KR20000053796A - Injection Mould for Light Guide Pipe - Google Patents

Abstract

PURPOSE: A mask for forming a light waveguide plate is provided to increase the accuracy of devices lengths and widths, so as to facilitate manufacturing operation of the devices. CONSTITUTION: A mask for forming a light waveguide plate includes a nozzle connection member(52), and a valve gate device(53). The nozzle connection member(52) is implemented on the center of the cavity center. The valve gate device(53) is used to form the light waveguide plate. The strength of the valve gate is greater than strength of the material near from the core of the fixing axis. The mask further includes a rectangular cutting pin for cutting the gate portion of the light waveguide plate. The mask further uses a stamper in order to transfer a light waveguide plate pattern on the light waveguide plate.

Description

Mold for light guide plate molding {Injection Mold for Light Guide Pipe}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for producing a light guide plate for guiding light generated in a cold cathode tube on an LCD surface of a backlight structure of a thin film transistor liquid crystal display (LCD) by injection.

Conventional molds combine a mold consisting of a movable side and a fixed side, and an injection inlet is provided on the fixed side to supply liquid resin into the cavity formed by the combination of the movable side mold and the fixed side mold to form a light guide plate. The light guide plate thus formed is patterned by screen printing to reflect and disperse the light generated from the cold cathode fluorescent tube so that the LCD brightens. When producing a product of a general polymer material, considering the shape of the product is installed in a location that is well formed. However, since the light guide plate must reflect and disperse light as a whole, an injection hole is installed on the side of the light guide plate. Therefore, when the high-pressure molten resin is injected into the mold during the injection process, the movable side and the fixed side mold are separated, resulting in poor product dimensions. Such a mold is installed in the injection molding machine using the fixed side fixed base plate 1 and the movable side fixed base plate 3, as shown in FIG. 1, and the fixed side core 10 and the movable side core 58. The light guide plate is formed by injecting molten resin through the nozzle contact portion 50 into the cavity 70 formed by the burner, and retreating the movable side fixed base plate 3 to open the cavity 70 to form the light guide plate. Extract At this time, the resin in the gate portion from the nozzle contact portion 50 to the cavity 70 sticks to the light guide plate. This part is removed by separate work. Looking at the mold in more detail as follows.

The nozzle of the injection machine is in contact with the nozzle contact portion 50 so that the liquid resin is injected into the resin passage 52. In order to shorten the resin passage 52, the nozzle contact part 50 is provided in the outer part of the fixed side fixed base plate 1 near the said gate 54, and liquid resin flows from here to a fixed side mold base. Install a manifold block (60) with incoming passages. There are problems in producing a light guide plate using such a mold. Since the gate to which the liquid resin is supplied is biased to one side at the center line of the mold, the pressure generated in the cavity causes poor matching between the fixed side and the movable side mold, so that the dimension of the formed light guide plate is not accurate. In addition, the resin in the resin passage of the manifold is attached to the product and comes out with the product. For this reason, the operation | movement which removes this after extracting a light-guide plate is necessary, and raw materials are wasteful. In addition, since the time required for the resin to be filled in the passage in the manifold during the injection operation is required, the injection time is long and productivity is reduced. In addition, in order to use a light guide plate formed using such a mold in an LCD backlight, a pattern for reflecting and dispersing light through screen printing must be formed on one surface of the light guide plate. Therefore, the production process is very complicated and expensive.

Therefore, the present invention improves the problems such as misalignment, dimensional inaccuracy, waste of raw materials, productivity decrease, etc., which are problems generated when manufacturing a light guide plate using a conventional mold, and prints a pattern that serves to reflect and scatter light. It is to provide a mold that can omit the process.

To achieve this purpose, the nozzle contact portion is installed at the center of the mold to prevent mold defects, and the resin injection hole portion attached to the light guide plate is reduced by using a valve gate system, and the remaining resin injection hole portion is removed from the mold. In order to have a means for cutting in and to eliminate the printing process of the light guide plate pattern, it is characterized in that the stamper core made of the concave-convex of the light guide plate pattern in the reverse phase is installed inside the movable side or the fixed side of the mold.

1; Schematic configuration drawing of a conventional mold.

2; Configuration drawing of the mold of the present invention.

3; 2 is a partial view of the gate.

4; Figure 2 is a schematic perspective view showing the part of the tanggut cutting mill pin of Figure 2.

5; Schematic perspective view of the hairline pattern stamper core used in FIG. 2.

6; A schematic perspective view of the spline curve pattern stamper core used in FIG. 2.

Explanation of symbols on the main parts of the drawings

10: movable side mold core

70: cavity

50: injection machine nozzle contact

52: resin passage

53: valve gate pin

54: gate

55: valve gate system

56: valve seat

60: manifold block

58: fixed side mold core (stamper core)

80: pneumatic piston

35: cutting-edge mill pin

20: Milpin Return Spring

30: eject pin entrance

65: sprue

Hereinafter, the present invention will be described with reference to the accompanying drawings.

The mold of the present invention is shown in Figure 2, in order to solve the disadvantages of the conventional mold, the manifold block and the injection port portion for injecting the liquid resin was improved. As shown in the figure, the nozzle of the injection molding machine contacts the nozzle contact portion 50 so that the liquid resin is injected into the resin passage 52. The resin passage 52 is connected to the gate 54 provided near the cavity 70 via the manifold block 60 and the valve gate system 55. The nozzle contact portion 50 is provided on the fixed side fixed base plate 1 at the centerline position of the cavity 70 to compensate for the disadvantages of the conventional mold. In this mold, since the resin passage 52 is long and the temperature of the resin falls, the heater 57 is surrounded by the manifold block 60 and the valve gate system 55 as shown in FIG. 3. ) To prevent the resin temperature from dropping. In addition, the valve pin 53 is driven forward and backward by the pneumatic piston 80 to open and close the gate 54. Retract the valve pin 53 to open the gate 54 so that resin flows into the cavity 70, and after the filling is completed, the valve pin 53 is advanced to close the gate 54. . This operation is controlled in conjunction with the injection machine screw in the injection machine control device.

In addition, as shown in the detailed drawing enlarged in FIG. 3, the portion where the valve pin 53 is in contact with the fixed side core fixing plate 10 of the mold may be worn in repetitive operation, so that the strength is high to prevent this. The valve seat 56 is manufactured using cemented carbide material and installed by brazing welding.

Also, as shown in FIG. 4, since the hot-drain portion from the gate 54 to the cavity 70 is attached to the light guide plate, a square mill pin 35 is installed to cut the inside of the mold. While the resin is being filled, it retreats, and after the filling of the resin is completed in the cavity, the mill pin is advanced to cut the hot water mouth part 65. In this manner, when the light guide plate is taken out, the resin passage part including the hot water spout portion 65 is attached to the light guide plate in the conventional mold, whereas in the metal mold of the present invention, Since only a part remains in the light guide plate, material loss is reduced and post-extraction cutting is simplified.

In addition, the cavity 70 is formed using the high side stamper core 15 or the movable side stamper core 59 to omit the printing process of the light guide plate pattern as described above. The stamper core 15 or 59 is manufactured as shown in FIG. 5 or FIG. 6 in a shape in which the light guide plate pattern and the unevenness are reversed. The stamper core 15 is fixed to the fixed side core support plate 10 or the stamper core 59 to the movable side core support plate 58 in a detachable manner. Therefore, when the molten resin is filled in the cavity 70, the pattern formed on the stamper core 15 or 59 is transferred to the light guide plate. When the stamper core as shown in FIG. 5 is used, a hairline pattern is formed. When the stamper core as shown in FIG. 6 is used, a pattern having a bidirectional spline curve is transferred.

Looking at the stamper core (15 or 59) in more detail as follows. As shown in FIG. 5, the hairline pattern of FIG. 5 has irregular heights and irregularities, and has a size of several tens of microns. In addition, in the bidirectional spline pattern of FIG. 6, the distance between the patterns is wider at the side where the cold cathode fluorescent tube is installed, and the distance between the patterns is narrower at the central part farther from the cold cathode fluorescent tube.

As described above, since the molding can be maintained during the filling process, the dimensions of the product are accurate, the material loss is prevented, the squeeze cutting operation is simplified after extraction, and the pattern of the light guide plate is transferred from the mold to the printing process. Can be omitted. Therefore, production cost can be reduced and high quality products can be produced.

Claims (6)

In the metal mold | die used for injection molding a light guide plate, A mold characterized in that the contact portion of the injection nozzle is installed in the center of the cavity In using a heart runner valve gate device in a metal mold | die used for injection molding a light guide plate, A mold that prevents abrasion by using a material that is harder than the core material at the part where the valve gate pin contacts the fixed core. In the metal mold | die used for injection molding a light guide plate, A mold characterized by installing a rectangular cutting mill pin in a mold to cut the gate portion attached to the light guide plate In the metal mold | die used for injection molding a light guide plate, In order to transfer a pattern for reflecting and dispersing light to the light guide plate, a mold characterized in that a stamper core having a reversed pattern and irregularities is installed inside a fixed side or a movable side mold. The method of claim 4, Mold using the stamper for transferring the light guide plate pattern in the form of a hairline The method of claim 4, A mold characterized by using a stamper for transferring a light guide plate pattern in the form of a spline curve