KR101603533B1 - Optical complex light guide plate with multi-layer and manufacturing method the same - Google Patents

Abstract

The present invention relates to an optical complex light guide plate having a multilayer structure and a manufacturing method thereof and, more specifically, to an optical complex light guide plate having a multilayer structure and a manufacturing method thereof, capable of preventing scratch defects due to friction with another optical sheet and obtaining an excellent optical feature and excellent light resistance by co-extruding a skin layer on one surface or both surfaces of a light guide plate to form a multilayer structure.

Description

TECHNICAL FIELD [0001] The present invention relates to an optical composite light guide plate having a multi-layer structure and a method of manufacturing the same,

The present invention relates to an optical composite light guide plate having a multilayer structure and a method of manufacturing the same, and more particularly to a composite light guide plate having an excellent optical characteristic and a high light resistance by forming a skin layer on one or both surfaces of a light guide layer by co- To a composite light guide plate for optical devices capable of preventing and preventing scratch defects due to friction with other optical sheets and a method of manufacturing the same.

Polymethyl methacrylate (PMMA) is a typical transparent resin which is used in various fields requiring excellent transparency and weather resistance and excellent mechanical properties. With the recent growth of the display industry, the demand for such transparent materials has been greatly increased, attracting great interest. In particular, in the case of a light guide plate, which is an important material of an LCD display backlight, polymethyl methacrylate has excellent optical transmittance, is small in birefringence and excellent in light resistance, and is used as a main material of optical components.

The light guide plate for backlight is a plate-shaped molded article having a function of transmitting light so as to convert the linear light source emitted from the side surface of the light guide plate to a surface light source that emits light from the entire front surface of the plate. This is because a light transmitting distance in the light guide plate is relatively long and a material having high light transmittance is required in order to prevent the light loss in the light guide plate from increasing.

However, the light guide plate made of polymethyl methacrylate has a problem in that it has low heat resistance and impact strength, has a dimensional change rate due to hygroscopicity, and has a white turbidity phenomenon, which is a limit to apply to electronic and electrical equipment which is thin.

Particularly, as the size of LCD light guide plate is increased due to the enlargement of electronic equipment, the deformation due to moisture absorption at the high temperature of polymethyl methacrylate resin light guide plate is becoming an important problem. As a result, the MS resin (MMA-styrene copolymer) partially substitutes for the MS resin (MMA-styrene copolymer) having low moisture absorption, but the MS resin (MMA-styrene copolymer) has a problem that the deformation due to moisture absorption is small but the permeability is lowered. The lowering of the luminance occurs due to the lowering of the transmittance, and the deviation of the color difference at the light-entering portion and the light-entering / leaving portion is increased. In addition, problems such as surface scratches due to optical films due to the surface of MMA-styrene copolymer being relatively more soluble than polymethyl methacrylate remain.

Korean Patent Laid-Open No. 10-2001-0095111 (Patent Document 1) discloses a resin molded article for an optical material made of a copolymer containing methyl methacrylic acid and a styrene-based monomer as a main component, and a light guide plate made of the same. However, although the water hygroscopicity is partially reduced, the visible light transmittance is decreased, and the defect due to the surface scratch is greatly increased due to the friction due to the diffusion plate.

Korean Patent Laid-Open No. 10-2010-0070143 (Patent Document 2) discloses a thermoplastic resin composition for a light guide plate having excellent moisture resistance and light resistance including a methacrylic-styrene copolymer, an ultraviolet absorber and a light stabilizer, And the light guide plate. Although the initial optical characteristics and the light resistance were excellent, there still remained a problem that the deflection of the bending property and the defective surface scratch were increased.

Therefore, development of optical composite light guide plate which can reduce defective surface scratches due to friction with other optical films such as diffuser plate and the like without causing deterioration in optical characteristics and occurrence of warping and dimensional change due to moisture And the like.

Korean Patent Publication No. 10-2001-0095111 Korean Patent Publication No. 10-2010-0070143

Disclosure of the Invention In order to solve the above problems, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide an optical film which is excellent in optical characteristics, Which is capable of remarkably reducing defective surface scratches due to friction of the light guide plate.

It is another object of the present invention to provide a method of manufacturing a composite light guide plate for an optical module having a multilayer structure as described above.

In order to accomplish the above object, the present invention provides a light guide layer comprising a methacrylic-styrene copolymer resin; And a skin layer containing a polymethylmethacrylate resin laminated on one or both surfaces of the light guide layer.

According to an embodiment of the present invention, the thickness of the skin layer is not limited, but is 5 to 15% of the total thickness of the optical composite light guide plate. The thickness of the light guide layer is not limited, Lt; / RTI > to 95% of the thickness.

According to an embodiment of the present invention, the optical composite light guide plate may be manufactured by coextrusion.

According to an embodiment of the present invention, the methacrylic-styrene copolymer resin is not limited in the content of the methacrylic resin, but may be 50 to 80% by weight. The methacrylic resin may be a methyl methacrylate homopolymer or a copolymer of methyl methacrylate and (meth) acrylic monomers, but is not limited thereto.

According to an embodiment of the present invention, the optical composite light guide plate may satisfy the following equations (1) to (2).

H? PH? 4H [Formula 1]

DE? 3.0 [Formula 2]

(In the formula 1, PH is the pencil hardness measured at a load of 500 g at 23 DEG C in accordance with JIS K5401 standard, DE is a pencil hardness measured according to JIS K7103 standard for 200 hours of QUV, It shows the difference in the value of one color (DE).)

According to another aspect of the present invention, there is provided a method of manufacturing a light guide layer including a methacrylate-styrene copolymer resin, comprising the steps of pneumatically delivering a polymethylmethacrylate-based skin layer on one side or both sides of a light- The present invention relates to a method of manufacturing a composite light guide plate.

According to an embodiment of the present invention, the manufacturing method of the optical composite light guide plate may satisfy the following expression (3).

[식 3]

[Formula 3]

(In the formula 3, T _R is the roll (Roll) setting temperature (℃) of the extruder, T _C is a set temperature (℃) of the cylinder of the extruder, T _D is a set temperature (℃) of the extruder die. )

According to an embodiment of the present invention, the thickness of the skin layer is not limited, but may be 5 to 15% of the total thickness of the optical composite light guide plate. The thickness of the light guide layer is not limited, May be 85 to 95% of the total thickness of the light guide plate.

According to the optical composite light guide plate having the multilayer structure of the present invention and the method of manufacturing the same, a polymethyl methacrylate skin layer is co-extruded on either or both sides of the light guide layer containing the methacrylic- It is possible to prevent the occurrence of warpage and increase in dimensional change due to moisture absorption and to prevent the increase in the dimensional change due to friction with other optical films such as diffusion plates There is an advantage that the surface scratch defect can be remarkably reduced.

1 is a view showing a configuration of a conventional side-type backlight.
FIG. 2 is a view illustrating a configuration of a side-view type backlight including an optical composite light guide plate according to an embodiment of the present invention.
3 is a view illustrating the configuration of a side-type backlight including a composite light guide plate for an optical system according to another embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment and a method for measuring properties of a composite light guide plate for an optical system having a multilayer structure of the present invention and a method of manufacturing the same will be described in detail below. The present invention may be better understood by the following examples, which are for the purpose of illustrating the invention and are not intended to limit the scope of protection defined by the appended claims.

The present invention has been made to suppress the occurrence of warping due to moisture absorption of the light guide plate and to remarkably reduce defective surface scratches due to friction with other optical films such as diffusion plates, And a skin layer containing a polymethylmethacrylate resin formed on either or both of the light guide layer and the light guide layer are co-extruded to produce a composite light guide plate having a multilayer structure, whereby the optical characteristics are excellent, It is possible to manufacture an optical composite light guide plate capable of preventing occurrence of warpage and increase in the dimensional change rate due to moisture absorption and significantly reducing defective surface scratches due to friction with other optical films such as diffusion plates And completed the present invention.

Hereinafter, one embodiment of the present invention will be described in more detail.

According to an embodiment of the present invention, there is provided a composite light guide plate for an optical module comprising: a light guide layer including a methacrylic-styrene copolymer resin; And a skin layer containing a polymethylmethacrylate resin formed on one or both sides of the light guide layer.

According to an embodiment of the present invention, the light guide layer may be formed to improve the visible light transmittance of the composite light guide plate of the present invention and to reduce the moisture absorption rate to prevent a change such as the occurrence of warpage.

The methacrylic-styrene copolymer resin forming the light-guiding layer may be a polymer in which a methacrylic resin and a styrene monomer are copolymerized with an optically transparent resin, as is well known in the art. The methacrylic resin may be, for example, a homopolymer of methyl methacrylate monomer or a copolymer of methyl methacrylate and (meth) acrylate monomer, but is not limited thereto.

When the methacrylic resin is a copolymer of methyl methacrylate and a (meth) acrylate monomer, the content of the (meth) acrylate monomer is not limited but may be copolymerized within about 40 wt% It is preferably copolymerized within about 30% by weight, more preferably within about 20% by weight.

The (meth) acrylate-based monomer is not limited as long as it is a monofunctional (meth) acrylate-based monomer copolymerizable with methyl methacrylate for improving processability of the light guide layer. For example, one or more of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate and octyl acrylate may be selected.

According to an embodiment of the present invention, the content of the methacrylic resin in the methacrylic-styrene copolymer resin is not limited, but may be 50 to 80% by weight, and the content of the styrene resin may be 20 to 50% by weight. When the content of the methacrylic resin and the styrene resin is within the above-mentioned range, the visible light transmittance of the light guide layer can be improved and the moisture absorption rate can be effectively reduced.

According to an embodiment of the present invention, the thickness of the light guide layer is not limited, but may be 85 to 95% of the total thickness of the optical composite light guide plate, and more preferably 80 to 90%. When the thickness of the light guide layer is less than 85% of the total thickness of the optical composite light guide plate, the moisture absorption rate may increase as the thickness of the skin layer becomes relatively thick, thereby increasing the dimensional change such as warpage . In addition, when the thickness of the light guide layer is more than 95% of the total thickness of the optical composite light guide plate, the thickness of the skin layer is relatively too thin, and the improvement in scratch resistance due to contact with the optical film, It is effective to have the thickness in the above-mentioned range.

According to an embodiment of the present invention, the skin layer may be formed to improve visible light transmittance of the composite light guide plate of the present invention and significantly reduce surface scratch defects due to friction with other optical films such as diffusion plates .

The skin layer may be formed by laminating on one or both surfaces of the light guide layer, and may contain a polymethyl methacrylate resin.

According to one embodiment of the present invention, the polymethylmethacrylate resin may be a polymethylmethacrylate resin that is optically transparent resin and is known in the art. For example, it may be a methyl methacrylate homopolymer or a copolymer of methacrylate and (meth) acrylic monomers, but is not limited thereto.

When the polymethyl methacrylate resin is a copolymer of methyl methacrylate and a (meth) acrylate monomer, the content of the (meth) acrylate monomer is not limited but may be copolymerized within about 30 wt% Preferably, it is copolymerized within about 20% by weight, more preferably within about 10% by weight.

The (meth) acrylate monomer is not limited as long as it is an alkyl acrylate monomer copolymerizable with methyl methacrylate for improving the workability of the skin layer. For example, an alkyl acrylate having 1 to 10 carbon atoms is preferable, and an alkyl acrylate having 1 to 8 carbon atoms is more preferable for improvement of processability. More specifically, one or more of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate and octyl acrylate may be selected.

According to an embodiment of the present invention, the thickness of the skin layer is not limited, but may be 5 to 15%, more preferably 6 to 13% of the total thickness of the optical composite light guide plate. When the thickness of the skin layer is less than 5% of the total thickness of the optical composite light guide plate, the increase in the thickness of the light guide layer may cause a slight improvement in scratch resistance due to contact with the optical film such as a diffusion plate, When the thickness of the skin layer is more than 15% of the total thickness of the optical composite light guide plate, the thickness of the light guide layer is too thin to increase the moisture absorption rate, and there is a fear that the dimensional change And the optical characteristics such as transmittance may be deteriorated.

The light guide layer or the skin layer according to an exemplary embodiment of the present invention may further include one or more additives selected from an antioxidant, a plasticizer, a heat stabilizer, an antistatic agent, a nucleating agent, a flame retardant, a lubricant, an impact modifier, can do.

The content of the additive may be appropriately included within a range that does not impair the physical properties of the optical composite light guide plate of the present invention. Specifically, it may be included in an amount of 0.01 to 100 parts by weight based on 100 parts by weight of the composition constituting the light guide layer or the skin layer, but is not limited thereto.

The optical composite light guide plate according to an embodiment of the present invention can satisfy the following equations (1) to (2).

H? PH? 4H [Formula 1]

DE? 3.0 [Formula 2]

(In the formula 1, PH is the pencil hardness measured at a load of 500 g at 23 DEG C in accordance with JIS K5401 standard, DE is a pencil hardness measured according to JIS K7103 standard for 200 hours of QUV, It shows the difference in the value of one color (DE).)

According to another embodiment of the present invention, there is provided a method of manufacturing a composite light guide plate for optical use comprising the step of pneumatically delivering a polymethyl methacrylate skin layer to one or both surfaces of a light guide layer comprising a methacrylic- A manufacturing method can be provided.

The methacrylic-styrene copolymer resin forming the light-guiding layer may be a polymer in which a methacrylic resin and a styrene monomer are copolymerized with an optically transparent resin, as is well known in the art.

According to an embodiment of the present invention, the content of the methacrylic resin in the methacrylic-styrene copolymer resin is not limited, but may be 50 to 80% by weight, and the content of the styrene resin may be 20 to 50% by weight.

According to an embodiment of the present invention, the thickness of the skin layer is not limited, but may be 5 to 15% of the total thickness of the optical composite light guide plate. The thickness of the light guide layer is not limited, Extruded to 85 to 95% of the total thickness.

 The co-extrusion method may be applied without limitation as long as it is a co-extrusion method well known in the art. For example, in a biaxial extruder in which a central supply block and an auxiliary supply block are connected, co-extruded in a three-layer structure of a skin layer / a light guide layer / a skin layer, or coextruded in a two-layer structure of a skin layer / But it is not limited thereto.

The method of manufacturing a composite optical waveguide plate according to an embodiment of the present invention may more preferably satisfy the following expression (3).

[식 3]

[Formula 3]

(In the formula 3, T _R is the roll (Roll) setting temperature (℃) of the extruder, T _C is a set temperature (℃) of the cylinder of the extruder, T _D is a set temperature (℃) of the extruder die. )

Set temperature and more particularly, a roll (Roll) setting temperature (T _R) of the extruder is 85 to 130 ℃, the set temperature of the extruder cylinder (T _C) is 220 to 260 ℃, the extruder die (T _D) is It is preferably 200 to 250 ° C.

According to one embodiment of the present invention, when the processing conditions of the above-mentioned temperature range are satisfied, the adhesive strength to the co-extrusion of the light guide layer and the skin layer is excellent and the water hygroscopicity is reduced. It is possible to manufacture an optical composite light guide plate having an improved transmittance and an improved transmittance.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a preferred embodiment and a method for measuring a physical property of a composite optical waveguide plate and method of the present invention will be described in detail.

Property measurement

1. Transmittance measurement

The composite light guide plate was cut into a size of 150 mm x 100 mm according to JIS K7361 standard, and then the range of 380 nm to 780 nm was measured using a transmission meter (HM-150) of Murakami Color Research Laboratory.

2. Measurement of bending properties

After cutting the specimen of the composite light guide plate according to the present invention to a size of 150 mm x 100 mm, the specimen was left in a thermo-hygrostat at 80 ° C and 90% humidity for 72 hours, and the distortion of the specimen was visually observed. According to the bending state of the specimen, it was judged as follows.

○: No bending occurred

Δ: slight bending

X: severe bending

3. Pencil hardness measurement

A specimen having a thickness of 3 mm, a length of 10 mm and a width of 10 mm was prepared, and a load of 500 g was applied to the surface of the specimen at 23 ° C five times according to JIS K5401 standard. Pencil hardness grades 4B to 4H were judged when the pencil scratch marks occurred more than once.

4. My scratch characteristics

The specimen of the composite light guide plate according to the present invention was cut into a size of 100 mm x 100 mm and then rubbed against the diffusion sheet to confirm the scratch phenomenon visually. According to the scratch state of the specimen, it was judged as follows.

○: No scratch occurred

Δ: Occurrence of scratches slightly

X: Severe scratches

5. Light Resistance

The composite light guide plate according to the present invention was irradiated with ultraviolet rays for 200 hours in a weather resistance tester (QUV, light source UVB), and then the color difference (DE) before and after irradiation was measured with a colorimeter (Color-Eye 7000A, GretagMacbeth) according to JIS K7103 Respectively.

[Example 1]

As shown in the following Table 1, a methacrylic-styrene copolymer resin (TS-1000S, Denka) for a light guide layer was supplied to a central supply block (50Φ, L / D 34, Korea Emme) of a sheet biaxial extruder, Polymethylmethacrylate resin (MMA: MA = 97: 3 copolymer, weight average molecular weight 120,000 g / mol, HP202, LGMMA) was supplied to a block (30Φ, L / D 32,

Extruded with a double layer structure of a light guide layer and a skin layer. The processing conditions were set at a cylinder set temperature of 240 占 폚, a set temperature of three rolls of 115/108/95 占 폚 and a die setting temperature of 230 占 폚, A composite light guide plate for optical use of 300 mm x 600 mm was manufactured. The thickness of the skin layer was 100 mu m and the total thickness was 3 mm. Physical properties were measured and are shown in Table 2 below.

[Example 2]

As shown in the following Table 1, a composite light guide plate for optical was produced in the same manner as in Example 1, except that coextrusion was performed with a triple structure of skin layer / light guide layer / skin layer. The thickness of the skin layer was 100 mu m, the total thickness was 3 mm, and physical properties were measured and shown in Table 2 below.

[Example 3]

As shown in the following Table 1, a composite light guide plate for optical was produced in the same manner as in Example 1, except that coextrusion was performed with a triple structure of skin layer / light guide layer / skin layer. The thickness of the skin layer was 200 mu m, and the total thickness was 3 mm. Physical properties were measured and are shown in Table 2 below.

[Comparative Example 1]

As shown in the following Table 1, a composite light guide plate for an optical device was manufactured in the same manner as in Example 1, except that the skin layer was formed to a thickness of 50 탆 in Example 1. The total thickness of the composite light guide plate was 3 mm, and physical properties were measured and shown in Table 2 below.

[Comparative Example 2]

As shown in the following Table 1, a light guide plate having a thickness of 3 mm alone was prepared as a light guide layer, and physical properties thereof were measured and shown in Table 2 below.

[Comparative Example 3]

As shown in the following Table 1, a light guide plate having a thickness of 3 mm alone as a light guide layer was prepared and polymethylmethacrylate resin alone was measured.

[Comparative Example 4]

As shown in the following Table 1, the processing conditions were set at a cylinder setting temperature of 230 占 폚, a set temperature of three rolls of 115/108/95 占 폚 and a die setting temperature of 205 占 폚, . The thickness of the skin layer was 100 mu m and the total thickness was 3 mm. Physical properties were measured and are shown in Table 2 below.

[Table 1]

[Table 2]

As shown in Table 2, the optical composite composite light guide plates of Examples 1 to 3 had a skin layer formed of methyl methacrylate resin on one side or both sides of a light guide layer composed of a methacrylic-styrene copolymer resin, It was found that not only the transmittance but also the moisture absorption was prevented and the warpage property was improved and the scratch resistance due to friction with other optical films such as diffusion plates was remarkably improved.

On the other hand, in Comparative Example 1, it was found that the skin layer was formed too thin and the improvement in the scratch resistance was insignificant. In Comparative Example 2, it was found that the scratch resistance was remarkably reduced and the pencil hardness and the light resistance were lowered by forming the light guide layer alone with the methacrylic-styrene copolymer resin. In addition, in Comparative Example 3, the warpage phenomenon was increased according to the water absorption by forming the light-guiding layer by using the polymethylmethacrylate resin alone, and in Comparative Example 4, the warpage phenomenon was increased as the processing condition was deviated, .

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Accordingly, the above description should not be construed as limiting the scope of the present invention defined by the limits of the following claims.

100: light guide plate
200: diffusion sheet
300: reflective sheet
400: light source
110: Skin layer
120: light guide layer
A: Composite light guide plate

Claims (8)

A light-guiding layer comprising a methacrylic-styrene copolymer resin;
And a skin layer containing a polymethylmethacrylate resin laminated on one or both surfaces of the light guide layer, and satisfying the following formulas 1 to 2.
H? PH? 4H [Formula 1]
DE? 3.0 [Formula 2]
(In the formula 1, PH is the pencil hardness measured at a load of 500 g at 23 DEG C in accordance with JIS K5401 standard, DE is a pencil hardness measured according to JIS K7103 standard for 200 hours of QUV, It shows the difference in the value of one color (DE).)
The method according to claim 1,
Wherein the thickness of the skin layer is 5 to 15% of the total thickness of the optical composite light guide plate and the thickness of the light guide layer is 85 to 95% of the total thickness of the optical composite light guide plate.
The method according to claim 1,
Wherein the optical composite light guide plate is manufactured by co-extrusion.
The method according to claim 1,
The methacrylic-styrene copolymer resin has a methacrylic resin content of 50 to 80% by weight,
The methacrylic resin is a methyl methacrylate homopolymer or a copolymer of methyl methacrylate and a (meth) acrylic monomer.
delete A step of pneumatically delivering a polymethyl methacrylate-based skin layer to one or both surfaces of a light guide layer formed of a methacrylic-styrene copolymer resin, and the manufacturing method of optical composite light guide plate satisfies the following formula 3 Wherein the light guide plate is made of a metal.

[Formula 3]
(In the formula 3, T _R is the roll (Roll) setting temperature (℃) of the extruder, T _C is a set temperature (℃) of the cylinder of the extruder, T _D is a set temperature (℃) of the extruder die. )
delete The method according to claim 6,
Wherein the thickness of the skin layer is 5 to 15% of the total thickness of the optical composite light guide plate and the thickness of the light guide layer is 85 to 95% of the total thickness of the optical composite light guide plate. Way.

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