KR20060057194A - A reflecting sheet, method of manufacturing the reflecting sheet, back light assembly having the reflecting sheet and display device having the back light assembly - Google Patents

Abstract

Disclosed are a reflective sheet, a method of manufacturing the same, a backlight assembly having the same, and a display device having the same, in which a leaked light is reflected to improve an image quality. The reflective sheet includes a reflective layer and a light shielding layer, and the reflective layer reflects incident light, and includes a first side and a second side opposite to the first side. The light shielding layer is integrally formed on the first surface of the reflective layer to absorb and block light directed toward the reflective layer. A method of manufacturing a reflective sheet includes forming a light shielding layer that absorbs and shields light on a first side or a second side opposite to the first side of the reflective layer while forming a reflective layer including a light reflective material. The backlight assembly includes a reflective sheet and the display device includes a backlight assembly. As a result, the display quality of the display device is improved.

Display device, reflective sheet, display quality, visibility, light transmission

Description

A reflective sheet, a method of manufacturing the same, a backlight assembly having the same, and a display device having the same.

1 is a cross-sectional view of a reflective sheet according to a first embodiment of the present invention.

2 is a graph illustrating the transmittance of light with respect to the reflective sheet according to the first embodiment of the present invention.

3 is a cross-sectional view of a reflective sheet according to a second embodiment of the present invention.

4 is a cross-sectional view of a reflective sheet according to a third embodiment of the present invention.

5 is a view for explaining a method of manufacturing a reflective sheet according to a fourth embodiment of the present invention.

6 is a conceptual diagram of a backlight assembly according to a fifth embodiment of the present invention.

7 is a conceptual diagram of a display device according to a sixth embodiment of the present invention.

The present invention relates to a reflective sheet, a method of manufacturing the same, a backlight assembly having the same, and a display device having the same. More particularly, the present invention relates to a reflective sheet having reduced light transmittance, a method of manufacturing the same, a backlight assembly having the same, and a display device having the same.

In general, the liquid crystal has both electrical and optical characteristics that change the transmittance of light according to the intensity of the electric field.

Liquid crystal display devices (LCDs) display images by using the electro-optical characteristics of liquid crystals (LCs). Since the liquid crystal is a passive element that does not generate light by itself, the liquid crystal display includes a backlight assembly to display an image in a dark place.

The backlight assembly includes a light source and optical films. Optical films improve the optical properties of light by reflecting, diffusing, condensing, refraction, and diffraction light generated from a light source. Reflecting sheet, which is a kind of optical film, reflects light generated from a light source toward the display panel to increase the amount of light incident on the display panel.

However, about 3 to 5% of light incident to the conventional reflective sheet passes through the reflective sheet. The light transmitted through the reflective sheet is reflected at the bottom surface of the storage container of the backlight assembly, and then passes through the reflective sheet to enter the display panel. Therefore, the shape of the storage container is seen on the display panel, which causes a problem in that the display quality of the display device is degraded.

 Accordingly, it is an object of the present invention to substantially eliminate one or more problems and limitations of the prior art.

It is a first object of the present invention to provide a reflective sheet in which a light shielding layer is integrally formed on one surface of a reflective layer that reflects leaked light.

It is a second object of the present invention to provide a method of manufacturing the reflective sheet.

It is a third object of the present invention to provide a backlight assembly including the reflective sheet.

A fourth object of the present invention is to provide a display device including the backlight assembly.

Reflective sheet according to one feature for realizing the first object of the present invention includes a reflective layer and a light shielding layer. The reflective layer reflects incident light and includes a first side and a second side opposite to the first side. The light shielding layer is formed on the first surface of the reflective layer to absorb and block the light directed to the reflective layer. The light shielding layer is formed integrally with the first surface.

Optionally, the light shielding layer may comprise aluminum oxide or titanium oxide, and the reflective layer may comprise, for example, barium sulfate as a reflecting material.

According to one aspect of the present invention, there is provided a method of manufacturing a reflective sheet, which absorbs light on a first surface or a second surface of the reflective layer while forming a reflective layer including a light reflective material. Forming a light shielding layer to shield.                     

According to one aspect for realizing a third object of the present invention, a backlight assembly includes a container, a light source, and a reflective sheet. The storage container includes a bottom surface on which a storage space is formed. The light source is disposed in the receiving space to generate light. The reflective sheet is disposed on the bottom surface of the storage container and includes a reflective layer and a light shielding layer. The reflective layer includes a first face in contact with the bottom face and a second face opposite the first face. The light shielding layer is formed on the first surface of the reflective layer to absorb and block the light directed to the reflective layer. The light shielding layer is integrally formed on the first surface of the reflective layer.

According to another aspect of the present invention, a display device includes a storage container, a light source, a light guide plate, a reflective sheet, and a display panel. The storage container includes a bottom surface on which a storage space is formed. The light source is disposed in the receiving space to generate light. The conduit plate has a plate shape and is disposed on the bottom surface to receive light emitted from the light source. The reflective sheet is interposed between the light guide plate and the bottom surface to reflect the leakage light leaked from the light guide plate toward the light guide plate. The reflective sheet includes a reflective layer and a light shielding layer. The reflective layer includes a first face in contact with the bottom face and a second face opposite the first face. The light shielding layer is integrally formed on the first surface of the reflective layer to absorb and block light directed toward the reflective layer. The display panel displays an image based on the light emitted from the light guide plate.

The change in the transmittance of light with respect to the reflective sheet has a great influence on the visibility of the display device. Reflective sheet according to the present invention includes a light shielding layer for reducing the transmittance of light, but form the reflective layer and the light shielding layer in the same process.

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

Reflective Sheet

Example 1

1 is a cross-sectional view of a reflective sheet according to a first embodiment of the present invention.

Referring to FIG. 1, the reflective sheet 100 according to the present exemplary embodiment includes a reflective layer 110 and a light shielding layer 130. The reflective layer 110 reflects light incident on the reflective sheet 100. The reflective layer 110 includes a first face 115 and a second face 117 opposite the first face 115. Examples of the material forming the reflective layer 110 include polyethylenetelephthalate (PET) and barium sulfate as a reflective material. The light shielding layer 130 absorbs light directed toward the reflective layer 110. The light shielding layer 130 may be formed on, for example, the first surface 115 of the reflective layer 110. Examples of the material constituting the light shielding layer 130 include polyethylene terephthalate (PET), aluminum oxide or titanium oxide as a light absorbing material. Most of the light incident on the reflective sheet 100 is reflected by the reflective layer 110, and the light leaked unexpectedly through the reflective layer 110 is absorbed by the light shielding layer 130. In this embodiment, the light shielding layer 130 is preferably formed integrally with the first surface of the reflective layer 110.

The reflective sheet 100 according to the present embodiment may further include a protective layer 150. The protective layer 150 is formed on the reflective layer 110 to protect the reflective layer 110. The protective layer 150 may be formed of, for example, a transparent layer having a high light transmittance or may include a material that reflects light. The protective layer 150 is formed on the second surface 117 of the reflective layer 110. Examples of the material constituting the protective layer 150 include polyethylene terephthalate (PET).

2 is a graph illustrating the transmittance of light with respect to the reflective sheet 100 according to the first embodiment of the present invention.

Referring to FIG. 2, the horizontal axis of the graph represents wavelengths (380 nm to 760 nm) of light in the visible light region among the light incident on the reflective sheet 100, and the vertical axis represents the amount of light incident on the reflective sheet 100. The ratio of the amount of light passing through the reflective sheet 100 is shown.

Referring to graph A, in which the reflective sheet 100 includes only the reflective layer 110, the light transmittance of the reflective sheet 100 is about 3% to 5%. Referring to graph B in which the reflective sheet 100 is disposed on the metal plate, most of the light incident toward the reflective sheet 100 is blocked by the metal plate. Referring to graph C, which is a case where the reflective sheet 100 is introduced into the reflective layer 110 and the light shielding layer 130, the transmittance of light with respect to the reflective sheet 100 is about 2% or less.

When the light transmittance of the reflective sheet 100 is about 3% or more, the light transmitted through the reflective sheet 100 is reflected by an object disposed on the rear surface of the reflective sheet 100 to look at the reflective sheet 100 from the front. When the shape of the object disposed on the back of the reflective sheet 100 is recognized.

When the reflective sheet 100 and the metal plate having excellent reflection efficiency are disposed together, the light transmitted through the reflective sheet 100 does not pass through the metal plate, thereby preventing the object disposed on the rear surface of the reflective sheet 100 from being recognized. . However, for this purpose, since a separate metal plate or a metal layer must be formed on the reflective sheet 100, the steps of the manufacturing process of the reflective sheet 100 are added.

When the light shielding layer 130 including the light absorbing material is formed on the reflective layer 110 of the reflective sheet 100, the light transmittance of the reflective sheet 100 is 2% or less, so that the rear surface of the reflective sheet 100 is formed. The objects placed in the are hardly recognized. Therefore, in order to improve the reflection efficiency of the reflective sheet 100, it is preferable to form the light shielding layer 130 on the reflective layer 110 of the reflective sheet 100. In addition, when forming the reflective layer 110 to improve the productivity of the reflective sheet 100, it is more preferable to form the light shielding layer 130 together on the first surface 115 of the reflective layer 110.

According to the reflective sheet 100 according to the present exemplary embodiment, the reflective sheet 100 is easily reduced by reducing the steps of the manufacturing process of the reflective sheet 100 while solving the problem of the object being visually recognized through the reflective sheet 100. Can be prepared.

Example 2

3 is a cross-sectional view of a reflective sheet according to a second embodiment of the present invention.

The reflective sheet 200 according to the present exemplary embodiment is substantially the same as the reflective sheet 100 according to the first exemplary embodiment of the present invention except for the light shielding layer 230.

Referring to FIG. 3, the reflective sheet 200 according to the present exemplary embodiment includes a reflective layer 210, a light shielding layer 230, and a protective layer 250.

The light shielding layer 230 includes beads 231 and a binder 233. Beads 231 are disposed on first surface 215 of reflective layer 210. Examples of the material constituting the beads 231 include polymethylmethacrylate (PMMA) -based materials, which are synthetic resins having high mechanical strength and excellent chemical resistance, and titanium oxide or aluminum oxide, which are light absorbing materials.

The binder 233 fixes the beads 231 on the first surface 215 of the reflective layer 210. Examples of the materials constituting the binder 233 may include acrylic-based synthetic resins and light absorbing materials such as titanium oxide and aluminum oxide that block light transmitted between the beads 231 or the beads 231.

When a part of the light incident on the reflective sheet 200 unexpectedly passes through the reflective layer 210, the beads 231 included in the light shielding layer 230 and the light shielding material included in the binder 233 may be a reflective layer. Absorb light transmitted through 210. The light shielding layer 230 absorbs light transmitted through the reflective sheet 200 to prevent the shape of the object disposed on the rear surface of the reflective sheet 200 from being recognized. Alternatively, it is also preferable to diffuse the incident light by adjusting the refractive indices of the beads 231 and the binder 233 in order to suppress the transmission of light to the light shielding layer 230.

According to the reflective sheet 200 according to the present embodiment, when viewed from the front of the reflective sheet 200, the shape of the object on the rear surface of the reflective sheet 200 may be greatly reduced.

Example 3

4 is a cross-sectional view of a reflective sheet according to a third embodiment of the present invention.

The reflective sheet 300 according to the present exemplary embodiment is substantially the same as the reflective sheet 100 according to the first exemplary embodiment of the present invention except for the reflective layer 310.                     

Referring to FIG. 4, the reflective sheet 300 according to the present exemplary embodiment includes a reflective layer 310, a light shielding layer 330, and a protective layer 350.

Examples of the material forming the reflective layer 310 include a polyethylene terephthalate (PET), a reflective material such as barium sulfate, and a blowing agent. The foaming agent included in the reflective layer 310 forms bubbles by foaming inside the reflective layer 310 by foaming conditions. Bubbles formed inside the reflective layer 310 form a myriad of interface surfaces within the reflective layer 310, and light greatly improves the reflection efficiency of the reflective sheet 300 by reflection, transmission, and diffusion at the interface.

Manufacturing Method of Reflective Sheet

Example 4

5 is a view for explaining a method of manufacturing a reflective sheet according to a fourth embodiment of the present invention. Referring to FIG. 5, in the method of manufacturing the reflective sheet according to the present exemplary embodiment, the reflective sheet 110 may include a first surface or a first surface of the reflective layer 110 while forming the reflective layer 110 including a light reflective material. And forming a light shielding layer 130 that absorbs and blocks the light on the opposite second surface.

For example, a reflective layer base material including a reflective material, a light shielding layer base material including a light absorbing material, and a protective layer base material are supplied to the first to third extruders 410, 430, and 450, respectively. The first to third extruders 410, 430, and 450 extrude the reflective layer base material, the light shielding layer base material, and the protective layer base material through the discharge unit 460, thereby protecting the protective layer 150 and the protective layer 150. The reflective layer 110 formed on and the light shielding layer 130 formed on the reflective layer 110 are simultaneously formed. At this time, the protective layer base material, the reflective layer base material and the light shielding layer base material discharged from the discharge unit 460 in the form of sheets are integrally formed on the first roller 481 and they are the second roller 483 and the third roller. By passing through the roller 484, the protective layer 150, the reflective layer 110, and the light shielding layer 130 are compressed to each other to form a slim reflective sheet 100.

In this embodiment, the reflective material may include, for example, barium sulfate and / or further include a blowing agent. The light absorbing material includes, for example, titanium oxide and / or aluminum oxide.

According to the method of manufacturing the reflective sheet according to the present embodiment, the productivity of the reflective sheet manufacturing process is improved by reducing the steps of the reflective sheet manufacturing process.

Backlight assembly

Example 5

6 is a conceptual diagram of a backlight assembly according to a fifth embodiment of the present invention.

Referring to FIG. 6, the backlight assembly 600 according to the present exemplary embodiment includes a storage container 610, a light source 620, and a reflective sheet 100. In the present embodiment, since the reflective sheet 100 is substantially the same as the reflective sheet 100 according to the first embodiment of the present invention, the same reference numerals are used.

The storage container 610 includes a bottom surface 611 and sidewalls forming an accommodation space on the bottom surface 611. The light source 620 includes a lamp 621 disposed in the storage space and generating a light, and a lamp reflector 625 that collects and emits the light generated by the lamp 621. The light guide plate 630 in which the light emitted from the light source 620 is incident is disposed inside the storage container 610, and the reflective sheet 100 is disposed between the light guide plate 630 and the bottom surface 611. Optical members 650 and 670 are disposed on a surface of the light guide plate 630 opposite to the surface of the light guide plate 630 facing the reflective sheet 100. The optical members 650 and 670 include a diffusion sheet 650 facing the light guide plate 630 and diffusing light, and a light collecting sheet 670 condensing the diffused light.

The reflective sheet 100 reflects light leaked unexpectedly from the light guide plate 630 toward the light guide plate 630. Light leaked from the light guide plate 630 is reflected by the reflective layer 110 of the reflective sheet 100 and is incident again to the light guide plate 630, and the light transmitted through the reflective layer 110 is absorbed and blocked by the light shielding layer 130. . The ratio of the amount of light transmitted through the reflective sheet 100 to the amount of light incident on the reflective sheet 100 is about 2% or less. In this case, when viewed from the front of the backlight assembly 600, the shape of the bottom surface 611 of the storage container 610 is hardly recognized.

According to the backlight assembly 600 according to the present embodiment, it is possible to provide light having excellent optical characteristics in which unnecessary signals are not included.

Display device

Example 6

7 is a conceptual diagram of a display device according to a sixth embodiment of the present invention.

Referring to FIG. 7, the display device 800 according to the present exemplary embodiment includes a storage container 610, a light source 620, a light guide plate 630, a reflective sheet 100, and a display panel 750. The storage container 610, the light source 620, the light guide plate 630, and the reflective sheet 100 may include the storage container 610, the light source 620, and the backlight assembly 600 according to the fifth embodiment of the present invention. Since the light guide plate 630 and the reflective sheet 100 are substantially the same, the same reference numerals are given.

The display panel 750 receives the light emitted from the optical members 650 and 670 and converts the light into image light including image information. The display panel 750 includes a first substrate 710, a second substrate 730 facing the first substrate 710, and a liquid crystal layer (not shown) disposed between both substrates. When predetermined voltage signals are applied to the first substrate 710 and the second substrate 720 from the outside, an electric field is formed between the first substrate 710 and the second substrate 730 to change the arrangement of the liquid crystal layer. The amount of light passing through the display panel 750 is controlled to display an image.

As described above in detail, it is possible to easily manufacture the reflective sheet by eliminating the problem that the shape of the object is visually recognized through the reflective sheet and reducing the steps of the manufacturing process of the reflective sheet.

In addition, according to the method of manufacturing the reflective sheet according to the present invention, the productivity of the reflective sheet manufacturing process is improved by reducing the steps of the reflective sheet manufacturing process.

In addition, according to the backlight assembly according to the present invention, it is possible to provide a light having excellent optical characteristics that does not contain unnecessary signals.

In addition, according to the display device according to the present invention, the ratio of the amount of light transmitted through the reflective sheet by the light shielding layer integrally formed on one surface of the reflective layer of the reflective sheet is about 2% or less with respect to the incident light. Therefore, the bottom surface of the storage container is not visually seen from the front of the display device. Thus, the display quality of the display device is improved.

In the detailed description of the present invention described above with reference to the preferred embodiments of the present invention, those skilled in the art or those skilled in the art having ordinary skill in the art will be described in the claims to be described later It will be understood that various modifications and variations can be made in the present invention without departing from the scope of the present invention.

Claims (20)

A reflective layer reflecting the incident light and having a first surface and a second surface opposite the first surface; And And a light shielding layer formed on the first surface to absorb and block light directed toward the reflective layer. The reflective sheet of claim 1, wherein the light shielding layer is integrally formed on the first surface. The reflective sheet of claim 1, wherein the light shielding layer comprises beads including titanium oxide or aluminum oxide. The reflective sheet of claim 1, wherein the reflective layer comprises barium sulfate. The reflective sheet of claim 1, wherein the reflective layer further comprises bubbles. Forming a reflective layer including a light reflective material and forming a light shielding layer for absorbing and blocking the light on a first surface of the reflective layer or on a second surface opposite to the first surface; Way. The method of manufacturing a reflective sheet according to claim 6, wherein the light shielding layer comprises titanium oxide or aluminum oxide. The method of claim 6, wherein the reflective material comprises barium sulfate. The method of claim 6, wherein the reflective material further comprises a foaming agent for forming bubbles in the reflective sheet. A storage container including a bottom surface on which a storage space is formed; A light source disposed in the accommodation space to generate light; A reflective layer disposed on the bottom surface and having a first surface in contact with the bottom surface and a second surface facing the first surface and reflecting the light and formed on the first surface of the reflective layer to the reflective layer; A backlight assembly comprising a reflective sheet comprising a light shielding layer that absorbs and blocks directed light. The backlight assembly of claim 10, wherein the light shielding layer is integrally formed on the first surface. The backlight assembly of claim 10, wherein the light shielding layer comprises beads comprising titanium oxide or aluminum oxide. The backlight assembly of claim 10, wherein the reflective layer comprises barium sulfate. The backlight assembly of claim 10, wherein the reflective layer further comprises bubbles. The backlight assembly of claim 10, wherein a light guide plate is disposed on the second surface of the reflective layer. A storage container including a bottom surface on which a storage space is formed; A light source disposed in the accommodation space to generate light; A plate-shaped light guide plate disposed on the bottom surface to receive the light; A reflective layer disposed between the light guide plate and the bottom surface to reflect the leakage light leaked from the light guide plate toward the light guide plate, the reflective layer having a first surface in contact with the bottom surface and a second surface facing the first surface; A reflection sheet formed on the first surface of the reflection layer and including a light shielding layer for absorbing and blocking light directed toward the reflection layer; And And a display panel configured to display an image based on the light emitted from the light guide plate. The display device of claim 16, wherein the light shielding layer is integrally formed on the first surface. The display device of claim 16, wherein the light shielding layer comprises beads including titanium oxide or aluminum oxide. The display device of claim 16, wherein the reflective layer comprises barium sulfate. The display device of claim 16, wherein the reflective layer further comprises bubbles.

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