KR101213790B1 - Method for preparing the same - Google Patents

Abstract

 The light guide plate manufacturing method of the present invention is attached to the UV-sensitive protective film on at least one side of the extruded optical film; And irradiating UV to the optical film to which the UV-sensitive protective film is attached to form a pattern on the optical film simultaneously with curing. The method enables light guide plate extrusion and surface printing pattern formation on an extrusion in-line process to shorten process steps and time.

Description

Light guide plate manufacturing method {METHOD FOR PREPARING THE SAME}

The present invention relates to a light guide plate manufacturing method. More specifically, the present invention relates to a light guide plate manufacturing method capable of shortening a process step and time by making light guide plate extrusion and surface printing pattern formation possible in an extrusion in-line process.

Since the liquid crystal display device is not a self-luminous device, it should have a back light unit as a light source for generating light, and the light generated from the backlight unit is emitted from the panel portion where the liquid crystal is constantly arranged. An image and the like are displayed while adjusting the amount of permeation.

1 is an exploded perspective view illustrating a backlight unit of a general liquid crystal display device. As shown in FIG. 1, the LCD backlight unit includes a light source 105, a light guide plate 110, a reflector plate 115, a diffusion sheet 120, a prism sheet 125, and a protection sheet 130.

The light guide plate 110 is formed on the lower side of the LCD panel 100 and on one side of the light source 105, and converts spot light generated from the light source 105 into plane light to convert the light to the front surface. It serves to project.

A reflecting plate 115 is formed on the rear surface of the light guide plate 110 and reflects the light from the light source 105 in the direction of the LCD panel 100 on the front surface, and evenly distributes the light on the upper surface of the light guide plate 110. The diffusion sheet 120 is formed. A prism sheet 125 is positioned on the upper surface of the diffusion sheet 120 to increase brightness by refracting and condensing light. The protective sheet 130 is used on the upper surface of the prism sheet 125 to prevent scratches of the prism sheet 125 and to prevent moire effects.

As such, the light guide plate 110 guides the light emitted from the lamp to reach the entire light guide plate plane to have a uniform luminance distribution, and at the same time, reflects the front surface to change the linear light source of the lamp into a planar light source. It is.

The light guide plate 10 is manufactured by injection, extrusion, molding using acrylic resin, and in recent years, an extrusion method is preferred due to advantages such as production cost and large size.

Since the light guide plate by itself cannot produce a uniform distribution over the entire surface of the light guide plate, the surface of the light guide plate is printed with white ink (SiO 2 type) or a groove is formed to scatter and reflect the light by the pattern. A similar amount of light is emitted across the surface. The uniformly emitted rays show color and image quality to the observer's eye through various light paths and instruments.

However, when the light guide plate 110 has a very small defect on its surface, the light emitted to the front of the light guide plate 110 may be unnecessarily scattered, which may cause a fatal defect in the product. Therefore, the light guide plate 110 is attached to the protective film must be protected from a variety of external damage until the patterning process after extrusion and cooling.

2 illustrates a conventional light guide plate manufacturing process. As shown, the extruded optical film is attached to the upper and lower parts of the optical film as a protective film after polishing and cooling. Subsequently, the light guide plate raw material single piece of the desired size is produced through the cutting process with the protective film attached thereto.

After the protective film is removed in the production process of the lighting device to form a pattern, the UV curable resin is applied to the surface of the optical film, and then a pattern is formed through roller pressing or the like, and then cured or stored at constant temperature and humidity when the pattern is formed by ink printing. And printing after pretreatment such as heating.

As described above, the conventional method requires a separate printing process such as a silk screen printing method and a pretreatment process such as constant temperature and humidity storage and heating for ink printing as well as the removal of the protective film that is already attached during the printing pattern forming process. Steps and time were required. Thus, a very wasteful and inefficient problem arises.

It is an object of the present invention to provide a method of manufacturing a light guide plate which can shorten the process step and time by forming on the extrusion in-line not only to protect the light guide plate product but also to form a surface print pattern for outputting to the light guide plate surface of the light source.

Another object of the present invention is to provide a method of manufacturing a light guide plate having improved productivity by simplifying further processes and reducing time by forming a printing pattern on the surface of the light guide plate when the protective film is removed when the protective film is removed.

These and other objects of the present invention can be achieved by the present invention which is described in detail.

An aspect of the present invention relates to a light guide plate manufacturing method. The method includes attaching a UV sensitive protective film to at least one side of the extruded optical film; And irradiating UV to the optical film to which the UV-sensitive protective film is attached to form a pattern on the optical film simultaneously with curing.

In one embodiment, the UV-sensitive protective film is laminated with a UV-sensitive printing pattern, the pattern can be transferred to the optical film when UV irradiation.

In another embodiment, the UV-sensitive protective film may contain a UV-sensitive transfer ink.

In another embodiment, the UV-sensitive protective film may have a structure in which a carrier film containing a UV-sensitive transfer ink is laminated on one surface of the protective film.

In embodiments, the UV-sensitive transfer ink is patterned on a carrier film, the pattern can be transferred to the optical film when UV irradiation.

In another embodiment, the UV-sensitive transfer ink is laminated on one side of the carrier film, the pattern can be transferred to the optical film by selective UV irradiation.

The extruded optical film may be attached to the UV-sensitive protective film after cooling.

The extruded optical film may be cooled after polishing.

The present invention can shorten the process step and time by forming on the extrusion in-line not only to protect the light guide plate product but also to form a surface printing pattern for outputting to the surface of the light guide plate of the light source, and when the protective film is removed, the surface of the light guide plate is cured. The invention has the effect of providing a method of manufacturing a light guide plate having improved productivity by forming a printing pattern on the substrate, thereby simplifying further processes and reducing time.

1 is an exploded perspective view illustrating a backlight unit of a general liquid crystal display device.
2 is a flowchart illustrating a conventional light guide plate manufacturing process.
3 shows a flowchart of a light guide plate manufacturing process according to an embodiment of the present invention.
4 is a process diagram schematically showing a light guide plate manufacturing method according to the present invention.
5 is a cross-sectional view of the UV-sensitive protective film according to an embodiment of the present invention.
6 (a) to (c) are specific examples of the protective film containing the UV-sensitive transfer ink of the present invention.

3 shows a flowchart of a light guide plate manufacturing process according to an embodiment of the present invention. As shown, the extruded optical film attaches a UV-sensitive protective film to at least one surface after cooling, and then irradiates UV to the optical film to which the UV-sensitive protective film is attached, thereby curing and forming a pattern on the optical film.

As described above, unlike the conventional process, the present invention does not require a pretreatment process for removing or printing the protective film, thereby simplifying the process and improving productivity.

4 is a process diagram schematically showing a light guide plate manufacturing method according to the present invention. As shown, the transparent resin is continuously fed to the extruder and extruded to form an optical film.

The optical film may be extruded using a conventional resin used in the light guide plate. In the embodiment, an acrylic resin may be preferably applied.

The extruded sheet-like optical film is polished on a polishing roll and then cooled while being transferred from a cooling conveyor.

At least one surface of the cooled optical film is laminated by bonding or laminating a UV-sensitive protective film. In embodiments, the UV-sensitive protective film may be attached to one side or both sides of the optical film.

In an embodiment, the UV-sensitive protective film is laminated with a UV-sensitive printing pattern. Accordingly, the pattern can be transferred to the optical film during UV irradiation.

In one embodiment, the UV-sensitive protective film may contain a UV-sensitive transfer ink. The UV-sensitive transfer ink is well known by those skilled in the art to which the present invention pertains and is easy to purchase commercially. In a specific embodiment, the UV-sensitive transfer ink may be one containing an acrylic copolymer, an EVA copolymer, an organic solvent, and the like in a UV reactive ink. The UV-sensitive transfer ink is disclosed in Korean Laid-Open Publication No. 2000-74223, which includes the same.

5 is a cross-sectional view of the UV-sensitive protective film according to an embodiment of the present invention. As shown, the UV-sensitive protective film may have a structure in which the carrier film 20 containing the UV-sensitive transfer ink is laminated on one surface of the protective film 10.

The protective film 10 may be a conventional protective film well known by those skilled in the art to which the present invention pertains, and is easy to purchase commercially.

The other surface of the carrier film 20 may be an optical film that is a raw film of the light guide plate. In another embodiment, the optical film may be located on the other surface of the protective film 10.

6 (a) to (c) are specific examples of the protective film containing the UV-sensitive transfer ink of the present invention.

As shown in FIG. 6A, the UV-sensitive transfer ink 220 may be patterned on the carrier film 20. The UV-sensitive transfer ink 220 may be impregnated in the resin portion 210 or formed on the surface of the resin portion 210. The UV-sensitive transfer ink 220 and the resin unit 210 may constitute a carrier film 20. The patterned UV-sensitive transfer ink 220 as described above is to transfer the pattern to the light guide plate as it is during UV irradiation. The protective film 10 may be attached to one surface of the carrier film 20 in which the UV-sensitive transfer ink 220 is patterned.

FIG. 6 (b) shows the carrier film 20 having a structure in which the UV-sensitive transfer ink 220 is stacked on one surface of the resin part 210. In this case, since no pattern is formed, UV is selectively irradiated during UV irradiation, which is a next step, to transfer the pattern to the optical film. The selective UV irradiation may partially irradiate UV light only to a portion where a pattern is to be formed, or may irradiate the entire area by placing a mask on which the pattern is formed.

6 (c) shows a structure in which the UV-sensitive transfer ink 220 is patterned directly on the protective film 10 without the carrier film 20. Although the drawing illustrates that the UV-sensitive transfer ink 220 is patterned on the surface of the protective film 10, the V-sensitive transfer ink 220 may be impregnated inside the protective film 10. The optical film may be stacked on the surface on which the UV-sensitive transfer ink 220 is formed or on the opposite surface.

The invention can be better understood by the following examples, which are intended to illustrate the invention and are not intended to limit the scope of protection defined by the appended claims.

Example

Acrylic resin (Akema V021C grade (MI: 1.5 (230 ℃, 3.8kg conditions)) was extruded into an optical film using a Toshiba sheet extruder and cooled to 30 ℃ temperature on one side of the cooled optical film After attaching a protective film laminated with a UV-sensitive print pattern (lamination of a UV-sensitive printed pattern ink layer on a CPP-based basefilm), UV irradiation was performed at 150 mJ / cm ² , and the pattern was transferred to an optical film, thereby manufacturing a light guide plate.

Comparative example

A general protective film (ILSIN LF-CS101 grade) was attached to the optical film without using a UV-sensitive print pattern. Thereafter, the protective film was removed to form a pattern, and then the optical film was pretreated at a temperature of 40 to 42 ° C. and a constant humidity condition, and then a pattern was formed on the surface through a silk screen printing method.

In Examples and Comparative Examples, the light guide plate printing process time and the before and after processing time and production time were measured, and the results are shown in Table 1 below.

Example Comparative example LGP Printing Process
Time  2-3 seconds / every 20 sec to 30 sec / s Pre-treatment process
Time - Approximately 3,600 seconds of drying time before printing (100 sheets) Sum 200 ~ 300 seconds / 100 sheets Approx. 3,800 to 3,900 sec / 100 sheets Process time 2-3 seconds / every 38 to 39 seconds / second productivity 28,000 ~ 40,000 sheets / day 2,200 ~ 2,300 sheets / day Productivity improvement 1,200% improvement -

As shown in Table 1, in the case of applying the protective film laminated UV-sensitive printing pattern, the time required for the printing process was reduced to 10% level compared to the comparative example, and the overall process time was greatly reduced because no post-treatment was required. You can see that. In addition, a comparison of the daily production yields an improvement of about 1200%.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and may be manufactured in various forms, and a person of ordinary skill in the art to which the present invention belongs may have the technical idea of the present invention. However, it will be understood that other specific forms may be practiced without changing the essential features. It is therefore to be understood that the embodiments described above are in all respects illustrative and not restrictive.

10: protective film 20: carrier film
100: LCD panel 105: light source
110: light guide plate 115: reflector
120: diffusion sheet 125: prism sheet
130: protective sheet 210: resin
220: UV sensitive transfer ink

Claims (8)

Attaching a UV-sensitive protective film to at least one side of the extruded optical film; And
Irradiating UV on the optical film to which the UV-sensitive protective film is attached to form a pattern on the optical film simultaneously with curing;
Light guide plate manufacturing method comprising the step.
The method of claim 1, wherein the UV-sensitive protective film is laminated with a UV-sensitive printing pattern, and the pattern is transferred to the optical film when UV is irradiated.
The method of claim 1, wherein the UV sensitive protective film contains a UV sensitive transfer ink.
The method of claim 3, wherein the UV-sensitive protective film has a structure in which a carrier film containing a UV-sensitive transfer ink is laminated on one surface of the protective film.
The method of claim 4, wherein the UV-sensitive transfer ink is patterned on a carrier film, and the pattern is transferred to the optical film upon UV irradiation.
The method of claim 4, wherein the UV-sensitive transfer ink is stacked on one surface of the carrier film, and the pattern is transferred to the optical film by selective UV irradiation.
The method of claim 1, wherein the extruded optical film is cooled and then attached with a UV-sensitive protective film.
The method of claim 7, wherein the extruded optical film is polished and cooled.

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