KR20060024516A - Surface light source device and back light unit having the same - Google Patents

Abstract

The surface light source device includes a light source body having an inner space into which discharge gas is injected. Embossings are formed in the light source body to expand the surface area of the inner space. A fluorescent layer is formed along the embossings on the inner surface of the light source body. An electrode for applying a voltage to the discharge gas is provided in the light source body. Embossing increases the inner surface area of the discharge space. Therefore, the surface area of the fluorescent layer is also increased, so that the luminance of the surface light source device is greatly improved.

Description

Surface light source device and back light unit having the same {SURFACE LIGHT SOURCE DEVICE AND BACK LIGHT UNIT HAVING THE SAME}

1 is a cross-sectional view showing a conventional partition wall type surface light source device.

2 is a cross-sectional view showing a conventional barrier-integrated surface light source device.

3 is a perspective view showing a surface light source device according to Embodiment 1 of the present invention.

4 is a cross-sectional view taken along line IVa-IVb of FIG. 3.

5 is a cross-sectional view showing a surface light source device according to a second embodiment of the present invention.

6 is a cross-sectional view showing a surface light source device according to Embodiment 3 of the present invention.

7 is a cross-sectional view showing a surface light source device according to a fourth embodiment of the present invention.

8 is a cross-sectional view showing a surface light source device according to a fifth embodiment of the present invention.

9 is a perspective view showing a surface light source device according to a sixth embodiment of the present invention.

FIG. 10 is a cross-sectional view taken along the line VII-VIIb of FIG. 9.

11 is a sectional view showing a surface light source device according to a seventh embodiment of the present invention.

12 is a sectional view showing a surface light source device according to Embodiment 8 of the present invention.

13 is a sectional view showing a surface light source device according to a ninth embodiment of the present invention.

14 is a sectional view showing a surface light source device according to a tenth embodiment of the present invention.

15 is an exploded perspective view showing a backlight unit according to Embodiment 11 of the present invention.

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

110: light source body 111: first substrate

112: second substrate 115: embossing

120: partition 150: electrode

161: first fluorescent layer 162: second fluorescent layer

The present invention relates to a surface light source device and a backlight unit having the same, and more particularly, to a surface light source device for emitting light in the form of a plane, and a backlight unit having such a surface light source device as a light source.

In general, liquid crystals (LC) have both electrical and optical characteristics. The arrangement of the liquid crystal is changed in correspondence with the direction of the electric field by the electrical properties, and the transmittance of light is changed in response to the arrangement by the optical properties.

The liquid crystal display displays an image by using electrical and optical characteristics of the liquid crystal. Liquid crystal displays have the advantages of being very small in volume and light in weight compared to CRTs, etc. As a result, they are widely used in portable computers, communication devices, liquid crystal television receivers, and aerospace industries.

In order to control the liquid crystal, a liquid crystal display device requires a liquid crystal controlling part for controlling the liquid crystal and a light supplying part for supplying light to the liquid crystal.

The liquid crystal control part includes a pixel electrode disposed on the first substrate, a common electrode disposed on the second substrate, and a liquid crystal interposed between the pixel electrode and the common electrode. The pixel electrode is formed in plural in correspondence with the resolution, and the common electrode is made of one and facing the pixel electrode. A thin film transistor (TFT) is connected to each pixel electrode to apply a pixel voltage having a different level, and a reference voltage of the same level is applied to the common electrode. The pixel electrode and the common electrode are made of a transparent material having conductivity.

The light supply part supplies light to the liquid crystal of the liquid crystal control part. Light sequentially passes through the pixel electrode, the liquid crystal, and the common electrode. In this case, the display quality of the image passing through the liquid crystal is greatly influenced by the luminance and luminance uniformity of the light supply part. In general, the higher the luminance and the uniformity of the luminance, the better the display quality.

The light supply part of the conventional liquid crystal display device mainly uses a cold cathode fluorescent lamp (CCFL) having a rod shape or a light emitting diode (LED) having a dot shape. Cold cathode ray tube type lamp has a high brightness, long life, and has the advantage of having a very low heat generation compared to incandescent lamps. On the other hand, the light emitting diode has advantages of low power consumption and high brightness. However, the conventional cold cathode ray tube lamps or light emitting diodes have a disadvantage in that the luminance uniformity is weak.

Accordingly, the light supply part having the cold cathode ray tube type lamp or the light emitting diode as a light source is used to improve optical uniformity such as a light guide panel (LGP), a diffusion member, a prism sheet, and the like. It includes an optical member. As a result, a liquid crystal display using a cold cathode ray tube lamp or a light emitting diode has a problem in that the volume and weight of the optical member are greatly increased.

In order to solve this problem, a planar light source device has been proposed. The conventional surface light source device can be divided into a partition partition type and a partition wall type.

1 is a cross-sectional view showing a partition wall type surface light source device. Referring to FIG. 1, the conventional partition wall type surface light source device includes a first substrate 1, a second substrate 2 disposed on the first substrate 1, and first and second substrates 1 and 2. It is disposed between the edges of the sealing member 3 that defines an internal space. The partitions 4 are arranged in the inner space to partition the inner space into a plurality of discharge spaces 5 into which the discharge gas is injected. Electrodes 6 for applying a voltage to the discharge gas are formed along the outer edges of both edges of the first and second substrates 1, 2. Fluorescent layers (not shown) are formed on the first and second substrates 1 and 2 to transform the ultraviolet rays generated in the discharge space 5 into visible light.

2 is a cross-sectional view showing a barrier rib integrated surface light source device. Referring to FIG. 2, the conventional barrier-integrated surface light source device includes a first substrate 11 and a second substrate 12 disposed on the first substrate 11. The second substrate 12 has a plurality of partitions 13 integrally. The partition portions 13 abut against the first substrate 11, whereby a plurality of discharge spaces 15 into which the discharge gas is injected are formed. The outermost partitions 13 are joined to the first substrate 11 via the sealing frit 14. An electrode 16 for applying a voltage to the discharge gas surrounds the outer circumferential surfaces of the first and second substrates 1 and 2. Fluorescent layers (not shown) are formed on the first and second substrates 11 and 12 to transform the ultraviolet rays generated in the discharge space 5 into visible light.

The factor which most influences the brightness of the conventional surface light source devices described above is the surface area of the fluorescent layer. Since the fluorescent layer is formed on the inner surfaces of the first and second substrates forming the discharge space, the surface area of the fluorescent layer is determined by the inner surface surface area of the discharge space.

However, the conventional surface light source devices have a narrow inner surface area of the discharge space, and thus have a narrow surface area of the fluorescent layer. For this reason, the restriction was made to improve the brightness | luminance of the conventional surface light source device.

The present invention increases the inner surface area of the discharge space, thereby providing a surface light source device having improved luminance.

The present invention also provides a backlight unit having the above-described surface light source device as a light source.

The surface light source device according to an aspect of the present invention includes a light source body having an internal space into which discharge gas is injected. Embossings are formed in the light source body to expand the surface area of the inner space. A fluorescent layer is formed along the embossings on the inner surface of the light source body. An electrode for applying a voltage to the discharge gas is provided in the light source body.

According to one embodiment of the invention, the light source body is disposed on the first substrate, the second substrate on which the embossings are formed, the sealing member defining an inner space, and the inner space into a plurality of discharge spaces. Partitioning partitions.

According to another embodiment of the present invention, the light source body includes a first substrate and partition walls facing the first substrate to partition the inner space into a plurality of discharge spaces and a second substrate having the embossings.

According to another aspect of the present invention, a backlight unit includes a surface light source device, an upper and lower case for housing the surface light source device, an optical sheet interposed between the surface light source device and the upper case, and a discharge voltage for driving the surface light source device. It includes an inverter to apply. The surface light source device includes a light source body having an inner space into which discharge gas is injected. Embossings are formed in the light source body to expand the surface area of the inner space. A fluorescent layer is formed along the embossings on the inner surface of the light source body. An electrode for applying a voltage to the discharge gas is provided in the light source body.

According to the present invention as described above, by forming the embossing on the light source body, the inner surface of the discharge space is expanded. Therefore, the surface area of the phosphor is also increased, and the luminance of the surface light source device is improved. In addition, the light source body is closer to the diffuser plate by embossing. In particular, the luminance of the embossed portion appears relatively higher than the other portions. In addition, embossing also serves to diffuse light. As a result, the luminance of the surface light source device is increased by embossing.

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

Example 1

3 is a perspective view illustrating a surface light source device according to Embodiment 1 of the present invention, and FIG. 4 is a cross-sectional view taken along line IVa-IVb of FIG. 3.

3 and 4, the surface light source device 100 according to the present embodiment includes a light source body 110 having an internal space into which discharge gas is injected, and an electrode 150 for applying a voltage to the discharge gas. Include. Meanwhile, mercury gas, argon gas, neon gas, xenon gas, or the like may be used as the discharge gas.

The surface light source device 100 according to the present embodiment is a partition wall separation type. Accordingly, the light source body 110 is disposed between the first substrate 111, the edges of the second substrate 112 disposed on the first substrate 111, and the edges of the first and second substrates 111 and 112, and thus the inside thereof. The sealing member 130 may define a space, and the partition walls 120 may divide the internal space into a plurality of discharge spaces 140. The partition walls 120 are arranged parallel to the inner space along the first direction to divide the inner space into a plurality of discharge spaces 140. Meanwhile, in order to communicate the discharge spaces 140 with each other, the partition walls 120 may be arranged in a meandering structure, or a through hole (not shown) may be formed in the partition wall 120.

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 is emitted.

A plurality of embossing 115 is formed on the second substrate 112. In particular, the embossing 115 is formed along a portion of the second substrate 112 positioned above the discharge space 140. Thus, the inner surface area of the discharge space 140 is increased by the embossing 115. In addition, since the embossing 115 formed on the second substrate 112 is closer to the diffuser plate, the front luminance of the embossing 115 portion is higher and the light is easily diffused. On the other hand, in this embodiment, the embossing 115 has a substantially semicircular cross section.

The electrode 150 is formed on the outer surface of the edges of the first and second substrates 111 and 112 in a second direction substantially perpendicular to the first direction. Therefore, since the electrode 150 is formed along the surface of the embossing 115 formed on the second substrate 112, the electrode 150 also has an embossing structure corresponding to the shape of the embossing 115. Therefore, the surface area of the electrode 150 surrounding the discharge space 140 is increased, so that the discharge efficiency of the surface light source device 100 is improved. Meanwhile, the electrode 150 includes a material having excellent conductivity, for example, copper (Cu), nickel (Ni), silver (Ag), gold (Au), aluminum (Al), chromium (Cr), and the like. The electrode 150 may be formed by attaching a conductive tape made of the above material to the outer circumferential surface of the light source body or coating the metal powder of the above material on the outer circumferential surface of the light source body.

The reflective layer 170 is formed on the surface of the first substrate 111. The reflective layer 170 reflects the light directed toward the first substrate 111 among the light generated in the discharge space 140 toward the second substrate 112.

In addition, the first fluorescent layer 161 is formed on the surface of the reflective layer 170. The second fluorescent layer 162 is formed on the bottom surface of the second substrate 112. Since the second fluorescent layer 162 is formed along the inner surface of the second substrate 112, it is formed along the bottom surface of each embossing 115. Therefore, the surface area of the second fluorescent layer 162 is greatly increased by the embossing 115. As a result, the ratio of transforming the ultraviolet rays generated in the discharge space 140 into visible light is increased, thereby improving the luminance of the surface light source device.

Example 2

5 is a cross-sectional view illustrating a surface light source device according to Embodiment 2 of the present invention.

The surface light source device according to the present embodiment is substantially the same as the surface light source device according to the first embodiment except for embossing. Therefore, the same members are denoted by the same reference numerals and the description of the same members is omitted.

Referring to FIG. 5, a semicircular first embossing 117 is formed on the first substrate 111. A semi-circular second embossing 115 is formed on the upper surface of the second substrate 112. That is, according to the present embodiment, embossing 115 and 117 are formed on both the first and second substrates 111 and 112.

Thus, not only the second fluorescent layer 162 but also the first fluorescent layer 161 is formed along the first embossing 117 of the first substrate 111. Therefore, the surface area of the first fluorescent layer 161 is greatly increased by the first embossings 117. As a result, the surface area of the fluorescent layer is further expanded than in Example 1.

In addition, since the embossing structure is formed not only on the upper part of the electrode 150 but also on the lower part of the electrode 150, the surface area of the electrode 150 surrounding the discharge space 140 is increased. As a result, the discharge efficiency of the surface light source device 100 is improved.

Example 3

6 is a cross-sectional view illustrating a surface light source device according to Embodiment 3 of the present invention.

The surface light source device according to the present embodiment is substantially the same as the surface light source device according to the first embodiment except for the electrode. Therefore, the same members are denoted by the same reference numerals and the description of the same members is omitted.

Referring to FIG. 6, internal electrodes 155 are disposed inside the light source body instead of the external electrodes. The internal electrodes 155 are disposed in each discharge space to directly apply a voltage to discharge gas injected into the discharge space.

Example 4

7 is a cross-sectional view illustrating a surface light source device according to Embodiment 4 of the present invention.

The surface light source device according to the present embodiment is substantially the same as the surface light source device according to the first embodiment except for embossing. Therefore, the same members are denoted by the same reference numerals and the description of the same members is omitted.

7, the embossing 115a has a trapezoidal shape. A trapezoidal embossing 115a is formed on the upper surface of the second substrate 112. In addition, the trapezoidal embossing 115a may be formed on the bottom surface of the first substrate 111.

Example 5

8 is a cross-sectional view illustrating a surface light source device according to a fifth embodiment of the present invention.

The surface light source device according to the present embodiment is substantially the same as the surface light source device according to the first embodiment except for embossing. Therefore, the same members are denoted by the same reference numerals and the description of the same members is omitted.

Referring to FIG. 8, the embossing 115b has a triangular shape. A triangular embossing 115b is formed on the top surface of the second substrate 112. In addition, the triangular embossing 115b may be formed on the bottom surface of the first substrate 111.

Example 6

9 is a perspective view illustrating a surface light source device according to a sixth embodiment of the present invention, and FIG. 10 is a cross-sectional view taken along line VII-VIIb of FIG. 9.

9 and 10, the surface light source device 200 according to the present embodiment includes a light source body 210 having an internal space into which discharge gas is injected, and an electrode 250 for applying a voltage to the discharge gas. Include.

The surface light source device 200 according to the present embodiment is a partition wall integrated type. Thus, the light source body 210 includes a first substrate 211 and a second substrate 212 disposed on the first substrate 211 and having the partition portions 220 integrally. The partition walls 220 arranged along the first direction may face the first substrate 211 to form a plurality of discharge spaces 240. The outermost partition walls 220 are bonded to the first substrate 211 via the sealing frit 280. Meanwhile, in order to communicate the discharge spaces 240 with each other, the partition walls 220 may be arranged in a meandering structure, or a through hole (not shown) may be formed in the partition walls 220.

A plurality of embossings 215 are formed in the second substrate 212 positioned on the discharge space 240. Thus, the inner surface area of the discharge space 240 is increased by the embossing 215. In addition, since the distance between the embossing 215 formed on the second substrate 212 is closer to the diffusion plate, the front luminance of the embossing 215 may be higher and the light may be easily diffused. On the other hand, in this embodiment, the embossing 215 has a substantially semicircular cross section.

The electrode 250 is formed on the outer surface of the edges of the first and second substrates 211 and 212 in a second direction substantially perpendicular to the first direction. Accordingly, the electrode 250 also has an embossing structure corresponding to the shape of the embossing 215.

The reflective layer 270 is formed on the surface of the first substrate 211. The first fluorescent layer 261 is formed on the surface of the reflective layer 270. The second fluorescent layer 262 is formed on the bottom surface of the second substrate 212. Since the second fluorescent layer 262 is formed along the inner surface of the second substrate 212, it is formed along the bottom surface of each embossing 215. Therefore, the surface area of the second fluorescent layer 262 is greatly increased by the embossings 215. As a result, the ratio of transforming the ultraviolet rays generated in the discharge space 240 into visible light is increased, thereby improving the luminance of the surface light source device.

Example 7

11 is a cross-sectional view illustrating a surface light source device according to a seventh embodiment of the present invention.

The surface light source device according to the present embodiment is substantially the same as the surface light source device according to the sixth embodiment except for embossing. Therefore, the same members are denoted by the same reference numerals and the description of the same members is omitted.

Referring to FIG. 11, a semicircular first embossing 217 is formed on the first substrate 211. A semi-circular second embossing 215 is formed on the bottom surface of the second substrate 212. That is, according to this embodiment, embossings 215 and 217 are formed on both the first and second substrates 211 and 212.

Thus, not only the second fluorescent layer 262 but also the first fluorescent layer 261 is formed along the first embossing 217 of the first substrate 211. Therefore, the surface area of the first fluorescent layer 261 is greatly increased by the first embossings 217. As a result, the surface area of the fluorescent layer is further expanded than in Example 6.

In addition, since the embossing structure is formed not only on the upper part of the electrode 250 but also on the lower part of the electrode 250, the surface area of the electrode 250 surrounding the discharge space 240 is increased. As a result, the discharge efficiency of the surface light source device 200 is improved.

Example 8

12 is a cross-sectional view illustrating a surface light source device according to Embodiment 8 of the present invention.

The surface light source device according to the present embodiment is substantially the same as the surface light source device according to the sixth embodiment except for the electrode. Therefore, the same members are denoted by the same reference numerals and the description of the same members is omitted.

Referring to FIG. 12, internal electrodes 255 are disposed inside the light source body instead of the external electrodes. The internal electrodes 255 are disposed in each discharge space to directly apply a voltage to discharge gas injected into the discharge space.

Example 9

FIG. 13 is a cross-sectional view illustrating a surface light source device according to a ninth embodiment of the present invention. FIG.

The surface light source device according to the present embodiment is substantially the same as the surface light source device according to the sixth embodiment except for embossing. Therefore, the same members are denoted by the same reference numerals and the description of the same members is omitted.

Referring to FIG. 13, the embossing 215a has a trapezoidal shape. A trapezoidal embossing 215a is formed on the upper surface of the second substrate 212. In addition, the trapezoidal embossing 215a may be formed on the bottom surface of the first substrate 211.

Example 10

14 is a cross-sectional view illustrating a surface light source device according to a tenth embodiment of the present invention.

The surface light source device according to the present embodiment is substantially the same as the surface light source device according to the sixth embodiment except for embossing. Therefore, the same members are denoted by the same reference numerals and the description of the same members is omitted.

Referring to FIG. 14, the embossing 215b has a triangular shape. Triangular embossing 215b is formed on the upper surface of the second substrate 212. In addition, a triangular embossing 215b may be formed on the bottom surface of the first substrate 211.

Example 11

15 is an exploded perspective view showing a backlight unit according to Embodiment 11 of the present invention.

Referring to FIG. 15, the backlight unit 1000 according to the present exemplary embodiment includes the surface light source device 200, the upper and lower cases 1100 and 1200, the optical sheet 900, and the inverter 1300 according to the sixth embodiment. do.

Since the surface light source device 200 has substantially the same configuration as the surface light source device shown in FIG. 9, the description of the surface light source device 200 will be omitted. Meanwhile, the surface light source device 100 according to the first embodiment shown in FIG. 3 may be employed in the backlight unit 1000.

The lower case 1200 includes a bottom portion 1210 and a plurality of sidewalls 1220 extending to form an accommodation space from an edge of the bottom portion 1210 for accommodating the surface light source device 200. The surface light source device 200 is accommodated in the storage space of the lower case 1200.

The inverter 1300 is disposed on the rear surface of the lower case 1200 and generates a discharge voltage for driving the surface light source device 200. The discharge voltage generated from the inverter 1300 is applied to the electrodes 250 of the surface light source device 200 through the first and second power lines 1352 and 1354, respectively.

The optical sheet 900 may be formed of a diffusion plate (not shown) for uniformly diffusing the light emitted from the surface light source device 200, and a prism sheet (not shown) for imparting straightness to the diffused light.

The upper case 1100 is coupled to the lower case 1200 to support the surface light source device 200 and the optical sheet 900. The upper case 1100 prevents the surface light source device 200 from being separated from the lower case 1200.

Meanwhile, a liquid crystal display panel (not shown) for displaying an image may be disposed on the upper case 1100.

According to the present invention as described above, by embossing the light source body, the surface area of the discharge space is expanded. Therefore, the surface area of the phosphor is also increased, and the luminance of the surface light source device is improved.

In addition, the light source body is brought closer to the diffuser plate by embossing. In particular, the luminance of the embossed portion appears relatively higher than the other portions. In addition, embossing also serves to diffuse light. As a result, the luminance of the surface light source device is increased by embossing.

In addition, since the surface area of the electrode is also increased by embossing, the plasma generation efficiency in the discharge space can be 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 (13)

A light source body having an inner space into which discharge gas is injected and formed with embossings for expanding the surface area of the inner space; A fluorescent layer formed along the embossing on an inner surface of the light source body; And And an electrode for applying a voltage to the discharge gas. The method of claim 1, wherein the light source body A first substrate; A second substrate disposed on the first substrate and having the embossments formed thereon; A sealing member disposed between edges of the first and second substrates to define the internal space; And And a partition wall arranged in the inner space and partitioning the inner space into a plurality of discharge spaces. The method of claim 2, wherein the fluorescent layer is A first fluorescent layer formed on the surface of the first substrate; And And a second fluorescent layer formed along the bottom surface of the second substrate and the embossings. The surface light source device of claim 3, further comprising a reflective layer interposed between the first substrate and the first fluorescent layer. The surface light source device according to claim 2, wherein the embossings are formed on the first substrate, and the first fluorescent layer is formed along the embossing image. The method of claim 1, wherein the light source body A first substrate; And And a second substrate disposed on the first substrate, the barrier ribs integrally opposed to the first substrate to partition the internal space into a plurality of discharge spaces, and having the embossed portions formed thereon. Light source device. The method of claim 6, wherein the fluorescent layer A first fluorescent layer formed on the surface of the first substrate; And And a second fluorescent layer formed along the bottom surface of the second substrate, the embossings and the partitions. 8. The surface light source device according to claim 7, further comprising a reflective layer interposed between the first substrate and the first fluorescent layer. The surface light source device according to claim 6, wherein the embossings are formed on the first substrate, and the first fluorescent layer is formed along the embossing image. The surface light source device according to claim 1, wherein the electrode is formed on an outer surface of the light source body along a surface of the embossing, and has a structure corresponding to the shape of the embossing. The surface light source device of claim 1, wherein the electrode is disposed inside the light source body. The surface light source device according to claim 1, wherein the embossing has a semicircular cross section, a trapezoidal cross section, or a triangular cross section. A surface light source device having an internal space into which discharge gas is injected, the light source body having embossings for diffusing light generated in the internal space, and an electrode for applying a voltage to the discharge gas; Upper and lower cases accommodating the surface light source device; An optical sheet interposed between the surface light source device and the upper case; And And an inverter for applying a discharge voltage for driving the surface light source device to the electrode.

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