KR20100026417A - Hybrid-optical sheet and back light unit using hybrid-optical sheet - Google Patents

Abstract

PURPOSE: A hybrid-optical sheet and a back light unit using a hybrid-optical sheet are provided to induce light coming from a light source efficiently to a liquid crystal panel by forming a diffusion sheet, a prism sheet, and a protection sheet as one. CONSTITUTION: An optical sheet(20) forms a constant pattern. A protection coating film(30) is formed between each pattern. An optical diffusion coating film(40) is formed on the lower face of the optical sheet.

Description

Hybrid optical sheet for backlight {HYBRID-OPTICAL SHEET AND BACK LIGHT UNIT USING HYBRID-OPTICAL SHEET}

The present invention relates to a hybrid optical sheet that can replace a diffusion sheet, a prism sheet, and a protective sheet which are conventionally manufactured and assembled independently. Specifically, the optical sheet is manufactured integrally to realize the functions of the diffusion sheet, the prism sheet, and the protective sheet in one body, thereby implementing a slim, and easy to install during assembly, and the luminance of light incident on the liquid crystal display panel. The present invention relates to providing a hybrid optical sheet capable of realizing a high brightness liquid crystal display device, and preventing contamination and scratches caused by foreign substances on the surface of each sheet during the assembly process.

LCD is a non-light-emitting electronic display device, and has to provide a separate light source, that is, a backlight, in order to produce a clear and natural natural color of a moving image with good quality. The complex that irradiates light from the back of the liquid crystal module is called the Backlight Unit (BLU), which is classified into two types: direct type BLU and edge type BLU according to the irradiation method. In the LCD backlight unit, an edge type using a metering lamp is applied.

The direct type backlight unit is a structure in which the light generated from the lamp is uniformized using a diffusion sheet and then scans the light into the liquid crystal panel. The edge type backlight unit is a structure in which the light of the lamp is guided to the liquid crystal panel through the light guide plate. .

A configuration of a direct type backlight unit will be described with reference to FIG. 1.

As illustrated, the direct type backlight unit includes a plurality of lamps 120 installed inside the reflecting plate 110, and a diffusion plate 130 and a diffusion sheet 140 each having a predetermined pattern formed on the upper side of the lamp 120. ) Is installed. The reflector 110 reflects the light emitted from the lamp 12 toward the diffuser plate 130 and simultaneously diffuses the light emitted from the lamp 120 to reduce the number of bright lines generated by the number of lamps 120. Let's do it. The diffusion plate 130 and the diffusion sheet 140 scatter the light to uniform the brightness and at the same time remove the bright line of the lamp 120 that is not completely removed. The diffusion plate 130 may have a thickness of about 5 mm to support the panel and the backlight unit of the liquid crystal display.

On the upper side of the diffusion sheet 140, a prism sheet 150 in which a triangular prism is arranged on an upper surface of the transparent resin is installed. The light passing through the diffusion sheet 140 is spread in all directions, the prism sheet 150 is focused on the light spread to the outside to increase the luminance at the front of the panel.

However, at present, the most common structure is located at the rear of the lamp and the distance between the lamp and the diffuser plate should be maintained so that an even distribution of luminance can be obtained in the plane of the panel without the difference in luminance of the linear shape in the direction of the lamp. As a result, it requires a certain amount of volume, so that there is some difficulty in thinning can be said to be the limitation of the direct backlight unit.

In addition, the distance between the lamp and the diffuser plate must be kept constant, and it is not easy to obtain a uniform distribution of brightness. As the number of lamps increases, an inverter, a driving circuit for driving the lamp, increases and power consumption increases. do.

In addition, since the diffuser plate, the diffusion sheet, and the prism sheet, which are inserted to improve the brightness of the direct backlight unit, are separately manufactured and assembled in a stacked form, the thickness of the entire backlight unit becomes thick and the cost increases. Will occur.

The present invention has been made to solve the above-described problem, an object of the present invention is to form a diffusion sheet, a prism sheet and a protective sheet used in the backlight unit of the liquid crystal display as a single liquid crystal panel to efficiently emit light emitted from the light source The present invention provides a hybrid optical sheet for backlight that can reduce the production cost by inducing the thickness of the entire display equipment and simplifying the structure and manufacturing process.

In particular, the integrated optical sheet makes it easy to mount the backlight and improves the luminance of the light incident on the liquid crystal display panel, thereby realizing a high-brightness liquid crystal display device. It is another object of the present invention to significantly reduce the defective rate by preventing the occurrence of contamination and scratches.

The present invention provides a hybrid optical film for backlight comprising the optical sheet having a predetermined pattern and a protective coating film formed between the respective patterns and a light diffusion coating film formed on the lower surface of the optical sheet. Provide a sheet. In particular, the pattern shape of the optical sheet is controlled, the efficiency of the particles is improved by controlling the particle distribution and diameter of the transparent resin constituting the protective coating film, and the metal oxide fine particles are further added to the light diffusion coating film and the protective coating film to perform the task. Promote. That is, by integrally forming the diffusion sheet, the prism sheet, and the protective sheet used in the conventional backlight structure, it is possible to reduce the thickness of the entire backlight unit, simplify the process during manufacturing assembly, and improve the brightness.

In addition, the above-described optical sheet of the present invention may use any one selected from a prism sheet having a plurality of unit prism lens patterns, a microlens array (MLA) sheet, or a lenticular lens sheet.

In addition, the refractive index of the lens pattern formed on the optical sheet of the present invention is formed to 1.5 ~ 1.8, so that the light can be focused in the normal direction of the light exit surface.

In addition, the protective coating film of the present invention can be formed of a transparent resin in which the transparent fine particles are mixed, to improve the efficiency of light diffusion to improve the brightness.

In addition, the protective coating film of the present invention can be formed in a concave shape having a curvature so as to diffuse the light, it is possible to suppress the color unevenness, the light passing through the protective coating film can be diffused to uniform the brightness of the light Make sure

In addition, the protective coating film of the present invention may have a refractive index of 0.1 ~ 1.5.

In addition, the content of the transparent fine particles to be mixed on the protective coating film of the present invention is formed to 0.1 to 55wt% in the total weight of the protective coating film, to improve the light transmission characteristics.

In addition, the particle size of the transparent fine particles may be formed to 0.01 ~ 50㎛.

In addition, the light diffusion coating film of the present invention may be formed by dispersing the beads. This diffuses the light transmitted from the light source to remove the bright lines.

In addition, the beads described above are formed to have a particle diameter of 1 ~ 50㎛, to maximize the removal efficiency of the bright line, and to improve the light efficiency.

In addition, the beads are formed in 30 ~ 95 wt% of the total weight of the light diffusion coating film to maximize the light diffusion characteristics, and to improve the fixability of the beads.

In addition, the light diffusion coating film of the present invention may further comprise a conductive metal oxide fine particles to have an antistatic property in the light diffusion coating film.

In addition, the present invention can manufacture a backlight unit by providing a hybrid sheet for backlight according to the present invention having the above-described features. This can minimize the thickness of the entire unit, it is possible to provide a liquid crystal display panel through a high quality backlight unit excellent in the short manufacturing time and the effect of removing the bright lines due to the convenience of the manufacturing process.

According to the present invention, by forming a diffusion sheet, a prism sheet and a protective sheet used in the backlight unit of the liquid crystal display device as one, efficiently induces the light emitted from the light source to the liquid crystal panel and at the same time slimming the thickness of the entire display equipment, structure And by simplifying the manufacturing process, there is an effect of providing a hybrid optical sheet for backlight that can reduce the production cost.

In addition, by eliminating the process of assembling separate sheets and implementing various functions with one optical sheet, it eliminates the possibility of contamination or scratches that may occur during many assembly processes, shortens the production process, and It is easy to install and has the effect of providing a hybrid optical sheet capable of mass production while minimizing the defect rate.

The present invention is a hybrid optical sheet that can replace a diffusion sheet, a prism sheet, a protective sheet that is manufactured independently of the prior art and assembled in the backlight unit as described above. This simple and high brightness of the light incident on the liquid crystal display panel can realize a high purity liquid crystal display device, and can prevent contamination and scratches caused by foreign substances on the surface of each sheet during the assembly process and significantly reduce the defective rate. It is an object of the present invention to provide a hybrid optical sheet that can be made.

Hereinafter, with reference to the accompanying drawings will be described the configuration and operation of the present invention.

Referring to FIG. 2, the hybrid optical sheet 1 for backlight according to the present invention has a predetermined pattern on the upper surface of the optical sheet 10, and a protective coating film 30 is formed between the respective patterns thus formed. . In addition, a light diffusion coating film 40 is formed on the lower surface of the optical sheet 10.

Various patterns may be applied to the pattern in the optical sheet on which the predetermined pattern is formed. For example, a lenticular lens sheet or a micro lens array (MLA) in which a prism sheet or a lenticular lens is formed by arranging a prism lens at a predetermined pitch; Micro Lens Array) sheet may be utilized. In FIG. 2, an optical sheet on which a prism lens is formed will be described as an example.

That is, when the optical sheet 20 is a prism sheet on which a prism lens is formed, a prism sheet including a plurality of unit prism lenses having a specific refractive index is formed, and the light is diffused at adjacent intervals of the unit prism lens. A protective coating film 30 having a curvature is formed. In addition, the lower surface of the optical sheet 10 is formed in a structure in which a light diffusion coating film 40 is provided.

The pattern formed on the optical sheet 20 is basically capable of forming a lens pattern uniformly or non-uniformly with a micro size pitch, and the light transmitted through the light diffusion coating layer 40 from a light source is transmitted through the transparent substrate. Through the pattern (prism lens, lenticular lens, microlens, etc.), it is possible to focus a specific direction (especially the normal direction to the light emitting surface) to improve the efficiency of the backlight. The refractive index of the efficient light diffusion coating film is preferably adjusted in the range of 1.5 ~ 1.8.

Light passing through the protective coating layer 30 is diffused to serve to uniform the luminance of the light emitted from the hybrid optical sheet. In particular, the protective coating film is preferably formed to have a specific curvature, the shape of the curvature is more preferably formed to have a concave curvature in the optical sheet 10 direction. In addition, the refractive index of the protective coating film may be adjusted between 0.1 ~ 1.5.

 In particular, such curvature can suppress the occurrence of color unevenness. In addition, the protective coating film may include transparent fine particles, thereby improving light diffusion characteristics, thereby enhancing the effect of making luminance uniform.

Such transparent particles or the light diffusing beads described above may be formed using organic beads, inorganic beads, or a mixture of organic beads and inorganic beads. The inorganic beads usable include at least one compound selected from the group consisting of silica, alumina, glass, calcium carbonate, talc, mica, barium sulfate, zinc oxide, cesium oxide, titanium dioxide and tourmaline. Corresponds to

The organic beads may be at least one homopolymer selected from the group consisting of silicone resins, polyacrylates, polyurethanes, polyethylenes, polypropylenes, nylons, polystyrenes, polymethylmethacrylates and polycarbonates or copolymers of these monomers. Can be used.

The content of the transparent fine particles is preferably 0.1 to 55wt% based on the total weight of the protective coating film, in consideration of the light transmission characteristics. In addition, the average particle diameter of the transparent fine particles is preferably 0.01 ~ 50㎛.

In particular, the light diffusion coating film 40 is preferably made of a light diffusion bead having a random structure (arrangement of patterns of uniform or non-uniform size), which serves to remove the bright lines by diffusing the light transmitted from the lamp. .

The content of the light diffusion beads that are dispersed and fixed to the light diffusion coating film is preferably 30 to 95 wt% based on the total weight of the light diffusion coating film in order to enhance the properties of light diffusion and fixability of the light diffusion beads. Moreover, it is preferable that the particle diameter of the said beads is 1-50 micrometers.

In addition, to the light diffusion coating layer 40 described above, conductive metal oxide fine particles may be further added to provide antistatic properties.

The conductive metal compound fine particles may be a metal alkoxide or a protective film-forming composition including metal fine particles or metal ions and a solvent having conductivity selected from the group consisting of Li, Be and Al.

The metal alkoxide may be Si (OR) 4, Ti (OR) 4, Sn (OR) 4, Zr (OR) 4, Al (OR) 4, In (OR) 4, where R is an alkyl group having 1 to 4 carbon atoms Im) and mixtures thereof.

Alternatively, the content of the metal fine particles or metal ions may be used in the protective film forming composition of 0.01 to 10% by weight based on the solid content of the metal alkoxide.

FIG. 3 illustrates a hybrid optical sheet having the same configuration as that of FIG. 2 and implementing different shapes of patterns constituting the optical sheet 20.

That is, in addition to the prism shape described above as an embodiment, a semi-elliptic arrangement may be formed as a prism sheet as illustrated, and unit prism lenses having various shapes may be arranged in a category having the same refractive index and diffusion function. For example, hemispherical, lenticular, and polygonal shapes may also be applied.

In the case of forming the backlight unit using the hybrid optical sheet according to the present invention in which the backlight unit is integrally formed with a diffuser plate, a reflector plate, and a protective sheet, which are conventionally used in the configuration, a process of assembling a separate sheet is eliminated. In order to realize various functions with one optical sheet, it eliminates the possibility of contamination or scratch that can occur during many assembly processes, shortens the production process, and is easy to install during assembly, thereby minimizing defect rate and mass production. There is an advantage to improving productivity by enabling it. Of course, as described above, it is possible to implement a device having a high efficiency and a high brightness while thinning a device such as an LCD using the backlight unit.

In the detailed description of the invention as described above, specific embodiments have been described. However, many modifications are possible without departing from the scope of the invention. The technical spirit of the present invention should not be limited to the described embodiments of the present invention, but should be determined not only by the claims, but also by those equivalent to the claims.

1 is a view showing the configuration of a conventional direct type backlight unit.

2 is a diagram illustrating a configuration of a hybrid optical sheet according to the present invention.

3 is a view showing the configuration of a hybrid optical sheet according to another embodiment according to the present invention.

Claims (13)

An optical sheet having a predetermined pattern formed thereon; A protective coating film formed between the patterns; And And a light diffusion coating film formed on the lower surface of the optical sheet. The method according to claim 1, The optical sheet is any one selected from among a prism sheet, a microlens array (MLA) sheet, or a lenticular lens sheet having a plurality of unit prism lens patterns. The method according to claim 2, The refractive index of the lens pattern formed on the optical sheet is a hybrid optical sheet for backlight, characterized in that 1.5 ~ 1.8. The method according to claim 1, The protective coating film is a hybrid optical sheet for a backlight, characterized in that formed of a transparent resin mixed with transparent fine particles. The method according to claim 1, The protective coating film is a hybrid optical sheet for a backlight, characterized in that formed in a concave shape having a curvature so as to diffuse light. The method according to claim 1, The protective coating film is a hybrid optical sheet for backlight, characterized in that the refractive index is 0.1 ~ 1.5. The method according to claim 4, The content of the transparent fine particles is a hybrid optical sheet for backlight, characterized in that 0.1 to 55wt% in the total weight of the protective coating film. The method according to claim 4, The particle size of the transparent fine particles is a hybrid optical sheet for backlight, characterized in that 0.01 ~ 50㎛. The method according to claim 1, The light diffusion coating film is a hybrid optical sheet for backlight, characterized in that the beads are formed by dispersing arrangement. The method according to claim 9, The bead hybrid optical sheet for a backlight, characterized in that the particle diameter of 1 ~ 50㎛. The method according to claim 9, The bead is a hybrid optical sheet for backlight, characterized in that 30 to 95 wt% of the total weight of the light diffusion coating film. The method according to claim 9, The light diffusion coating film is a hybrid optical sheet for a backlight, characterized in that further comprises conductive metal oxide fine particles. In the backlight unit comprising a hybrid optical sheet for transmitting the light of the light source in the upward direction, The hybrid optical sheet, A predetermined pattern is provided on the optical sheet, and a protective coating film is formed between the patterns, and a light diffusion coating film is provided on the lower surface of the optical sheet.

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