KR20060118110A - Backlight unit employed in a liquid crystal display, and optical film in employed in the same - Google Patents

Abstract

A backlight unit used in an LCD and an optical film used in the backlight unit are provided to reduce thickness and weight of the backlight unit, by forming the optical film where a prism part and a diffusion part are integrated in one body. An optical film comprises a diffusion part and a prism part(410). The diffusion part diffuses the light supplied from a light guiding plate, and has an upper surface with a triangle shape. The prism part condenses the light diffused by the diffusion part. The prism part and the prism part are integrated in one body. The prism part includes a first sub-diffuser(404) for diffusing the light supplied from the light guiding plate, a supporter(406) disposed above the first sub-diffuser, and a second sub-diffuser(408) for diffusing the light passing through the first sub-diffuser and the supporter.

Description

BACKLIGHT UNIT EMPLOYED IN A LIQUID CRYSTAL DISPLAY, AND OPTICAL FILM IN EMPLOYED IN THE SAME}

1 is a block diagram illustrating a general liquid crystal display.

2A is a cross-sectional view illustrating a conventional backlight unit.

FIG. 2B is a cross-sectional view illustrating the optical film of FIG. 2A.

3 is a plan view illustrating a liquid crystal display using a backlight unit according to an exemplary embodiment of the present invention.

4 is a plan view showing an optical film according to a first embodiment of the present invention.

5 is a cross-sectional view showing an optical film according to a second preferred embodiment of the present invention.

6 is a cross-sectional view showing an optical film according to a third preferred embodiment of the present invention.

7 is a cross-sectional view showing an optical film according to a fourth preferred embodiment of the present invention.

The present invention relates to a backlight unit, and more particularly to a backlight unit including an integrated optical film.

The backlight unit is a device that provides light to a liquid crystal display (LCD).

1 is a block diagram illustrating a general liquid crystal display.

Referring to FIG. 1, the liquid crystal display includes an LCD panel 100 and a backlight unit 102.

The LCD panel 100 displays a predetermined image by using light provided from the backlight unit 102.

FIG. 2A is a cross-sectional view of a conventional backlight unit, and FIG. 2B is a cross-sectional view of the optical film of FIG. 2A.

Referring to FIG. 2A, the backlight unit 102 includes a light source unit 200, a light guide plate 206, a reflective sheet 208, and an optical film 210.

The light source unit 200 includes one or more cold cathode fluorescent lamps 202 and CCFLs and a mounting unit 204.

The cold cathode fluorescent lamp 202 generates light having a predetermined wavelength.

Generally, the light is white light.

The mounting unit 204 mounts the cold cathode fluorescent lamp 202 and reflects the light generated from the cold cathode fluorescent lamp 202.

The light guide plate 206 controls the reflection conditions of the upper and lower surfaces thereof to evenly distribute the light generated from the light source unit 200 over the entire light guide plate 206.

In addition, the light guide plate 206 propagates the diffused light toward the LCD panel 100.

The reflective sheet 208 reflects light passing through the light guide plate 206.

2A and 2B, the optical film 210 includes a diffusion sheet 220, a prism sheet 222, and a protective sheet 224 sequentially positioned.

The diffusion sheet 220 is positioned on the light guide plate 206 and includes a first sub diffusion part 230, a first support part 232, and a second sub diffusion part 234.

In addition, the diffusion sheet 220 condenses or diffuses the light propagated from the light guide plate 206 by using beads 248 included therein.

The prism sheet 222 is positioned on the diffusion sheet 220 and includes a second support 236 and a prism-shaped layer 238.

In addition, the prism sheet 222 condenses the light diffused by the diffusion sheet 220.

The protective sheet 224 is positioned on the prism sheet 222 and includes a third sub diffusion part 240, a third support part 242, and a fourth sub diffusion part 246.

In addition, the protective sheet 224 diffuses the light collected by the prism sheet 222, and provides the diffused light to the LCD panel 100.

In other words, in the conventional backlight unit 102, the diffusion sheet 220, the prism sheet 222, and the protective sheet 224 were isolated from each other, so that each of the supporting members 232, 236, and 242 supporting each of them must be separately. did.

As a result, the backlight unit 102 became thick, that is, the LCD using the conventional backlight unit 102 became thick.

It is an object of the present invention to provide a lightweight thin backlight unit and an optical film used therefor.

In order to achieve the above object, the optical film used in the backlight unit including a light guide plate for providing light according to an embodiment of the present invention includes a diffusion portion and a prism portion. The diffusion part diffuses the light provided from the light guide plate, and the upper surface has a triangular shape. The prism portion condenses the light diffused by the diffusion portion. Here, the diffusion portion and the prism portion are formed integrally.

According to another preferred embodiment of the present invention, an optical film used in a backlight unit including a light guide plate for providing light includes a diffusion part and a prism part. The diffusion unit diffuses the light provided from the light guide plate and has an upper surface. The prism part is positioned above the diffusion part and condenses the light diffused by the diffusion part. Here, the diffusion portion and the prism portion are formed integrally.

According to another embodiment of the present invention, an optical film used in a backlight unit including a light guide plate for providing light includes a prism portion and a protection portion. The prism portion collects light provided from the light guide plate. The protection part is located above the prism part and diffuses the light collected by the prism part. Here, the prism portion and the protection portion are formed integrally.

The backlight unit used in the liquid crystal display device including the liquid crystal display panel according to the exemplary embodiment of the present invention includes a light source unit, a light guide plate, and an optical film. The light source unit generates light of a predetermined wavelength. The light guide plate propagates the light generated from the light source unit toward the liquid crystal display panel. The optical film is positioned above the light guide plate, and includes a light collecting unit for collecting light transmitted from the light guide plate and a protecting unit for diffusing the collected light and providing the light to the liquid crystal display panel. Here, the light collecting portion and the protective portion are formed integrally.

The backlight unit used in the liquid crystal display device including the liquid crystal display panel according to another exemplary embodiment of the present invention includes a light source unit, a light guide plate, a light collecting unit, and a protection unit. The light source unit generates light of a predetermined wavelength. The light guide plate propagates the light generated from the light source unit toward the liquid crystal display panel. The light collecting part may be positioned on an upper portion of the light guide plate, and may include a diffusion part for diffusing light transmitted from the light guide plate and a prism part for condensing light passing through the diffusion part. The protection part is positioned above the light collecting part, and diffuses the collected light and provides the light to the liquid crystal display panel. Here, the light collecting portion and the protective portion are formed integrally.

The backlight unit used in the liquid crystal display device including the liquid crystal display panel according to another exemplary embodiment of the present invention includes a light source unit, a light guide plate, and an optical film. The light source unit generates light of a predetermined wavelength. The light guide plate propagates the light generated from the light source unit toward the liquid crystal display panel. The optical film is positioned on the light guide plate, and includes a prism unit for collecting light transmitted from the light guide plate and a protection unit for diffusing the collected light and providing the light to the liquid crystal display panel. Here, the prism portion and the protection portion are formed integrally.

Since the optical film is integrated in the backlight unit according to the present invention, the thickness of the backlight unit may be reduced.

Hereinafter, with reference to the accompanying drawings will be described in detail preferred embodiments of the backlight unit and the optical film used according to the present invention.

3 is a plan view illustrating a liquid crystal display using a backlight unit according to an exemplary embodiment of the present invention, and FIG. 4 is a plan view illustrating an optical film according to a first exemplary embodiment of the present invention.

Referring to FIG. 3, a liquid crystal display (LCD) includes a liquid crystal display panel 300 and a backlight unit 302.

The LCD panel 300 includes a lower polarizing film 304, an upper polarizing film 306, a lower glass substrate 308, an upper glass substrate 310, a color filter 312, a black matrix 314, and a pixel electrode 316. ), A common electrode 318, a liquid crystal layer 320, and a TFT array 322.

The color filter 312 includes color filters corresponding to red, green, and blue, and generates an image corresponding to red, green, or blue when light is applied.

The TFT array 322 switches the pixel electrode 316 as a switching element.

The common electrode 318 and the pixel electrode 316 arrange molecules of the liquid crystal layer 320 according to a predetermined voltage applied from the outside.

The liquid crystal layer 320 is composed of predetermined molecules, and the molecules are arranged corresponding to the voltage difference between the pixel electrode 316 and the common electrode 318.

As a result, light provided from the backlight unit 302 below is incident on the color filter 312 corresponding to the molecular arrangement of the liquid crystal layer 320.

The backlight unit 302 is a device that provides light, for example, white light, to the LCD panel 300 and includes a light source unit 328, a light guide plate 334, an optical film 336, and a reflective sheet 338.

The light source unit 328 includes one or more cold cathode fluorescent lamps (330, CCFL) and a mounting unit 332.

The cold cathode fluorescent lamp 330 generates light having a predetermined wavelength.

Generally, the light is white light.

The light source unit 328 according to another embodiment of the present invention may generate light using a light emitting diode (LED) instead of a cold cathode fluorescent lamp.

The mounting unit 332 mounts the cold cathode fluorescent lamp 330 and reflects the light generated from the cold cathode fluorescent lamp 330.

The light guide plate 334 controls the reflection conditions of the upper and lower surfaces thereof, and evenly spreads the light generated from the light source unit 328 throughout the light guide plate 334.

In addition, the light guide plate 334 advances the diffused light toward the LCD panel 300.

The reflective sheet 338 reflects light passing through the light guide plate 334 toward the light guide plate 334.

The optical film 336 collects and diffuses the light propagated from the light guide plate 334 and provides the light to the LCD panel 300.

Hereinafter, the light emission operation of the LCD will be described in detail.

The backlight unit 302 provides the planar light, which is white light, to the LCD panel 300.

Subsequently, the TFT array 322 switches the pixel electrode 316.

Subsequently, a predetermined voltage difference is applied between the pixel electrode 316 and the common electrode 318, so that the molecules of the liquid crystal layer 320 are arranged corresponding to the red color filter, the green color filter, and the blue color filter, respectively.

In this case, the amount of light is adjusted while the plane light provided from the backlight unit 302 passes through the liquid crystal layer 320, and the plane light whose light amount is adjusted is provided to the color filter 312.

As a result, the color filter 312 implements an image with a predetermined gray scale.

Specifically, the red color filter, the green color filter, and the blue color filter form one pixel, and the red color filter, the green color filter, and the blue color filter implement a predetermined image by the combination of the light passing through. do.

Hereinafter, the optical film 336 included in the backlight unit 302 of the present invention will be described in detail.

Referring to FIG. 4, the optical film 336 includes a light collecting part 400 and a protection part 402.

The light collecting part 400 includes a diffusion part and a prism part 410.

The diffusion part includes a first sub diffusion part 404, a first support part 406, and a second sub diffusion part 408.

The first sub-diffusion unit 404 is positioned on the light guide plate 334, and diffuses or condenses the light traveling from the light guide plate 334.

In detail, the first sub-diffusion unit 404 diffuses or condenses the light traveling from the light guide plate 334 according to an angle formed by the light traveling from the light guide plate 334 and the normal of the light guide plate 334.

Hereinafter, the case where the first sub-diffusion unit 404 diffuses the light traveling from the light guide plate 334 will be described in detail.

The first support 406 supports the sub diffusions 404 and 408.

The second sub diffuser 408 diffuses or condenses the light passing through the first sub diffuser 404 and the first support 406.

In addition, a triangular protrusion is continuously formed on the second sub diffusion part 408.

Each of the sub diffusions 404 and 408 is made of polyester (PET) and includes beads 418.

Here, the beads 418 diffuse or condense light.

As shown in FIG. 4, the prism portion 410 is formed along the upper surface of the protrusion of the second sub diffusion portion 408 and is made of UV resin.

In addition, the prism unit 410 collects the light diffused by the second sub-diffusion unit 408.

In detail, the prism unit 410 condenses the light diffused by the second sub-diffusion unit 408 in the direction of the LCD panel 300, for example, the normal direction of the LCD panel 300.

As a result, the luminance of the LCD panel 300 is improved.

The protection part 402 includes a third sub diffusion part 412, a second support part 414, and a fourth sub diffusion part 416.

The third sub-diffusion unit 412 diffuses the light collected by the prism unit 410.

The second support 414 supports the third and fourth sub diffusions 412 and 416.

The fourth sub diffuser 416 diffuses the light passing through the third sub diffuser 412 and the second support 414, and provides the diffused light to the LCD panel 300.

In addition, the fourth sub-diffusion unit 416 protects the components of the optical film 338 that are sensitive to dust or scratches.

The third and fourth sub-diffusion portions 412 and 416 diffuse the light passing through the prism portion 410, thus widening the viewing angle of the LCD.

In addition, each of the third and fourth sub diffusions 412 and 416 is made of polyester and includes beads 420.

As described above, the backlight unit 302 of the present invention includes an integrated optical film 338 unlike the conventional backlight unit, which was divided into a diffusion sheet, a prism sheet, and a protective sheet.

Therefore, the backlight unit 302 of the present invention can be thinner while performing the same function as the conventional backlight unit.

As a result, the LCD using the backlight unit 302 of the present invention can be reduced in thickness than the LCD using the conventional backlight unit.

That is, the LCD using the backlight unit 302 of the present invention can be thinner than the LCD using the conventional backlight.

5 is a cross-sectional view showing an optical film according to a second preferred embodiment of the present invention.

Referring to FIG. 5, the optical film 338 of the present invention includes a light collecting part 500 and a protection part 502.

The light collecting part 500 includes a diffusion part 504 and a prism part 506.

The diffuser 504 diffuses or condenses the light propagated from the light guide plate 334, and is made of polyester.

In addition, the diffuser 504 includes beads 508 for diffusing light, and triangular protrusions are continuously formed thereon.

The prism portion 506 is formed along the upper surface of the diffusion portion 504 and condenses the light diffused or collected by the diffusion portion 504.

In addition, the prism portion 506 is made of UV resin and supports the diffusion portion 504 and the protection portion 502.

The protection unit 502 protects the prism portion 506 and the diffusion portion 504, diffuses the light collected by the prism portion 506, and provides the diffused light to the LCD panel 300.

In addition, the protection part 502 is made of polyester, and includes the beads 510.

Hereinafter, the optical film of the first embodiment and the optical film of the second embodiment will be compared.

Unlike the optical film of the first embodiment, the optical film of the second embodiment does not have a support portion separately, and supports the components by using the prism portion 506.

Therefore, the optical film of the second embodiment is smaller in thickness than the optical film of the first embodiment.

As a result, the LCD using the optical film of the second embodiment can be reduced in thickness than the LCD using the optical film of the first embodiment.

6 is a cross-sectional view showing an optical film according to a third preferred embodiment of the present invention.

Referring to FIG. 6, the optical film 338 of the present invention includes a light collecting part 600 and a protection part 602.

The light collecting part 600 includes a first diffusion part 604, a first support part 606, and a prism part 608.

The first diffuser 604 is made of polyester and includes beads 616.

In addition, the first diffuser 604 diffuses or condenses the light propagated from the light guide plate 334 using the beads 616.

The first support 606 supports the first diffuser 604 and the prism portion 608.

The prism portion 608 includes an upper surface on which a plurality of triangular protrusions are formed in succession, and is made of UV resin.

The prism portion 608 also diffuses or condenses the light passing through the first diffuser 604 and the first support 606 using beads 616 contained therein, and then diffuses or condenses the light. The collected light is focused by using an upper surface having a triangular shape.

The protection part 602 includes a second diffusion part 610, a second support part 612, and a third diffusion part 614.

The second diffuser 610 diffuses the light collected by the prism unit 608.

The second support 612 supports the second and third diffusions 610 and 614.

The third diffuser 614 protects the components of the optical film 338 and diffuses the light passing through the second diffuser 610 and the second support 612 to widen the viewing angle of the LCD.

Each of the second and third diffusions 610 and 614 is made of polyester and includes beads 618.

Hereinafter, the optical film of the first embodiment and the optical film of the third embodiment will be compared.

The prism portion 608 of the third embodiment corresponds to the second sub-diffusion portion 408 and the prism portion 410 of the first embodiment, and performs the same function.

However, the prism portion 608 of the third embodiment is entirely made of UV resin, whereas in the first embodiment, only the prism portion 410 is made of UV resin.

Here, since UV resin is more expensive than polyester, the unit price of the optical film of the first embodiment is lower than that of the optical film of the third embodiment.

However, from the process aspect, the process of forming the prism portion 608 of the third embodiment is easier than the process of forming the second sub-diffusion portion 408 and the prism portion 410 of the first embodiment.

That is, the process of forming the optical film of the third embodiment is easier than the process of forming the optical film of the first embodiment.

7 is a cross-sectional view showing an optical film according to a fourth preferred embodiment of the present invention.

Referring to FIG. 7, the optical film 338 includes a light collecting part 700 and a protection part 702.

The light collecting part 700 has an upper surface on which a plurality of triangular protrusions are formed in succession, and diffuses or condenses the light from the light guide plate 334 using the beads 704, and then the diffused or condensed light. To condense using the upper surface.

In addition, the light collecting part 700 is made of UV resin.

The protection unit 702 diffuses the light collected by the light collecting unit 700 using the beads 706, and provides the diffused light to the LCD panel 300.

In addition, the protection part 702 is made of polyester.

Hereinafter, the optical film of the third embodiment and the optical film of the fourth embodiment will be compared.

The optical film of the fourth embodiment does not have a support separately from the optical film of the third embodiment.

Therefore, the optical film of the fourth embodiment is smaller in thickness than the optical film of the third embodiment.

As a result, the LCD using the optical film of the fourth embodiment can be reduced in thickness than the LCD using the optical film of the third embodiment.

Preferred embodiments of the present invention described above are disclosed for purposes of illustration, and those skilled in the art having ordinary knowledge of the present invention will be able to make various modifications, changes, additions within the spirit and scope of the present invention, such modifications, changes and Additions should be considered to be within the scope of the following claims.

As described above, since the optical film is integrated in the backlight unit according to the present invention, there is an advantage that the backlight unit may be light and thin.

Claims (26)

In the optical film used in the backlight unit including a light guide plate for providing light, A diffuser for diffusing light provided from the light guide plate and having an upper surface with a triangular shape; And Includes a prism for condensing light diffused by the diffusion, The diffusing part and the prism part are formed integrally with the optical film used in the backlight unit. The method of claim 1, wherein the diffusion unit, A first sub diffuser configured to diffuse light provided from the light guide plate; A support located above the first sub-diffusion; And Located on the support, the optical film for a backlight unit comprising a first sub-diffusion and a second sub-diffusion to diffuse the light passing through the support. The optical film of claim 2, wherein the sub-diffusion portions are made of polyester, and the prism portion is made of UV resin. The optical film of claim 3, wherein each of the sub-diffusion portions includes beads. The optical film of claim 1, wherein the diffusion part is made of polyester and comprises beads. The optical film of claim 1, wherein the prism portion is made of UV resin. The method of claim 1, wherein the optical film, Located in the upper portion of the prism portion, the optical film used in the backlight unit, characterized in that it further comprises a protection unit for diffusing the light collected by the prism portion. The method of claim 7, wherein the protection unit, A first sub-diffusion unit positioned above the prism unit and configured to diffuse light collected by the prism unit; A support located above the first diffusion; And The optical film used in the backlight unit, which is positioned above the support, and includes a first diffuser and a second diffuser configured to diffuse light passing through the support. 8. The optical film of claim 7, wherein the sub-diffusion portions are made of polyester and include beads. The optical film of claim 8, wherein the protective part is made of polyester and comprises beads. In the optical film used in the backlight unit including a light guide plate for providing light, A diffuser for diffusing light provided from the light guide plate and having an upper surface; And Located above the diffuser, and includes a prism for condensing light diffused by the diffuser, The diffuser and the prism portion are formed integrally with the optical film for use in the backlight unit. The optical film of claim 11, wherein the diffusion part is made of polyester and the prism part is made of UV resin. The optical film of claim 12, wherein the diffusion part and the prism part each comprise beads. The method of claim 11, wherein the optical film, Further comprising a support located between the diffusion portion and the prism portion, The diffusing part, the supporting part and the prism part are integrally formed with the optical film used in the backlight unit. 12. The optical film of claim 11, wherein triangular protrusions are continuously formed on an upper surface of the prism portion. The method of claim 11, wherein the optical film, Located in the upper portion of the prism portion, the optical film used in the backlight unit, characterized in that it further comprises a protection unit for diffusing the light collected by the prism portion. The method of claim 16, wherein the protection unit, A first sub-diffusion unit positioned above the prism unit and configured to diffuse light collected by the prism unit; A support located above the first diffusion; And The optical film used in the backlight unit, which is positioned above the support, and includes a first diffuser and a second diffuser configured to diffuse light passing through the support. 18. The optical film of claim 17, wherein the sub-diffusion portions are made of polyester and include beads. 17. The optical film of claim 16, wherein the protection part is made of polyester and comprises beads. In the optical film used in the backlight unit including a light guide plate for providing light, A prism portion for collecting light provided from the light guide plate; And Located on top of the prism portion, including a protection for diffusing the light collected by the prism portion, The prism portion and the protection portion is an optical film for use in the backlight unit, characterized in that formed integrally. 21. The optical film of claim 20, wherein triangular protrusions are continuously formed on the prism portion. 21. The optical film of claim 20, wherein the prism portion is made of UV resin and comprises beads. 21. The optical film of claim 20, wherein the protection part is made of polyester and comprises beads. A backlight unit for use in a liquid crystal display device including a liquid crystal display panel, A light source unit generating light having a predetermined wavelength; A light guide plate configured to advance light generated from the light source unit toward the liquid crystal display panel; And An optical film positioned on an upper portion of the light guide plate, the optical film including a light collecting unit for collecting light transmitted from the light guide plate and a protecting unit to diffuse the collected light and provide the light to the liquid crystal display panel; And the light collecting portion and the protecting portion are integrally formed. In the backlight unit used in the liquid crystal display device including the liquid crystal display panel, A light source unit generating light having a predetermined wavelength; A light guide plate configured to advance light generated from the light source unit toward the liquid crystal display panel; And A light concentrator positioned on an upper portion of the light guide plate, the light concentrating part including a diffuser for diffusing light propagated from the light guide plate and a prism part for condensing light passing through the diffuser; And Located on the light collecting portion, and includes a protection unit for diffusing the collected light to provide to the liquid crystal display panel, And the light collecting portion and the protecting portion are integrally formed. A backlight unit for use in a liquid crystal display device including a liquid crystal display panel, A light source unit generating light having a predetermined wavelength; A light guide plate configured to advance light generated from the light source unit toward the liquid crystal display panel; And An optical film positioned on an upper portion of the light guide plate, the optical film including a prism unit for condensing light emitted from the light guide plate and a protection unit configured to diffuse the collected light and provide the light to the liquid crystal display panel; And the prism portion and the protection portion are integrally formed.

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