner; 33. Outlet runner; 4. Trapezoidal protrusion; 5. First groove; 6. Second groove; 7. Cavity; Detailed Implementation

[0032] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0033] This application discloses a light guide plate mold structure for improving flow channels. (Refer to...) Figure 1 A light guide plate mold structure for improving flow channels includes a front mold 1 and a rear mold 2. The front mold 1 includes a front mold flow channel block 12 and a front mold core 11. The rear mold 2 includes a rear mold flow channel block 22 and a rear mold core 21. The front mold flow channel block 12 is fixedly connected to the front mold core 11, and the rear mold flow channel block 22 is fixedly connected to the rear mold core 21. When the front mold core 11 and the rear mold core 21 are closed, their opposing surfaces abut against each other. The front mold flow channel block 12 and the rear mold flow channel block 22 are provided with an opposing gap to form a melt flow cavity 3. The melt flow cavity 3 includes a flipping flow channel 31, which has an irregular curved structure.

[0034] This shows that the inverted flow channel 31 has an irregular curved structure, which can change the flow direction of the melt and make the melt more disturbed during the flow process. This disturbance helps to break the velocity gradient in the melt and reduce stress concentration caused by the difference in flow velocity.

[0035] Reference Figure 2 Specifically, the front mold runner block 12 is provided with a front mold runner insert 13, and the rear mold runner block 22 is provided with a rear mold runner insert 23. The front mold runner insert 13 is fixedly connected to the front mold runner block 12, and the rear mold runner insert 23 is fixedly connected to the rear mold runner block 22. When the front mold core 11 and the rear mold core 21 are closed, the front mold runner block 12 and the rear mold runner block 22 are driven to close and form a counter-clearance fit, which further drives the front mold runner insert 13 and the rear mold runner insert 23 to close and form a counter-clearance fit. The flip runner 31 is formed by the counter-clearance setting of the front mold runner insert 13 and the rear mold runner insert 23.

[0036] Reference Figure 3 and Figure 4 Furthermore, in this embodiment, there are two front mold runner inserts 13 and two rear mold runner inserts 23, which are evenly distributed on the front mold runner block 12 and the rear mold runner block 22. Both the front mold runner inserts 13 and the rear mold runner inserts 23 are provided with a number of trapezoidal protrusions 4, and the rear mold runner inserts 23 are also provided with a number of first grooves 5.

[0037] Specifically, both front mold runner inserts 13 are provided with a trapezoidal protrusion 4. The trapezoidal protrusion 4 of one front mold runner insert 13 is larger than the trapezoidal protrusion 4 of the other. The front mold runner insert 13 with the smaller trapezoidal protrusion 4 is provided with a trapezoidal protrusion 4 and a first groove 5 in the corresponding clearance fit with the rear mold runner insert 23. The front mold runner insert 13 with the larger trapezoidal protrusion 4 is provided with a first groove 5 in the corresponding clearance fit with the front mold runner insert 13.

[0038] Meanwhile, the rear mold runner block 22 is provided with a first recess 221, and the rear mold runner insert 23 is provided with a second recess 231. The depths of the first recess 221 and the second recess 231 are matched. Both the rear mold runner insert 23 and the rear mold runner block 22 have a structure that is low in the middle and high on both sides. The rear mold runner insert 23 is provided with a trapezoidal protrusion 4 and a first groove 5. The trapezoidal protrusion 4 is vertically fixed on the second recess 231, and the first groove 5 is located on both sides of the second recess 231. The front mold runner insert 13 is provided with a first groove 5, and the first groove 5 is also located on both sides of the second recess 231.

[0039] This explains that when the front mold core 11 and the rear mold core 21 are closed, their opposing surfaces abut against each other. Since there are two front mold runner inserts 13 and two rear mold runner inserts 23, two flip runners 31 are formed. At the same time, the first recess 221 is in clearance fit with the surface of the front mold runner block 12, and the second recess 231 is in clearance fit with the surface of the front mold runner insert 13. The second recess 231 and the surface of the front mold runner insert 13 form the flip runners 31.

[0040] To further explain, the irregularly curved structure of the edge of the trapezoidal protrusion 4 and the edge of the first groove 5 are fitted with a gap to form a flipping channel 31 with an irregularly curved structure. During the process of the melt flowing and flipping channel 31, the irregularly curved structure breaks the velocity gradient distribution in the melt, making the shear stress and pressure distribution caused by the flow velocity difference tend to be uniform, thereby significantly reducing the stress concentration phenomenon caused by the flow velocity difference.

[0041] Meanwhile, the inverting flow channel 31 is divided into an inlet end 311, an inverting end 312 and an outlet end 313 in sequence along the melt flow direction. The inlet end 311 and the outlet end 313 are distributed on both sides of the inverting end 312. The inlet end 311, the inverting end 312 and the outlet end 313 are connected. The flow channel width of the inlet end 311 is greater than the flow channel width of the outlet end 313.

[0042] Furthermore, the second recess 231 of the rear mold runner insert 23, which has a trapezoidal protrusion 4 and a first groove 5, is fitted with the surface of the front mold runner insert 13 to form a flipping runner 31 with two flipping ends 312. The second recess 231 of the front mold runner insert 13, which has a first groove 5, is fitted with the surface of the front mold runner insert 13 to form a flipping runner 31 with one flipping end 312.

[0043] This demonstrates that the wider flow channel at the inlet end 311 increases the cross-sectional area of ​​the melt flow. According to the principles of fluid dynamics, with a constant flow rate, an increase in cross-sectional area will correspondingly reduce the flow velocity. Therefore, when the melt enters the inlet end 311, the flow velocity will be relatively low, which helps to slow down the speed at which the melt enters the turning end 312 and the outlet end 313. A higher flow velocity may cause the melt to generate greater shear stress during the flow process. A lower flow velocity reduces the shear stress of the melt during the flow process, reduces the occurrence of bending deformation at the edge of the light guide plate, and reduces the probability of cracks in the light guide plate, thereby improving the forming quality of the light guide plate and increasing production efficiency.

[0044] In addition, the melt flow chamber 3 is also provided with an inlet flow channel 32 and an outlet flow channel 33. The inlet flow channel 32 and the outlet flow channel 33 are connected to the inverting flow channel 31. The inlet flow channel 32 and the outlet flow channel 33 are formed by the surface clearance fit between the first recess 221 and the front mold flow channel block 12. The inlet flow channel 32 and the outlet flow channel 33 are connected to the inverting flow channel 31. The inlet flow channel 32 is responsible for guiding the melt into the inverting flow channel 31, while the outlet flow channel 33 guides the melt to flow out from the inverting flow channel 31, thus realizing the stable flow of the melt in the mold.

[0045] Both the front mold core 11 and the rear mold core 21 are provided with a second groove 6. The second groove 6 is located on both sides of the melt flow cavity 3. When the front mold core 11 and the rear mold core 21 are closed, the second groove 6 of the front mold core 11 and the rear mold core 21 form a cavity 7. The cavity 7 is connected to the melt flow cavity 3, so that the melt flows from the melt flow cavity 3 into the cavity 7 and forms a light guide plate after cooling and solidification.

[0046] Furthermore, a gate 111 is provided on the side of the front mold core 11 away from the moving mold core. The gate 111 passes through the front mold core 11 and connects the melt flow cavity 3 and the mold cavity 7. The gate 111 can guide the melt to flow smoothly from the gate 111 into the melt flow cavity and the mold cavity 7, ensuring that the melt can be evenly filled during the molding process.

[0047] On the other hand, the rear mold core 21 is provided with several ejector pin holes 211. The ejector pin holes 211 penetrate the rear mold core 21 and provide guidance for the ejector pins. This allows the ejector pins to smoothly and steadily eject the light guide plate from the rear mold core 21 after injection molding, reducing deformation or damage to the light guide plate and ensuring the integrity and quality of the light guide plate.

[0048] The implementation principle of the light guide plate mold structure for improving the flow channel in this application embodiment is as follows:

[0049] When the front mold and the rear mold are closed, the front mold core and the rear mold core partially abut each other, and the front mold runner insert and the rear mold runner insert partially abut each other. The front mold runner insert and the rear mold runner insert form two independent flipping runners through clearance fit. The irregular curved structure of the flipping runner is formed by the clearance fit between the trapezoidal protrusions and the edge of the first groove of the front mold runner insert and the rear mold runner insert.

[0050] The melt is injected into the melt flow chamber through the gate, and then enters the tumbling flow channel through the inlet channel. In the tumbling flow channel, the irregular bending structure of the tumbling flow channel forces the melt to change direction multiple times, disturbing the fluid and homogenizing the velocity gradient, thus reducing the shear stress concentration caused by the difference in flow velocity.

[0051] During the flow of the melt, the wider inlet end of the tumbling channel helps to slow down the speed at which the melt enters the tumbling end and exits. Higher flow rates may cause the melt to generate greater shear stress during the flow process, while lower flow rates reduce the shear stress of the melt during the flow process, reduce the occurrence of bending deformation at the edge of the light guide plate, and reduce the probability of cracks in the light guide plate, thereby improving the forming quality of the light guide plate and increasing production efficiency.

[0052] The melt flows out of the outlet channel and into the cavity through the inverting channel, completing the uniform filling of the cavity. The outlet channel and the inverting channel are connected to ensure the flow stability of the melt.

[0053] After filling is completed, the mold enters the pressure holding stage to maintain pressure to compensate for the cooling and shrinkage of the melt. After the mold opens, the ejector pin slides in a straight line along the ejector pin hole and contacts the edge of the light guide plate. The force of the ejector pin is evenly transmitted to the surface of the light guide plate, reducing local stress concentration on the light guide plate and reducing deformation or cracks during demolding.

[0054] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A light guide plate mold structure for improving flow channels, characterized in that, The mold includes a front mold (1) and a rear mold (2). The front mold (1) includes a front mold runner block (12) and a front mold core (11). The rear mold (2) includes a rear mold runner block (22) and a rear mold core (21). The front mold runner block (12) is fixedly connected to the front mold core (11), and the rear mold runner block (22) is fixedly connected to the rear mold core (21). When the front mold core (11) and the rear mold core (21) are closed, the front mold core (11) and the rear mold core (21) partially abut against each other. The front mold runner block (12) and the rear mold runner block (22) are provided with opposing gaps to form a melt flow. The moving cavity (3) includes a reversing flow channel (31), which is an irregularly curved structure. The reversing flow channel (31) is divided into an inlet end (311), a reversing end (312), and an outlet end (313) along the melt flow direction. The inlet end (311) and the outlet end (313) are distributed on both sides of the reversing end (312). The inlet end (311), the reversing end (312), and the outlet end (313) are connected. The width of the flow channel at the inlet end (311) is greater than the width of the flow channel at the outlet end (313).

2. The light guide plate mold structure for improving flow channels according to claim 1, characterized in that, The front mold runner block (12) is provided with a front mold runner insert (13), and the rear mold runner block (22) is provided with a rear mold runner insert (23). The front mold runner block (12) and the front mold runner insert (13) are fixedly connected. The runner of the rear mold (2) is fixedly connected with the rear mold runner insert (23). When the front mold core (11) and the rear mold core (21) are closed, the front mold runner insert (13) and the rear mold runner insert (23) are provided with a gap to form the flip runner (31).

3. The light guide plate mold structure for improving flow channels according to claim 2, characterized in that, Both the front mold runner insert (13) and the rear mold runner insert (23) are provided with a number of trapezoidal protrusions (4). The rear mold runner insert (23) is also provided with a number of first grooves (5). When the front mold runner insert (13) and the rear mold runner insert (23) are arranged opposite each other, the number of first grooves (5) and the number of trapezoidal protrusions (4) are fitted together to form the flipping runner (31).

4. The light guide plate mold structure for improving flow channels according to claim 1, characterized in that, The melt flow cavity (3) further includes an inlet flow channel (32) and an outlet flow channel (33). The inlet flow channel (32) and the outlet flow channel (33) are both connected to the invert flow channel (31). The inlet flow channel (32) and the outlet flow channel (33) are formed by the front mold flow channel block (12) and the rear mold flow channel block (22) facing each other.

5. The light guide plate mold structure for improving flow channels according to claim 2, characterized in that, The rear mold runner block (22) is provided with a first recess (221), and the rear mold runner insert (23) is provided with a second recess (231). The depths of the first recess (221) and the second recess (231) are matched. When the front mold core (11) and the rear mold core (21) are closed, the front mold core (11) and the rear mold core (21) abut against each other. The first recess (221) is in clearance fit with the surface of the front mold runner block (12), and the second recess (231) is in clearance fit with the surface of the front mold runner insert (13).

6. The light guide plate mold structure for improving flow channels according to claim 1, characterized in that, Both the front mold core (11) and the rear mold core (21) are provided with a second groove (6). The second groove (6) is located on both sides of the melt flow cavity (3). When the front mold core (11) and the rear mold core (21) are closed, the second groove (6) of the front mold core (11) and the rear mold core (21) form a cavity (7), which is connected to the melt flow cavity (3).

7. The light guide plate mold structure for improving flow channels according to claim 1, characterized in that, The front mold core (11) is provided with a gate (111) on the side away from the moving mold core. The gate (111) passes through the front mold core (11), and the front mold core (11) is connected to the melt flow cavity (3).

8. The light guide plate mold structure for improving flow channels according to claim 1, characterized in that, The rear mold core (21) is provided with a plurality of ejector pin holes (211), which penetrate the rear mold core (21).

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