KR20090086720A - Surface light source device and backlight unit having same - Google Patents

Abstract

The present invention includes a first substrate and a second substrate in which a discharge space into which discharge gas is injected is formed, and an electrode formed on at least one of the first and second substrates. The present invention provides a surface light source device capable of improving efficiency and brightness by adding a gas used to generate ultraviolet rays having a wavelength of 254 nm to increase the amount of ultraviolet rays generated, and a backlight unit having the same.

Description

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

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface light source device using a discharge gas free of mercury, and more particularly to a surface light source device using a discharge gas capable of increasing the amount of ultraviolet light emission in detail 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 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.

Such a conventional surface light source device is not only environmentally problematic because it contains mercury (Hg) in the discharge gas, and the luminance stabilization time is long when driving at low temperatures, and the temperature sensitivity of the surface light source itself is affected by the temperature sensitivity of the mercury. Accordingly, there is a problem in that the luminance uniformity is lowered.

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 and a backlight unit having the same, which can increase the amount of ultraviolet rays emitted by adding a discharge gas that forms ultraviolet rays of a specific wavelength and thereby improve efficiency and brightness.

The surface light source device according to an exemplary embodiment of the present invention includes a first substrate and a second substrate on which a discharge space into which a discharge gas is injected is formed, and an electrode formed on at least one of the first substrate and the second substrate, and discharged. As the gas, a discharge gas excluding mercury is used, and a gas generating ultraviolet rays having a wavelength of 254 nm is added.

The discharge gas is a gas that generates xenon (Xe), argon (Ar), neon (Ne), helium (He) or other inert gas, or a mixture thereof, and generates ultraviolet rays of 254 nm wavelength, at least one of XeI and KrI It is characterized by being used.

The backlight unit according to the present invention includes a first substrate and a second substrate on which a discharge space into which a discharge gas is injected is formed, and electrodes formed on at least one of the first and second substrates, and the discharge gas excludes mercury. And a surface light source device to which a discharge gas is used, and a gas for generating ultraviolet rays of 254 nm wavelength is added, a chassis for accommodating 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 an advantage of providing an environment-friendly surface light source device by injecting a discharge gas in which mercury is excluded in a discharge space.

In addition, by adding an inert gas capable of forming ultraviolet rays of a specific wavelength as a discharge gas to increase the infrared emission amount, there is an advantage that can improve the efficiency and brightness of the 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 the 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 for forming a discharge space into which discharge gas is injected, and electrodes 200 and 300 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 has a flat plate shape. Is formed. In the drawing, the discharge channel 140 is formed on the first substrate 120, but is not limited thereto. The discharge channel 140 may be formed on the second substrate 130, or the first substrate 120 and the second substrate ( 130) can be molded to both.

The discharge channels 140 may be formed at regular intervals in the transverse direction of the first substrate 120, and may be formed at regular intervals in the longitudinal direction of the first substrate 120.

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. Accordingly, the molded portion of the first substrate 120 in contact with the second substrate 130 serves as a partition wall 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 portion where the first substrate and the second substrate are in contact with each other (the portion formed to form the discharge channel of the first substrate and the upper surface of the second substrate) may be joined with a sealing member such as a frit. It can fuse directly using a heating means, such as a laser.

Phosphors may be applied to the inner surface of the discharge channel 140 formed on the first substrate 120, and reflectors and phosphors may be applied to the inner surfaces 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. The degradation of the phosphor can be prevented by the MgO coating layer, thereby preventing deterioration in brightness and efficiency and ensuring long-term reliability.

Various types of discharge gas may be selected as the discharge gas injected into the discharge space 160, but preferably, gases that exclude mercury, such as xenon (Xe), argon (Ar), neon (Ne), and helium (He) And other inert gases or mixtures thereof and the like can be used.

In particular, although Xen and Ne are given and used, in this case, ultraviolet rays of 147 nm and 173 nm wavelengths are generated. However, since the ultraviolet rays of the 147 nm and 173 nm wavelengths generate a small amount of ultraviolet rays, the amount of ultraviolet rays that excite the phosphor coated on the inner surface of the discharge space is relatively small, and thus the amount of visible light generated decreases and the luminance decreases. Thus, an inert gas having a large amount of ultraviolet rays is added as a discharge gas to improve the brightness and efficiency of the surface light source device.

As an inert gas capable of increasing the amount of ultraviolet rays generated, an inert gas capable of generating ultraviolet rays of 254 nm wavelength is preferably used.

That is, when at least one of XeI and KrI as the discharge gas is added to the existing discharge gas, ultraviolet rays having a wavelength of 254 nm may be generated, thereby increasing the amount of ultraviolet rays generated.

 As such, 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 electrodes 200 and 300 are surface discharge type electrodes in which the first electrode 200 and the second electrode 300 are formed at a predetermined interval on a surface of one of the first substrate 120 and the second substrate 130. Can be. As another example, as illustrated in FIG. 3, the electrode part is formed on the surface of the first substrate 120, and the second electrode 300 is formed on the surface of the second substrate 130. The first electrode 200 and the second electrode 300 may be formed diagonally with respect to the discharge space to form a diagonal discharge type electrode which causes discharge in the diagonal direction.

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 so as to face the discharge electrode. In 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 200 and the second electrode 300 may be formed directly on the surface of the first substrate 120 and the second substrate 130, and attached with a conductive tape in the shape of a stripe wire or band. Can be formed.

The first electrode 200 and the second electrode 300 may use a transparent electrode (eg, ITO), other conductive materials may be used, and preferred materials include copper, silver, gold, aluminum, nickel, and chromium. , ITO, a carbon-based conductive material, a conductive polymer, or any one material selected from these materials 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 which are formed of a transparent flat glass substrate and form a discharge space 540 therein.

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.

Discharge gas is injected into the discharge space, which is discharged in a 254 nm wavelength to an inert gas such as xenon (Xe), argon (Ar), neon (Ne), helium (He) and the like as described in the above embodiment. At least one of XeI and KrI, which may generate ultraviolet rays, is added.

As such, by adding a discharge gas capable of generating ultraviolet rays having a wavelength of 254 nm to the existing discharge gas, the amount of ultraviolet rays generated may be increased, thereby improving brightness and efficiency of the surface light source device.

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.

For the electrode, any one of the electrode structures described in the above embodiment may be used.

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 by the first electrode 210 and the wire 810, and electrically connected by the second electrode 220 and the wire 820 to generate a high potential discharge voltage. The surface light source device 100 is driven by supplying it to 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 showing another electrode structure of the surface light source device according to the 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 (9)

A first substrate and a second substrate on which a discharge space into which discharge gas is injected is formed; An electrode formed on at least one of the first substrate and the second substrate, As the discharge gas, a discharge gas excluding mercury is used, and a gas for generating ultraviolet rays having a wavelength of 254 nm is added. The method of claim 1, The discharge gas is a surface light source device, characterized in that xenon (Xe), argon (Ar), neon (Ne), helium (He) or other inert gas or a mixture thereof. The method of claim 1, And at least one of XeI and KrI is used as a gas for generating ultraviolet rays having a wavelength of 254 nm. The method of claim 1, At least one of the first substrate and the second substrate is a surface light source device, characterized in that for forming a plurality of discharge channels. The method of claim 1, The first substrate and the second substrate is a surface light source device, characterized in that formed of a flat glass substrate. The method of claim 1, And the electrode comprises a first electrode and a second electrode formed on a surface of at least one of the first substrate and the second substrate. A first substrate and a second substrate on which a discharge space into which discharge gas is injected is formed, and an electrode formed on at least one of the first and second substrates, wherein the discharge gas includes a discharge gas excluding mercury; A surface light source device to which a gas for generating ultraviolet rays having a wavelength of 254 nm is added; A chassis 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 7, wherein The discharge gas is a backlight unit, characterized in that xenon (Xe), argon (Ar), neon (Ne), helium (He) or other inert gas or a mixture thereof is used. The method of claim 7, wherein And at least one of XeI and KrI is used as a gas for generating ultraviolet rays having a wavelength of 254 nm.

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