KR100845738B1 - Prism type light guide plate of a backlight unit and method - Google Patents

Abstract

The present invention relates to a light guide plate of a backlight unit.

The light guide plate of the present invention is a light guide plate of a backlight unit provided to switch a shape and a path of light incident from a light source, the prism pattern formed on one surface to reflect the light incident from the light source, and the prism pattern image. It is characterized in that it comprises a scattering pattern which is finely formed in and scatters the incident light.

Therefore, a light guide plate capable of providing not only a high brightness characteristic but also a wide viewing angle characteristic and a white line / dark line prevention effect at the light incident part is provided, thereby making it possible to realize a significant performance improvement, and also having a very poor manufacturing efficiency. Since the light guide plate can be mass-produced smoothly even at least once, the productivity can be improved and the light guide plate can be manufactured with high quality.

Backlight Unit, BLU, Light Guide Plate, Pattern, Prism, Dot, Reflection, Condensing, Scattering, Luminance, Viewing Angle, Stamper, Plating, Reproduction, Mold, Injection

Description

Light guide plate of backlight unit {PRISM TYPE LIGHT GUIDE PLATE OF A BACKLIGHT UNIT AND METHOD}

1 is a schematic view showing a conventional backlight unit structure,

2 is a schematic view showing a light guide plate provided in a conventional backlight unit;

3 is a cross-sectional view showing a light guide plate of the backlight unit according to the present invention;

4 is a flowchart illustrating a method of manufacturing a light guide plate of a backlight unit according to the present invention;

5 is a schematic view showing a step of manufacturing a master block in a straight working according to the present invention,

6 is a schematic view showing an electroplating apparatus used in forming a plating film according to the present invention;

7 is a schematic diagram showing a step of obtaining a mother stamper plated on a master block according to the present invention;

8 is a schematic view showing a mother stamper made in accordance with the present invention;

9 is a schematic diagram illustrating a step of forming a scattering pattern on a prism pattern of a mother stamper according to the present invention;

10 is a schematic view showing obtaining a sun stamper plated on a mother stamper according to the present invention;

11 is a schematic view showing a sun stamper made according to the present invention;

12 is a schematic view for explaining a step of manufacturing a light guide plate through injection molding using a sun stamper according to the present invention.

<Description of the symbols for the main parts of the drawings>

10: light source 20: reflective sheet

30: light guide plate 32: prism pattern

34: scattering pattern 40: prism sheet

50: diffusion sheet 100: master block

102: prism pattern 104: diamond bite

200: electroplating apparatus 202: cathode

204: anode 206: electrolytic plating solution

300: mother stamper 302: prism pattern

304: scattering pattern 400: sun stamper

402: prism pattern 404: scattering pattern

500: Mold Core

The present invention relates to a light guide plate of a backlight unit, and more particularly to a light guide plate having a wide viewing angle characteristics as well as high brightness characteristics.

In general, a liquid crystal display (LCD) has been widely used as a display device in recent years, and since the liquid crystal display uses liquid crystal, which is a light receiving element that does not have a light emitting capability, a backlight unit (BLU), which is a separate back lighting device, is used. Back light unit).

The backlight unit is classified into an edge type and a direct type according to the position of the light source provided, and the direct type is a method in which a light source is disposed at the lower side of the liquid crystal display panel to directly illuminate the front of the panel. In the edge type, the present invention relates to the edge type in such a way that a light source is disposed at the side so that the light emitted from the light source is redirected to the front side while passing through the light guide plate.

1 shows an example of a conventional edge type backlight unit.

A light source 10 provided at the side to generate light, a light guide plate 30 provided at an end portion of the light source 10 to be in contact with the light source 10, and a prism sheet 40 stacked on the light guide plate 30. ) And a diffuser sheet 50 stacked on the prism sheet 40, and a reflector sheet 20 is provided on the lower side of the light guide plate 30.

Therefore, the light incident from the light source 10 to the light guide plate 30 is reflected by the reflective surface, which is the bottom surface of the light guide plate 30, and the reflective sheet 20 on the lower side of the light guide plate 30, so that the emission surface is the top surface of the light guide plate 30. The light emitted from the light guide plate 30 is collected while passing through the prism sheet 40, and then diffused while passing through the diffusion sheet 50, and finally, the liquid crystal display panel (not shown). The front is illuminated.

In the backlight unit as described above, the light guide plate 30 is a key factor that determines the performance of the light guide plate. It will play a role.

The light guide plate 30 is formed of a hexahedral transparent plate, and the material is an inorganic transparent material such as acrylic resin, polycarbonate resin, transparent glass, or glass, or a composite thereof.

In addition, since the light guide plate 30 does not change the medium therein and cannot change the path of light by itself, the light guide plate 30 additionally has a prism pattern for reflecting the incident light as shown in FIG. The prism pattern 32 is generally formed, and the light guide plate 30 having the prism pattern 32 is thus called a prism light guide plate 30.

Here, the prism pattern 32 is a substantially triangular cross-sectional shape, and a plurality of prismatic patterns 32 are formed in a line shape parallel to each other. In addition to the triangle, various shapes such as a circular shape and a curved (elbow) shape are employed.

Accordingly, the light incident from the light guide plate 30 is reflected at a predetermined angle through each inclined surface of the prism pattern 32 formed on the bottom surface of the light guide plate 30 and is directed upward, or each of the inclined surfaces of the prism pattern 32. After passing through the light reflected by the reflective sheet 20 on the lower side passes through the light guide plate 30 to the upper side.

At this time, since the prism pattern 32 on the light guide plate 30 reflects light and condenses the light, thereby increasing the luminance, the prism light guide plate 30 is mainly used for the backlight unit for high brightness. It is adopted.

In the manufacturing of the prism light guide plate 30, the prism pattern 32 may be directly manufactured on the light guide plate 30 by laser or mechanical processing, or the like. Since manufacturing efficiency decreases extremely, the light guide plate 30 is manufactured such that the prism pattern 32 is simultaneously formed through injection molding.

That is, the manufacturing of the light guide plate 30 through injection molding prepares the mold core in which the prism pattern 32 is formed through direct processing in advance, and then increases the productivity of the light guide plate 30 through repeated injection molding using the mold core. To manufacture.

On the other hand, the prism sheet 40 laminated on the light guide plate 30 is integrally provided with a prism pattern portion (not shown) formed so that a triangular prism is repeated on the upper surface, which is an exit surface thereof, to condense light. The prism pattern portion is formed to be orthogonal to the prism pattern 32 on the light guide plate 30.

Therefore, it can be said that the light guide plate 30 and the prism sheet 40 having the prism patterns condense light to improve luminance.

In addition, the diffusion sheet 50 stacked on the prism sheet 40 serves to spread the light emitted through the prism sheet 40 uniformly while widening the wide viewing angle.

However, in the light guide plate 30 and the manufacturing method of the conventional backlight unit as described above, the following problems occur.

First, the display field continuously demands a wide viewing angle characteristic while having the highest luminance. The above-described prism light guide plate 30 has only a single prism pattern 32, and thus the prism pattern 32 This can provide a certain degree of high brightness characteristics, but has a relatively narrow viewing angle, thereby degrading display quality.

Second, in the conventional light guide plate 30, the edge portion has low luminance and the center portion has high luminance due to the unevenness of the amount of light in the light incident portion of the light source 10 side, and the white line and the luminance have a high luminance portion. Since dark lines are generated in a relatively low portion, there is a problem of degrading display quality.

Third, since a limited quantity of light guide plate 30 can be injection molded through one mold core, a large number of mold cores are required for mass production of the light guide plate 30. It takes a lot of time, manpower and cost to manufacture through processing, there is a problem that the manufacturing efficiency is extremely low, and also the accuracy and reproducibility of the prism pattern 32 is not secured.

The present invention was devised to solve the above problems, and an object thereof is to provide a light guide plate capable of providing not only high brightness characteristics but also wide viewing angle characteristics.

The light guide plate of the backlight unit of the present invention for achieving the above object is a light guide plate of the backlight unit provided to switch the shape and path of the light incident from the light source, on one surface to reflect the light incident from the light source And a scattering pattern which is formed on the prism pattern and scatters the light that is finely formed and incident on the prism pattern.

In addition, the light guide plate manufacturing method of the backlight unit of the present invention for achieving the above object comprises the steps of: manufacturing a master block formed with a prism pattern through direct processing; Forming a plating film on the prism pattern of the master block; Removing the plating film from the master block to obtain a mother stamper; Forming a scattering pattern on a prism pattern formed to correspond to the mother stamper; Forming a second plating film on the prism pattern of the mother stamper; Removing the second plating film from the mother stamper to obtain a sun stamper; Attaching the sun stamper to a mold core and then obtaining a light guide plate having a prism pattern and a scattering pattern corresponding to the prism pattern and the scattering pattern on the sun stamper through injection molding using the mold core; It includes.

The above objects and various advantages of the present invention will become more apparent from the preferred embodiments of the invention described below with reference to the accompanying drawings by those skilled in the art.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Prior to the description, the same constituent parts as in the prior art are denoted by the same reference numerals, and detailed description thereof will be omitted.

According to the present invention, as shown in the cross-sectional view of FIG. 3, in order to enhance the viewing angle characteristic of the prism light guide plate 30, the fine scattering pattern 34 is generally formed on the prism pattern 32.

In this case, the scattering pattern 34 may be generally formed on the inclined surface of the prism pattern 32, and may be formed in an intaglio or an embossment, and may have a periodicity or be randomly formed.

Preferably, the scattering pattern 34 may be formed in a dot pattern, the shape is not particularly limited, such as circular.

As a result, the light incident into the light guide plate 30 is reflected by the prism pattern 32 on the bottom surface and directed to the upper side, and is scattered by hitting the scattering patterns 34 on the prism pattern 32 to have a wider viewing angle. It can be emitted from the upper surface of the light guide plate 30.

Meanwhile, according to the present invention, a method of manufacturing the light guide plate 30 having the scattering pattern 34 together with the prism pattern 32 can be more efficiently manufactured.

The method first manufactures the master block by direct machining, and then sequentially manufactures the mother stamper and the sun stamper through two copies of plating using the master block. Then, mass production of light guide plates is made through injection molding using a sun stamper.

Hereinafter, the manufacturing method will be described sequentially in detail.

4 is a flowchart illustrating a light guide plate manufacturing method of a backlight unit according to the present invention.

First, as shown in FIG. 5, the master block 100 is manufactured by directly embossing the prism pattern 102 on the metal plate as a whole (S102).

In this case, as an example, the prism pattern 102 may be cut by using the diamond bite 104.

Thereafter, the master block 100 is further formed on the upper surface of the prism pattern 102 by using the electroplating apparatus 200 shown in FIG. 6 (S104). .

At this time, the master block 100 to be coated is connected to the cathode 202 and the anode 204 and the cathode 202 are impregnated in the electrolytic plating solution 206 together with the anode 204. A current is flowed between them so that the plating film 300 is coated on the prism pattern 102 of the master block 100, and the plating film 300 may be formed of a nickel (Ni) metal film. have.

Subsequently, as shown in FIG. 7, when the plating film 300 formed on the master block 100 is removed and separated, the plated film 300 corresponds to the embossed prism pattern 102 on the master block 100. The engraved prism pattern 302 is duplicated and formed (S106).

The plated film 300 thus manufactured is referred to as a mother stamper 300 (see FIG. 8).

Next, a fine scattering pattern 304 is generally formed on the intaglio prism pattern 302 of the mother stamper 300 in an intaglio (S108) (see FIG. 9), in which case the scattering pattern 304 is formed. As the method, all possible methods such as a printing method, a sand blasting method, a corrosion method, and a mechanical processing method which are well known to those skilled in the art may be used.

Subsequently, the mother stamper 300 is duplicated again by using the electroplating apparatus 200 described above, that is, the second plating film (e.g., electrolytic plating on the intaglio prism pattern 302 of the mother stamper 300). 400 is formed (S110), and as shown in FIG. 10, when the second plating film 400 is separated from the mother stamper 300 and separated, the second plating film 400 is obtained. The embossed prism pattern 402 and the scattering pattern 404 corresponding to the intaglio prism pattern 302 and the scattering pattern 304 on the mother stamper 300 are duplicated and formed (S112). The manufactured second plated film 400 is referred to as a son stamper 400 (see FIG. 11).

Here, the manufacture through plating of the sun stamper 400 using the mother stamper 300 is repeatedly performed to manufacture a large number of sun stampers 400.

Thereafter, as shown in FIG. 12, the manufactured sun stamper 400 is attached onto the mold core 500, and then a plurality of light guide plates are formed through repeated injection molding using the mold core 500. 30) (S114), and thus the prism pattern 32 and the scattering pattern 34 on the light guide plate 30 manufactured according to the embossed prism pattern 402 and scattering pattern 404 on the sun stamper 400 On the contrary, the intaglio is formed.

Thus, after a very long time direct processing is carried out only once once to manufacture the master block 100, using the master block 100 to manufacture the mother stamper 300 and a large number of sun stamper 400 And, since it is possible to mass-produce the light guide plate 30 using the sun stampers 400, it is possible to greatly improve the manufacturing efficiency, and also to manufacture the light guide plate 30 with excellent reproducibility and quality Will be.

In addition, although the scattering pattern 34 is formed on the prism pattern 32 of the light guide plate 30 as a whole, the light guide plate 30 is different from the light source 10 at the light incident part side of the light incident part. As a result, a dark line is generated at the edge portion with low luminance, and a white line is generated at the center portion with high luminance. Thus, in order to overcome this problem, the scattering pattern 34 is formed only at the light incident portion, or compared to other portions. By forming the scattering pattern 34 densely, it is possible to scatter the light more so that the luminance unevenness is not generated, thereby improving the display quality in accordance with the prevention of white line, dark line generation.

Finally, the prism pattern 102 on the master block 100 is first embossed to allow the prism pattern 32 on the light guide plate 30 to be finally formed to be intaglio, but the reverse may also be performed. Naturally, the scattering pattern 304 is intaglio formed on the mother stamper 300 so that the scattering pattern 34 on the light guide plate 30 is finally formed intaglio, but this may be reversed. Of course it will. That is, when the prismatic pattern 102 on the master block 100 is first formed intaglio, the prism pattern 32 on the light guide plate 30 finally manufactured is embossed, and the scattering pattern on the mother stamper 300 is also embossed. When the 304 is embossed, the scattering pattern 34 on the light guide plate 30 finally manufactured is embossed.

In the foregoing description, it should be understood that those skilled in the art can make modifications and changes to the present invention without changing the gist of the present invention as merely illustrative of a preferred embodiment of the present invention.

According to the present invention, a light guide plate capable of providing not only high brightness characteristics but also a wide viewing angle characteristic and a white line / dark line prevention effect at the light incident part is provided, thereby making it possible to achieve a significant performance improvement, and also having extremely poor manufacturing efficiency. Since the direct processing can smoothly mass-produce the light guide plate while using only once, the productivity can be improved, as well as the effect of being able to manufacture a light guide plate of excellent quality.

Claims (7)

The light guide plate of the backlight unit provided to switch the shape and path of the light incident from the light source, The light guide plate fabricates a master block on which a prism pattern is formed through direct processing, forms a plating film on the prism pattern of the master block, and removes the plating film from the master block to obtain a mother stamper. Forming a scattering pattern on the prism pattern formed to correspond to and forming a second plating film on the prism pattern of the mother stamper, and removing the second plating film from the mother stamper to obtain a sun stamper. And the step of attaching the sun stamper to a mold core and then performing injection molding using the mold core. A prism pattern formed on one surface to reflect the light incident from the light source; The scattering pattern is finely formed on the prism pattern to scatter the incident light. When the prism pattern on the master block is embossed or engraved, the prism pattern on the light guide plate, which is finally manufactured, is formed engraved or embossed, The scattering pattern on the light guide plate is finally formed when the scattering pattern is intaglio or embossed on the mother stamper is formed in the intaglio or embossed light guide plate. delete The method of claim 1, The scattering pattern is, A light guide plate of a backlight unit, characterized in that the dot (dot) pattern. The method of claim 1, The scattering pattern is, The light guide plate of the backlight unit, characterized in that formed on only the light incident portion portion to which the light is incident from the light source, or the light incident portion portion is formed more densely than other portions. delete delete delete

Images