KR101169385B1 - Method of manufacturing prism sheet having distorted surface - Google Patents

Abstract

Provided are a method of manufacturing a prism sheet having a curved surface using a difference in curing rate, and a prism sheet produced thereby. In the method of manufacturing a prism sheet according to the present invention, the prism shape formed of the photocurable resin is selectively cured by using a mask, and then cured secondly with the mask removed to form a curved surface in the prism shape. The prism sheet according to the present invention comprises a plurality of prismatic features consisting of a plurality of first and second curing regions cured by different curing rates.

Prism sheet, photocurable resin, curing rate

Description

Method of manufacturing a prism sheet having a curved surface using a difference in curing rate {METHOD OF MANUFACTURING PRISM SHEET HAVING DISTORTED SURFACE}

1 is a cross-sectional view illustrating a backlight unit of a conventional liquid crystal display device.

2 is a perspective view of a prism sheet used in a conventional backlight unit.

3 is a perspective view of another prism sheet used in a conventional backlight unit.

4 is a front view of the prism sheet of FIG. 3.

5 is a view schematically showing a method of manufacturing a prism sheet according to an embodiment of the present invention.

6 is a perspective view of a portion of a prism sheet according to one embodiment of the present invention.

7 is a plan view of a mask used in the method of manufacturing a prism sheet according to another embodiment of the present invention.

8 is a perspective view of a portion of a prism sheet according to another embodiment of the present invention.

The present invention relates to a prism sheet and a method of manufacturing the same, and more particularly, to a prism sheet having a prism shape having a curved surface and a method of manufacturing the same.

In general, a liquid crystal display device (hereinafter referred to as an LCD device) converts various electrical information generated by various devices into visual information by using a change in liquid crystal transmittance according to an applied voltage. It is an electronic device.

Since the LCD element is a display element of various information and does not have its own light emitting source, a separate device is required to lightly illuminate the entire screen of the LCD element by placing a light source on the rear thereof, wherein the device providing the light is a backlight. Unit (Back Light Unit).

According to the installation method of Cold Cathode Fluorescent Lamp (hereinafter referred to as "CCFL"), the backlight unit has a direct method of placing the lamp under the liquid crystal panel and an edge-light method of placing the lamp on the side of the light guide plate. edge-light method).

1 is a cross-sectional view illustrating a backlight unit of a conventional liquid crystal display device.

Referring to FIG. 1, the backlight unit 100 is driven by an edge-light method and includes a light source unit 110, a light guide plate 120, a reflective sheet 130, and an optical film 140. .

The light source unit 110 includes one or more CCFLs 112 and a light source reflector 114.

CCFL 112 generates light having a predetermined wavelength.

The light generated from the CCFL 112 is incident through the light guide plate 120, and the light source reflector 114 reflects the light generated from the CCFL 112 toward the light guide plate 120 so that the light is incident on the light guide plate 120. Improve the efficiency.

The reflective sheet 130 reflects the light not incident on the light guide plate 120 among the light generated by the CCFL 112 and traveling to the rear surface of the light guide plate 120 toward the light guide plate 120. The light guide plate 120 allows the light to travel toward the liquid crystal panel (not shown).

The optical film 140 includes a diffusion plate 142, a prism sheet 144, and a protective sheet 146.

The light emitted from the light guide plate 120 toward the liquid crystal panel passes through the diffuser plate 142. The diffuser plate 142 disperses the light incident from the light guide plate 120 to prevent the light from being partially concentrated and improves the luminance. Make it uniform.

The light passing through the diffusion plate 142 is sharply lowered in brightness, the prism sheet 144 is used to prevent this.

2 is a perspective view of a prism sheet used in a conventional backlight unit.

The prism sheet 144 includes a prism support 150 and a plurality of prism shapes 160 formed side by side over the entire surface of the prism support 150. The prism shape 160 has a side portion formed of the first surface 161 and the second surface 162 and forms a substantially isosceles triangle when viewed from the front. The first surface 161 and the second surface 162 generally form an angle of 90 °, but may be configured differently according to a selection.

A plurality of prism-shaped portions 160 are continuously formed on the prism support 150 to alternately form the valleys 164 and the peaks 163. The prism sheet 144 configured as described above refracts the light incident on the prism support 150 while passing through the prism shape 160. As a result, light incident at a low angle is concentrated toward the front, thereby increasing luminance in the effective viewing angle range.

However, the prism shape of the conventional prism sheet has a problem in that it is not suitable for refracting light in two dimensions because the side surface thereof is flat and refracts incident light in only one direction.

In order to solve this problem, a prism sheet having a prism shape curved to refracted incident light in two dimensions is conventionally disclosed.

3 is a perspective view of another prism sheet used in a conventional backlight unit, and FIG. 4 is a front view of the prism sheet of FIG. 3.

Referring to FIG. 3, the prism sheet 200 includes a prism support 210 and a plurality of prism shapes 220 formed on the front surface of the prism support.

The prism shape portion 220 includes a plurality of prism units 221, and the prism units 221 are formed in a line to form one prism shape portion 220.

Referring to FIG. 4, the side surface of the prism unit 221 includes a first surface 230 and a second surface 240, and both of the first surface 230 and the second surface 240 are curved. Cotton.

Since the side portions of each prism unit 221 are curved, the light passing through the prism sheet 200 is refracted in two dimensions.

The prism sheet 200 has an advantage of improving two-dimensional optical performance as compared to the conventional prism sheet 144, but there is a problem that a complicated mold design is required to manufacture the prism sheet 200.

It is an object of the present invention to provide a method for producing a prism sheet capable of producing a prism sheet having a curved surface in a relatively simple method.

Another object of the present invention is to provide a prism sheet having a curved surface capable of two-dimensionally refracting incident light.

It is still another object of the present invention to provide a method of manufacturing a prism sheet, in which defects are difficult to be visually found, and a prism sheet produced thereby.

According to an aspect of the present invention, there is provided a method of manufacturing a prism sheet, comprising: forming a plurality of prism-shaped portions of photocurable resin on a prism support; Providing a light source for irradiating light capable of curing the photocurable resin on an upper portion of the prism shape portion; Selectively irradiating light onto the prism-shaped portion to primarily cure only a portion of the prism-shaped portion; And second curing the prism-shaped portions by irradiating light to the entire region of each prism-shaped portion.

In this case, light may be selectively irradiated to the prism shape portion through a mask on which a plurality of slits or dots are formed, so that only a partial region of the prism shape portion may be first cured.

In addition, after the primary curing, light may be irradiated onto the entire surface of the prism-shaped portion in a state where the mask is removed, thereby performing secondary curing.

According to an aspect of the present invention, a prism sheet includes a prism support and a plurality of prism shapes formed on the prism support, wherein each prism shape includes a first hardened region and a second hardened region cured by different curing rates. Include.

In this case, the first hardened region and the second hardened region may be alternately formed at each prism shape.

In addition, the first and second curing regions have different refractive indices, and the first and second curing regions have different densities.

In addition, at least some of the prism shapes of the prism sheet may be formed to be irregularly curved.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred method of manufacturing a prism sheet according to the present invention and a prism sheet produced thereby.

5 is a view schematically showing a method of manufacturing a prism sheet according to an embodiment of the present invention.

First, as shown in FIG. 5, the prism sheet 300 having a plurality of prism shapes 320 having side surfaces formed on the prism support part 310 on one surface thereof is prepared. The prism shape part 320 may be formed on the prism support part 310 by a known molding process using a photocurable resin.

Next, the mask 330 in which the slit 331 is formed at regular intervals on the prism sheet 300 is positioned, and light is irradiated while the light source 340 is positioned on the mask 330. A part of the light emitted from the light source passes through the slit 331 provided in the mask 300 and is irradiated only to a part of the prism shape part 320 corresponding to the slit 331, and the remaining light is blocked by the mask. do. Therefore, only a part of the light emitted from the light source 340 passes through the slit 331 to cure only a part of the prism shape part 320 made of the photocurable resin. For convenience of description, this is referred to as primary curing, and the region of the prism shape 320 to which light is irradiated by the primary curing step is referred to as a primary curing region. Here, the amount of light may be adjusted so that the external shape of the prism shape portion 320 of the first curing region does not change during the primary curing. Although a plurality of slits are formed in the mask at regular intervals in the present embodiment, any configuration may be used so long as only a part of the light from the light source 340 can reach the prism shape portion 320 instead of the slits 331. For example, a mask in which a plurality of dots passing through the mask are regularly arranged may be used.

Next, while the mask 330 is removed, light is irradiated onto the entire surface of the prism sheet 300. This is called secondary curing, and although light is not irradiated in the first curing, the region to which light is irradiated in the secondary curing is called a secondary curing region. At the time of the second curing, the entire region of the prism shape 320 is completely cured.

 Although the change of the external shape of the prism shape part 320 does not occur at the time of primary hardening, the change of a material phase is accompanied in the photocurable resin which comprises the prism shape part 320, and the said 1st hardening area | region and the 2nd Differences in the curing rate occur between the secondary curing regions. The difference in the curing rate causes distortion in the photocurable resin constituting the prism shape part 320 during the secondary curing, and thus, the side surface of the prism shape part 320 has a curved surface at regular intervals. The configuration of the prism sheet formed by the manufacturing method will be described in more detail below with reference to the drawings.

6 is a perspective view of a portion of a prism sheet according to one embodiment of the present invention.

The prism sheet 400 according to an embodiment of the present invention includes a prism support 410 and a plurality of prism shapes 420 formed on the front surface of the prism support.

The prism-shaped portion 420 is not a straight line as the peak is shown by the dotted line due to the difference in the curing rate of the first and second curing regions, the recessed portion 440 and the protrusion 430 is predetermined It is formed at intervals, and the side surfaces thereof are also bent at predetermined intervals.

The first hardened region may form a protrusion 430, and the second hardened region may form a recessed portion 440, or vice versa.

Since the primary cured region and the secondary cured region are cured at different curing rates, after being cured, not only the geometric differences as described above, but also the density and the refractive index are different.

Since the prism sheet 400 according to the exemplary embodiment of the present invention has a curved side surface portion of the prism shape portion 420, unlike the conventional prism sheet having a flat side surface portion, the prism sheet 400 refracts light in two dimensions to provide a two-dimensional structure of the prism sheet. Optical performance can be further improved.

The above embodiment describes an example in which the prism-shaped portion 420 of the final prism sheet 400 is bent regularly by using a mask in which a plurality of slits or dots are regularly arranged, but according to the present invention described below. The embodiment describes a case of using a mask in which a plurality of dots are irregularly arranged.

7 is a plan view of a mask used in the method of manufacturing a prism sheet according to another embodiment of the present invention.

In the method of manufacturing a prism sheet according to another embodiment of the present invention, instead of a mask in which a slit is formed, a prism using a mask 500 including a plurality of dots 530 irregularly arranged on the entire surface as shown in FIG. It is distinguished from the manufacturing method of the prism sheet according to the embodiment of the present invention described above in that it comprises the step of selectively curing a part of the shape. Other configurations are the same as the configuration of the embodiment of the present invention described above, and will not be repeated. The configuration of the prism sheet formed by the manufacturing method according to another embodiment of the present invention will be described in more detail below with reference to the drawings.

8 is a perspective view of a portion of a prism sheet 600 according to another embodiment of the present invention.

The prism sheet 600 according to another embodiment of the present invention includes a prism support 610 and a plurality of prism shapes 620, 621, and 622 formed on the front surface of the prism support 610.

The prism shapes 620, 621, and 622 are irregularly vertically and vertically, rather than a straight line as shown by a dotted line, due to the difference in the curing rate between the first and second hardened regions. It is bent to form the depression 640 and the protrusion 650, and the side portion thereof is also irregularly bent. Here, the shapes of the prism shapes 620, 621, and 622 are distinguished from the prism sheet 400 shown in FIG. 6 in that the shapes of the prism shapes 620, 621, and 622 are not identical to each other, and the recesses of the respective prism shapes 620, 621, and 622 are different. The portion 640 and the protrusion 650 are not repeated at regular intervals as in the prism sheet 400 shown in FIG. 6.

This is because the pattern of the dot 530 formed in the mask 500 used in the present embodiment is irregular and light passing through the mask is irradiated to the prism sheet shapes 620, 621, and 622 irregularly during the first curing. .

After the final curing, the first and second cured regions selectively cured through the mask 500 and the second cured regions except the first cured region are cured at different curing rates. In addition to the difference, the density and the refractive index are also different.

The prism sheet 600 according to another embodiment of the present invention, because the prism-shaped portions 620, 621, 622 are irregularly curved, unlike the conventional prism sheet having a flat side surface, the prism by refracting the light in two dimensions The two-dimensional optical performance of the sheet can be further improved.

In addition, in the case where the shapes of the prism shapes 620, 621, and 622 of the prism sheet 600 are irregularly formed as described above, another optical sheet contacting the upper surface of the prism sheet 600 (not shown) Defects, such as those caused by crushed peaks 630 of the prism-shaped portions 620, 621, and 622 due to physical contact with each other, are not easily visually detected, and even when employed in the backlight, Does not affect image quality.

Preferred embodiments of the present invention described above are disclosed for purposes of illustration, and those skilled in the art having ordinary knowledge of the present invention will be able to make various modifications, changes, additions within the spirit and scope of the present invention, such modifications, changes and Additions should be considered to be within the scope of the following claims.

According to the method for producing a prism sheet according to the present invention, it is possible to produce a prism sheet having a curved surface by a relatively simple method.

The prism sheet according to the present invention has an improved two-dimensional optical performance compared to the conventional prism sheet because it refracts incident light two-dimensionally. Further, there is an advantage that a defect caused by contact with another optical sheet member or the like is difficult to be visually detected from the outside.

Claims (9)

(a) forming a plurality of prism shapes made of a photocurable resin on the prism support; (b) providing a light source for irradiating light capable of curing the photocurable resin on the prism shape portion; (c) selectively irradiating light on the prism-shaped portion to primarily cure only a portion of the prism-shaped portion; And (d) irradiating the entire area of each prism shape portion with light to cure the prism shape portions secondly, Providing a mask in which a plurality of slits or dots are formed between said steps (b) and (c) for irregularly passing light from a light source; Removing the mask between steps (c) and (d), The primary cured region and the secondary cured region are alternately formed in the prism shape, The primary curing region and the secondary curing region are different from each other in refractive index, And the primary cured region and the secondary cured region are different in density from each other. delete delete delete delete delete delete delete The method of claim 1, At least some of the prism shape is irregularly curved method of producing a prism sheet.

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