KR20090061281A - Surface light source and backlight unit having the same - Google Patents

Abstract

A surface light source and backlight unit having the same is provided to secure the clear and natural image by applying voltage to each discharge channel. The light source body comprises a first substrate(120) and a second substrate(130). The first substrate and the second substrate are formed of the transparent glass. The first substrate and the second substrate are arranged to be faced with each other. The first substrate has a structure for forming a plurality of discharge channels. The second substrate arranged in the bottom side is formed as the flat board form. The edge of the second substrate and the first substrate are sealed by the sealing member(180) including the frit etc. The bent portion(230) is formed between the discharge space forming section(210) and a barrier wall portion(220).

Description

Surface light source device and backlight unit having the same {SURFACE LIGHT SOURCE AND BACKLIGHT UNIT HAVING THE SAME}

The present invention relates to a surface light source device having a plurality of discharge channels, and more particularly, to a surface light source device having a plurality of discharge channels that are resistant to impact and can minimize cracks, and a backlight unit having the same.

The liquid crystal display displays an image by using electrical and optical characteristics of the liquid crystal. Since the liquid crystal part of the liquid crystal display is a light receiving element that does not generate light by itself, it separately requires a rear light source, that is, a backlight.

Light supplied from the rear light source sequentially passes through the pixel electrode, the liquid crystal, and the common electrode of the liquid crystal display. In this case, the display quality of the image passing through the liquid crystal largely depends on the luminance and luminance uniformity of the rear light source. In general, the higher the luminance and the uniformity of the luminance, the better the display quality.

Conventionally, a rear light source of a liquid crystal display device has been mainly used a cold cathode fluorescent lamp (CCFL) or a light emitting diode (LED). Cold cathode fluorescent lamp has the advantage of high brightness, long life, and very low heat generation compared to incandescent lamps. On the other hand, the light emitting diode has a high power consumption, but has an advantage of excellent brightness. However, cold cathode fluorescent lamps or light emitting diodes have poor luminance uniformity. Therefore, existing back light sources require optical members such as a light guide panel (LGP), a diffusion member, a prism sheet, and the like to increase luminance uniformity. As a result, the liquid crystal display has a problem in that the volume and weight of the optical member are greatly increased.

As a back light source for a liquid crystal display, a flat fluorescent lamp (FFL) in the form of a flat plate has been proposed.

The conventional surface light source device comprises a light source body and an electrode.

The light source body has a first substrate and a second substrate disposed to face the first substrate, and has a discharge space into which a discharge gas is injected. The first substrate and the second substrate are sealed at their edges to have a discharge space between the first substrate and the second substrate.

Phosphors are coated on the surfaces of the first substrate and the second substrate, and when the discharge voltage is applied to the discharge gas by the electrodes, ultraviolet rays are generated by the discharge of the discharge gas. The generated ultraviolet rays excite the phosphor to generate visible light, and the generated visible light is transmitted forward through the substrate.

Currently, in order to improve the image quality of a large area liquid crystal display device and to realize a clearer and more natural display quality, the surface light source device needs a technology for locally controlling the luminance of the surface light source device used as a backlight.

In addition, due to the harmfulness of mercury, which is mainly used as the discharge gas, there is a demand for the development of an environment-friendly surface light source device that can use a discharge gas without mercury.

An object of the present invention is to provide a surface light source device that can use a discharge gas free of mercury.

Another object of the present invention is to provide a surface light source device capable of locally controlling a luminance by dividing a discharge space into a plurality of discharge channels and applying a voltage to each divided channel.

Still another object of the present invention is to provide a surface light source device and a backlight unit having the same, which are resistant to impact and minimize the occurrence of cracks by improving the shape of an edge portion of the discharge channel.

A surface light source device according to an embodiment of the present invention includes a light source body having a first substrate and a second substrate on which a plurality of discharge channels are formed, and an electrode formed on a surface of the light source body, wherein the discharge channel is a discharge space. And a radius of curvature of the bent portion formed between the discharge space forming portion and the partition wall portion, wherein both edge portions of each discharge channel are different from each other. It is formed larger than the portion to strengthen the strength of both edge portions of each discharge channel.

The width of the discharge space forming portion is formed such that both edge portions of the discharge channel are narrower than the other portions of the discharge channel so that the area inside the discharge channel can be uniformly distributed throughout.

The discharge space forming portion is formed in a form in which the width gradually narrows at both edge portions of the discharge channel, and the curvature radius of the bent portion is formed in a form that gradually increases in both edge portions of each discharge channel.

The backlight unit according to the present invention includes a light source body having a first substrate and a second substrate on which a plurality of discharge channels are formed, and an electrode formed on a surface of the light source body, wherein the discharge channel is a discharge space forming a discharge space. And a radius of curvature of the bent portion formed between the discharge space forming portion and the partition wall portion, wherein both edge portions of each discharge channel are larger than other portions of each discharge channel. A surface light source device to be formed, a case for housing the surface light source device and an inverter for applying a voltage to the first electrode and the second electrode.

The surface light source device of the present invention configured as described above has the advantage of improving the quality by minimizing the occurrence of cracks at the edge portion of the discharge channel to which the concentrated stress is applied by increasing the radius of curvature of the edge portion of each discharge channel. have.

In addition, it is possible to inject a discharge gas of mercury is excluded in the discharge channel can provide an environmentally friendly surface light source device.

In addition, a plurality of discharge channels may be applied with voltages for respective channels or for divided regions to obtain light emission characteristics having locally controlled luminance. Therefore, the brightness of the surface light source can be partially controlled according to the brightness of the screen of the liquid crystal display device, thereby ensuring clear and natural image quality.

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

1 is a perspective view of a surface light source device according to an embodiment of the present invention, FIG. 2 is an enlarged view of a portion A of FIG. 1, FIG. 3 is a cross-sectional view of the BB line of FIG. 2, and FIG. 4 is a cross-sectional view of the CC line of FIG. 2. 5 is a plan view of a surface light source device according to an embodiment of the present invention.

The illustrated surface light source device 100 includes a light source body 110 forming a discharge space into which discharge gas is injected, and electrodes 150 and 160 for applying a discharge voltage to the discharge gas. The light source body 110 includes a first substrate 120 and a second substrate 130. The first substrate 120 and the second substrate 130 are preferably formed of a transparent glass substrate. The first substrate 120 and the second substrate 130 are disposed to face each other, and one of the two substrates 120 and 130 has a structure formed in a predetermined shape to form a plurality of discharge channels 140.

In the present embodiment, the first substrate 120 disposed at the upper side to emit light has a structure formed to form a plurality of discharge channels 140, and the second substrate 130 disposed at the lower side is formed in a flat plate shape. do. In the drawing, the discharge channel 140 is formed on the first substrate 120, but the discharge channel 140 is formed on the second substrate 130, or the first substrate 120 and the second substrate 130 are not limited thereto. It can be molded to everything.

The first substrate 120 is formed with a plurality of discharge channels 140 at equal intervals, and is attached to the upper surface of the second substrate 130. Therefore, the molded part of the first substrate 120 in contact with the second substrate 130 serves as a partition for partitioning each discharge space 160 and also serves as a spacer for maintaining the discharge space.

Such a substrate forming type does not require a separate spacer for supporting a discharge space between the first substrate and the second substrate, thereby simplifying the manufacturing process and having strength that can sufficiently cope with the impact stress of the surface light source device.

Edges of the first substrate 12O and the second substrate 130 may be joined by a sealing member 180 such as a frit, or may be directly fused using a heating means such as a laser.

A fluorescent layer (not shown) is applied to the inner surface of the discharge space 160 of the first substrate 120, and a reflective layer (not shown) and the fluorescent layer are disposed on the inner surface of the discharge channel 140 formed on the second substrate 130. (Not shown) may be applied respectively. In addition, an MgO coating layer may be formed on the inner surface of the discharge channel 140 to prevent phosphor deterioration due to ion collision. By the MgO coating layer 300 it is possible to prevent the degradation of the phosphor to prevent degradation of the brightness and efficiency and to ensure long-term reliability.

Various types of discharge gas may be selected as the discharge gas injected into the discharge space 160, but preferably, a gas excluding mercury such as xenon, argon, neon, other inert gas, or a mixed gas thereof is used.

In particular, when a discharge gas excluding mercury is used, it not only provides an environmentally friendly advantage, but also shortens the luminance stabilization time even when driving at low temperature. In addition, due to the temperature sensitivity of the mercury, it provides an advantage that can minimize the problem that the brightness uniformity of the surface light source device in accordance with the temperature deviation.

The discharge channels 140 are formed in plural at regular intervals in the transverse or longitudinal direction of the substrate. The discharge channel 140 may extend from both sides of the discharge space forming unit 210 and the discharge space forming unit 210 to form a discharge space 160 into which discharge gas is injected, and the second substrate ( The barrier rib 220 is in contact with the surface of the 130 and partitions between the plurality of discharge spaces.

The discharge space forming unit 210 may be formed in various forms, the cross section of which may be formed in any one of an oval shape, trapezoidal shape, polygonal shape, semicircular shape, and the like.

The bent part 230 is formed between the discharge space forming part 210 and the partition wall part 220. That is, the barrier rib portion 220 is formed by bending at both sides of the discharge space forming portion 210, and the bent portion is called the bent portion 230.

The length of the discharge channel 140 at both ends in the longitudinal direction is referred to as the edge portion E of the discharge channel, and the remaining portion other than the both edge portions E is referred to as the other portion C of the discharge channel. .

The bent portion 230 between the discharge space forming portion 210 and the partition wall portion 220 is bent with a predetermined radius of curvature. In most cases, when the radius of curvature is large, the stress-bearing force is large and when the radius of curvature is small, the bending portion 230 is bent. The force becomes small.

In the discharge channel 140, stress concentration occurs at both edge portions E of the discharge channel 140. That is, when the exhaust operation for the vacuum in the discharge channel 140, the stress is concentrated on both edge portions (E) of the discharge channel 140 compared to the other portion (C) of the discharge channel 140, the risk of cracking Will become large.

Therefore, the radius of curvature R2 of both edge portions E of the discharge channel 140 is larger than the radius of curvature R1 of the other portions C of the discharge channel 140 so as to increase both edges of the discharge channel 140. The strength of the part E is strengthened to increase the force to withstand the stress.

At this time, the width T2 of the discharge space forming unit 210 corresponding to both edge portions E of the discharge channel 140 so that the area of the discharge channel 140 is uniformly distributed along the longitudinal direction of the discharge channel 140. ) Is narrower than the width T1 of the discharge space forming unit 210 corresponding to the other portion C of the discharge channel 140.

In addition, the edge portion E of the discharge channel 140 has a shape in which the width T2 of the discharge space forming portion 210 gradually decreases toward the end of the discharge channel 140, and the bend portion 230 is formed. Has a structure in which the radius of curvature R2 is gradually increased.

As such, the radius of curvature R2 of both edge portions E of the discharge channel 140 is formed larger than that of the other portions C of the discharge channel 140, thereby strengthening the strength of the edge portion E, thereby concentrating stress. By being able to withstand, the occurrence of cracks in the discharge channel 140 can be minimized.

In addition, the width T2 of the discharge space forming portion 210 of both edge portions E of the discharge channel 140 is narrower than the width T1 of the discharge space forming portion 210 of the other portion C. Thus, the entire area is uniformly distributed in the longitudinal direction of the discharge channel 140.

The first electrode 150 and the second electrode 160 are formed on the surface of the second substrate 130 and disposed to be horizontal to the longitudinal direction of the discharge channel 140, and the first electrode at one edge of the discharge channel 140. When the 150 is disposed, the second electrode 160 is disposed on the other edge of the discharge channel 160. Accordingly, the first electrode 150 and the second electrode 160 are arranged to face each other on the same horizontal surface to cause surface discharge. In addition, the interval between the first electrode 150 and the second electrode 160 may maintain a sufficient distance to improve the brightness.

6, the first electrode 310 and the second electrode 320 may be disposed on both sides of the discharge channel 140 to generate a counter discharge. The structure shown in FIG. 7 may be applied. As described above, a structure in which the first electrode 330 is formed on the surface of the first substrate 120 and the second electrode 340 is formed on the surface of the second substrate 130 to generate discharge in a diagonal direction can also be applied. have.

The first electrode and the second electrode may be directly coated on the surfaces of the first substrate 120 and the second substrate 130, and may be formed by attaching a stripe-type wire or band-shaped conductive tape.

The first electrode and the second electrode may use a transparent electrode (eg, ITO), other conductive materials may be used, and preferred materials include copper, silver, gold, aluminum, nickel, chromium, ITO, and carbon-based conductive materials. , Any one material selected from a conductive polymer, or a composite material thereof may be used.

As such, since electrodes are formed for each discharge channel, sequential or selective division driving may be performed for each discharge channel. Therefore, the luminance of the surface light source device can be controlled locally.

8 is an exploded perspective view showing a backlight unit related to an embodiment of the present invention.

As illustrated, the backlight unit includes the surface light source device 100 described above, the bottom chassis 500, the fixed frame 600, and the inverter 700.

The bottom chassis 500 accommodates the surface light source device 100.

As the surface light source device 100, the surface light source device described above is used.

The optical sheet 800 is disposed on the top surface of the surface light source device 100. The optical sheet 800 may be composed of a diffusion sheet and a prism sheet.

The fixing frame 600 is coupled to the bottom chassis 500 to fix the optical sheet 800 to be disposed on the top surface of the surface light source device 100.

In the LCD, the liquid crystal panel is positioned in front of the fixed frame 600.

The inverter 700 is electrically connected to the first electrode 210 and the wire 710, and electrically connected to the second electrode 220 and the wire 720 to generate a high potential discharge voltage. ), The surface light source device 100 is driven.

Although described above with reference to preferred embodiments of the present invention, those skilled in the art or those skilled in the art without departing from the spirit and scope of the invention described in the claims to be described later Various modifications and variations can be made in the present invention without departing from the scope thereof.

1 is a perspective view of a surface light source device according to an embodiment of the present invention.

FIG. 2 is an enlarged view of the portion A of FIG. 1.

3 is a cross-sectional view taken along the line BB of FIG. 2.

4 is a cross-sectional view taken along the line C-C in FIG.

5 is a plan view of a surface light source device according to an embodiment of the present invention.

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

7 is a sectional view showing the electrode structure of the surface light source device according to the third embodiment of the present invention.

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

Claims (9)

A light source body having a first substrate and a second substrate on which a plurality of discharge channels are formed, and an electrode formed on a surface of the light source body, The discharge channel is composed of a discharge space forming unit for forming a discharge space, and partition walls for partitioning between each discharge space, The curvature radius of the bent portion formed between the discharge space forming portion and the partition wall portion is characterized in that both edge portions of each discharge channel is formed larger than the other portions of each discharge channel. The method of claim 1, The first substrate is a surface light source device, characterized in that the substrate itself is formed so that a plurality of discharge channels are formed. The method of claim 1, The surface light source device, characterized in that the discharge gas in which mercury is removed is injected into the discharge channel. The method of claim 1, The width of the discharge space forming portion is a surface light source device, characterized in that both edge portions of the discharge channel is formed narrower than the other portions of the discharge channel. The method of claim 1, And the discharge space forming portion is formed to have a width gradually narrowing at both edge portions of the discharge channel. The method of claim 1, Surface area light source device characterized in that the inner area of the discharge channel is formed uniformly as a whole. The method of claim 1, The radius of curvature of the bent portion is a surface light source device characterized in that it is formed in a form that gradually increases at both edge portions of each discharge channel. A light source body having a first substrate and a second substrate on which a plurality of discharge channels are formed, and an electrode formed on a surface of the light source body, wherein the discharge channel includes a discharge space forming unit forming a discharge space; And a curvature radius of the bent portion formed between the discharge space forming portion and the partition wall portion, the surface light source device of which both edge portions of each discharge channel are larger than other portions of each discharge channel. ; A case accommodating the surface light source device; And And an inverter for applying a voltage to the first electrode and the second electrode. The method of claim 8, The width of the discharge space forming portion is a backlight unit, characterized in that both edge portions of the discharge channel is formed narrower than the other portions of the discharge channel.

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