KR20090062425A - Surface light source and backlight unit having the same - Google Patents

Abstract

A surface light source device and a backlight unit including the same are provided to prevent a yellowing phenomenon on a substrate by precisely coating the electrode in a part of both surfaces of a glass substrate. A surface light source device includes a light source body and an electrode(210,220). The light source body includes a first substrate(120) and a second substrate(130) in which a discharge space is formed. The substrate is comprised of a flat glass substrate or the glass substrate in which a plurality of discharge channels are formed. The discharge gas excluding the hydrargyrum is injected to the inside of the discharge space. An electrode is formed on the surface of the light source body. The electrode is coated in an air side of the substrate.

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 an electrode applied to one surface of a flat substrate and having a discharge space inside the substrate, 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 the advantage of high power consumption but 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 includes a first substrate and a second substrate that are disposed to face each other and are formed in a flat plate type, and have a discharge space in which discharge gas is injected. The edges of the first substrate and the second substrate are sealed to seal the discharge space.

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.

Due to the harmfulness of mercury, which is mainly used as a discharge gas, it is required to develop an environment-friendly surface light source device that can use a discharge gas free of mercury.

SUMMARY OF THE INVENTION An object of the present invention is to provide a surface light source device capable of precisely applying the electrode on both sides of a glass substrate to prevent yellowing from occurring on the substrate, thereby extending its lifespan and improving luminance. .

The surface light source device according to the exemplary embodiment of the present invention includes a light source body having a first substrate and a second substrate having a discharge space formed thereon, and an electrode formed on a surface of the light source body, wherein the electrode has an air surface ( air side) is characterized in that it is applied.

The substrate is formed of a soda lime glass substrate, one side of which is formed an air side (Air Side) is characterized in that the other side is divided into a tin side (Tin Side).

The backlight unit according to the present invention includes a light source body having a first substrate and a second substrate on which a discharge space is formed, and an electrode formed on a surface of the light source body, wherein the electrode is disposed on an air side of the substrate. And a surface light source device to be coated, a chassis accommodating the surface light source device, and an inverter for applying a voltage to the electrodes.

The surface light source device according to the present invention configured as described above has the advantage that the electrode is applied to the air side of the substrate (Air Side) to prevent the yellowing generated in the substrate, thereby preventing the lowering of brightness and extend the life have.

In addition, mercury-free discharge gas can be used to provide an environment-friendly surface light source device.

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, Figure 2 is a cross-sectional view of an embodiment of the present invention.

The illustrated surface light source device 100 includes a light source body 110 for forming a discharge space into which discharge gas is injected, and electrodes 210 and 220 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 exemplary 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 is not limited thereto. The discharge channel 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.

Discharge channels 140 are formed in plural at regular intervals in the transverse or longitudinal direction of the substrate. In addition, the discharge channel 140 may be applied to any shape that can form the discharge space 160 such as an elliptical shape, a semicircle shape, a polygonal shape, and the like.

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. In addition, a sealing member such as a frit may be formed at a portion where the first substrate 120 and the second substrate 130 contact each other (a portion formed to form a discharge channel of the first substrate and an upper surface of the second substrate). May be bonded together, or may be directly fused using a heating means such as a laser.

A fluorescent layer may be coated on the inner surface of the discharge channel 140 formed on the first substrate 120, and a reflective layer and a fluorescent layer may be applied on the inner surface of the discharge space 160 of the second substrate 130, 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.

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 is possible to minimize the luminance uniformity of the surface light source device in accordance with the temperature deviation.

Here, the first substrate 120 and the second substrate 130, as shown in Figure 3, is formed of a soda-lime (Soda-Lime) glass substrate, one side of the air surface in contact with the air in the manufacturing process Air Side S1, and the other side is Tin Side S2 in contact with Tin.

In addition, electrodes 210 and 220 for applying a discharge voltage are formed on a surface of at least one of the first substrate 120 and the second substrate 130.

In this case, the electrodes 210 and 220 are applied to the air side S1 of the substrate. If the electrode is formed on the tin side (S2) of the substrate, silver (Ag) contained in the electrode reacts with the Fe component to generate yellowing on the surface of the substrate, thereby shortening the life of the electrode. This lowers the luminance of the surface light source device.

Accordingly, the electrodes 210 and 220 are coated on the air side S1 of the substrate to prevent yellowing from occurring on the substrate, thereby extending the life of the electrode and lowering the luminance of the surface light source device. Can be prevented.

The electrodes 210 and 220 are surface discharge type electrodes in which the first electrode 210 and the second electrode 220 are formed at a predetermined interval on a surface of one of the first substrate 120 and the second substrate 130. Can be. In another embodiment, the first electrode is formed on the surface of the first substrate, the second electrode is formed on the surface of the second substrate, and the first electrode and the second electrode are disposed to face each other to form a counter discharge electrode. Can be configured.

In another embodiment, the first electrode is formed on the surface of the first substrate, and the second electrode is formed on the surface of the second substrate, and the second electrode is disposed diagonally around the first electrode and the discharge space to be diagonally formed. Can be composed of a diagonal discharge type electrode that causes a discharge,

As another embodiment, the electrode may be disposed on both sides of the discharge channel to generate a counter discharge.

The electrode may use any type of electrode that can cause a discharge in the discharge space, in addition to the electrode described above.

The first electrode 210 and the second electrode 220 may be directly coated on the surfaces of the first substrate 120 and the second substrate 130, and attached with a stripe-shaped wire or band-shaped conductive tape. Can be formed.

The first electrode 210 and the second electrode 220 may use a transparent electrode (eg, ITO), other conductive materials may be used, and preferred materials include copper, silver, gold, aluminum, nickel, chromium, Any one material selected from ITO, a carbon-based conductive material, a conductive polymer, or a composite material thereof may be used.

4 is a perspective view of a surface light source device according to a second embodiment of the present invention, and FIG. 5 is a cross-sectional view of the surface light source device according to a second embodiment of the present invention.

The light source body 500 according to the second embodiment includes a first substrate 510 and a second substrate 520 formed of a transparent flat glass substrate.

The first substrate 510 and the second substrate 520 are disposed to face each other with a predetermined interval therebetween, and the partition 530 partitioning the discharge space 540 into a plurality of discharge spaces 540 isolated from each other. ) Is installed. The partition wall 530 may be integrally molded with the substrate and may be molded separately from the substrate and attached to the surface of the substrate.

In the manufacturing process, the first substrate 510 and the second substrate 520 become one side of the air side S1 and the other side of the first substrate 510 and 520.

Electrodes 560 and 570 for applying a discharge voltage are formed on a surface of at least one of the first and second substrates 510 and 520.

The electrodes 560 and 570 are applied to the air side S1 of the substrate to prevent yellowing from occurring on the substrate, thereby extending the life of the electrode and lowering the luminance of the surface light source device. prevent.

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

As shown, the backlight unit includes the surface light source device 100 described above, the bottom chassis 600, the fixed frame 700 and the inverter 800.

The bottom chassis 600 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 900 is disposed on the top surface of the surface light source device 100. The optical sheet 900 may be composed of a diffusion sheet and a prism sheet.

The fixing frame 700 is coupled to the bottom chassis 600 to fix the optical sheet 900 to be disposed on the top surface of the surface light source device 100.

In the LCD, a liquid crystal panel is positioned in front of the fixed frame 700.

The inverter 800 is electrically connected to the plurality of first electrodes 210 and the wires 810, respectively, and electrically connected to the plurality of second electrodes 220 and the wires 820, respectively. The surface light source device 100 is driven by generating a voltage and supplying it to the electrodes 210 and 220.

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.

2 is a cross-sectional view of a surface light source device according to an embodiment of the present invention.

3 is a cross-sectional view of a substrate according to an embodiment of the present invention.

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

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

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

Claims (5)

A light source body having a first substrate and a second substrate on which discharge spaces are formed; An electrode formed on the surface of the light source body, And the electrode is applied to an air side of the substrate. The method of claim 1, The substrate is a surface light source device, characterized in that formed of a flat glass substrate or a glass substrate in which a plurality of discharge channels are molded. The method of claim 1, The substrate is formed of a soda lime glass substrate, one side of the air surface (Air Side) is formed and the other side is a surface light source device, characterized in that divided into (Tin Side). The method of claim 1, And a discharge gas excluding mercury is injected into the discharge space. A light source body having a first substrate and a second substrate having a discharge space formed thereon, and an electrode formed on a surface of the light source body, the electrode being applied to an air side of the substrate; A chassis for housing the surface light source device; And an inverter configured to apply a voltage to the electrode unit.

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