KR20060017999A - Light guide plate, back-light assembly having the light guide plate and display apparatus having the back-light assembly - Google Patents

Abstract

Disclosed are a light guide plate, a backlight assembly having the same, and a display device capable of increasing luminance and reducing manufacturing cost. The light guide plate includes a light incident surface, a light reflecting surface connected to face the light incident surface, and a flat light emitting surface. The light reflecting surface has a curved shape in which the thickness of the light emitting surface and the light reflecting surface decreases from the light incident surface to the opposite surface facing the light incident surface. As the light is reflected perpendicularly to the light exit surface by the light reflecting surface, the brightness of the light is further increased and the manufacturing cost is reduced.

Description

LIGHT GUIDE PLATE, BACK-LIGHT ASSEMBLY HAVING THE LIGHT GUIDE PLATE AND DISPLAY APPARATUS HAVING THE BACK-LIGHT ASSEMBLY}

1 is a perspective view illustrating a light guide plate according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the light guide plate shown in FIG. 1.

3 is a perspective view illustrating a backlight assembly according to a second embodiment of the present invention.

4 is a cross-sectional view of the backlight assembly shown in FIG. 3.

5 is a cross-sectional view illustrating a backlight assembly according to a third embodiment of the present invention.

6 is an exploded perspective view illustrating a display device according to a fourth exemplary embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

    100: light guide plate 110: light incident surface

    120: light exit surface 130: light reflection surface

    200: light generator 300: reflector

    400: storage container 500: backlight assembly

    600: display panel 700: top chassis                 

    1000: display device

The present invention relates to a light guide plate, a backlight assembly having the same, and a display device having the same. More specifically, the present invention relates to a light guide plate having improved front luminance, a backlight assembly having the same, and a display device having the same.

In general, an information processing apparatus includes a display device for displaying data having an electrical signal format as an image.

Cathode ray tube (CRT), which is a typical display device, has a low manufacturing cost and is suitable for displaying moving images.

Recently, the liquid crystal display (LCD) displays an image by a liquid crystal layer having a thickness of only a few micrometers, so that it is thinner and lighter than a cathode ray tube display. This has the advantage of low power consumption and low operating voltage.

For these reasons, liquid crystal displays are widely used as display devices of various electronic devices such as desktop computers, notebook computers, mobile phones, and the like.

Conventional liquid crystal display devices include a display panel displaying an image using light, a backlight assembly providing light to the display panel, and a storage container accommodating the display panel and the backlight assembly.                         

The conventional backlight assembly includes a light source such as a cold cathode ray tube lamp, and the conventional backlight assembly is divided into a direct type backlight assembly and an edge type backlight assembly according to the arrangement of the lamps.

The direct type backlight assembly is suitable for supplying light to a large display panel, and a plurality of lamps are arranged in parallel under the display panel to directly supply light to the display panel.

The edge type backlight assembly is suitable for supplying light to small and medium sized display panels. The edge type backlight assembly is disposed on a side portion of the display panel to provide light to the display panel indirectly through a light guide plate (LGP).

The edge type backlight assembly includes a lamp for generating light and a light guide plate (LGP) for guiding the light and emitting the light upward.

Most of the light emitted from the light guide plate is emitted in an inclined direction with respect to the surface of the light guide plate. For example, a display panel using a twisted nematic liquid crytal displays an image using light that is substantially perpendicular to the light guide plate, so that light emitted obliquely from the light guide plate does not enter the display panel. The display quality of the image is greatly degraded.

An optical member such as a diffusion sheet and a prism sheet is disposed on the light guide plate so that the light emitted from the light guide plate is substantially perpendicular to the display panel.

On the other hand, a reflecting plate is disposed under the light guide plate so as to reuse light that is not emitted from the light guide plate to the display panel and leaked from the light guide plate in the opposite direction of the display panel.

As such, the light emitted from the light guide plate is partially lost while passing through the diffusion sheet and the prism sheet, thereby reducing the amount of light incident on the display panel, thereby reducing the brightness of the image.

In addition, the volume and weight of the display device are increased by the diffusion sheet and the prism sheet, and manufacturing costs are greatly increased.

Accordingly, the present invention has been made in view of such a conventional problem, and a first object of the present invention is to provide a light guide plate which increases the front luminance of light incident on the display panel and reduces the manufacturing cost.

In addition, a second object of the present invention is to provide a backlight assembly having the light guide plate.

In addition, a third object of the present invention is to provide a display device having the backlight assembly.

The light guide plate for achieving the first object of the present invention includes a light incident surface, a light reflecting surface connected to face the light incident surface and a flat light emitting surface. The light reflecting surface has a curved shape in which the thickness of the light emitting surface and the light reflecting surface decreases from the light incident surface to the opposite surface facing the light incident surface.                     

In addition, the backlight assembly for achieving the second object of the present invention includes a light generating device, a light guide plate and a reflecting plate. The light generating device includes a light source for generating light. The light guide plate includes a light incident surface to which light is incident, a light reflecting surface connected to face the light incident surface, and a flat light emitting surface, and the light reflecting surface has a thickness formed by the light emitting surface and the light reflecting surface from the light incident surface. It has a curved shape that decreases toward the opposite surface facing the incident surface. The reflecting plate has substantially the same curvature as the light reflecting surface for injecting light leaked into the light reflecting surface into the light guide plate.

In addition, the display device for achieving the third object of the present invention includes a backlight assembly and a display panel. The backlight assembly includes a light generating device, a light guide plate, a reflecting plate, and a storage container. The light generating device includes a light source for generating light. The light guide plate includes a light incident surface to which light is incident, a light reflecting surface connected to face the light incident surface, and a flat light emitting surface, and the light reflecting surface has a thickness formed by the light emitting surface and the light reflecting surface from the light incident surface. It has a curved shape that decreases toward the opposite surface facing the incident surface. The reflecting plate has substantially the same curvature as the light reflecting surface for injecting light leaked into the light reflecting surface into the light guide plate. The storage container houses the lamp assembly, the light guide plate and the reflecting plate. The display panel is disposed above the backlight assembly to change light into image light including information.

According to the present invention, the light incident on the light guide plate is reflected perpendicularly to the light exit surface by the reflection plate disposed on the reflection surface, whereby the brightness of the backlight assembly can be increased, and the member for additional diffusion and front brightness increase Can be made unnecessary and the manufacturing cost of the backlight assembly can also be reduced.

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

Light guide plate

Example  One

1 is a perspective view illustrating a light guide plate according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of the light guide plate shown in FIG. 1.

1 and 2, the light guide plate 100 includes side surfaces 150 including a light incident surface 110, a flat light emitting surface 120, and a light reflecting surface 130.

The light incident surface 110 has a flat surface, for example, and light generated from a light source (not shown) is incident into the light guide plate 100 through the light incident surface 110.

The light emitting surface 120 and the light reflecting surface 130 are connected to the light incident surface 110, and in this embodiment, the light emitting surface 120 and the light reflecting surface 130 are disposed to face each other.

The light reflecting surface 130 reflects light incident through the light incident surface 110, and thus the light incident on the light incident surface 110 may be emitted to the light emitting surface 120.

In the present embodiment, the light reflecting surface 130 may have the same flat shape as the light emitting surface 120, but the light reflecting surface 130 and the light emitting surface 120 have a flat or wedge shape. By the law of refraction, most of the light emitted from the light exit surface 120 is emitted in an inclined direction with respect to the light exit surface 120. When the light emitted to the light exit surface 120 is inclined with respect to the light exit surface 120 as described above, the brightness characteristic and the viewing angle characteristic of the image are greatly reduced.

To prevent this, in the present embodiment, the light reflecting surface 130 has a curved shape. Specifically, the light reflecting surface 130 has a curved shape in which the thickness formed with the light exit surface 120 decreases from the light incident surface 110 to the opposing surface 140 facing the light incident surface 110. desirable. Alternatively, the light reflecting surface 130 having the curved shape and the light emitting surface 120 having the flat surface may meet each other at one corner.

In this case, the curvature of the light reflecting surface 130 may be such that the light reflected from the light reflecting surface 130 and then emitted to the light emitting surface 120 has a direction perpendicular to the light emitting surface 120.

Backlight assembly

Example  2

3 is a perspective view illustrating a backlight assembly according to a second embodiment of the present invention. 4 is a cross-sectional view of the backlight assembly shown in FIG. 3.

3 and 4, the backlight assembly 500 according to the present embodiment includes a light generating device 200, a light guide plate 100, and a reflecting plate 300.

The light generator 200 includes a light source 210 and a light source cover 220. The light source 210 according to the present embodiment consumes electrical energy to generate light. In this embodiment, the light source 210 is, for example, a Cold Cathode Fluorescent Lamp (CCFL).

The light source cover 220 condenses and emits light generated radially from the light source 210 in one direction. To implement this, the light source cover 220 may be made of a metal having excellent reflectivity, or a light reflection layer (not shown) having excellent reflectance may be further formed inside the light source cover 220.

The light guide plate 100 includes side surfaces 150 including a light incident surface 110, a flat light emitting surface 120, and a light reflecting surface 130.

The light incident surface 110 is disposed to face the light source 210 of the light source assembly 200, and the light generated by the light source 210 and reflected from the light source cover 220 is guided through the light incident surface 110. Is incident into the interior of 100).

The light emitting surface 120 and the light reflecting surface 130 are connected to both ends of the light incident surface 110 and disposed to face each other.

The light reflecting surface 130 reflects the light incident through the light incident surface 110 to the light exit surface 120.

In the present embodiment, the light reflecting surface 130 may have the same flat shape as the light emitting surface 120, but the light reflecting surface 130 and the light emitting surface 120 have a flat or wedge shape. By the law of refraction, most of the light emitted from the light exit surface 120 is emitted in an inclined direction with respect to the light exit surface 120. When the light emitted to the light exit surface 120 is inclined with respect to the light exit surface 120 as described above, the brightness characteristic and the viewing angle characteristic of the image are greatly reduced.                     

To prevent this, in the present embodiment, the light reflecting surface 130 has a curved shape. Specifically, the light reflecting surface 130 has a curved shape in which the thickness formed with the light exit surface 120 decreases from the light incident surface 110 to the opposing surface 140 facing the light incident surface 110. desirable. Alternatively, the light reflecting surface 130 having the curved shape and the light emitting surface 120 having the flat surface may meet each other at one corner.

In this case, the curvature of the light reflecting surface 130 may be such that the light reflected from the light reflecting surface 130 and then emitted to the light emitting surface 120 has a direction perpendicular to the light emitting surface 120.

The reflecting plate 300 is preferably disposed to face the light reflecting surface 230 of the light guide plate 200. Preferably, the reflector 300 may reflect light leaked from the light reflecting surface 230 of the light guide plate 200 into the light guide plate 200 to further improve the luminance of light emitted from the light guide plate 200.

In the present embodiment, the reflecting plate 300 is in close contact with the light reflecting surface 230, and thus, the reflecting plate 300 has a curved shape having the same curvature as the light reflecting surface 230.

The backlight assembly 500 according to the present embodiment further includes a storage container 400. The storage container 400 includes a bottom surface 410 and sidewalls 420 extending or disposed from an edge of the bottom surface 410. A storage space is formed in the storage container 400 by the bottom surface 410 and the side wall 420, and the lamp assembly 100, the light guide plate 200, and the reflecting plate 300 are accommodated in the storage space.

Example  3

5 is a cross-sectional view illustrating a backlight assembly according to a third embodiment of the present invention. Except for the light guide plate and the reflecting plate, the backlight assembly according to the third embodiment of the present invention has the same configuration as the backlight assembly of the second embodiment described above, and thus a duplicated description thereof will be omitted. Like reference numerals refer to like elements. The code and name will be used.

Referring to FIG. 5, the backlight assembly 500 according to the present embodiment includes a light generating device 200, a light guide plate 100, a reflecting plate 300, and a storage container 400.

The light guide plate 100 includes side surfaces 150 including a light incident surface 110, a flat light emitting surface 120, and a light reflecting surface 130.

The light incident surface 110 is disposed to face the light source 210 of the light source assembly 200, and the light generated by the light source 210 and reflected from the light source cover 220 is guided through the light incident surface 110. Is incident into the interior of 100).

The light emitting surface 120 and the light reflecting surface 130 are connected to both ends of the light incident surface 110 and disposed to face each other.

The light reflecting surface 130 reflects the light incident through the light incident surface 110 to the light exit surface 120.

In the present embodiment, the light reflecting surface 130 may have the same flat shape as the light emitting surface 120, but the light reflecting surface 130 and the light emitting surface 120 have a flat or wedge shape. By the law of refraction, most of the light emitted from the light exit surface 120 is emitted in an inclined direction with respect to the light exit surface 120. As such, when the light emitted to the light exit surface 120 is inclined with respect to the light exit surface 120, the brightness characteristics and the viewing angle characteristics of the image are greatly reduced.

To prevent this, in the present embodiment, the light reflecting surface 130 has a curved shape. Specifically, the light reflecting surface 130 has a curved shape in which the thickness formed with the light exit surface 120 decreases from the light incident surface 110 to the opposing surface 140 facing the light incident surface 110. desirable. Alternatively, the light reflecting surface 130 having the curved shape and the light emitting surface 120 having the flat surface may meet each other at one corner.

In this case, the curvature of the light reflecting surface 130 may be such that the light reflected from the light reflecting surface 130 and then emitted to the light emitting surface 120 has a direction perpendicular to the light emitting surface 120.

The reflecting plate 310 according to the present exemplary embodiment includes a plurality of sub reflecting plates 310, and a plurality of sub reflecting plates 310 is disposed on the light reflecting surface 130 of the light guide plate 200 in parallel. The sub-reflective plates 310 reflect light emitted from the light reflecting surface 130 among the light generated by the lamp 210 and incident through the light incident surface 210 to further improve the brightness of the light.

Display

Example  4

6 is an exploded perspective view illustrating a display device according to a fourth exemplary embodiment of the present invention. Since the backlight assembly according to the fourth embodiment of the present invention has the same configuration as the backlight assembly of the second and third embodiments described above, duplicate description thereof will be omitted, and the same reference numerals and names are used for the same components. I will use it.

Referring to FIG. 6, the display device 100 according to the present embodiment includes a backlight assembly 500 and a display panel 600.

The display panel 600 changes the light emitted from the light exit surface 120 of the light guide plate 100 into image light including information.

The display panel 600 includes a first substrate 610, a second substrate 620, a liquid crystal layer 630, a printed circuit board 640, and a flexible circuit board 650.

The first substrate 610 includes pixel electrodes arranged in a matrix and thin film transistors (TFTs) electrically connected to the pixel electrodes to apply driving voltages to the pixel electrodes. A gate signal line and a data signal line are formed on the first substrate 610 to apply a corresponding driving signal to each pixel electrode by the thin film transistors. The gate electrode of each thin film transistor is connected to a gate signal line, the source electrode is connected to a data signal line, and the drain electrode of the thin film transistor is connected to a pixel electrode, respectively.

The second substrate 620 has a smaller area than the first substrate 620 and is disposed to face the second substrate 620. The second substrate 620 includes a transparent and conductive common electrode and a plurality of color filters disposed to face each pixel electrode.

The liquid crystal layer 630 is interposed between the first substrate 610 and the second substrate 620 and rearranged by an electric field formed between the pixel electrode and the common electrode. The rearranged liquid crystal layer 630 adjusts the light transmittance of the light generated by the backlight assembly 500, and the light whose light transmittance is adjusted passes through the color filter to display an image.

The printed circuit board 640 includes a driving circuit therein, and the driving circuit generates a driving signal for controlling the thin film transistor.

The flexible circuit board 650 electrically connects the printed circuit board 640 and the first substrate 610 to provide a driving signal generated from the printed circuit board 640 to the first substrate 610.

The display device according to the present exemplary embodiment may further include a top chassis 700.

The top chassis 700 surrounds the edge of the display panel 600 and is coupled to the side wall 420 of the storage container 400 to fix the display panel 600 to the upper portion of the backlight assembly 500.

The top chassis 700 prevents damage or damage to the fragile display panel 600 due to an external shock and vibration, and prevents the display panel 600 from being separated from the storage container 400.

As described above in detail, since the light incident on the light guide plate is reflected perpendicularly to the light exit surface by the reflection plate disposed on the reflection surface, the brightness of the backlight assembly may be increased.

In addition, the manufacturing cost of the backlight assembly may be reduced as a separate member for diffusion and front brightness increase, such as a diffusion sheet and a prism sheet, becomes unnecessary.

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 (9)

A light incident surface, a light reflecting surface connected to face the light incident surface and a flat light emitting surface, The light reflecting surface has a curved shape in which the thickness formed by the light emitting surface and the light reflecting surface is reduced from the light incident surface toward the opposite surface facing the light incident surface. A light generator including a light source for generating light; A light incident surface to which the light is incident, a light reflecting surface connected to the light incident surface, and a flat light emitting surface, wherein the light reflecting surface has a thickness formed by the light emitting surface and the light reflecting surface; A light guide plate having a curved shape that decreases from an incident surface to an opposite surface facing the light incident surface; And And a reflector having a curvature substantially the same as that of the light reflecting surface for injecting light leaked into the light reflecting surface into the light guide plate. The backlight assembly of claim 2, wherein the reflector has a curved shape. The backlight assembly of claim 2, wherein the reflector comprises a plurality of sub reflector. The backlight assembly of claim 2, wherein the light generating device, the light guide plate, and the reflecting plate are accommodated in a storage container. 3. The backlight assembly of claim 2, wherein the light generating device further comprises a light source cover for enclosing a portion of the light source to reflect the light to the light incident surface. A light generator including a light source for generating light, A light incident surface to which the light is incident, a light reflecting surface connected to the light incident surface, and a flat light emitting surface, wherein the light reflecting surface has a thickness formed by the light emitting surface and the light reflecting surface; A light guide plate having a curved shape that decreases from an incident surface to an opposite surface facing the light incident surface; A reflector having substantially the same curvature as the light reflecting surface for injecting light leaked into the light reflecting surface into the light guide plate; and  A backlight assembly including a receiving container accommodating the lamp assembly, the light guide plate, and the reflecting plate; And And a display panel disposed on the backlight assembly to change the light into image light including information. The display device of claim 7, wherein the reflective plate has a curved shape. The display device of claim 7, wherein the reflective plate comprises a plurality of sub reflective plates.

Images