KR100581996B1 - Mold for manufacturing of light guide panel and light guide panel insert molded from it - Google Patents

Abstract

The present invention is a mold for manufacturing a light guide plate according to the present invention for achieving the above object, in the mold in which the light guide plate is injection-molded, while maintaining a temperature between 100 to 120 degrees with a circular base mold (10 ') of a predetermined thickness A mold line 20 'and a light guide plate are formed in the circular base mold 10' in a circumferential direction to form a cooling line through which a liquid coolant flows. In order to form an inverted concave-convex pattern to be transferred to the light guide plate is formed on the surface in contact with the injection raw material injected into the mold core 20 'to include a cross-shaped stamper (30') fixed to the mold core 20 ' A metal mold for manufacturing a light guide plate, and a cruciform light guide plate which is injection molded therefrom.

Light guide plate, high temperature mold core, high temperature injection, circular cooling line, cross stamper, skin layer

Description

MOLD FOR MANUFACTURING OF LIGHT GUIDE PANEL AND LIGHT GUIDE PANEL INSERT MOLDED FROM IT}             

1 is a vertical cross-sectional view of a mold for manufacturing a light guide plate according to the prior art.

Figure 2 is a view for explaining that a skin layer (skin layer) is generated when using a mold for manufacturing a light guide plate according to the prior art.

Figure 3a is a plan view showing a mold for manufacturing a light guide plate according to the present invention.

3B is a cross-sectional view of a mold for manufacturing a light guide plate corresponding to AA ′ surface of FIG. 3A.

Figure 4a is a plan view of a mold core according to the present invention.

Figure 4b is a cross-sectional view of the mold core in accordance with the present invention.

Figure 4c is a rear view of the mold core according to the present invention.

Explanation of symbols on the main parts of the drawings

10, 10 ': base mold

20, 20 ': mold core

30, 30 ': stamper

40: nozzle

The present invention relates to a mold for manufacturing a light guide plate and a light guide plate injection molded therefrom, and more particularly, to improve transferability through high temperature injection (injection temperature 250 to 280 degrees), and to configure a cooling line optimized on a mold to form a high mold. The light guide plate manufacturing mold and the injection molding therefrom, which enable the rapid cooling while maintaining the core temperature (100 to 120 degrees) and at the same time solve the problem of unfilling by the skin layer. To a light guide plate.

1 is a vertical cross-sectional view of a mold for manufacturing a light guide plate according to the prior art.

A light guide plate, which is one of the structures constituting a back light unit (BLU) of a liquid crystal display (LCD), has been injection molded by a mold for manufacturing a light guide plate as shown in FIG. 1.

Referring to FIG. 1, a light guide plate manufacturing mold according to the related art is a base mold 10 having a predetermined thickness and a low-temperature mold core 20 attached to an upper portion of the base mold 10 and having a temperature between 60 and 80 degrees. It is composed.

In the mold core 20, the number of cavities (number of products coming out of the mold once) is formed, and then the pattern is processed directly or mechanically on the surface of the inlet formed in the mold core 20. The pattern is formed using an etching method that corrodes with acid. Alternatively, after forming the uneven pattern on one surface of the stamper 30, the surface on which the uneven pattern is formed is fixed to the inlet portion of the mold core 20 so that the surface into which the resin material as the injection material is injected. The upper nozzle 40 injects and fills a resin material, which is a material of the light guide plate, to the inlet portion of the mold core 20. A resin material, which is a material of the light guide plate, is filled in the inlet portion of the mold core 20 having the uneven pattern formed through the nozzle 40, and then injection molded to produce a light guide plate having the uneven pattern on one side.

2 is a view for explaining the skin layer (skin layer) is generated when using a mold for manufacturing a light guide plate according to the prior art.

Generally, resin materials used as injection materials show viscoelastic behavior, which combines the properties of an ideal elastic solid with the properties of an ideal viscous fluid. If the temperature is raised above the reference temperature (glass transition temperature), the resin material has fluid characteristics and softens. In particular, a polymer material such as acrylic has a property of having fluidity such as liquid easily when the temperature rises. Acrylic disc has excellent transparency and durability, and has a transparent appearance. Melting characteristics are soft at low temperatures due to low glass transition temperature.

According to the prior art, since the injection temperature is formed between 150 to 180 degrees during injection molding of the light guide plate, the transferability decreases due to the low temperature injection. In addition, the skin transition is caused by a large difference from the glass transition of the support material (a phenomenon of rapid solidification in the temperature region of the material when cooling the liquid), and the larger the difference is, the larger the thickness of the skin layer is. Thickening will occur. That is, as shown in the drawing, a portion of the surface of the stamper 30 is skinned in the process of spreading the hot injection raw material to the surface of the stamper 30 fixed to the mold core 20 having a relatively low temperature between 60 and 80 degrees. There is a problem that a skin layer is generated, and the skin layer tends to unfill or unfill the surface of the stamper 30, or cause surface defects such as a flow mark. In addition, the production time per light guide plate was about 15 to 20 seconds (based on two cavities), and the injection time tended to be long, and the productivity tended to decrease.

Accordingly, an object of the present invention is to solve the conventional problems as described above, to provide a light guide plate manufacturing mold and injection molded light guide plate that can improve the transferability through a high temperature injection (injection temperature 250 ~ 280 degrees). have.

Another object of the present invention is to configure the cooling line optimized on the mold to enable fast cooling while maintaining a high mold core temperature (100 to 120 degrees), while unfilling (unfilling) by the skin layer The present invention provides a mold for manufacturing a light guide plate that can solve the problem, and a light guide plate injection molded therefrom.

It is still another object of the present invention to provide a light guide plate manufacturing mold capable of shortening the production time (about 4 to 6 seconds based on 4 cavities) and a light guide plate injection molded therefrom.

The mold for manufacturing a light guide plate according to the present invention for achieving the above object is a circular base mold 10 'having a predetermined thickness and a temperature between 100 and 120 degrees in a mold in which the light guide plate is injection molded, A cooling line is formed in a circular shape along the circumferential direction of the circular base mold 10 'to allow a liquid coolant to flow to form a mold core 20' mounted on the circular base mold 10 'and a light guide plate. Inverted concave-convex pattern to be transferred to the light guide plate is formed on the surface in contact with the injection raw material injected into the mold core (20 ') is characterized in that it comprises a cross-shaped stamper (30') fixed to the mold core (20 '). .

Preferably, the cooling line formed in the mold core 20 'is formed by integrating a two-pronged line formed along an inner circumference and a two-pronged line formed along an outer circumference, thereby forming an inner circumference of the mold core 20'. Characterized in that it is optimized to maintain the mold temperature of the outer periphery.

In addition, the light guide plate injection-molded from the mold for manufacturing the light guide plate according to the present invention, the light source is made of a light-transmitting acrylic-based material, the cross-shaped injection molding is to produce a final light guide plate of 4 cavities (cavity) in one injection It is a cross-shaped light guide plate characterized in that.

In the following description with reference to the accompanying drawings, preferred embodiments of the present invention in detail, when it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. Do it.

FIG. 3A is a plan view illustrating a mold for manufacturing a light guide plate according to the present invention, and FIG. 3B is a cross-sectional view of a mold for manufacturing a light guide plate corresponding to AA ′ surface of FIG. 3A.

3A and 3B, the light guide plate manufacturing mold according to the present invention includes a circular base mold 10 ′ having a predetermined thickness, a mold core 20 ′ above the circular base mold 10 ′, and a mold core 20 ′. It consists of a cross stamper (30 ') and the like fixed to.

Inside the mold core 20 ', an optimized cooling line is configured to enable rapid cooling of the injection raw material while maintaining the temperature of the mold core 20' relatively high between 100 and 120 degrees.

The cruciform stamper 30 'is fixed to the mold core 20', but the cruciform stamper 30 'is inverted and uneven pattern transferred to the light guide plate on a surface where the resin material injected into the mold core 20' contacts the light guide plate. It is fixed so that the formed pattern formation surface is located. The pattern forming surface of the cruciform stamper 30 'can be located anywhere above or below by simple mold design changes.

In order to omit the printing process of the light guide plate pattern, a light guide plate is manufactured using a cross stamper 30 '. The cross stamper 30 'is cross-shaped, and the concave-convex shape of the light guide plate pattern may be reversed by using a steel material such as nickel or stainless steel. At this time, if a material such as nickel is used, in order to solve the problem that it is difficult to form irregularities minutely and evenly on the surface by cutting using a bite, a predetermined thickness is formed on the surface of the metal master on which the irregularities are formed. As a pole plating can be adopted. When the molten resin material is filled in the inlet portion of the mold core 20 ', the reverse concave-convex pattern formed on the cross stamper 30' is transferred to the light guide plate.

Each wing of the cruciform stamper 30 'is formed with a reverse concave-convex pattern to be transferred to the light guide plate, thereby producing a cruciform light guide plate molded in a cross shape in the injection step. Cruciform light guide plate is composed of acrylic polymer melt material that can transmit light such as polymethacrylate (PMMA), polycarbonate (PC), cycloolefin copolymer (COC), and cross-shaped injection molding By cutting, the final light guide plate of 4 cavities is manufactured in one injection. Therefore, the production time can be improved by shortening the production time compared to the conventional method in which the final light guide plate of 2 cavities is manufactured in one injection. Can be. In general, most polymer materials have a chain shape, and are long linear and usually formed in a tangled form. When a stress is applied thereto, they are straightened and then returned to their original state when the stress is released. In the case of injection molding, the polymer is subjected to a strong stress, and the tangled form is straightened and injected into the mold core 20 '. In the case of injection molding, it is quenched to improve productivity. As it is cooled at a high speed, the polymer material hardens as it is, and is always in an unstable state without being returned to its original state in an expanded state. That is, die swell remains. In this state, the die swell is released and cracked due to factors such as heat or summer temperature rise. Alternatively, the impact may be applied externally, causing the die to dissipate momentarily, resulting in cracking.

According to the present invention, it is possible to manufacture the light guide plate in a stabilized state by minimizing the stress generated in the injection molding during injection, and to improve the production efficiency by minimizing the production time through the cross stamper (30 ') and the optimized cooling line. .

4a to 4c show a plan view, a sectional view, and a rear view of the mold core according to the present invention, respectively. One surface of the mold core 20 'shown in FIG. 4A is a surface to be mounted when mounted on the circular base mold 10', and the other surface of the mold core 20 'shown in FIG. 4C is a cross stamper 30'. It becomes a fixed surface.

Inside the mold core 20 ', a two-pronged line is formed along the inner circumference as shown in FIG. 4A in order to enable rapid cooling of the injection material while maintaining the temperature of the mold core 20' relatively between 100 and 120 degrees. Two branched lines formed along the outer periphery are formed in an integrated form. The cooling line is formed in a circle along the circumferential direction in the mold core 20 'so that liquid coolant such as cooling water or cooling oil flows therein. As shown in Figure 4a, the cooling line of the shape that can maintain the mold temperature of the inner and outer circumference of the mold core 20 'is the same, the flow direction of the liquid coolant and the flow direction of the injection material is designed to be the same to prevent warpage It is possible to bring the surface layer and the occurrence of the surface defects such as the flow mark according to this minimizes the defect rate is reduced.

The present invention may be modified in various ways without departing from the basic concept according to the needs of those skilled in the art.

As described above, according to the present invention, there is an effect of providing a light guide plate manufacturing mold capable of improving transferability through high temperature injection (injection temperature 250 to 280 degrees) and a light guide plate injection molded therefrom.

In addition, according to the present invention, by forming an optimized cooling line on the mold to enable high-speed cooling while maintaining a high mold core temperature (100 ~ 120 degrees), unfilling (unfilling) by the skin layer There is an effect that a mold for manufacturing a light guide plate that can solve the problem and an injection molded light guide plate therefrom.

In addition, according to the present invention, there is an effect of providing a light guide plate manufacturing mold capable of shortening the production time (about 4 to 6 seconds based on four cavities) and a light guide plate injection molded therefrom.

Claims (3)

In a mold in which the light guide plate is injection molded, Circular base mold 10 'of predetermined thickness; While maintaining a temperature between 100 and 120 degrees, a cooling line is formed inside the circular base mold 10 'in the circumferential direction and flows the liquid coolant therein, thereby forming a circular base mold 10'. A mold core 20 'mounted; And a cross-shaped stamper 30 'fixed to the mold core 20' by forming an inverted concave-convex pattern formed on a surface in contact with the injection raw material injected into the mold core 20 'for molding the light guide plate. The die for manufacturing a light guide plate, characterized in that the configuration. The method of claim 1, The cooling line configured in the mold core 20 ', The light guide plate is characterized in that the two-pronged line formed along the inner circumference and the two-pronged line formed along the outer circumference are integrated to maintain the same mold temperature of the inner and outer circumferences of the mold core 20 '. Mold for manufacturing. Cooling line in which a liquid coolant flows through a circular base mold 10 'having a predetermined thickness and a temperature between 100 and 120 degrees, and formed in a circle along the circumferential direction of the circular base mold 10'. In this configuration, a reversed concave-convex pattern transferred to the light guide plate is formed on a surface of the mold core 20 'mounted on the circular base mold 10' and the injection raw material injected into the mold core 20 'for molding the light guide plate. To be manufactured by a light guide plate manufacturing mold, characterized in that it comprises a cross-shaped stamper (30 ') fixed to the mold core (20'), A cross-shaped light guide plate, characterized in that the light source is made of a translucent acrylic-based material, and injection molding in a cross shape to produce a final light guide plate of 4 cavities in a single injection.

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