TWI404625B - Method for injecting lightguide - Google Patents

Abstract

A method for injecting lightguide is related. The method comprises the following steps: under the clamp force of 4000 to 4500 kN the injection pressure of 2000 to 4000 kgf/cm<SP>2</SP>, injection velocity of 600 to 1000 mm/s to inject the lightguide. High injection pressure and fast injection velocity can improve the precision and decrease the thickness.

Description

Method for manufacturing light guide plate by injection molding

The present invention relates to a method of manufacturing a light guide plate, and more particularly to a method of injection molding a thin light guide plate.

At present, the more mature technology for manufacturing light guide plates uses an injection molding machine to melt the light guide plate material and then push it into the cavity of the injection molding machine, maintain the pressure of the cavity and cool the material of the light guide plate, and then mold the product. take out.

However, the injection speed and injection pressure of the conventional injection molding machine are relatively low, and the thickness of the formed light guide plate is thick, so that the backlight module using the light guide plate has a large volume and a large mass, and is not suitable for the light and thin products.

In view of the above, it is necessary to provide a method of injection molding a thin light guide plate.

A method for producing a light guide plate by injection molding, comprising: injection molding a light guide plate at a clamping force of 4000 to 4500 kN, an injection pressure of 2000 to 4000 kgf/cm, and an injection speed of 600 to 1000 mm/sec.

This embodiment injection molding light guide plate at high injection pressure and injection speed, high injection Speed and pressure can increase the dimensional accuracy of the product, and can produce thin products. This method can not only manufacture thinner light guide plates, but also save materials and reduce the volume of backlight modules using light guide plates.

10‧‧‧moving

20‧‧ ‧ fixed mode

30‧‧‧ cavity

40‧‧‧ screw

50‧‧‧Materials

60‧‧‧Light guide plate

1 is a flow chart of a method for injection molding a light guide plate according to an embodiment of the present invention.

2 is a schematic view of an injection molding machine provided during the injection molding process of manufacturing a light guide plate according to an embodiment of the present invention.

3 is a schematic view showing a mold clamping process in the process of injection molding a light guide plate according to an embodiment of the present invention.

4 is a schematic view showing an injection material during injection molding of a light guide plate according to an embodiment of the present invention.

FIG. 5 is a schematic view showing the removal of a light guide plate in the process of injection molding a light guide plate according to an embodiment of the present invention.

The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

As shown in FIG. 1, the method for manufacturing a light guide plate by injection molding according to an embodiment of the present invention mainly comprises the following steps: clamping a movable mold and a fixed mold to form a cavity, and having a lock of 4000 to 4500 kN between the movable mold and the fixed mold. Mould force; injecting material into the cavity at an injection speed of 6000 to 1000 mm/sec and an injection pressure of 2000 to 4000 kgf/cm; Maintain the pressure of the cavity; cool; open the mold and remove the product.

As shown in FIG. 2, an injection apparatus for injection molding a light guide plate includes a movable mold 10 and a stationary mold 20. During operation, the fixed mold 20 is relatively fixed, and the movable mold 10 is moved relative to the fixed mold 20.

As shown in FIG. 3, the movable mold 10 is driven by the driving device to be close to the fixed mold 20, so that a cavity 30 is formed between the movable mold 10 and the fixed mold 20.

In this embodiment, the movable mold 10 and the fixed mold 20 are clamped by a double-crank type clamping device driven by a servo motor, and the clamping device can generate a clamping force of up to 4000 to 4500 kN (kN). The power of the motor is 30 to 35 kW. The high clamping force ensures that no flashing occurs between the movable mold 10 and the fixed mold 20 during injection molding.

The mechanical performance factor of the crankshaft is 35.

As shown in FIG. 4, the screw 40 injects the molten material 50 into the cavity 30 at an injection speed of 600 to 1000 mm/sec (mm/s) and an injection pressure of 2000 to 4000 kgf/cm2 (kgf/cm2). in.

The injection pressure is preferably 3,000 to 4,000 kgf/cm, and the injection speed is preferably 800 to 1000 mm/sec.

Material 50 is polymethyl methacrylate (PMMA), polycarbonate (PC) or copolymerized cyclic olefin (COC).

As shown in Fig. 5, after the pressure in the cavity 30 is maintained and cooled for a while, the movable mold 10 and the fixed mold 20 are separated by the mold clamping device, and then the light guide plate 60 is taken out.

The above process can produce a light guide plate having a thickness of 0.4 to 0.8 millimeters (mm), especially a light guide plate having a thickness of 0.4 to 0.6 mm.

Taking PC as an example, when the injection pressure is 4000 kgf/cm, the thickness of the light guide plate 60 can reach 0.15 to 0.6 mm.

Increasing the injection pressure can form a thin piece, increase the injection speed, and can form a product with complex shape and thin thickness, and is beneficial to product stability and dimensional accuracy.

In addition, because of the high injection pressure and injection speed, a thinner product can be produced, thereby saving material and reducing the volume of the product using the light guide plate.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

Claims (7)

A method of injection molding a light guide plate, comprising: injection molding a light guide plate at a clamping force of 4000 to 4500 kN, an injection pressure of 2000 to 4000 kgf/cm, and an injection speed of 600 to 1000 mm/sec. The method of manufacturing a light guide plate by injection molding according to the first aspect of the invention, wherein the injection pressure is 3000 to 4000 kgf/cm. A method of manufacturing a light guide plate by injection molding according to the invention of claim 1, wherein the injection speed is 800 to 1000 mm/sec. A method of manufacturing a light guide plate by injection molding according to claim 1, wherein a double crank type mold clamping device driven by a servo motor is used to generate a clamping force. The method of manufacturing a light guide plate by injection molding according to claim 4, wherein the servo motor has a power of 30 to 35 kW. The method of manufacturing a light guide plate by injection molding according to claim 1, wherein the light guide plate has a thickness of 0.4 to 0.8 mm. The method of manufacturing a light guide plate by injection molding according to claim 7, wherein the light guide plate has a thickness of 0.4 to 0.6 mm.