CN1755401A - Blooming, have the backlight assembly of this film and have the display device of this film - Google Patents

Abstract

An optical film includes a base layer, a resin layer, and a plurality of hollow particles. The resin layer is provided on the surface of the base layer. The hollow particles are disposed within the resin layer. Each of the hollow particles has an outer shell defining an interior space of the hollow particle. The hollow particles reflect or transmit light due to the difference in refractive index between the outer shell and the inner space.

Description

Optical film, back light assembly with the film and display device with the film

This application claims the benefit of Korean Patent Application No. 2004-78310 filed on October 1, 2004 and Korean Patent Application No. 2004-99383 filed on November 30, 2004, the contents of which are hereby incorporated by reference in their entirety.

technical field

The present invention generally relates to an optical film, a backlight assembly having the optical film, and a display device having the optical film. In particular, the present invention relates to an optical film having improved diffusivity and reflectivity, a rear light assembly having the optical film, and a display device having the optical film.

Background technique

Generally, since a liquid crystal display panel is not self-illuminating, a liquid crystal display device displays images using external light passing through the liquid crystal display panel or internal light provided by a rear light assembly provided, for example, on the liquid crystal display panel. light source under the board.

The rear light assembly includes a lamp unit, a light guide plate, a reflection plate (or a reflection sheet) and an optical sheet. The lamp unit generates light, and the light guide plate guides the light emitted from the lamp unit to the liquid crystal display panel. The reflective plate is disposed under the light guide plate and reflects light leaked from the light guide plate back to the light guide plate. The optical sheet enhances brightness of light emitted from the light guide plate.

Figures 1A through 1C depict a variety of conventional optical films. In particular, FIG. 1A is a cross-sectional view of a diffusely reflective sheet, FIG. 1B is a cross-sectional view of a laminated reflective sheet, and FIG. 1C is a cross-sectional view of a metallized film.

Referring to FIG. 1A , the diffuse reflection sheet includes polyethylene terephthalate (PET) 10 formed therein with air spaces 12 such as air bubbles. The diffuse reflection sheet has a first protective PET 14 disposed on the first surface of the PET 10 and a second protective PET 16 disposed on the second surface of the PET 10. The diffuse reflection sheet utilizes the different diffuse reflection light of the PET 10 and the refractive index of the air space 12. The diffuse reflection sheet has beneficial properties such as low manufacturing cost and high diffusion of light, and also has beneficial properties such as low reflectivity of light and relatively large thickness.

Referring to FIG. 1B, the laminated reflective sheet includes a plurality of first films 20, 24 and 28 having isotropic materials, and second films 22 and 26 having a different refractive index from the first films 20, 24 and 28. . Second films 22 and 26 are disposed between first films 20, 24 and 28, respectively. As a result, the laminated reflective sheet regularly reflects light. The laminated reflective sheet has some advantages, such as high reflectivity of light and relatively small thickness, but the diffused property of light of the laminated reflective sheet is low.

Referring to FIG. 1C , the metallized film has a PET layer 30 , a silver coating 32 and a passivation layer 34 . The silver coating 32 is formed on the surface of the PET layer 30 , and the passivation layer 34 is formed on the silver coating 32 . Disadvantages of this metallized film include low reflectivity of light and low diffusion of light.

Accordingly, there is a need for optical films with improved diffusivity and reflectivity.

Contents of the invention

The present invention provides a thinner optical film with improved diffusivity and reflectivity.

The present invention also provides a rear light assembly with the above optical film.

The present invention also provides a display device having the above-mentioned optical film.

In one aspect of the present invention, an optical film includes a base layer, a resin layer, and a plurality of hollow particles. The resin layer is provided on the base layer. The hollow particles are disposed within the resin layer.

In yet another aspect of the invention, a backlight assembly includes a lamp and an optical film. The lamp generates light, and the optical film reflects the light so that the optical characteristics of the light are improved. The optical film includes a base layer, a resin layer disposed on the base layer, and a plurality of hollow particles disposed within the resin layer.

In yet another aspect of the present invention, a display device includes a light source, a liquid crystal display panel, and an optical film. The light source generates light. The liquid crystal display panel displays images using a potential difference applied to a liquid crystal layer. The optical film diffusely reflects the light from the lamp toward the liquid crystal display panel. The optical film includes a base layer, a resin layer, and a plurality of hollow particles disposed in the resin layer.

In yet another aspect of the present invention, the display device includes at least two display panels and at least one backlight assembly. The display panel displays images. The rear light assembly provides light for the display panel and includes a reflective sheet to reflect the light. The reflection sheet includes a base layer, a resin layer arranged on the base layer, and a plurality of hollow particles arranged in the resin layer.

According to the above, since the hollow particles are coated on the base layer of the optical film, the diffusivity and reflectivity of the optical film can be improved.

Description of drawings

In conjunction with the accompanying drawings and the following detailed description, the above-mentioned and other beneficial effects of the present invention can be clearly drawn:

1A to 1C are cross-sectional views of common optical films;

Figure 2 is a cross-sectional view of an optical film according to a representative embodiment of the present invention;

3 is a cross-sectional view of hollow particles shown within the optical film of FIG. 2;

Fig. 4 is a schematic diagram of the size, reflection treatment and transmission treatment of the hollow particles shown in Fig. 2;

5A to 5C are views illustrating reflection viewing angle characteristics of an exemplary optical film;

6A to 6C are views illustrating reflection angle characteristics of an optical film;

7A to 7C are views illustrating reflection viewing angle characteristics of an optical film in a vertical direction;

8A to 8C are views illustrating reflection angle characteristics of an optical film in a horizontal direction;

9A is a schematic diagram of a method for measuring brightness;

Figure 9B is a schematic diagram of a test point positioned (map) on a test substrate;

Figure 10 is an exploded perspective view of a rear light assembly according to a representative embodiment of the present invention;

Fig. 11 is a schematic diagram of the light guiding process of the light guide plate in Fig. 10;

Figure 12 is an exploded perspective view of a rear light assembly according to yet another representative embodiment of the present invention;

13 is an exploded perspective view of a liquid crystal display device according to a representative embodiment of the present invention;

14 is an exploded perspective view of a liquid crystal display device according to yet another representative embodiment of the present invention;

15 is an exploded perspective view of a liquid crystal display device according to another representative embodiment of the present invention;

16 is an exploded perspective view of a liquid crystal display device according to another representative embodiment of the present invention;

17A is an exploded perspective view of a liquid crystal display device according to yet another representative embodiment of the present invention;

Figure 17B is a partially enlarged schematic view of the reflective sheet in Figure 17A;

Fig. 18 is an assembled perspective view of the liquid crystal display device in Fig. 17;

Figure 19 is a cross-sectional view along line I-I' in Figure 18; and

FIG. 20 is an enlarged schematic view of part "A" of FIG. 19 .

Detailed ways

It will be understood that when an element or layer is referred to as being "on," "connected to," or "coupled to" another element or layer, it means that it is directly on, connected to, or bonded to another element or layer. elements or layers, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers present. Like reference numerals refer to like elements throughout the text. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

It will be understood that although the terms first, second, etc., may be used herein to describe various elements, components, regions, layers and/or sections, which elements, components, regions, layers and/or sections Should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.

Spatial terms such as "under", "beneath", "below", "above", "above" and similar terms are used herein to make the The description of the relationship of one element or feature to another element or feature is simplified. It will be understood that spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "below" can include both an orientation below and an orientation above. The device may be positioned differently (rotated 90 degrees or at other orientations) and the spatially relative descriptions used herein interpreted accordingly.

The terminology used herein is only used to describe these typical embodiments, not to limit the present invention. As used herein, the singular forms, "a" and "the" also include plural forms unless the context clearly dictates otherwise. It will be further understood that the term "comprising", when used in the specification, indicates the presence of described features, integers, steps, operations, elements and/or components, but does not exclude the presence or addition of one or more other features , as a whole, steps, operations, elements, components and/or combinations thereof.

Unless otherwise defined, all terms (including technical and scientific terms) used herein are as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be construed in accordance with their meaning in the context of the relevant art, and not in an ideal or highly formal sense, unless explicitly so expressly in the text definition.

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

Figure 2 is a cross-sectional view of an optical film according to a representative embodiment of the present invention. 3 is a cross-sectional view of hollow particles of the optical film shown in FIG. 2 .

Referring to FIGS. 2 and 3 , the optical film 40 includes a base layer 41 , a resin layer 42 , a plurality of hollow particles 43 , a metal layer 44 and a passivation layer 45 . A resin layer 42 is formed on the base layer 41 with hollow particles 43 in the resin layer 42 . The metal layer 44 is formed under the base layer 41 , and the passivation layer 45 is formed under the metal layer 44 .

The base layer 41 comprises a polyethylene terephthalate material. The resin layer 42 includes a polyurethane material.

Hollow particles 43 may be round, spherical or similar in shape. The hollow particles 43 diffusely reflect light provided from an external light source through the outer surface of the hollow particles 43 . The outer surface of the hollow particle 43 can have various cross-sections, such as circular, elliptical, etc. shapes. The size of the diameter of the hollow particles 43 is determined in consideration of the wavelength of light supplied to the hollow particles 43 . Specifically, when red light is supplied to the hollow particle 43, in order to be able to effectively reflect the red light, the diameter of the hollow particle 43 corresponds to a wavelength of about 650 nm. Furthermore, when green light is supplied to the hollow microparticles 43, in order to effectively reflect the green light, the diameter of the hollow microparticles 43 corresponds to a wavelength of about 550 nm. In addition, when blue light is supplied to the hollow microparticles 43, in order to effectively reflect the blue light, the diameter of the hollow microparticles 43 corresponds to a wavelength of about 450 nm.

The diameter of the hollow particles 43 may be approximately 2.9λ/2 to 3.1λ/2. In a representative embodiment, the hollow particles 43 have a diameter of approximately 3λ/2. "λ" represents the wavelength of standard light of green light having a wavelength of about 550 nm. For example, when the wavelength of red light is about 650 nm, the diameter of the hollow particles 43 is about 97.5 angstroms. When the wavelength of green light is about 550 nm, the diameter of the hollow particles 43 is about 82.5 angstroms. When the wavelength of the blue light is about 450 nm, the diameter of the hollow particles 43 is about 67.5 angstroms.

As shown in FIG. 3, the thickness of the shell 43a of the hollow particle 43 is about 0.49λ to about 0.51λ. In a representative embodiment, the shell 43a has a thickness of about 22.0 Angstroms to 33.1 Angstroms.

The hollow particle 43 includes a first resin, and reflects light supplied to the hollow particle 43 using a difference in refractive index between the first resin and the inner space 43 b of the hollow particle 43 . The resin layer 42 includes a second resin having a different refractive index from the first resin. The resin layer 42 reflects the light provided to the resin layer 42 by utilizing the difference in refractive index between the first resin and the second resin. The second resin includes a transparent material.

The hollow particle 43 transmits the light supplied to the hollow particle 43 due to the difference in refractive index between the first resin and the inner space 43b.

The metal layer 44 includes a material with high reflectivity, such as silver (Ag) or aluminum (Al).

Hereinafter, the transmission operation and reflection operation of the hollow particles 43 will be described with reference to FIG. 4 .

FIG. 4 illustrates a schematic diagram of the reflection operation and transmission operation of the hollow particles 43 shown in FIG. 2 .

Referring to FIG. 4 , part LR1 of the first light LI1 provided to the outer surface of the hollow particle 43 is reflected by the outer surface at the same angle as the first incident angle θi11, and the remaining part LT1 of the first light LI1 is at the first angle of incidence θi11. A transmission angle θt11 passes through the outer surface, for example, the first transmission angle θt11 is smaller than the first incidence angle θi11.

A part LTR1 of the light LT1 transmitted through the outer surface is reflected by the inner surface of the hollow particle 43 at the same angle as the second incident angle θi12, and the remaining part LTT1 of the light LT1 passes through the inner surface at the second transmission angle θt12, For example, the second transmission angle θt12 is larger than the second incident angle θi12.

On the other hand, a part LR2 of the second light LI2 provided to the outer surface of the hollow particle 43 is reflected by the outer surface at the same angle as the third incident angle θi21, and the remaining part LT2 of the second light LI2 is reflected at the third incident angle θi21. A transmission angle θt21 passes through the outer surface, for example, the third transmission angle θt21 is smaller than the third incidence angle θi21.

The part LTR2 of the light LT2 transmitted through the outer surface is reflected by the inner surface of the hollow particle 43 at the same angle as the fourth incident angle θi22, and the remaining part LTT2 of the light LT2 passes through the inner surface at the fourth transmission angle θt22, For example, the fourth transmission angle θt22 is larger than the fourth incident angle θi22.

As described above, since the outer surface of the hollow particle 43 has a circular shape or the like, the hollow particle 43 can diffuse and reflect light supplied to the hollow particle 43 in a more efficient manner.

5A to 5C are views illustrating reflection viewing angle characteristics of an optical film. Particularly, Fig. 5 A represents the view that comprises the first diffuse reflection sheet of E60L (trade name produced by Toray, Japan), and Fig. 5B represents the view of the second diffuse reflection sheet comprising MCPET (trade name produced by Idemitsu Corporation, Japan). A view of reflection viewing angle characteristics, FIG. 5C shows a view of reflection viewing angle characteristics of a reflective sheet according to an embodiment of the present invention. The reflective viewing angle characteristics of the optical film were measured using an Ezcontrast (contrast) 160R instrument (trade name produced by ELDIM, France) when light was presented to the optical film at an angle of approximately 10 degrees to the front of the optical film . In FIGS. 5A to 5C , as the shaded area becomes darker, the amount of reflected light decreases, and as the distance from the shaded area increases, the amount of reflected light increases.

Referring to FIG. 5A to FIG. 5C , the first diffuse reflection sheet can increase the viewing angle of reflected light more than the second diffuse reflection sheet. However, the reflective sheet according to an embodiment of the present invention can increase the viewing angle of the reflected light even more than the first diffuse reflective sheet.

6A to 6C are views illustrating reflection angle characteristics of an optical film. In particular, FIG. 6A represents a view of the reflection angle characteristics of a first diffuse reflection sheet comprising E60L, FIG. 6B represents a view of the reflection angle characteristics of a second diffuse reflection sheet comprising MCPET, and FIG. A view of the reflective angle properties of a reflective sheet.

Referring to FIGS. 6A to 6C , the first diffuse reflection sheet in FIG. 6A can increase the reflection angle of reflected light more than the second diffuse reflection sheet in FIG. 6B . However, the reflective sheet according to one embodiment of the present invention (FIG. 6C) can increase the reflection angle of the reflected light even more than the first diffuse reflective sheet.

7A to 7C are views illustrating reflection viewing angle characteristics of an optical film in a vertical direction. In particular, FIG. 7A shows a view of the reflection viewing angle characteristics of the first diffuse reflection sheet including E60L in the vertical direction, and FIG. 7B shows a view of the reflection viewing angle characteristics of the second diffuse reflection sheet including MCPET in the vertical direction. FIG. 7C shows A view of the reflective viewing angle characteristics of the reflective sheet according to an embodiment of the present invention in the vertical direction.

8A to 8C are views illustrating reflection angle characteristics of an optical film in the horizontal direction. In particular, FIG. 8A shows a view of the reflection angle characteristics of the first diffuse reflection sheet including E60L in the horizontal direction, FIG. 8B shows a view of the reflection angle characteristics of the second diffuse reflection sheet including MCPET in the horizontal direction, and FIG. 8C shows A view of the reflection angle characteristics of a reflective sheet according to an embodiment of the present invention in the horizontal direction.

FIG. 9A is a schematic diagram of a method of measuring brightness. Figure 9B is a schematic diagram of the test points positioned (MAP) on the test substrate after one hour. Figure 9B shows the eighty-one test points positioned on the test substrate in the form of a matrix of nine rows and nine columns. The luminance in FIG. 9A was measured by a RISA test system produced by HI-LAND Corporation of Japan. In FIG. 9B , as the shaded area becomes darker, the amount of reflected light decreases, and as the distance from the shaded area increases, the amount of reflected light increases.

Referring to FIGS. 9A and 9B , a reflection sheet 52 is disposed under a plurality of lamps 50 , and a diffusion sheet 54 is disposed above the lamps 50 . Each lamp 50 comprises a cold cathode fluorescent tube having a diameter of about 1.8 mm and a length of about 91 mm. Furthermore, the thickness of the diffusion sheet 54 is about 2mm, and the reflective sheet according to the present invention is different from the traditional reflective sheet applied in the conventional liquid crystal display device.

Table 1 shows the measured luminance at the positioning test points on the test substrate one hour after the lamp was energized.

Table 1 Thickness s(μm) Brightness (49/81)[%] Average Brightness (49/81)[mcd] Average Brightness (25/81)[mcd] Maximum Brightness [mcd] Comparative example 1 975 99.7 2452 2800 3034 Comparative example 2 188 96.8 2416 2760 2989 Comparative example 3 65 89.6 2235 2516 2815 example 1 65 100 2495 2820 3067

In Table 1, Comparative Example 1 and Comparative Example 2 represent the first diffuse reflection sheet and the second diffuse reflection sheet which are substantially the same as the diffuse reflection sheet of FIG. 1A , respectively. Comparative Example 3 shows the laminated reflective sheet of FIG. 1B, and Example 1 shows a reflective sheet according to an embodiment of the present invention.

As shown in Table 1, the thicknesses of the first diffuse reflection sheet, the second diffuse reflection sheet and the laminated reflection sheet are 975 μm, 188 μm and 65 μm, respectively. On the contrary, the reflective sheet according to an embodiment of the present invention has a thickness of 65 μm. Therefore, the reflective sheet is thinner than the first and second diffuse reflective sheets.

Furthermore, Table 1 shows the brightness measured on 49 of the 81 positioning test points. When it is assumed that the measured luminance in Example 1 is 100%, the luminances in Comparative Example 1, Comparative Example 2, and Comparative Example 3 are represented by 99.2%, 96.8%, and 89.6%, respectively. That is, the luminance measured in Example 1 is larger than those measured in Comparative Example 1, Comparative Example 2, and Comparative Example 3.

Further, Table 1 shows the average brightness measured at 45 of the 81 positioning test points. The average luminances measured in Comparative Example 1, Comparative Example 2, and Comparative Example 3 are represented by 2452mcd, 2416mcd, and 2235mcd, respectively. In contrast, the average luminance measured in Example 1 is represented by 2495mcd. That is, the average luminance measured in Example 1 was greater than those in Comparative Examples 1, 2, and 3.

Further, Table 1 shows the average brightness measured at 25 positioning test points among the 81 test points. The average luminances measured in Comparative Example 1, Comparative Example 2, and Comparative Example 3 are represented by 2800 mcd, 2760 mcd, and 2516 mcd, respectively. On the contrary, the average luminance measured in Example 1 is represented by 2820mcd. That is, the average luminance measured in Example 1 was greater than those in Comparative Examples 1, 2, and 3.

The maximum luminances in Comparative Example 1, Comparative Example 2, and Comparative Example 3 are represented by 3040 mcd, 2989 mcd, and 2815 mcd, respectively. In contrast, the maximum luminance in Example 1 is represented by 3067mcd. That is, the maximum luminance measured in Example 1 was larger than those in Comparative Examples 1, 2 and 3.

Hereinafter, a representative embodiment of a rear light assembly having a reflective sheet according to the present invention will be described with reference to the accompanying drawings.

Figure 10 is an exploded perspective view of a backlight assembly according to a representative embodiment of the present invention.

Referring to FIG. 10 , the rear light assembly 100 includes a light generating part 110 , a light guide plate 120 , an inverted prism film 130 and a reflective sheet 140 .

The light generating part 110 has a lamp 112 , a lamp shade 114 , a first electric wire 115 , a second electric wire 116 and a connector 118 . A voltage is supplied to the lamp 112 via the connector 118, the first wire 115 and the second wire 116, and the lamp 112 generates light in response to the applied voltage. The lamp cover 114 partially covers the lamp 112 and a portion of the reflective sheet 140 . The structure of the reflective sheet 140 is substantially the same as that of the optical film 40 in FIGS. 2 and 3 .

The light guide plate 120 is disposed between the inverted prism film 130 and the reflective sheet 140 . A plurality of prisms are formed on a side of the light guide plate 120 facing the reflective sheet 140 , and the prisms extend in a direction substantially perpendicular to the longitudinal direction of the lamp 112 . The prisms of the light guide plate 120 guide light from the light generating part 110 and the reflective sheet 140 to the inverted prism film 130 .

In a cross-sectional view of the prism of the light guide plate 120, each pitch of the prism has a circular, parabolic shape, or the like. In a representative embodiment, the curvature of the prism tapers proportionally to the distance between the lamp 112 and the slope of the prism.

The inverted prism film 130 is disposed over the light emitting surface of the light guide plate 120 . The inverted prism film 130 diffuses and collects light guided by the light guide plate 120 to control brightness characteristics of the light. Each slope of the inverted prism film 130 extends in a direction substantially parallel to the longitudinal direction of the lamp 112 .

The reflective sheet 140 is disposed under the light guide plate 120 and reflects light leaked from the light guide plate 120 . In one representative embodiment, the backlight assembly 100 includes a flexible reflective sheet; however, it will be understood that a rigid reflective sheet could also be used for the backlight assembly 100 instead of a flexible reflective sheet.

As described above, in the rear light assembly 100 having the light guide plate 120 having the prisms formed on the rear surface of the light guide plate 120 facing the reflective sheet 140 . The prism extends in a direction substantially perpendicular to the longitudinal direction of the lamp 112, and the slope of the prism is circular in a region adjacent to the lamp. Accordingly, the rear light assembly can prevent light rays from appearing at corners of the light incident portion of the light guide plate 120 .

FIG. 11 is a schematic diagram of the light guide treatment of the light guide plate shown in FIG. 10 .

Referring to FIGS. 10 and 11 , the first light I from the lamp 112 is incident on the incident surface of the light guide plate 120 and is guided by the light guide plate 120 . As a result, the first light I is emitted from the light emitting surface of the light guide plate 120 through the first light guide process of the light guide plate 120 .

Part of the first light I is leaked from the reflective surface of the light guide plate 120 . The second light II representing a portion of the light leaked from the reflective surface is reflected by the reflective sheet 140 and diffused through the light guide plate 120 . As a result, the second light II is emitted from the light emitting surface of the light guide plate 120 through the second light guide process of the light guide plate 120 . Also, the third light III representing the remaining part of the light leaked by the reflective surface is reflected from the reflective sheet 140 and diffusely passes through the light guide plate 120 . As a result, the third light III is emitted from the light emitting surface through the third light guiding process of the light guiding plate 120 . The third light III diffused by the light guide plate 120 is more diffuse than the second light II.

12 is an exploded perspective view of a backlight assembly according to yet another representative embodiment of the present invention.

Referring to FIG. 12 , the rear light assembly 200 includes a light source 210 , a light guide plate 220 , a receiving container 230 and a reflection sheet 240 . The light source 210 generates light, and the light guide plate 220 receives the light of the light source 210 and changes the path of the light. The receiving container 230 receives the light source 210 and the light guide plate 220 . The reflective sheet 240 reflects light leaked from the light guide plate 220 . The reflective plate 240 has substantially the same structure as the optical film 40 in FIGS. 2 and 3 and includes hollow particles 43 (see FIGS. 2 and 3 ) to improve diffusivity and reflection characteristics.

The light source 210 includes a plurality of dot-shaped light emitting diodes (LEDs), and is disposed adjacent to the side of the light guide plate 220 .

The light guide plate 220 has an incident surface, a light emitting surface and a reflecting surface. The incident surface receives light from the light source 210 . The light emitting surface extends from a first end portion of the incident surface in a direction substantially perpendicular to the incident surface. The reflective surface extends from the second end of the incident surface in a direction substantially parallel to the light emitting surface.

The reflective sheet 240 is disposed between the reflective surface of the light guide plate 220 and the receiving container 230 and reflects the light leaked from the reflective surface to the light guide plate 220 . The size of the reflection sheet 240 corresponds to the size of the reflection surface of the light guide plate 220 .

The rear light assembly 200 further includes a plurality of optical sheets 250 disposed above the light emitting surface of the light guide plate 220 . The optical sheet 250 improves the optical characteristics of the light emitted from the light emitting surface. The optical sheet 250 includes a diffusion sheet and at least one collection sheet. Therefore, the optical sheet can improve the brightness and viewing angle of the light emitted from the light emitting surface.

Hereinafter, various liquid crystal display devices having the optical film will be described with reference to the accompanying drawings.

Fig. 13 is an exploded perspective view of a liquid crystal display device according to a representative embodiment of the present invention.

Referring to FIG. 13 , a liquid crystal display device 300 includes a light control part 320 , a polarizing plate (not shown), and a liquid crystal panel 360 . The light control portion 320 includes light from the lamp 330 , and the polarizing plate polarizes the light passing through the light control portion 320 . The liquid crystal panel 360 includes a color filter substrate 362 , a thin film transistor substrate 364 , a source printed circuit board 370 , a source driver 366 and a gate driver 368 . The liquid crystal panel 360 displays images using the light polarized by the polarizing plate.

Lamp 330 may include a variety of light sources such as cold cathode fluorescent, light emitting diode, external electrode fluorescent, and the like.

The lamp control part 320 includes sheets or plates to improve brightness and viewing angle of light from the lamp 330 and provides the liquid crystal panel 360 with light having improved brightness and an improved viewing angle.

The lamp 330 is disposed near a side of the light guide plate 322 . Light from the lamp 330 is provided to the light guide plate 322 and is reflected from the reflective surface of the light guide plate 322 or the reflective sheet 321 disposed under the light guide plate 322 . The reflected light is emitted from the light guide plate 322 and provided to the diffusion film 323 . The diffuser film 323 diffuses the reflected light and provides diffused light to the inverted prism film 324 . The inverted prism film 324 collects the diffused light from the diffusion film 323 and provides the collected light to the liquid crystal panel 360 . The structure of the reflection sheet 321 is substantially the same as that of the optical film 40 in FIGS. 2 and 3 , with hollow particles 43 therebetween (see FIGS. 2 and 3 ) to improve the diffusion and reflection characteristics of the reflection sheet 321 .

The inverted prism film 324 includes a plurality of prisms formed on a surface facing the diffusion film 323, and the light guide plate 322 includes a plurality of prisms formed on the reflective surface. The prisms of the inverted prism film 324 extend in a first direction, and the prisms of the light guide plate 322 (see FIG. 10 ) extend in a second direction substantially perpendicular to the first direction. Therefore, the prisms of the inverted prism film 324 straddle the prisms of the light guide plate 322 .

FIG. 14 is an exploded perspective view of a liquid crystal display device according to still another representative embodiment of the present invention.

Referring to FIG. 14 , a liquid crystal display device 400 includes a light control part 420 , a polarizing plate (not shown), and a liquid crystal panel 460 . The light control part 420 controls the light from the plurality of lamps 430 , and the polarizing plate polarizes the light passing through the light control part 420 . The liquid crystal panel 460 includes a color filter substrate 462 , a thin film transistor substrate 464 , a source printed circuit board 470 , a source driver 466 and a gate driver 468 . The liquid crystal panel 460 displays images using the light polarized by the polarizing plate.

Each lamp 430 may comprise a cold cathode fluorescent, light emitting diode, or external electrode fluorescent.

The lamp control part 420 includes a plurality of sheets or a plurality of plates to improve brightness and a viewing angle of light from the lamp 430 and provides the liquid crystal panel 460 with light having improved brightness and an improved viewing angle.

The lamps 430 are disposed under the liquid crystal panel 460 substantially parallel to each other. The light from the lamp 430 is directly supplied to the diffusion film 423 or is supplied to the diffusion film 423 after being reflected by the reflection sheet 421 disposed under the lamp 430 . The diffusion film 423 diffuses the light supplied to the diffusion film 423 , and the light diffused by the diffusion film 423 is supplied to the inverted prism film 424 . The inverted prism film 424 collects the light diffused by the diffusion film 423 . The structure of the reflection sheet 421 is basically the same as that of the optical film 40 in FIGS. 2 and 3 , and includes hollow particles 43 (see FIGS. 2 and 3 ) to improve the diffusion and reflection properties of the reflection sheet 421 .

The inverted prism film 424 includes a plurality of prisms formed on a face facing the diffusion film 423 . The prisms of the inverted prism film 424 extend in a first direction substantially parallel to the longitudinal direction of the lamp 430 .

Also, the light intensity of the first region of the inverted prism film 424 corresponding to the lamps 430 is greater than the light intensity of the second region of the inverted prism film 424 between the lamps 430 . In the present embodiment, the inclination angle of the prisms of the inverted prism film 424 is changed corresponding to the position of the lamp 430, so the brightness uniformity of the light from the inverted prism film 424 is improved. For example, prisms having a relatively large inclination angle may be formed at a first region of the inverted prism film 424 , and prisms having a relatively small inclination angle may be formed at a second region of the inverse prism film 424 .

Fig. 15 is an exploded perspective view of a liquid crystal display device according to yet another representative embodiment of the present invention.

Referring to FIG. 15 , a liquid crystal display device 500 includes a lamp 530 , a light control part 520 and a liquid crystal panel 560 . The light control part 520 includes a light guide plate 522 , a reflective sheet 521 and an inverted prism film 523 . The light guide plate 522 and the reflective sheet 521 provide light generated by the lamp 530 to the inverted prism film 523 . The inverted prism film 523 diffuses and collects light, and the liquid crystal panel 560 displays images through the light emitted from the inverted prism film. The liquid crystal panel 560 includes a color filter substrate 562 , a thin film transistor substrate 564 , a source printed circuit board 570 , a source driver 566 and a gate driver 568 . The structure of the reflection sheet 521 may be basically the same as that of the optical film 40 in FIGS. 2 and 3 and include hollow particles 43 (see FIGS. 2 and 3 ) to improve the diffusion and reflection properties of the reflection sheet 521 .

Lamp 530 may comprise a cold cathode fluorescent, light emitting diode, or external electrode fluorescent.

The light guide plate 522 has a plurality of prisms formed on the reflective surface of the light guide plate 522 facing the reflective sheet 521 . The prisms of the light guide plate 522 collect light supplied to the light guide plate 522, and thus the light collected by the prisms is output from the light emitting surface of the light guide plate 522 in a direction substantially perpendicular to the light emitting surface. The inverted prism film 523 receives the light output from the light guide plate 522 and collects the light. Accordingly, the light collected by the inverted prism film 523 is provided to the liquid crystal panel 560 .

The prisms of the inverted prism film 523 are formed on the face facing the light guide plate 522 and extend in a direction substantially parallel to the longitudinal direction of the lamp. The prisms of the light guide plate 522 extend in a direction substantially perpendicular to the longitudinal direction of the lamp 530 .

Fig. 16 is an exploded perspective view of a liquid crystal display device according to still another representative embodiment of the present invention.

Referring to FIG. 16 , the liquid crystal display device includes a rear light assembly 200 , a display unit 620 and a top plate 630 . The rear light assembly 200 generates light, and the display unit 620 displays images through the light from the rear light assembly 200 . The top plate 630 fixes the display unit 620 to the rear light assembly 200 .

In this embodiment, the structure of the rear light assembly 200 is basically the same as that of the rear light assembly 200 in FIG. 12 , so further repeated descriptions of these elements are omitted.

The receiving container 260 includes a chassis 262 and a molded frame 264 . The molding frame 264 has four sidewalls to guide the receiving positions of the light source 210 and the light guide plate 220 , and the bottom surface of the molding frame is open. The chassis 262 has a bottom surface and four sidewalls extending from the bottom surface of the chassis 262 . The chassis 262 is attached to the molded frame 264 by hooks.

The reflective sheet 240 , the light source 210 , the light guide plate 220 and the optical sheet 250 are sequentially received into the receiving container 260 .

The display unit 620 is disposed on the back light assembly 200 and displays an image using light output from the back light assembly 200 .

In particular, the display unit 620 includes a liquid crystal panel 624 , a driving device 626 and a flexible circuit part 628 . The drive device 626 can be implemented together with an IC chip.

The liquid crystal panel 624 has a first substrate, a second substrate and a liquid crystal layer (not shown). A second substrate is bonded to the first substrate and a liquid crystal layer is disposed between the first substrate and the second substrate.

A driving device 626 is mounted on the first substrate and provides driving signals for the data lines and the gate lines. The driving device 626 may have, for example, two chips, one for data lines and the other for gate lines. In an alternative embodiment, the driving device 626 may have one integrated chip for the data lines and the gate lines. The driving device 626 is mounted on the first substrate through a chip on glass (COG) process.

Furthermore, the flexible circuit component 628 is connected to the first substrate and provides control signals to the driving device 626 . An anisotropic conductive film electrically connects the flexible circuit component 628 to the first substrate. A timing controller to control the timing of the drive signals and a memory to store data signals are mounted on the flexible circuit member 628 .

FIG. 17A is an exploded perspective view of a liquid crystal display device according to still another representative embodiment of the present invention. FIG. 17B is a partially enlarged view of the reflective sheet in FIG. 17A.

Referring to FIGS. 17A and 17B , the liquid crystal display device 700 includes a display panel assembly 710 , a first rear light assembly 720 , a second rear light assembly 730 , a top plate 740 , a molding frame 750 and a bottom plate 760 . The first rear light assembly 720 and the second rear light assembly 730 generate light.

The display panel assembly 710 includes a main display panel 721 , a sub display panel 722 , a first printed circuit board 723 , a second printed circuit board 724 and an integrated circuit chip 725 .

The size of the main display panel 721 is larger than that of the sub-display panel 722 . Furthermore, the liquid crystal display device 700 can be used in a foldable mobile phone. In this foldable mobile phone, a main display panel 721 is provided inside the foldable mobile phone and a sub display panel 722 is provided outside the foldable mobile phone. Thus, when the foldable portable phone is closed, the sub-display panel 722 displays relatively little information on its display screen due to its small size. Likewise, when the foldable portable phone is opened, the main display panel 721 displays relatively much information on its display screen due to its large size.

Since the sub display panel 722 is smaller in size than the main display panel 721 , the second backlight assembly 730 is smaller in size than the first backlight assembly 720 .

In FIGS. 17A and 17B , a liquid crystal display device 700 having a main display panel 721 and a sub display panel 722 opposite to the main display panel 721 is described, however, the present invention is not limited to this embodiment, and the liquid crystal display device 700 The structure and composition can vary.

Further, although a liquid crystal display device 700 having two display panels 721 and 722 has been described in FIGS. 17A and 17B, the present invention should not be limited to this representative embodiment. That is, the liquid crystal display device 700 may have two or more display panels. Although a liquid crystal display device 700 having two liquid crystal display panels has been described in FIGS. 17A and 17B, the present invention should not be limited to this representative embodiment. That is, the liquid crystal display device 700 may have at least one liquid crystal display panel and a light receiving type display panel.

Hereinafter, the internal structure of the main display panel 721 will be described. The sub display panel 722 has the same structure as the main display panel 721, and thus the description of the sub display panel 722 will be omitted.

The main display panel 721 includes a thin film transistor substrate 721b having a transparent glass substrate on which a plurality of thin film transistors are formed in a matrix shape. The thin film transistor includes a source, a gate and a drain. The source is electrically connected to the data line, and the gate is electrically connected to the gate line. The drain is electrically connected to the pixel electrode. The pixel electrode includes a transparent conductive material such as indium tin oxide.

The main printed circuit board 770 is electrically connected to the data lines and the gate lines. When an electrical signal from the main printed circuit board 770 is applied to the data line and the gate line, the thin film transistor is turned on or turned on in response to an electrical signal supplied to the source and gate via the data line and the gate line. due. Therefore, the drain of the thin film transistor outputs electrical signals required for forming pixels.

The main display panel 721 further includes a color filter substrate 721a facing the thin film transistor substrate 721b. The color filter substrate 721a is disposed over the thin film transistor substrate 721b. The color filter substrate 721a has RGB pixels and a common electrode. RGB pixels are formed on a substrate by thin film processing, and a predetermined color is expressed by using light passing through the RGB pixels. A common electrode is formed on the RGB pixels and includes indium tin oxide. When the thin film transistor is turned on corresponding to an electrical signal applied to the source and the gate, an electric field is formed between the pixel electrode and the common electrode. The alignment angle of the liquid crystal injected into the space between the thin film transistor substrate 721b and the color filter substrate 721a is changed by the electric field. Therefore, the light transmittance (corresponding to the alignment angle of the liquid crystal) changes, so the main display The plate 721 can display desired pixels. Two polarizing plates (not shown) are connected to the outer surfaces of the thin film transistor substrate 721b and the color filter substrate 722a, respectively.

The secondary display panel 722 also includes a color filter substrate 722a and a TFT substrate 722b, and their configuration is substantially the same as that of the color filter substrate 721a and TFT substrate 721b of the main display panel 721 .

The integrated circuit chip 725 provides driving signals and clock signals for the gate lines and data lines, so as to control the alignment angle and alignment time of the liquid crystal. An integrated circuit chip 725 is connected to a thin film transistor substrate 721b and surrounded by a passivation layer 726 . The integrated circuit chip 725 generates data signals, data signals for driving the main display panel 721 and a plurality of clock signals to provide the main display panel 721 with data signals and gate signals in time. Gate signals and data signals are applied to the gate and data lines, respectively. The second printed circuit board 724 receives the driving signal from the main display board 721 and provides the driving signal to the auxiliary display board 722 through another integrated circuit chip.

A plurality of resistors 7703 are mounted on the main printed circuit board 770 for supplying signals to the first printed circuit board 723 , and a connector 7701 of the folder type portable phone is mounted on the main printed circuit board 770 . The first printed circuit board 723 electrically connects the main display board 721 with the main printed circuit board 770 . In FIGS. 17A and 17B , the first printed circuit board 723 may be divided into two parts, but the two parts of the first printed circuit board 723 are electrically connected to each other.

The first back light assembly 720 and the second back light assembly 730 are disposed between the main display panel 721 and the sub display panel 722 . The first rear light assembly 720 and the second rear light assembly 730 provide light to the main display panel 721 and the sub display panel 722, respectively.

The molding frame 750 receives the first rear light assembly 720 and the second rear light assembly 730 . The second backlight assembly 730 is smaller than the first backlight assembly 720 and their structures are substantially the same. Although a liquid crystal display device 700 having two backlight assemblies 720 and 730 has been described in FIGS. 17A and 17B, the present invention should not be limited to this representative embodiment. That is, the liquid crystal display device 700 may have a rear light assembly to provide light to the main display panel 721 and the sub-display panel 722 .

The first rear light assembly 720 includes a first light source 782 , a first light guide plate 727 , a first reflection sheet 728 and a first optical sheet 729 . The first light source 782 generates light, and the first light guide plate 727 guides the light to the main display panel 721 . The first reflective sheet 728 reflects the light to the first light guide plate 727 , and the first optical sheet 729 increases the brightness of the light and provides the light with the increased brightness to the main display panel 721 .

In FIGS. 17A and 17B , the first light source 782 includes light emitting diodes mounted on a substrate 786, but the first light source 782 may include lamps or line light sources and surface light sources using light emitting diodes. Also, in FIGS. 17A and 17B, the first light source 782 includes three light emitting diodes, but the number of light emitting diodes may be changed.

The substrate 786 is electrically connected to the main printed circuit board 770 and receives light control signals from the printed circuit board 770 . A first light source 782 disposed on a substrate 786 operates in response to the light control signal. The second backlight assembly 730 having substantially the same structure as the first backlight assembly 720 includes a second light source 784 , a second light guide plate 732 , a second reflective sheet 734 and a second optical sheet 736 .

The molding frame 750 receives the first light source 782 disposed on the substrate 786 , the display panel assembly 710 , the first backlight assembly 720 and the second backlight assembly 730 .

The top pan 740 is disposed above the display panel assembly 710 , and the bottom pan 760 is disposed below the display panel assembly 710 . A top pan 740 and a bottom pan 760 are joined to side surfaces of the molding frame 750 . The main printed circuit board 770 covers the bottom surface of the chassis 760 into which the molded frame 750 is received.

In the liquid crystal display device 700 according to a representative embodiment of the present invention, at least one of the first reflective sheet 728 and the second reflective sheet 734 may include a hybrid reflective sheet. Due to the inherent nature of multiple layers, the hybrid reflective sheet has a multilayer structure and reflects most of the light supplied to the hybrid reflective sheet. In particular, since the hybrid reflective sheet can be used instead of the blocking sheet, the liquid crystal display device 700 does not need to have the blocking sheet. Accordingly, the thickness of the liquid crystal display device 700 and the number of elements therein can be reduced, so that characteristics of the liquid crystal display device 700, such as thickness, weight, size, or strength, can be improved.

In the liquid crystal display device in FIGS. 17A and 17B , the first reflection sheet 728 includes an enhanced spectral reflection (ESR) sheet and the second reflection sheet 734 includes the hybrid type reflection sheet. However, the first reflective sheet 728 and the second reflective sheet 734 according to the present invention should not be limited to this representative embodiment. That is, the first reflective sheet 728 may include the hybrid reflective sheet and the second reflective sheet 734 may include the enhanced spectrum reflective sheet. Also, the first and second reflective sheets 728 and 734 may include the hybrid reflective sheet.

In the liquid crystal display device 700, since the second reflective sheet 734 is turned upside down, the rear surface and the front surface of the second reflective sheet 734 switch positions. Hereinafter, the structure of the second reflective sheet 734 viewed from the upper side of the liquid crystal display device 700 will be described with reference to FIG. 17B .

The second reflection sheet includes a base layer 734b and a resin layer 743a disposed on the base layer 734b. The resin layer 743a has a plurality of hollow particles 734a1 incorporated in the resin layer 743a. The second reflective sheet may further include still another layer as necessary. In particular, the second reflective sheet 734 may further include a reflective metal layer 734c disposed directly under the base layer and a passivation layer 734d directly disposed under the reflective metal layer 734c.

The resin layer 734a may include polyurethane. The hollow particle 734a1 may include a transparent resin layer and the inner space of the hollow particle 734a1 may be empty. Part of the light supplied to the resin layer 734a is reflected by the surface of the hollow particle 734a1, and the remaining part of the light is provided to the inner space of the hollow particle 734a1. Since the resin layer 734a has a different refractive index from the transparent resin layer of the hollow particles 734a1, the light supplied to the resin layer 734a is diffusely reflected. In particular, since the transparent resin layer of the hollow particles 734a1 has a different refractive index from the internal space, light supplied to the resin layer 734a is diffusely reflected. Since the inner space of the hollow particle 734a1 is filled with air, the refractive index of the inner space is about 1.

The hollow particles 734a1 have, for example, a cylindrical shape or a spherical shape, so light is diffusely reflected by the hollow particles 734a1. The diameter of the hollow particles 734a1 corresponds to the wavelength of light supplied to the resin layer 734a. When "λ" is assumed to be the wavelength of green light with a wavelength of about 550 nm, the diameter of the hollow particle 734a1 is about 2.9λ/2 to about 3.1λ/2 or approximately 3.0λ/2. Especially, when the wavelength of red light is about 650 nm, the diameter of the hollow particles 734a1 is about 97.5 angstroms. When the wavelength of green light is about 550nm, the diameter of the hollow particles 734a1 is about 82.5 angstroms. When the wavelength of the blue light is about 450 nm, the diameter of the hollow particles 734a1 is about 67.5 angstroms. The thickness of the shell of the hollow particle 734a1 is about 0.49λ to about 0.51λ or approximately 0.5λ, thereby improving the efficiency of diffuse reflection.

The base layer 734b includes a resin, such as a polyethylene terephthalate-based resin. The base layer 734b is disposed directly under the resin layer 734a and supports the resin layer 734a. The base layer 734b receives light passing through the resin layer 734a.

A reflective metal layer 734c is disposed directly under the base layer 734b and reflects light transmitted through the base layer 734b to the base layer 734b. The reflective metal layer 734c includes a material with high reflectivity, such as silver (Ag) or aluminum (Al). Therefore, the second reflective sheet 734 reflects most of the light provided to the second reflective sheet 734 , thereby reducing the light loss of the second reflective sheet 734 . The passivation layer 734d is disposed directly under the reflective metal layer 734c and can prevent the second reflective sheet 734 from splitting.

FIG. 18 is an assembled perspective view of the liquid crystal display device of FIG. 17A .

Referring to FIG. 18, a liquid crystal display device 700 has a reflective sheet according to the present invention, thereby increasing the brightness of light and displaying clear images. Also, since the liquid crystal display device 700 can prevent leakage of light, light can be provided to only one of the main display panel and the sub display panel on which an image is displayed.

Fig. 19 is a cross-sectional view taken on line I-I' in Fig. 18 . FIG. 20 is an enlarged schematic view of part "A" of FIG. 19 . FIG. 19 shows the main display panel 721, the first backlight assembly 720, the second backlight assembly 730, and the sub-display panel 722 stacked in sequence, and FIG. 20 shows a reflection path of light output from the light source.

Referring to FIG. 19 and FIG. 20 , the first reflective sheet 728 of the first rear light assembly 720 is in contact with the second reflective sheet 734 of the second rear light assembly 730 . Since the second reflective sheet 734 serves as a blocking sheet, light passing through the first reflective sheet 728 after being output from the first light source is reflected by the second reflective sheet 734 . Therefore, the liquid crystal display device does not require a separate barrier sheet.

As shown in FIG. 20 , the light output from the second light source is supplied to the second reflection sheet 734 through the resin layer 734 a of the second reflection sheet 734 . Light supplied to the second reflection sheet 734 is diffusely reflected by the resin layer 734a. Since the hollow particles 734a1 are incorporated into the resin layer 734a, the resin layer 734a can diffusely reflect the light efficiently. Next, light passing through the resin layer 734a is reflected from the reflective metal layer 734c. Therefore, the second reflective sheet 734 can reflect most of the light supplied to the second reflective sheet 734 , thereby reducing the light loss of the second reflective sheet 734 .

As described above, the optical film includes polyurethane resin and the hollow particles added to the polyurethane and covered on the metal-coated film, thereby improving the diffusivity and reflectance of the optical film. The hollow particles include a transparent resin, and the inner spaces of the hollow particles are empty. Therefore, the hollow particles can reflect the light due to the difference in refractive index between the transparent resin and the inner space.

Furthermore, the reflective sheet of the liquid crystal display device includes the base layer and the resin layer into which the hollow particles are incorporated, so that light supplied to the hollow particles can be efficiently diffusely reflected.

The reflection sheet further includes the metal layer and the passivation layer for reflecting the light passing through the resin layer. Therefore, the light loss of the reflective sheet can be reduced, and the durability of the reflective sheet can be improved.

In the rear light assembly according to the present invention, the light from the light source is first incident into the resin layer. Therefore, the brightness of the light emitted from the rear light assembly can be enhanced, and the liquid crystal display device can display clear images.

Furthermore, the shell of the hollow particle includes a transparent resin having a refractive index different from that of the inner space of the hollow particle, so the reflective sheet can diffusely reflect light supplied to the hollow particle efficiently. Light.

The resin layer has a different refractive index from the refractive index of the transparent resin, thereby improving diffuse reflection efficiency of the reflection sheet.

Furthermore, the reflective sheet can serve as the blocking sheet, so properties of the liquid crystal display device, such as thickness, weight, size, and strength, can be improved.

Although some representative embodiments of the present invention have been described, it should be understood that the present invention should not be limited to these representative embodiments, and those of ordinary skill in the art can implement various methods without departing from the spirit and scope of the invention described in the claims. Various changes and improvements.

Claims (34)

1. An optical film, comprising: grassroots; a resin layer disposed on the base layer; and A plurality of hollow particles arranged in the resin layer. 2. The optical film of claim 1, wherein the resin layer comprises a polyurethane-based resin. 3. The optical film according to claim 1, wherein a diameter of the hollow particles is determined by a wavelength of light supplied to the optical film. 4. The optical film according to claim 1, wherein the diameter of the hollow particles is approximately 3.0×λ/2, and λ represents a wavelength of light supplied to the optical film. 5. The optical film of claim 4, wherein the hollow particles have a diameter of about 62.5 Angstroms to about 100.7 Angstroms. 6. The optical film of claim 1, wherein the hollow particles comprise a shell having a thickness of approximately 0.5[lambda], where [lambda] represents a wavelength of light supplied to the optical film. 7. The optical film of claim 6, wherein the shell of the hollow particles has a thickness in the range of about 22 Angstroms to about 33.1 Angstroms. 8. The optical film of claim 1, wherein the base layer comprises a polyethylene terephthalate-based resin. 9. The optical film of claim 1, further comprising a metal layer disposed on the base layer, the metal layer being disposed on an opposite side of the resin layer with respect to the base layer. 10. The optical film of claim 9, further comprising a passivation layer disposed on the metal layer, the passivation layer being disposed on an opposite side of the base layer relative to the metal layer. 11. The optical film according to claim 1, wherein the hollow particles include a shell defining an inner space of the hollow particle, the shell includes a first resin having a refractive index different from that of the inner space, and since the The first resin and the inner space have different refractive indices, and the hollow particles reflect light supplied to the hollow particles. 12. The optical film according to claim 11 , the resin layer includes a second resin, and the resin layer reflects light supplied to the resin layer due to a difference in refractive index between the first resin and the second resin. . 13. The optical film of claim 11, wherein the first resin comprises a transparent material. 14. The optical film according to claim 1, wherein the hollow particles include a shell defining an inner space of the hollow particle, the shell includes a first resin having a refractive index different from that of the inner space, and since The first resin and the inner space have different refractive indices, and the hollow microparticles transmit light supplied to the hollow microparticles. 15. The optical film of claim 1, wherein the hollow particle comprises a spherical shell and diffuses light supplied to the hollow particle through the shell. 16. The optical film of claim 1, wherein an outer surface of the hollow particle reflects and transmits light supplied to the hollow particle. 17. The optical film of claim 1, wherein inner surfaces of the hollow particles reflect and transmit light supplied to the hollow particles. 18. The optical film of claim 1, wherein the resin layer has substantially the same material as the hollow particles. 19. The optical film according to claim 1, wherein the resin layer and the hollow particles have substantially the same refractive index. 20. The optical film of claim 1, wherein the resin layer has a different refractive index from that of the hollow microparticles. 21. A backlight assembly comprising: Lamps for producing light; and An optical film for reflecting light from the lamp, the optical film including a base layer, a resin layer disposed on the base layer, and a plurality of hollow particles disposed within the resin layer. 22. The rear light assembly of claim 21 , further comprising a light guide plate disposed adjacent to said lamp and said optical film, said light guide plate guiding light generated by said lamp and reflected by said optical film. path of light. 23. The rear light assembly as claimed in claim 22, wherein each of said hollow particles comprises a shell defining an interior space of the hollow particle, said shell comprising a resin having a refractive index different from that of said interior space. , and due to the difference in refractive index between the resin and the inner space, the hollow microparticles reflect or transmit light supplied to the hollow microparticles. 24. A display device comprising: a light source for generating light; A liquid crystal display panel that displays an image using a potential difference applied to a liquid crystal layer; and An optical film for diffusely reflecting light from the lamp toward the liquid crystal display panel, the optical film comprising a base layer, a resin layer disposed on the base layer, and a plurality of hollow particles disposed in the resin layer . 25. A display device comprising: at least two display panels for displaying images; At least one backlight assembly for providing light to the display panel, the backlight assembly includes a reflective sheet for reflecting light, the reflective sheet includes a base layer, a resin layer disposed on the base layer, and a plurality of arrangements hollow particles within the resin layer. 26. The display device according to claim 25, wherein the reflective sheet further comprises: a light reflective layer disposed on the base layer, the light reflective layer being disposed on an opposite side of the resin layer relative to the base layer; and A passivation layer disposed on the reflective layer, the passivation layer disposed on the opposite side of the base layer relative to the reflective layer. 27. The display device of claim 26, wherein the back light assembly further comprises a light source for generating the light, and the light is incident into the resin layer and reflected by the reflective layer. 28. The display device according to claim 26, wherein the reflective layer is a metal layer. 29. The display device according to claim 25, wherein the hollow particle comprises a case having a transparent resin. 30. The display device according to claim 29, wherein a refractive index of the resin layer is different from a refractive index of the shell of the hollow particle. 31. The display device of claim 25, wherein the base layer comprises polyethylene terephthalate, and the resin layer comprises polyurethane. 32. The display device as claimed in claim 25, wherein said at least one back light assembly comprises a first back light assembly and a second back light assembly smaller in size than said first back light assembly, said reflection sheet comprising said The first reflective sheet of the first rear light assembly and the second reflective sheet of the second rear light assembly, the first reflective sheet is in contact with the second reflective sheet. 33. The display device of claim 25, wherein the at least two display panels comprise at least one liquid crystal display panel. 34. The display device of claim 25, wherein the at least two display panels and the at least one backlight assembly are configured within a mobile phone.

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