KR20110030943A - Condensing type optical sheet - Google Patents

Abstract

PURPOSE: A condensing optical sheet is provided to have the excellent brightness and view angle as well as excellent productivity. CONSTITUTION: A structure layer(20) is formed on the base material layer(10) and has the streamline cross section. A structural layer(20) comprises a pattern part(21) and a resin part(25). The pattern part arranges the cubic structure(22) which is connected or not connected. The resin part is formed on the base material layer and the pattern part.

Description

Condensing type optical sheet

The present invention relates to a light collecting optical sheet used in a liquid crystal display device.

As the industrial society develops into an advanced information age, the importance of the electronic display device as a medium for displaying and transmitting various information is increasing day by day. CRT (Cathode Ray Tube), which has been widely used in the past, has limitations due to large installation space, which makes it difficult to increase the size. Therefore, such as liquid crystal display (LCD), plasma display panel (PDP), field emission display (FED), and organic EL It is being replaced by various flat panel display devices. Among such flat panel display devices, in particular, in the case of liquid crystal display devices (LCDs), due to the advantages of thin, light, and low power consumption as a technology-intensive device in which liquid crystal and semiconductor technologies are combined, its structure and manufacturing technology have been researched and developed. In addition to the areas where liquid crystal displays have been widely used, such as notebook computers, desktop computer monitors, and portable personal communication devices (PDAs and mobile phones), large-scale technology is gradually exceeding its limitations. It is being used as a new display device that can replace CRT, which is synonymous with display, as it is applied to large TV of TV.

In the liquid crystal display (LCD) device, since the liquid crystal itself cannot emit light, a separate light source is installed at the rear of the device to adjust the intensity of the passing light through the liquid crystal installed in each pixel to realize contrast. do. In more detail, the liquid crystal display device is a device for controlling the light transmittance by using the electrical properties of the liquid crystal material, the uniformity and the directionality is controlled by passing through various functional prism films or sheets by emitting light from the light source lamp on the back of the device Indirect light-emitting display device that implements an image by passing light through a color filter to realize red, blue, green (R, G, B) colors, and controlling the contrast of each pixel by an electric method As a light emitting device that provides a light source, it is an important component for determining image quality such as brightness and uniformity of a liquid crystal display device.

As the light emitting device, a backlight unit (BLU) is widely used, and in general, light emitted from a plurality of light sources, such as a cold cathode fluorescent lamp (CCFL), is sequentially spread on a diffusion plate, a diffusion sheet, and a prism. A sheet such as a sheet is passed through to reach the liquid crystal panel. Here, the diffusion sheet performs a function of obtaining a uniform light intensity over the entire screen, and at the same time concealing a device such as a light source mounted under the diffusion sheet from the front. The prism sheet, on the other hand, performs an optical path control function for causing the light beams from various directions passing through the diffusion sheet to be converted into a range of viewing angle θ suitable for the viewer to recognize the image.

The prism sheet has a triangular array structure having a 45 ° inclined surface for improving the brightness in the front direction. Therefore, since the angles emitted from the same type of prism are the same for each array, even if there is a small crush on the corners of the triangle or minute scratches on the inclined surface, the defects may be caused by the difference in the light paths emitted between the damaged parts and the normal parts. Will be processed. Therefore, fine foreign matters are not allowed in the production of the prism sheet, and in some cases, even the minute defects make it impossible to use the entire surface of the produced prism sheet. This leads to a decrease in productivity, which in turn is a burden of cost increase. In addition, when laminating the work on the backlight unit, several laminations are performed by manpower. The prism sheet also requires considerable attention when working by hand, and the back light unit is increased due to the increase in the TACT time required for assembling the backlight unit and the supply of manpower. This will lead to an increase in the supply cost.

In addition, the prism sheet exhibits high luminance from the front side due to side lobes, but rapidly decreases at an angle of 35 to 55 degrees from side to side, and increases to more than 55 degrees. Accordingly, the viewing angle is reduced when the prism sheet is applied. In this case, the viewing angle represents an angle at which the luminance decreases to 50% according to the angle when the luminance when viewed from the front is 100.

Accordingly, there has been a case where a prism sheet is replaced by a microlens array in a backlight unit of a display which does not require high luminance in order to prevent damage to a prism vertex angle and to remove a protective film while having good luminance and solving a viewing angle problem.

However, microlens array is not directly coated and is produced through secondary engraving using soft mold, and this secondary engraving method requires the soft mold to be replaced periodically and seams are generated at intervals as long as the circumference of the mold. There is a problem of low yield.

An object of the present invention is to provide a light collecting type optical sheet having good brightness and viewing angle and excellent productivity.

The present invention provides a preferred embodiment, comprising a base layer and a structural layer formed on the base layer and having a longitudinal cross-sectional structure, wherein the structural layer includes a pattern portion in which a three-dimensional structure is connected or not connected regularly; And a resin part formed on the pattern part or formed on the base layer and the pattern part, wherein the pattern part and the resin part provide a light converging optical sheet having the same refractive index.

In the above embodiment, the pattern portion and the resin portion may have a refractive index of 1.45 to 1.55.

In the above embodiment, the three-dimensional structure forming the pattern portion is a longitudinal cross-section is selected from the shape of circular, semi-circular, elliptical and semi-elliptic, the three-dimensional structure forming the pattern portion may be a linear arrangement or a non-linear arrangement.

In the above embodiment, the three-dimensional structure forming the pattern portion may be one of the longest length of the portion in contact with the substrate layer or the portion parallel to the substrate layer is 30 ~ 60㎛.

In the above embodiment, the three-dimensional structure forming the pattern portion is monodisperse, the dispersion degree (CV) may be less than 45%.

In the above embodiment, the resin portion may have a thickness of 10 μm or less on the pattern portion.

In the above embodiment, the resin portion may have a thickness of 15 ~ 30㎛ formed on the base layer.

In the above embodiment, the structural layer may be a height of 35 ~ 70㎛.

In the above embodiment, the structure layer may be one having a pitch of 30 ~ 80㎛.

In the above embodiment, the three-dimensional structure forming the pattern portion may be formed of selected from acrylic resin, urethane resin, styrene resin and glass.

In the above embodiment, the resin portion may be formed of one selected from acrylic resin, urethane resin and ester resin.

In the above embodiment, the base layer may be formed of a polyethylene terephthalate resin, polymethyl methacrylate resin, polycarbonate resin, polypropylene resin, polyethylene resin, polystyrene resin and styrene-acrylic copolymer resin.

As a second preferred embodiment of the present invention, a diffusion sheet; And it provides a backlight unit assembly comprising a light collecting optical sheet of the above embodiment.

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

1 is a longitudinal cross-sectional view of a light collecting optical sheet according to a preferred embodiment of the present invention, Figures 2 and 3 is a longitudinal cross-sectional view of a light collecting optical sheet according to another preferred embodiment of the present invention.

On the other hand, the accompanying drawings used the same reference numerals for the same components for convenience, they do not mean the same composition and form.

The light converging optical sheet of the present invention includes, in a first preferred embodiment, a base layer 10 and a structural layer 20 formed on the base layer 10 and having a streamlined longitudinal section, wherein the structural layer 20 The pattern portion 21 in which the connected or unconnected solid structures 22 are regularly arranged; And a resin part 25 formed on the pattern part 21 or on the base layer 10 and the pattern part 21, wherein the pattern part 21 and the resin part 25 have a refractive index. This same focusing optical sheet is provided.

After the light passing through the substrate layer 10 is incident on the structural layer 20, the pattern is refracted and diffused at the interface between the pattern portion 21 and the resin portion 25 to prevent the problem of condensing efficiency deterioration. The portion 21 and the resin portion 25 have the same refractive index.

At this time, the refractive index of the pattern portion 21 and the resin portion 25 may be in the range of 1.45 ~ 1.55 so as to favor the light collection in consideration of the optical path.

Since the three-dimensional structure 22 forming the pattern portion 21 determines the three-dimensional structure of the resin portion 25, the longitudinal cross-section may be one selected from circular, semi-circular, elliptical, and semi-elliptic to favor condensing. It may be made in only one form, or two or more different forms may be mixed, and even if the different forms are mixed or different sizes may be arranged regularly so as not to lower the light collection efficiency.

Each of the three-dimensional structures 22 forming the pattern portion 21 may be in contact with each other or may be spaced apart from each other at regular intervals.

The structure layer 20 may have a pitch (d) of 30 ~ 80㎛, each of the three-dimensional structure 22 of the portion in contact with the base layer 10 or the portion parallel to the base layer 10 The longest length (a) of the length may be 30 ~ 60㎛.

On the other hand, the structural layer 20 may have a height (h) of 35 ~ 70㎛.

The longest length (a) of the pitch (d), the height (h) of this structural layer 20 and the length of the portion in contact with the substrate layer 10 or parallel to the substrate layer 10 is emitted from the light source of the BLU High luminance can be realized while considering light diffusion.

The resin part 25 may be formed on the pattern part 21 formed of a plurality of three-dimensional structures 22 in the base layer 10, and at this time, the resin part 25 formed on the pattern part 21 may be formed. It is advantageous that the thickness b is less than or equal to 10 μm, but when the thickness b is more than 10 μm, the shape becomes smooth, the luminance is lowered, and the spacing between the three-dimensional structures 22 may be a problem for the concealable portion. Therefore, it is advantageous to provide the appropriate brightness and concealability by thinning the thickness (b) to 10 μm or less while maximally attaching the three-dimensional structure 22. This may be achieved by applying the resin for forming the resin portion 25 on the three-dimensional structure 22 and reducing the speed in the line by 0.2 to 0.5 times, but is not limited thereto.

The thickness c of the portion formed on the base layer 10 may be 15 to 30 μm to prevent the three-dimensional structure 22 from being separated.

The lower the degree of dispersion of the three-dimensional structure 22 forming the pattern portion 21, the higher the brightness, in the present invention, the dispersion degree (CV) is less than 45% to provide the appropriate brightness of the three-dimensional structure 22 good. The dispersion degree refers to the variation in the particle diameter of the three-dimensional structure 22, and the lower the dispersion degree, the more uniform the particle size may be provided in terms of brightness and concealment.

Meanwhile, the three-dimensional structure 22 may be linearly or nonlinearly arranged.

The light converging optical sheet of the present invention applies and cures a crude liquid including a three-dimensional structure 22 to one surface of the base layer 10 to form the resin portion 25 and the pattern portion 21 of the structural layer 20. It may be one. Possible coating methods may be any known coating methods such as gravure coating, and are not particularly limited.

As the base layer 10, a polyethylene terephthalate resin, a polymethyl methacrylate resin, a polycarbonate resin, a polypropylene resin, a polyethylene resin, a polystyrene resin, or a styrene-acrylic copolymer resin may be used. The base layer 10 may have a thickness of 10 to 1000 μm in terms of mechanical strength, thermal stability, and flexibility, and to prevent loss of transmitted light, and more preferably 15 to 400 μm.

As the structural layer 20, the three-dimensional structure 22 forming the pattern portion 21 may be formed of acrylic resin, urethane resin, styrene resin, and glass in consideration of refractive index, and the resin portion 25 ) May be formed of an acrylic resin, a urethane resin, and an ester resin in consideration of the refractive index.

On the other hand, although not shown, when the structural layer 20 is formed on one surface of the base layer 10, the bottom layer may be cured on the other side of the base layer 10, as known light diffusing particles Organic particles or inorganic particles can be used.

As such, the present invention may provide a backlight unit assembly including the light collecting optical sheet described above, and the light collecting optical sheet may be formed on the top layer to provide a backlight unit assembly that does not further include an additional protective sheet. .

Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited to the following Examples.

≪ Example 1 >

The 188 micrometer polyethylene terephthalate film T600 (Mitsubishi Corporation) (refractive index: 1.49) was used for the base material layer.

Designed as shown in FIG. 1 as a structural layer, 100 parts by weight of methyl ethyl ketone and 100 parts by weight of toluene were diluted in 100 parts by weight of an acrylic resin (Aekyung Chemical 52-666 (refractive index 1.49)), and the average particle diameter was 41 μm. Large diameter beads (KOLON Diasphere MH-40FD (dispersity 16.7%, refractive index 1.49)), which are spherical acrylic beads of the same type, are mixed with 200 parts by weight of the resin, dispersed in a mill, and then used as a 188 μm polyethylene terephthalate film T600. Coating on one side of (refractive index 1.494) using gravure and adjusting the line speed to 3 ~ 6m / min and dried to form a structural layer, specific values are shown in Table 1 below.

<Example 2>

Condensing was carried out in the same manner except that KOLON Diasphere MH-50FD (average particle diameter 49.7 µm, dispersion degree 14.9%, refractive index 1.49) was used as a large diameter bead to form a three-dimensional structure forming a structural layer in Example 1. A type optical sheet was prepared.

<Example 3>

Condensing was carried out in the same manner except that KOLON Diasphere MH-60FD (average particle diameter 61.2 µm, dispersion degree 18.4%, refractive index 1.49) was used as a large diameter bead to form a three-dimensional structure forming a structural layer in Example 1. A type optical sheet was prepared.

<Example 4>

In Example 1, KOLON KU-40 (average particle diameter 41 μm, dispersion degree 19%), which is a spherical urethane bead, is a large diameter bead using Aekyung Chemical AUP-310 urethane resin (refractive index 1.52) as a structural layer and forming a three-dimensional structure. A light converging optical sheet was manufactured in the same manner except for using a refractive index of 1.52).

Example 5

In Example 1, KOLON S-40P (average particle diameter 40㎛, dispersion), which is a spherical styrene bead, is a large diameter bead that uses a urethane acrylate (refractive index 1.54) of Hannong Chemical BP-032 as a structural layer and forms a three-dimensional structure. A light converging optical sheet was manufactured in the same manner except that FIG. 17.5% and a refractive index of 1.54) were used.

<Example 6>

In Example 1, a large diameter bead Soken MR-60G PMMA beads (average particle diameter 60㎛, dispersion degree 32%, refractive index 1.49) using Aekyung Chemical 52-666 acrylic resin (refractive index 1.49) as a structural layer and forming a three-dimensional structure A light converging optical sheet was manufactured in the same manner except for using).

Comparative Example 1

In Example 1, KOLON Diasphere MH-40FD (average particle diameter 41㎛, dispersion degree 16.7%, refractive index 1.49) using large diameter beads to form a three-dimensional structure using Aekyung Chemical AUP-310 urethane resin (refractive index 1.52) as a structural layer Except for using the light-collecting optical sheet was prepared in the same manner.

Comparative Example 2

In Example 1, KOLON KU-40 urethane beads (average particle diameter 41㎛, 19% dispersion, refractive index 1.52) as large-diameter beads using Aekyung Chemical 52-666 acrylic resin (refractive index 1.49) as a structural layer to form a three-dimensional structure A light converging optical sheet was manufactured in the same manner except for using).

Comparative Example 3

In Example 1, KOLON S-40P styrene beads (average particle diameter 41㎛, dispersion degree 17.5%, refractive index using large diameter beads to form a three-dimensional structure using Aekyung Chemical 52-666 acrylic resin (refractive index 1.49) as a structural layer A light converging optical sheet was manufactured in the same manner except that 1.54) was used.

<Comparative Example 4>

In Example 1, a large-diameter bead using Aekyung Chemical 52-666 acrylic resin (refractive index of 1.49) and forming a three-dimensional structure as non-spherical acryl beads KOLON Lab. A light converging optical sheet was manufactured in the same manner except that a product (refractive index of 1.47 and an average particle diameter of 39 μm) was used.

division Height (h) Pitch (d) (A) the longest of the lengths of the part which is in contact with the base material layer of the three-dimensional structure or parallel to the base material layer Thickness of the resin part formed on the three-dimensional structure (b) Thickness (c) of the resin part formed on the base material layer Example 1 43 49 41 3 20 Example 2 53 57 50 3 25 Example 3 65 69 62 4 31 Example 4 45 50 41 4 21 Example 5 45 50 41 4 21 Example 6 45 50 60 3 23 Comparative Example 1 43 49 41 3 20 Comparative Example 2 43 49 41 3 20 Comparative Example 3 43 49 41 3 20 Comparative Example 4 40 49 40 4 24

(Unit: μm)

The light converging optical sheets of Examples and Comparative Examples were laminated on the diffusion sheet (manufacturer: Kolon, trade name: LX210), and the physical properties thereof were evaluated as shown in Table 2 below.

(1) luminance evaluation

The light converging type optical sheets manufactured in Examples and Comparative Examples were mounted and fixed to the backlight unit for a 17-inch liquid crystal display panel as described above, and used at an arbitrary 13 points using a luminance meter (model name: BM-7, TOPCON, Japan). Was measured and the average value was calculated | required.

(2) half-angle

When the luminance meter (model name: BM-7, Japan TOPCON Co., Ltd.) is 100% luminance at the point perpendicular to the BLU viewed from the front of the BLU (0 degree angle), the luminance becomes 50%. The angle of measurement was measured and displayed.

division Luminance (cd / cm ² ) Relative luminance Half angle (°) Example 1 4142 100 45 Example 2 4154 100.29 45 Example 3 4152 100.24 45 Example 4 4193 101.23 46 Example 5 4217 101.81 46 Example 6 4117 99.4 44 Comparative Example 1 4082 98.55 44 Comparative Example 2 4086 98.65 44 Comparative Example 3 4068 98.21 44 Comparative Example 4 3927 94.81 43

1 is a longitudinal cross-sectional view of a light collecting optical sheet according to a preferred embodiment of the present invention;

2 and 3 are longitudinal cross-sectional views of a light converging optical sheet according to another preferred embodiment of the present invention;

4 is a SEM photograph of KOLON Diasphere MH-40FD, which is a spherical acryl beads used in Examples and Comparative Examples,

5 is a non-spherical acrylic bead used in Comparative Example 6 KOLON Lab. SEM photograph of the product.

* Explanation of the symbols of the main parts of the drawings

10: substrate layer 20: structure layer

21: pattern portion 22: three-dimensional structure

25: resin part

Claims (13)

A base layer and a structural layer formed on the base layer and having a longitudinal cross-section; The structural layer may include a pattern portion in which three-dimensional structures connected or not connected are regularly arranged; And a resin portion formed on the pattern portion or on the base layer and the pattern portion, wherein the pattern portion and the resin portion have the same refractive index. The method of claim 1, A light converging optical sheet having a refractive index of 1.45 to 1.55 in the pattern portion and the resin portion. The method of claim 1, The three-dimensional structure forming the pattern portion is a light converging optical sheet having a longitudinal cross-section, a shape selected from a circle, semicircle, ellipse, and semi-ellipse, and linearly or nonlinearly arranged. The method of claim 1, The three-dimensional structure which forms a pattern part is a light converging optical sheet whose longest length is 30-60 micrometers of the length of the part which contact | connects a base material layer, or the part parallel to a base material layer. The method of claim 1, The three-dimensional structure which forms a pattern part is monodisperse, and the light converging optical sheet whose dispersion degree (CV) is less than 45%. The method of claim 1, The resin part is a light converging optical sheet whose thickness of the part formed on the pattern part is 10 micrometers or less. The method of claim 1, The resin part is a light converging optical sheet whose thickness of the part formed on the base material layer is 15-30 micrometers. The method of claim 1, The structural layer is a light converging optical sheet having a height of 35 to 70 µm. The method of claim 1, The structural layer is a light converging optical sheet having a pitch of 30 to 80 µm. The method of claim 1, The three-dimensional structure for forming the pattern portion is a light converging optical sheet formed of selected from acrylic resin, urethane resin, styrene resin and glass. The method of claim 1, The resin part is a light converging optical sheet formed of an acrylic resin, a urethane resin, or an ester resin. The method of claim 1, The base material layer is a light converging optical sheet formed of polyethylene terephthalate resin, polymethyl methacrylate resin, polycarbonate resin, polypropylene resin, polyethylene resin, polystyrene resin, and styrene-acrylic copolymer resin. Diffusion sheet; And The backlight unit assembly comprising the light collecting optical sheet of any one of claims 1 to 12.

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