KR100750864B1 - Optical sheet for display - Google Patents

Abstract

Disclosed is a light sheet for a display that prevents generation of static electricity. Since the display optical sheet has a surface resistance of 10 ¹¹ Ω / cm ² or less and a constant voltage of 900 V or less, no static electricity is generated. Therefore, problems such as static marks generated in the conventional optical sheet, distortion of the optical sheet, and breakage of the sensitive LCD assembly apparatus are solved. This increases the yield of the LCD.

Description

Optical sheet for display {OPTICAL SHEET FOR DISPLAY}

1 is a diagram showing a schematic configuration of a backlight unit of a liquid crystal display device.

2 is a schematic diagram of a backlight unit of another liquid crystal display device;

Explanation of symbols on the main parts of the drawings

110,210: reflector 120,220: lamp

130: light sheet 230: diffusion / prism sheet

The present invention relates to an optical sheet for display that prevents the generation of static electricity.

Liquid crystals of a liquid crystal display (LCD), which is a kind of display, do not emit light by themselves and simply transmit or block light according to an applied electric signal. Therefore, in order to display information on the panel of the liquid crystal display device, a backlight unit that is a surface light emitting device for illuminating the panel from the rear of the panel is required.

The backlight unit has a light source for irradiating light, a light guide plate for uniformly spreading the light emitted from the light source, and a light sheet for diffusing and increasing the light passing through the light guide plate to uniformly reach the panel.

The optical sheet includes a diffuser plate for scattering light to uniform light intensity, a diffuser film, and a prism sheet for condensing the light spreading to the outside to improve luminance at the front of the panel.

By the way, the diffusion plate, the diffusion film and the prism sheet of the conventional optical sheet is a polymer resin such as polymethyl methacrylate (PMMA), polycarbonate (PC: Ploy carbonate), methyl methacrylate-styrene copolymer It is composed of a to cause static electricity. However, the static electricity generated when stacking the diffusion plate, the diffusion film, and the prism sheet of the light sheet generates static marks on the light sheet, leaving a residue, and decreasing the brightness of the LCD. When the sheets are stacked, the direction is distorted and the sensitive LCD assembly device is broken. Due to this, there is a disadvantage that the yield of the LCD is lowered.

The present invention has been made to solve the above problems of the prior art, an object of the present invention is to add a material to prevent the generation of static electricity to the optical sheet to prevent the generation of static electricity, thereby improving the yield of the product An optical sheet for display is provided.

The optical sheet for display according to the present invention for achieving the above object is a light having an upper surface is open, a lamp installed in the inside of the reflecting plate, the light is provided on the open surface side of the reflecting plate and has a diffuser plate, a diffusion film and a prism sheet A display provided with a sheet,

The light diffusion plate, the diffusion film, and the prism sheet of the optical sheet may be any one selected from a polymethyl methacrylate, a polycarbonate, and a methyl methacrylate-styrene copolymer: an antistatic oligomer = 60 to 95 wt%: 40 It forms by mixing -5 weight%.

In addition, a display optical sheet according to the present invention for achieving the above object comprises a plurality of lamps for emitting light; An upper surface of which is provided in an open case shape, the lamp is installed inside, and a reflection plate reflecting light emitted from the lamp upward; The diffuser plate of transparent resin material provided on the open surface of the reflector plate, a plurality of microlenses which are integrally formed on the bottom surface of the diffuser plate to face the lamp and diffuse the light emitted from the lamp and integrally on the top surface of the diffuser plate A diffusion / prism sheet having a plurality of prisms formed to collect light passing through the diffusion plate,

The microlens and the prism,

Formula I =

이고,

ego,

이며,

Is,

n is an integer of 8, m is an integer of 5, X is a halogen element,

It is formed of an antistatic oligomer comprising an antistatic monomer containing a quaternary ammonium salt using the amine represented by the formula (I) and a photocurable acrylate monomer (Acrylate Monomer).

Hereinafter, a display optical sheet according to embodiments of the present invention will be described in detail.

First embodiment

As shown in FIG. 1, a backlight unit of a liquid crystal display (LCD) includes a reflector 110 having an open top surface, a lamp 120 installed inside the reflector 110, and an opening of the reflector 110. It has the light sheet 130 provided in the side.

The lamp 120 emits light, and the reflector 110 reflects the light emitted from the lamp 120 toward the light sheet 130 and diffuses the light emitted from the lamp 120 to diffuse the reflection of the lamp 120. Reduces the number of bright lines generated.

The light sheet 130 passes through the diffuser plate 131, the diffuser film 133, and the diffuser film 133, which scatter light and uniform light intensity, and remove the bright lines of the lamp 120 that are not completely removed. The light has a prism sheet 135 that focuses on light that is spread outward.

The diffusion plate 131, the diffusion film 133, and the prism sheet 135 of the display optical sheet 130 according to the present embodiment are polymethyl methacrylate, polycarbonate, and methyl methacrylate in order to prevent static electricity. -A polymer resin of any one selected from styrene copolymers: antistatic oligomer = 60 to 95 wt%: 40 to 5 wt%.

The antistatic oligomer is composed of a combination of four monomers having antistatic properties and six ultraviolet-curable acrylate monomers (Acrylate Monomer), and is represented by the following Chemical Formula I.

Formula I =

이고,

ego,

이다.

to be.

At this time, it is an integer of n = 1-8, it is an integer of m = 1-5, X is a halogen element,

The optical sheet for display of Formula I is manufactured by the following method.

First, quaternary ammonium salts are synthesized using amines.

At this time, the amine used uses the secondary amine containing at least 2 hydroxyl group (-OH) in the alkyl terminal. Examples include dimethanol amines having 1 to 8 carbon atoms, diethanol amines, dipropanol amines, dibutanol amines, dipentanol amines, Dihexanol amine, diheptanol amine, dioctanol amine and the like are mainly used.

Next, the amine is neutralized with an acid to prepare a quaternary ammonium salt as an antistatic monomer. The acid used is chloric acid, sulfuric acid, phosphoric acid, acetic acid, monochloro acetic acid, trichloro acetic acid, trifluoride. Acids such as trifluoro acetic acid, fluoric acid, bromic acid, para-toluene sulfonic acid, dimethyl sulfate, diethyl sulfate, etc. Sulfuric acid derivatives and the like can be used.

Next, an epoxy alkyl acrylate is reacted with a quaternary ammonium salt in which the amine is neutralized to impart photocuring properties. In this case, the epoxy alkyl acrylates used may include 2,3-epoxypropyl acrylate (2,3-epoxypropyl acrylate), 3,4-epoxybutyl acrylate (3,4-epoxybutyl acrylate) in addition to the epoxy group, 4,5-epoxypentyl acrylate, 5,6-epoxyhexyl acrylate, 6,7-epoxyheptyl acrylate Etc. are mainly used.

For stability of the product, the quaternary ammonium salt having photocuring properties is reacted with tetrabromo dianol diacrylate (Tetrabromo dianol diacrylate, trade name saratomer 640, Saratomer) to synthesize an antistatic oligomer represented by Formula (I).

And the polymer resin of any one of the above-mentioned commercially available polymethyl methacrylate, polycarbonate and methyl methacrylate-styrene copolymer: antistatic oligomer produced by the above method = 60 to 95 wt%: 40 When it mixes-5 weight%, the optical sheet which prevents static electricity generation which concerns on a present Example is manufactured.

Next, a specific example of manufacturing the optical sheet according to the present embodiment will be described.

Production Example

Into a 2L resin kettle equipped with a strong stirrer, thermometer, dropping funnel, condenser and cooling jacket, add 105 g of ethanol amine and slowly add dropwise 114 g of trifluoroacetic acid (Aldrich, USA). At this time, the reaction temperature is completely added dropwise while not exceeding 50 ℃ and stirred at room temperature for 1 hour. Then, an antistatic quaternary ammonium salt is synthesized.

Then, 219 g of the quaternary ammonium salt and 129 g of 2,3-epoxypropyl acrylate are slowly added dropwise. At this time, the reaction temperature is completely added dropwise while taking care not to exceed 50 ℃ and stirred at room temperature for 1 hour. Then, a photocurable quaternary ammonium salt is synthesized.

Tetrabromo dianol diacrylate (Tetrabromo dianol diacrylate, trade name saratomer 640, Saratomer, Inc.) was added to 350 g of the synthesized antistatic ammonium salt, followed by stirring at room temperature for 2 hours while being careful not to exceed the reaction temperature of 50 ° C. Then, the antistatic oligomer according to the present embodiment is produced.

Then, the polymer resin of any one selected from commercially available polymethyl methacrylate, polycarbonate and methyl methacrylate-styrene copolymer: antistatic oligomer = 60 to 95% by weight: 40 to 5% by weight, and mixed The diffusion plate 131, the diffusion film 133, and the prism sheet of the optical sheet 130 according to the present embodiment were mixed by mixing 0.5 to 10% by weight of photoinitiator and 0.5 to 10% by weight of amine reaction accelerator with respect to 100% by weight of the antipolymer. (135) is prepared.

The diffusion plate 131, the diffusion film 133, and the prism sheet of the optical sheet 130 at a ratio of 5, 10, 15, 20, 25, 30, 35, 40 wt% of the antistatic oligomer according to the preparation example Each of (135) was prepared, dried at 80 ° C. with a hot wire, and cured at a light quantity of 400 mJ / cm ² . In addition, the surface resistance, constant voltage, and hardness of four corners and one center of the diffusion plate 131, the diffusion film 133, and the prism sheet 135 of the light sheet 130 are measured, respectively, and the highest values are measured. Table 1 shows.

Measured value of the display optical sheet according to the present embodiment Content (% by weight) 5 10 15 20 2 30 35 40 Surface resistance (10 ⁸ Ω / ㎠) 1000 1000 100 100 10 10 10 One Constant voltage (V) 860 850 550 350 310 130 100 80 Hardness (H) 4 3 3 3 2 2 2 2

Hardness: measured using the pencil hardness tester method of KS G2630

If the surface resistance is 10 ¹¹ Ω / cm 2 or less and the constant voltage is 1,000 V or less, no static electricity is generated. However, the display optical sheet according to the present embodiment, as shown in Table 1, the surface resistance is all 10 ¹¹ Ω / ㎠ or less, the constant voltage is 860V or less, which is much lower than the value that can generate static electricity. This prevents the generation of static electricity. And hardness is 2H and it belongs to the range of a reference value.

Second embodiment

As shown in FIG. 2, the backlight unit of a liquid crystal display (LCD) includes a reflector 210 having an open top surface, a lamp 220 installed inside the reflector 210 to irradiate light, and a diffuser. Has a prism sheet 230. The diffusion / prism sheet 230 is formed by forming the diffusion plate 131, the chemical diffusion film 133, and the prism sheet 135 as one shown in FIG. 1, and the Korean patent application 2004-81593 filed by the present applicant. It is disclosed in the call.

The diffusion / prism sheet 230 includes a diffusion plate 231 made of a transparent resin material and a microlens 233 and a prism 235 integrally formed on the bottom and top surfaces of the diffusion plate 231, respectively. The microlens 233 and the prism 235 are represented by Chemical Formula I, and are formed of an antistatic oligomer having an antistatic monomer containing a quaternary ammonium salt using an amine and a photocurable monomer bonded to the antistatic monomer. do.

The microlens 233 and the prism 235 of the diffusion / prism sheet 230 configured as described above have a surface resistance of 10 ⁷ Ω / cm 2 and 10 ¹¹ Ω / cm 2 or less, and a constant voltage of 75V and 1,000 V or less. The hardness is within 2H of the reference value.

Reference numeral 240 is a bead for increasing the transmittance.

As described above, since the display optical sheet according to the present invention has a surface resistance of 10 ¹¹ Ω / cm ² or less and a constant voltage of 900 V or less, no static electricity is generated. Therefore, problems such as static marks generated in the conventional optical sheet, distortion of the optical sheet, and breakage of the sensitive LCD assembly apparatus are solved. This increases the yield of the LCD.

In the above, the present invention has been described in accordance with one embodiment of the present invention, but those skilled in the art to which the present invention pertains have been changed and modified without departing from the spirit of the present invention. Of course.

Claims (4)

A display comprising a reflecting plate having an open top surface, a lamp provided inside the reflecting plate, and an optical sheet provided on an open surface side of the reflecting plate and having a diffusion plate, a diffusion film, and a prism sheet. The light diffusion plate, the diffusion film, and the prism sheet of the optical sheet may be any one selected from a polymethyl methacrylate, a polycarbonate, and a methyl methacrylate-styrene copolymer: an antistatic oligomer = 60 to 95 wt%: 40 It is formed by mixing -5 weight%. The display optical sheet characterized by the above-mentioned. The method of claim 1, Formula I =

ego,

Is, n is an integer of 8, m is an integer of 5, X is a halogen element, The antistatic oligomer is an optical sheet for display, characterized in that consisting of a combination of an antistatic monomer (Monomer) and a photocurable acrylate monomer (Acrylate Monomer) containing a quaternary ammonium salt using the amine represented by the formula (I). A plurality of lamps emitting light; An upper surface of which is provided in an open case shape, the lamp is installed inside, and a reflection plate reflecting light emitted from the lamp upward; The diffuser plate of transparent resin material provided on the open surface of the reflector plate, a plurality of microlenses which are integrally formed on the bottom surface of the diffuser plate to face the lamp and diffuse the light emitted from the lamp and integrally on the top surface of the diffuser plate A diffusion / prism sheet having a plurality of prisms formed to collect light passing through the diffusion plate, The microlens and the prism, Formula I =

ego,

Is, n is an integer of 8, m is an integer of 5, X is a halogen element, An optical sheet for display, characterized in that formed of an antistatic oligomer comprising a combination of an antistatic monomer (Monomer) and a photocurable acrylate monomer (Acrylate Monomer) containing a quaternary ammonium salt using the amine represented by the formula (I). The method of claim 2 or 3, The amine is a display optical sheet, characterized in that the secondary amine containing at least two hydroxyl groups (-OH) at the alkyl terminal.

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