KR20090067546A - Surface light source and backlight unit having the same - Google Patents

Abstract

A surface light source device and a backlight unit having the same are provided to control luminance voltage in a plurality of discharge channels as the approval box. A surface light source device comprises a light source body and electrode portions(210,220). The light source body forms a discharge space filled with the discharge gas. The light source body comprises a first substrate and a second substrate. The electrode portion is formed in the surface of the light source body. The electrode portion authorizes the discharge voltage in the discharge gas. A plurality of discharge channels(140) is formed in the first substrate. The concave-convex region(400) is formed in the surface of the second substrate according to the longitudinal direction of the discharge channel in order to expand the fluorescent coating area. The concave-convex region is formed by adhering one to the surface of the second substrate among the silicate glass and mortar ceramics.

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 suitable for using a discharge gas that is free of mercury, and more particularly to a surface light source device that can improve the brightness by expanding the contact area of the phosphor and ultraviolet rays and a backlight unit having the same. will be.

 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 including the same, which can improve luminance by expanding a phosphor coating area in a discharge space and widening an area in which phosphors and ultraviolet rays contact each other.

The surface light source device according to the embodiment of the present invention includes a light source body having a first substrate and a second substrate having a plurality of discharge spaces formed therein, and an electrode portion formed on a surface of the light source body, and having an inner surface of the discharge space. It is characterized in that the uneven portion for expanding the phosphor coating area is formed.

The uneven portion is formed along the longitudinal direction of the discharge channel on the surface of the second substrate, characterized in that any one of water glass and mortar ceramic is attached to the surface of the substrate.

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 spaces are formed, and an electrode part formed on a surface of the light source body, and an inner surface of the discharge space includes a phosphor coating area. And a surface light source device having a concave-convex portion formed therein for extending the shape thereof, a chassis accommodating the surface light source device, and an inverter applying voltage to the first electrode and the second electrode.

In the surface light source device of the present invention configured as described above, the concave-convex portion may be formed in the discharge space to increase the phosphor coating area, thereby increasing the contact area between the phosphor and the ultraviolet ray, thereby improving luminance.

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.

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 electrode portions 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 any 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 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.

The phosphor 300 is coated on the inner surface of the discharge channel 140 formed on the first substrate 120, and the reflective layer 310 and the phosphor 320 are coated on the inner surface of the second substrate 130. Can be.

An uneven portion 400 may be formed on the inner surface of the discharge space 160 to extend the coating area of the phosphor 320.

The uneven portion 400 may be formed along the longitudinal direction of the discharge channel 140 on the upper surface of the second substrate 130 constituting the discharge space, the shape of the uneven portion 400 is a concave portion and convex portion is repeated It may be shaped, and may be formed in various shapes such as a circle, a polygon, and an oval.

In addition, since the phosphor 320 is coated on the surface of the uneven portion 400, the coating area of the phosphor may be increased by about 10% to about 50% compared to when the phosphor is coated on a flat surface.

The uneven portion 400 may be a water glass or ceramic mortar that is attached in the form of a band at a predetermined interval in the longitudinal direction of the discharge channel on the surface of the second substrate.

For example, Cs, Mg, Ba, and the like may be added to the material forming the uneven parts 400 as the secondary electron emission material. like this,

The uneven parts 400 may be integrally formed on the second substrate 130 and may also be formed on the surface of the first substrate 120, that is, the inner surface of the discharge channel 140.

As such, by forming the uneven portion 400 on the inner surface of the discharge space 160 to expand the application area of the phosphor, ultraviolet rays generated in the discharge space 160 can increase the contact area with the phosphor, thereby increasing the luminance. It can be improved.

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 electrode parts 210 and 220 are surface discharge 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 configured. In another embodiment, the first electrode 210 is formed on the surface of the first substrate 120, and the second electrode 220 is formed on the surface of the second substrate 130 to form the first electrode 210. And the second electrode 220 may be disposed to face each other and may be configured as a counter discharge electrode.

As another embodiment, the first electrode 210 is formed on the surface of the first substrate 120, and the second electrode 220 is formed on the surface of the second substrate 130, and the first electrode 210 is formed. ) And the second electrode 220 may be configured as a diagonal discharge type electrode which is disposed in a diagonal direction with respect to the discharge space to cause discharge in a diagonal direction.

As another embodiment, the electrode unit may be disposed on both sides of the discharge channel 140 to generate a counter discharge.

The electrode unit may use any type of electrode capable of causing a discharge in the discharge space in addition to the electrode unit described above.

The electrode portions 210 and 220 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 electrode portion 210.220 may use a transparent electrode (eg, ITO), may use other conductive materials, and a preferred material may be copper, silver, gold, aluminum, nickel, chromium, ITO, carbon-based conductive material, or conductive material. Any one material selected from polymers or composite materials thereof may be used.

3 is a perspective view of a surface light source device according to a second embodiment of the present invention, and FIG. 4 is a partial 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.

An uneven portion 560 having the same function as the uneven portion 400 described in the above embodiment may be formed on an inner surface of the discharge space of at least one of the first substrate 510 and the second substrate 520. Can be.

Since the action of the uneven portion 560 is the same as the uneven portion 400 described in one embodiment, description thereof will be omitted.

 In addition, electrode portions 610 and 620 for applying a discharge voltage are formed on a surface of at least one of the first and second substrates 510 and 520.

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

As illustrated, the backlight unit includes the surface light source device 100 described above, a bottom chassis 600, a fixed frame 700, and an 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 partial cross-sectional view of a surface light source device according to an embodiment of the present invention.

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

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

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

Claims (6)

A light source body having a first substrate and a second substrate on which a plurality of discharge spaces are formed; An electrode part formed on a surface of the light source body, The surface light source device, characterized in that the concave-convex portion for extending the phosphor coating area is formed on the inner surface of the discharge space. The method of claim 1, And the first substrate is self-molded to form a plurality of discharge channels. The method of claim 2, The uneven portion is a surface light source device, characterized in that formed along the longitudinal direction of the discharge channel on the surface of the second substrate. The method of claim 1, The concave-convex portion is a surface light source device, characterized in that any one of water glass, mortar ceramic is attached to the surface of the substrate. The method of claim 1, A surface light source device, characterized in that the secondary electron emitting material is added to the material forming the uneven portion. A light source body having a first substrate and a second substrate having a plurality of discharge spaces formed therein, and an electrode portion formed on a surface of the light source body, wherein an uneven portion for expanding a phosphor coating area is formed on an inner surface of the discharge space. Surface light source device; A chassis accommodating the surface light source device; And And an inverter for applying a voltage to the first electrode and the second electrode.

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