KR20070073061A - Back light unit - Google Patents

Abstract

A backlight unit is provided to equip a diffusion pattern for diffusing the light emitted from the edge of a light source device to an inside mold. A light source device(100) includes the first surface for emitting the light and the second surface opposite to the first surface. A chassis(700) supports the second surface of the light source device. An outside mold(300) supports the first surface of the light source device. An inside mold(400) is interposed between the outside mold and the light source device and supports the light source device. A diffusion pattern is equipped to the inside mold and diffuses the light emitted from the edge of the light source device. The diffusion pattern is integrally formed to the inside surface of the inside mold. A tape is attached at the inside surface of the inside mold and includes the integrally formed diffusion pattern.

Description

Back light unit {BACK LIGHT UNIT}

1 is an exploded perspective view showing a backlight unit according to a first embodiment of the present invention.

FIG. 2 is a perspective view illustrating a partition wall type surface light source device that may be applied to the surface light source device of FIG. 1.

3 is a perspective view illustrating a barrier rib integrated surface light source device that may be applied to the surface light source device of FIG. 1.

4 is a perspective view illustrating the inner mold of FIG. 1.

FIG. 5 is a front view of the diffusion pattern in enlarged view of the region of FIG. 4.

6 is a front view illustrating a diffusion pattern according to another exemplary embodiment.

7 is a front view illustrating a diffusion pattern according to yet another embodiment.

8 is a front view illustrating a diffusion pattern according to yet another embodiment.

9 is an exploded perspective view showing a backlight unit according to a second embodiment of the present invention.

-Explanation of symbols for the main parts of the drawing-

100: light source device 700: chassis

300: outer mold 400: inner mold

500: optical member: 600: tape

The present invention relates to a backlight unit, and more particularly to a backlight unit having a surface light source device as a light source.

In general, a display device converts data processed by an information processing device into an image. Such display devices include liquid crystal display devices, plasma display devices, and the like, and light sources of such display devices include fluorescent lamps and surface light source devices.

A conventional backlight unit having such a light source device as a light source includes a chassis for accommodating the light source device. The chassis supports the second surface opposite to the light exit surface of the light source device. The outer mold supports the first surface, which is the light exit surface of the light source device. An inner mold that assists the light source device is interposed between the light source device and the outer mold. An optical member for uniformly diffusing the light emitted from the light source device is interposed between the inner mold and the outer mold.

As the display device is gradually enlarged, the size of the light source device is gradually increasing. For this reason, there arises a problem that the luminance of light emitted from the edge portion is lower than that of the center portion of the light source device. In order to solve this problem, a method of compensating for the luminance of the edge portion of the light source device has been proposed by inducing a deviation of the tube current flowing in the light source device. However, the conventional method described above increases the operating time of the light source device. Inevitably, the deviation of the tube current is inevitably caused, which causes another problem of greatly shortening the life of the light source device.

The present invention provides a backlight unit capable of exhibiting uniform luminance uniformity.

According to one aspect of the present invention, a backlight unit includes a light source device having a first surface emitting light toward a front surface and a second surface opposite to the first surface. The chassis supports the second side of the light source device. The outer mold supports the first side of the light source device. An inner mold is interposed between the outer mold and the light source device to support the light source device. A diffusion pattern for diffusing light emitted from the edge region of the light source device is provided in the inner mold.

According to one embodiment of the invention, the diffusion pattern may be integrally formed on the inner surface of the inner mold.

According to another embodiment of the present invention, the diffusion pattern may be integrally formed on the tape attached to the inner side of the inner mold.

According to another embodiment of the present invention, an optical member may be interposed between the inner mold and the outer mold.

According to another embodiment of the present invention, the light source device may include a light source for generating light in tubular or planar form.

According to the present invention, since the diffusion pattern is provided on the edge surface of the inner mold, the light emitted from the edge portion of the light source device is diffused by the diffusion pattern. Therefore, the luminance at the edge of the backlight unit is improved. As a result, the backlight unit has improved luminance uniformity.

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

Example 1

1 is an exploded perspective view showing a backlight unit according to a first embodiment of the present invention, Figure 2 is a perspective view showing a partition surface-type surface light source device that can be applied to the surface light source device of Figure 1, Figure 3 is FIG. 4 is a perspective view illustrating the barrier rib-integrated surface light source device applicable to the surface light source device, FIG. 4 is a perspective view of the inner mold of FIG. 1, FIG. 5 is a front view of a diffusion pattern in an enlarged portion of FIG. 4, and FIG. 6. 7 is a front view showing a diffusion pattern according to another embodiment, FIG. 7 is a front view showing a diffusion pattern according to another embodiment, and FIG. 8 is a front view showing a diffusion pattern according to another embodiment.

Referring to FIG. 1, the backlight unit 1000 according to the present exemplary embodiment includes a light source device 100, a chassis 700, an outer mold 300, an inner mold 400, and an optical member 500.

The light source device 100 employed in this embodiment is a surface light source device. The surface light source device 100 emits surface light. The surface light source device 100 has a first surface on which light is emitted and a second surface opposite to the first surface. The surface light source device 100 may be divided into a partition wall type surface light source device shown in FIG. 2 and a partition surface integrated surface light source device 200 shown in FIG. 3.

Referring to FIG. 2, the partition wall type surface light source device 100 includes a light source body having a plurality of discharge spaces 140 into which a discharge gas is injected, and an electrode 150 applying a voltage to the discharge gas.

The light source body is disposed between the edges of the first substrate 111, the second substrate 112 disposed on the first substrate 111, and the first and second substrates 111 and 112 to define an internal space. The member 130 and partition walls 120 partitioning the inner space into a plurality of discharge spaces 140 are included.

The first and second substrates 111 and 112 are made of a glass material that transmits visible light and blocks ultraviolet rays. The second substrate 112 is an emission surface from which light generated in the discharge space 140 is emitted. That is, the bottom surface of the first substrate 111 corresponds to the second surface of the surface light source device 100, and the top surface of the second substrate 112 corresponds to the first surface of the surface light source device 100.

The partition walls 120 are arranged parallel to the inner space along the first direction to partition the inner space into a plurality of discharge spaces 140 having a stripe shape. Lower surfaces of the partition walls 120 may face the first substrate 111 and the upper surface may face the second substrate 112. In order to inject the discharge gas into each of the discharge spaces 140, the partition walls 120 may be arranged in a meandering structure, or a communication path (not shown) may be formed in the partition walls 120.

The electrode 150 includes a first electrode 152 formed on the bottom surface of the first substrate 111, and a second electrode 154 formed on the top surface of the second substrate 112. In particular, the first and second electrodes 152 and 154 are disposed at both edges of the first and second substrates 111 and 112 along a second direction substantially perpendicular to the first direction. Meanwhile, the electrode 150 may include a conductive tape or a conductive paste.

The reflective layer 160 is formed on the surface of the first substrate 111. The reflective layer 160 reflects the light directed toward the first substrate 111 among the light generated in the discharge space 140 toward the second substrate 112. The first fluorescent layer 171 excited by the ultraviolet rays generated from the discharge gas to which the voltage is applied is formed on the surface of the reflective layer 160. The second fluorescent layer 172 having the same function as the first fluorescent layer 171 is formed on the bottom surface of the second substrate 112.

The partition surface integrated light source device 200 illustrated in FIG. 3 includes a light source body having an internal space into which a discharge gas is injected, and an electrode 250 for applying a voltage to the discharge gas.

The light source body includes a first substrate 211 and a second substrate 212 disposed on the first substrate 211 and having the partition walls 220 integrally. The partition walls 220 arranged along the first direction are opposed to the first substrate 211 to form a plurality of discharge spaces 240 having a substantially arch shape. In order to inject the discharge gas into each of the discharge spaces 240, the partition walls 220 may be arranged in a meandering structure, or a communication path 225 may be formed in the partition walls 220. In particular, the communication path 225 may be formed in a diagonal or S-shape on the partition wall portion 220. The partition walls 220 have a width of about 1 to 5 mm.

The electrodes 250 are arranged along both edges of the light source body 210 along a second direction substantially perpendicular to the first direction. The electrode 250 includes a first electrode 252 formed on the bottom surface of the first substrate 211, and a second electrode 254 formed on the top surface of the second substrate 212.

The reflective layer 260 is formed on the surface of the first substrate 211. The first fluorescent layer 271 is formed on the surface of the reflective layer 260. The second fluorescent layer 272 is formed on the bottom surface of the second substrate 212.

Any one of the two surface light source devices 100 and 200 described above may be employed as a light source of the backlight unit 1000 according to the present invention. In the present embodiment, the partition wall type surface light source device 100 is adopted and described.

The chassis 700 supports the second surface of the surface light source device 100. That is, the second substrate 112 is supported by the chassis 700.

The outer mold 300 supports the first surface of the surface light source device 100. Since the first surface is a light exit surface, the light emitted from the surface light source device 100 should not interfere with the outer mold 300. Therefore, the outer mold 300 has a rectangular frame shape so as to support the outer side of the first surface of the surface light source device 100.

An optical member 500 for diffusing light emitted from the surface light source device 100 is interposed between the outer mold 300 and the inner mold 400.

Since the inner mold 400 should not interfere with the light emitted from the surface light source device 100, the inner mold 400 has a rectangular shape corresponding to the outer mold 300. Here, since the light emitted from the surface light source device 100 travels in various directions, such light is irradiated to the inner mold 400. In order to improve the light efficiency of the backlight unit 1000 by reflecting the light irradiated to the inner mold 400, the inner mold 400 may be made of an acrylic material having excellent light reflectivity. In addition, a light reflector may be included in the inner mold 400.

In addition, as the size of the surface light source device 100 gradually increases, light emitted from the edge portion of the surface light source device 100 has a lower luminance. In order to compensate for this, in the present invention, the diffusion pattern 410 is provided in the inner mold 400.

4 and 5, the diffusion pattern 410 is provided on the inner side surface of the inner mold 400. In particular, the diffusion pattern 410 according to the present exemplary embodiment has a structure in which a plurality of circular protrusions are irregularly arranged. Since light emitted from the edge of the surface light source device 100 is diffused by the diffusion pattern 410, the edge portion of the backlight unit 1000 may have improved luminance.

Alternatively, as shown in FIG. 6, the diffusion pattern 420 may have a structure in which a plurality of triangular protrusions are arranged. In particular, the projections of each triangle may be alternately arranged. That is, the protrusions of neighboring triangles are arranged to face opposite to each other.

On the contrary, as shown in FIG. 7, the triangular diffusion patterns 430 may be arranged to face the same direction.

Alternatively, as shown in FIG. 8, the diffusion pattern 440 may have a structure in which a plurality of lozenge-shaped protrusions are arranged in a line.

In addition to the structures of the diffusion pattern described above, the diffusion pattern of the present invention may be formed by arranging protrusions having other shapes. That is, the diffusion pattern may be provided in the inner mold 400 by forming a plurality of protrusions on the inner surface of the inner mold 400.

Meanwhile, in the present embodiment, the diffusion patterns 410, 420, 430, and 440 are integrally formed in the inner mold 400.

Here, although the surface light source device is illustrated as being employed as the light source device 100 in this embodiment, other light source devices, for example, a tube-shaped fluorescent lamp in addition to the surface light source device, may be employed in the backlight unit 1000. have.

Example 2

9 is an exploded perspective view showing a backlight unit according to a second embodiment of the present invention.

The backlight unit 1100 according to the present exemplary embodiment includes substantially the same components as the backlight unit 1000 of the first exemplary embodiment except that the backlight unit 1100 additionally includes the tape 600. Therefore, the same elements are denoted by the same reference numerals, and repeated descriptions of the same elements are omitted.

Referring to FIG. 9, the circular diffusion pattern 610 is not integrally formed on the inner mold 400, but is integrally formed on a separate tape 600. Tape 600 is attached to the inner side of inner mold 400. That is, the backlight unit 1100 according to the present exemplary embodiment includes a tape 600 in which the diffusion pattern 610 is integrally formed in the backlight unit 1000 of the first exemplary embodiment. Of course, the diffusion patterns 420, 430, and 440 illustrated in FIGS. 6 to 8 may be formed on the tape 600.

As described above in detail, the diffusion pattern provided on the inner surface of the inner mold diffuses the light emitted from the edge of the light source device. Therefore, the luminance at the edge of the backlight unit is improved. As a result, the backlight unit has improved luminance uniformity.

In the detailed description of the present invention described above with reference to a preferred embodiment of the present invention, those skilled in the art or those skilled in the art having ordinary knowledge in the scope of the invention 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 (7)

A light source device having a first surface for emitting light and a second surface opposite to the first surface; A chassis supporting a second surface of the light source device; An outer mold supporting the first surface of the light source device; An inner mold interposed between the outer mold and the light source device to support the light source device; And a diffusion pattern provided in the inner mold and configured to diffuse light emitted from an edge region of the light source device. The backlight unit of claim 1, wherein the diffusion pattern is integrally formed on an inner surface of the inner mold. The backlight unit of claim 1, further comprising a tape attached to an inner surface of the inner mold and in which the diffusion pattern is integrally formed. The backlight unit of claim 1, wherein the diffusion pattern has a circular, triangular, or rhombic cross-sectional shape. The backlight unit of claim 1, wherein the inner mold is made of acrylic. The backlight unit of claim 1, further comprising an optical member interposed between the inner mold and the outer mold. The backlight unit of claim 1, wherein the light source device comprises a light source for generating tubular or planar light.

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