KR101998851B1 - Composition for preparing optical film, optical film manufactured by the same and liquid crystal display device comprising the same - Google Patents

Abstract

The composition for forming an optical film according to an embodiment includes a UV ink, wherein the UV ink includes an oligomer, a monomer, an adhesion promoter, an initiator, and an additive.

Description

TECHNICAL FIELD [0001] The present invention relates to a composition for forming an optical film, an optical film manufactured using the same, and a liquid crystal display device including the same. BACKGROUND ART [0002]

The present invention relates to a composition for forming an optical film, an optical film, and a liquid crystal display including the same.

2. Description of the Related Art Recently, various portable electronic devices such as a mobile phone, a PDA, and a notebook computer have been developed. Accordingly, there is a growing need for a flat panel display device for a light and small size. As such flat panel display devices, a liquid crystal display (LCD), a plasma display panel (PDP), a field emission display (FED), and a vacuum fluorescent display (VFD) have been actively studied. Particularly, a liquid crystal display (LCD) is attracting attention due to advantages such as mass production technology, ease of driving means, realization of high image quality, and realization of a large area screen.

The liquid crystal display device is a transmissive display device, and displays a desired image on the screen by adjusting the amount of light transmitted through the liquid crystal layer by refractive index anisotropy of liquid crystal molecules. Therefore, in a liquid crystal display element, a back light, which is a light source that transmits the liquid crystal layer for displaying an image, is provided. Generally, the backlight can be roughly divided into two types.

The first is a side-view backlight that is installed on the side of the liquid crystal panel to provide light to the liquid crystal layer, and the second is a direct-type backlight that provides light directly below the liquid crystal panel.

The side-type backlight is provided on the side surface of the liquid crystal panel and can supply light to the liquid crystal layer through the reflection plate and the light guide plate. Therefore, since the thickness can be made thinner, it is mainly used for a notebook or the like requiring a thin display device.

However, the side-type backlight is difficult to apply to a large-area liquid crystal panel because the lamp that emits light is located on the side surface of the liquid crystal panel, and light is supplied through the light guide plate. Therefore, there has been a problem in that it is not suitable for large-area liquid crystal panel for LCD TV, which has recently been spotlighted.

The direct-type backlight is mainly used for manufacturing a liquid crystal panel for LCD TV since light emitted from a light source is directly supplied to a liquid crystal layer and thus can be applied not only to a large-area liquid crystal panel but also to a high-

On the other hand, on the other hand,

The characteristics are changed while being supplied to the liquid crystal display panel. Such an optical film can diffuse, reflect, and shield the light to maximize light efficiency and process efficiency.

Embodiments provide a composition for forming an optical film capable of improving image quality uniformity and reducing manufacturing cost, an optical film produced using the same, and a liquid crystal display device including the same.

The composition for forming an optical film according to an embodiment includes a UV ink, wherein the UV ink includes an oligomer, a monomer, an adhesion promoter, an initiator, and an additive.

An optical film according to an embodiment includes: a base layer comprising a first side and a second side opposite to each other; A support pattern located on a first surface of the base layer and including a plurality of supports; And a light shielding pattern located on a second surface of the substrate layer and including a plurality of light shielding portions including an oxide, wherein the plurality of light shielding portions include a first light shielding portion and a second light shielding portion, And at least any one of the plurality of support portions is located in an area corresponding to the space between the second light-shielding portions.

A liquid crystal display device according to an embodiment includes a liquid crystal display panel; A light source positioned behind the liquid crystal display panel; An optical film positioned between the light source and the liquid crystal display panel, the optical film comprising: a base layer comprising a first side and a second side opposite to each other; A support pattern located on a first surface of the base layer and including a plurality of supports; And a light shielding pattern located on a second surface of the substrate layer and including a plurality of light shielding portions including an oxide, wherein the plurality of light shielding portions include a first light shielding portion and a second light shielding portion, And at least any one of the plurality of support portions is located in an area corresponding to the space between the second light-shielding portions.

The composition for forming an optical film according to the embodiment includes a UV ink, and the UV ink has high viscosity and strong cohesive force. Therefore, when screen printing is performed with the UV ink, a transparent hemispherical protrusion can be formed. In addition, a plurality of hemispherical protrusions formed from the UV ink may be uniform.

An optical film according to an embodiment includes a support pattern including a plurality of supports. The support may include an air layer and a support layer. The air layer may serve as a light diffusion layer. The support can keep the substrates positioned on the optical film flat without bending mechanically.

In the liquid crystal display device according to the embodiment, it is possible to improve a hot spot phenomenon that occurs due to uneven light, especially when an LED light source is used. Further, it is possible to prevent locally unevenness and ensure the uniformity of the light irradiated from the light source. As a result, luminance and image quality uniformity can be improved. Further, only one of the diffusion plates can be used, which can reduce the cost and improve the process yield.

1 is a perspective view of an optical film according to an embodiment.
2 is a front view of a first side of an optical film according to an embodiment.
3 is a front view of a second surface of an optical film according to an embodiment.
4 is a cross-sectional view showing a section cut along the line A-A 'in Fig.
5 is an exploded perspective view of a liquid crystal display device according to an embodiment.

In the description of the embodiments, it is to be understood that each layer (film), area, pattern or structure may be referred to as being "on" or "under / under" Quot; includes all that is formed directly or through another layer. The criteria for top / bottom or bottom / bottom of each layer are described with reference to the drawings.

The thickness or the size of each layer (film), region, pattern or structure in the drawings may be modified for clarity and convenience of explanation, and thus does not entirely reflect the actual size.

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

First, a composition for forming an optical film according to an embodiment will be described in detail.

The composition for forming an optical film according to an embodiment includes a UV ink.

UV ink refers to an ink that can be cured from liquid to solid phase in seconds by causing a photochemical reaction by ultraviolet rays. The UV inks have recently been used in a wide variety of applications due to the functions of instant drying, low-temperature high-speed productivity, and pollution-free. The UV inks have high resistance to abrasion, heat resistance, solvent, and chemicals, and do not have a problem of backward sticking and blocking.

The UV ink according to this embodiment may include an oligomer, a monomer, an adhesion promoter, an initiator, and an additive.

The oligomers may include polyester acrylates, epoxy acrylates, and urethane acrylates. It is preferable to use urethane acrylate. The urethane acrylate is excellent in curability and can obtain a strong coating film, and has an advantage of curing even when the oxygen concentration is high.

The oligomer may be contained in an amount of 65 wt% to 90 wt%. When the oligomer is contained in an amount of 65 wt% or more, it can have a sufficiently high viscosity and can improve corrosion resistance and hardness. When the oligomer is contained in an amount of 90% by weight or less, the hardness can be improved while maintaining the adhesive force with the substrate surface on which the UV ink is formed.

The monomer may then comprise an acrylate monomer. The monomer can serve as a reactive diluent having viscosity control, hardenability and adhesiveness of the ink.

The monomer may be included in an amount of 5 to 15% by weight. When the monomer is contained in an amount of 5 wt% or more, the curability and adhesiveness can be improved. When the content of the monomer is 15 wt% or less, the viscosity of the UV ink can be increased.

The adhesion promoter may act to reinforce the adhesive force to the material and enhance the strength of the UV ink composition through a chemical action on the binder and the composition.

The adhesion promoter may be included in an amount of 1 wt% to 5 wt%. When the adhesion promoter is contained in an amount of 1 wt% or more, adhesion between the UV ink and the substrate surface on which the UV ink is formed can be improved. When the adhesion promoter is 5% by weight or less, it can play a role of improving the adhesive strength without lowering the physical properties of other compositions contained in the UV ink.

The initiator may generate radicals from ultraviolet light and react with the oligomer or the monomer to cause polymerization. The initiator may include a carbonyl compound, a sulfur compound, and an azo compound.

The initiator may comprise from 1% to 10% by weight. When the initiator is contained in an amount of 1% by weight or more, the curing time can be reduced. When the initiator is contained in an amount of 10% by weight or less, the polymerization can be caused well without dissolving the other composition.

The additive may include a polymerization inhibitor and an auxiliary agent. Various additives such as stabilizers and dispersants are used as the adjuvants, and they can serve as a coating reinforcing agent. The polymerization inhibitor can improve the storage stability of the UV ink.

The additive may be included in an amount of 1 wt% to 5 wt%. When the additive is contained in an amount of 1% by weight or more, the stability and dispersibility of the UV ink can be secured. When the additive is contained in an amount of 5% by weight or less, it can play a role of improving stability and dispersibility without deteriorating physical properties of other compositions.

The UV inks according to this embodiment have high viscosity and strong cohesive force. Therefore, when screen printing is performed with the UV ink, a transparent hemispherical protrusion can be formed. In addition, a plurality of hemispherical protrusions formed from the UV ink may be uniform.

The composition may vary depending on the size of the hemispherical protrusion, the degree of curing, the material of the object to be printed, the printing conditions, and the like.

Hereinafter, the optical film according to the embodiment will be described in detail with reference to Figs. 1 to 4. Fig. For the sake of clarity and conciseness, parts that are the same as or slightly similar to those described above will not be described in detail and will be described in detail in different parts.

1 is a perspective view of an optical film according to an embodiment. 2 is a front view of a first side of an optical film according to an embodiment. 3 is a front view of a second surface of an optical film according to an embodiment. 4 is a cross-sectional view showing a section cut along the line A-A 'in Fig.

1 to 4, an optical film according to an embodiment may include a base layer 10, a support pattern, and a light shielding pattern.

The base layer 10 may include a first surface 10a and a second surface 10b opposite to each other. The base layer 10 can support the support pattern and the light-shielding pattern formed thereon.

The base layer 10 may include a light-transmitting resin. The base layer 10 may include a thermoplastic resin such as polyethylene terephthalate (PET) and polycarbonate (PC).

Other additives may be further included in the base layer 10 to maintain the mechanical properties and optical stability of the optical film. For example, at least one of an ultraviolet absorber, an infrared absorber, an antioxidant, a heat stabilizer, a selective wavelength absorbent, a flame retardant, a plasticizer, a stabilizer, a lubricant, a colorant, a fluorescent whitener, and an antistatic agent may be contained in the base layer 10 .

A support pattern may be located on the first surface 10a of the substrate layer 10. [ The support pattern may include a plurality of supports 20.

The support portion 20 may have a protruding shape. The support portion 20 may have a hemispherical projection shape. That is, the support portion 20 may be in the form of a lenticular lens.

The support 20 may include an air layer 24 and a support layer 22.

The air layer 24 may have a height H of 1.0 mm to 2.0 mm. The air layer 24 may serve as a light diffusion layer.

The support layer (22) may surround the air layer (24). The support layer 22 may support the air layer 24. The support layer 22 may comprise UV inks.

The support portion 20 may have a height H of 1.0 mm to 2.0 mm. When the support portion 20 has a height H of 1 mm or more, the height of the air layer 24 included in the support portion 20 may be increased to support another substrate positioned on the optical film. When the height H of the support portion 20 is 2.0 mm or less, the amount of UV ink forming the support portion 20 can be reduced, thereby reducing the cost.

The support portion 20 may have a diameter (R) of 1 mm to 30 mm. Preferably, the support 20 may have a diameter (R) of 10 mm to 15 mm. When the diameter R of the support portion 20 is 1 mm or more, the air layer 24 included in the support portion 20 is enlarged to support the other substrate positioned on the optical film. When the diameter R of the support portion 20 is 30 mm or less, the support pattern may be invisible while supporting the other substrate. Also, the amount of the UV ink constituting the support portion 20 can be reduced, thereby reducing the cost.

The plurality of supports 20 may have the same thickness and the same diameter. In addition, the plurality of support portions 20 may be positioned with a gap corresponding to each other.

The support portion 20 can keep the substrates positioned on the optical film flat without bending mechanically.

The support 20 may be formed by printing the UV ink. In particular, the support portion 20 may be formed through a thick film screen printing. Screen printing can be performed by placing the paste on a screen having a pattern, then placing the paste directly on the substrate on which the conductive film has been formed through a screen in which the space is left empty by pushing the squeegee.

The UV inks are printed so as to be spaced apart from each other by a predetermined distance, and the diameters and heights of the respective UV inks, intervals between the UV inks and the like can be changed.

In particular, thick film screen printing is a special printing technique that increases the thickness of an image to be printed. The film thickness is raised to a certain height by applying emulsion several times, and then a screen printing plate frame is produced. The completed screen printing plate is closed except for the area where the UV ink is printed, that is, the through hole.

Next, when the prepared screen printing plate is printed by a screen printing method, UV ink is printed on the surface of the object through the through holes formed in the printing plate. That is, a transparent hemispherical protrusion is generated. At this time, hemispherical protrusions formed on the surface of the object are in a liquid state. Accordingly, the object on which the hemispherical protrusion is formed is exposed to ultraviolet (UV) light while passing through a UV drying furnace, and is instantaneously dried to form a solid support 20.

Then, the light-shielding pattern may be located on the second surface 10b of the base layer 10. The light-shielding pattern may include a plurality of light-shielding portions (30, 32).

The light shielding portions 30 and 32 may include first layers 30a and 32a and second layers 30b and 32b. The first layers 30a and 32a may function to absorb and shield light. The first layers 30a and 32a may include titanium oxide and silicon oxide.

The second layers 30b and 32b may function as diffusion diffusers for diffusing and inducing light. Further, it can function to reflect light. This makes it possible to prevent a bright line of light. That is, the light can be guided to be uniformly diffused. The second layers 30b and 32b may include titanium oxide.

When the optical film is formed on the liquid crystal display, the light shielding portions 30 and 32 may be positioned to correspond to the light source.

Referring to FIG. 3, the plurality of light-shielding portions 30 and 32 include a first light-shielding portion 30 and a second light-shielding portion 32. At least any one of the plurality of support portions 20 may be positioned in a region A between the first light shielding portion 30 and the second light shielding portion 32. [ That is, the support portion 20 may be located beside the region corresponding to the light-shielding portions 30 and 32. That is, the support portion 20 and the light shielding portions 30 and 32 may be staggered from each other.

Hereinafter, the liquid crystal display will be described in detail with reference to FIG. 5 is an exploded perspective view of a liquid crystal display device according to an embodiment.

The liquid crystal display device 1 according to the embodiment includes the upper cover 100, the liquid crystal display panel 200, the panel support 800, the protective film 330, the prism film 320, the diffusion plate 410, Film 310, a light source 510, a reflector 610, and a lower cover 700.

The liquid crystal display panel 200 may be received between the upper cover 100 and the lower cover 700. The liquid crystal display panel 200 may be seated on the panel support portion 800.

The liquid crystal display panel 200 includes a first substrate 210 on which a thin film transistor is formed and a second substrate 220 facing the first substrate 210. A liquid crystal layer (not shown) may be disposed between the first and second substrates 210 and 220. The liquid crystal display panel 200 forms a screen by adjusting the arrangement of the liquid crystal layers. However, the liquid crystal display panel 200 must receive light from the light source 510 located on the back because it is a non-light emitting device.

A driver 250 for applying a driving signal is provided on one side of the first substrate 210. The driving unit 250 includes a flexible printed circuit board (FPC) 260, a driving chip 270 mounted on the flexible printed circuit board 260, and a circuit board 260 connected to the other side of the flexible printed circuit board 260. [ (PCB, 280). The driving unit 250 shown in FIG. 3 shows a COF (chip on film) method, and other known methods such as a tape carrier package (TCP) and a chip on glass (COG) are also possible. Also, the driving unit 250 may be directly mounted on the first substrate 210.

A protective film 330, a prism film 320, a diffusion plate 410, and an optical film 310 may be formed on the back surface of the liquid crystal display panel 200.

The protective film 330 positioned at the uppermost position can protect the prism film 320 which is weak against the scratch.

The prism film 320 has a triangular columnar prism formed on a top surface thereof with a predetermined arrangement. The prism film 320 functions to condense the light diffused in the optical film 310 in a direction perpendicular to the plane of the upper liquid crystal display panel 200. Usually, two prism films 320 are used, and the micro prisms formed on each prism film 320 have predetermined angles. The light passing through the prism film 320 is almost vertically propagated to provide a uniform luminance distribution.

The diffusion plate 410 can uniformly diffuse the light passing through the optical film 310. That is, the amount of light passing through the optical film 310 may be uneven, and the diffusing plate 410 may maximize the diffusivity and uniformity of the light. This can improve the uniformity of image quality. Usually, two diffuser plates 410 are used, but only one diffuser plate 410 included in the liquid crystal display apparatus according to the embodiment can be used. That is, the uniformity of the image quality can be sufficiently improved by using only one diffusion plate 410. This is because the support pattern included in the optical film 310 described below serves as a light diffusion layer.

The optical film 310 may include a base layer (reference numeral 10 in FIG. 1, hereinafter the same), a support pattern, and a light shielding pattern.

The light-shielding pattern includes a plurality of light-shielding portions (reference numeral 30 in Fig. 1, hereinafter the same). The light-shielding portion 30 may be located in a region corresponding to the light source 510. Light may be relatively weak in the region corresponding to the region between the light source 510 and the light source 510, whereas light is strong in the region corresponding to the light source 510. That is, there is a difference in brightness of light, and light and darkness may exist. Therefore, the light-shielding portion 30 is located on the light source 510 and absorbs and shields the light, thereby reducing the contrast of the light. That is, the uniformity of light can be improved.

The support pattern includes a plurality of support portions (reference numeral 20 in Fig. 1, the same applies hereinafter). The support portion 20 may be located in a region corresponding to the space between the plurality of light-shielding portions 30. [ That is, the support portion 20 may be located in a region corresponding to the region between the light source 510 and the light source 510. When the support portion 20 is positioned directly above the light source 510, the support portion 20 can change the light path. Therefore, the shape of the support portion 20 can be seen, which may cause the support pattern to be visible and the visibility may be lowered.

The support portion 20 can keep the substrates positioned on the optical film 310 flat without mechanically bending it. Therefore, the more the number of the support portions 20 is, the more advantageous it is. In addition, the support portion 20 may be formed by the number of the light sources 510.

The light-shielding pattern, the base layer 10, and the support pattern may be sequentially disposed along the direction in which the light emitted from the light source 510 proceeds.

The light source 510 may be disposed over the entire rear surface of the liquid crystal display panel 200. The light source 510 may include a light emitting diode (LED).

The reflection plate 610 is positioned below the light source 510 and reflects the light directed downward to reflect the light to the optical film. The reflector 610 may be made of a plastic material such as polyethylene terephthalate (PET) or polycarbonate (PC).

Although not shown in the drawing, the liquid crystal display device according to the embodiment may further include a dual brightness enhanced film (DBEF). The DBEF can pass light polarized in a specific direction and reflect light vertically polarized therewith. The reflected light is turned into a polarization state that can pass through the DBEF through an optical material such as a scatterer or a retarder. Therefore, the ratio of the light used in the actual display among the lights in the non-polarized state, that is, the light utilization efficiency can be increased.

In the liquid crystal display device 1 according to the embodiment, it is possible to improve a hot spot phenomenon which occurs due to unevenness of light especially when an LED light source is used. Further, it is possible to prevent locally unevenness and ensure the uniformity of the light irradiated from the light source. As a result, luminance and image quality uniformity can be improved. In addition, since only one diffusion plate 410 can be used, the cost can be reduced and the process yield can be improved.

Here, when a light source is a light emitting diode (LED), a hot spot refers to a phenomenon that the light emitting portion is relatively brighter than the other portions in two or more arrangement structures due to the nature of the point light source itself. This is a factor that greatly degrades the quality and brightness uniformity of a screen in a case where a uniform surface light source is required.

The features, structures, effects and the like described in the foregoing embodiments are included in at least one embodiment of the present invention and are not necessarily limited to one embodiment. Further, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified in other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the present invention. It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiments may be modified and implemented. It is to be understood that the present invention may be embodied in many other specific forms without departing from the spirit or essential characteristics thereof.

Claims (23)

A base layer comprising a first side and a second side;
A support pattern located on a first surface of the base layer and including a plurality of supports; And
And a light shielding pattern located on a second surface which is an opposite surface of the first surface and including a plurality of light shielding portions including an oxide,
The plurality of light-shielding portions include a first light-shielding portion and a second light-shielding portion,
At least one supporting portion of the plurality of supporting portions is located in an area corresponding to the space between the first light-shielding portion and the second light-
Wherein the support portion comprises an air layer and a support layer surrounding the air layer,
Wherein the support layer comprises UV ink,
Wherein the UV ink comprises an oligomer, a monomer, an adhesion promoter, an initiator, and an additive. The method according to claim 1,
Wherein the oligomer comprises a polyester acrylate, an epoxy acrylate, and a urethane acrylate. The method according to claim 1,
Wherein the monomer comprises an acrylate monomer. The method according to claim 1,
Wherein the oligomer is contained in an amount of 65 wt% to 90 wt%. The method according to claim 1,
Wherein the monomer is contained in an amount of 5 to 15% by weight. The method according to claim 1,
Wherein the adhesion promoter is contained in an amount of 1 wt% to 5 wt%. The method according to claim 1,
Wherein the initiator comprises 1 wt% to 10 wt%. The method according to claim 1,
Wherein the additive is contained in an amount of 1 wt% to 5 wt%. delete The method according to claim 1,
Wherein the supporting portion has a protruding shape. The method according to claim 1,
Wherein the support has a thickness of 1.0 mm to 2.0 mm. The method according to claim 1,
Wherein the support has a diameter of 1 mm to 30 mm. The method according to claim 1,
Wherein the air layer has a height of 1.0 mm to 2.0 mm. The method according to claim 1,
The support is a transparent optical film. delete A liquid crystal display panel;
A light source positioned behind the liquid crystal display panel;
And an optical film positioned between the light source and the liquid crystal display panel,
The optical film
A base layer comprising a first side and a second side;
A support pattern located on a first surface of the base layer and including a plurality of supports; And
And a light shielding pattern located on a second surface which is an opposite surface of the first surface and including a plurality of light shielding portions including an oxide,
The plurality of light-shielding portions include a first light-shielding portion and a second light-shielding portion,
At least any one of the plurality of supporting portions is located in a region corresponding to the space between the first light-shielding portion and the second light-
Wherein the support portion comprises an air layer and a support layer surrounding the air layer,
Wherein the support layer comprises UV ink,
Wherein the UV ink comprises an oligomer, a monomer, an adhesion promoter, an initiator, and an additive. delete 17. The method of claim 16,
And the support portion has a protruding shape. 17. The method of claim 16,
And the support portion has a height of 1.0 mm to 2.0 mm. 17. The method of claim 16,
And the support portion is provided in a transparent manner. 17. The method of claim 16,
And the plurality of light blocking portions are located in regions corresponding to the light sources. 17. The method of claim 16,
And the oligomer comprises 65 wt% to 90 wt%. 17. The method of claim 16,
Wherein the light shielding pattern, the base layer, and the support pattern are sequentially disposed along a direction in which light emitted from the light source travels.

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