KR20090058718A - Surface light source and backlight unit having the same - Google Patents

Abstract

A surface light source and a backlight unit having the same are provided to prevent degradation of phosphor and improve the uniformity of image quality by setting a communication hole to a part having an electrode. The first substrate(510) faces the second substrate(520) in an interval. A partition(530) for a plurality of discharge spaces(540) is installed in the interval. Electrode portions(550,560) generating the discharge voltage are formed in the surface of the second substrate and the first substrate. The communicating hole communicating the discharge space is formed in the partition. The bottom chassis receives the surface light source device. The optical sheet is arranged in the upper side of the surface light source device. The rigid frame is combined with the bottom chassis.

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 for performing a scan drive by separating the electrode unit into a plurality of blocks and applying a voltage to each section, 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.

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 performing scan driving by dividing a discharge space into a plurality of discharge channels and separating electrodes into a plurality of blocks to apply a voltage to each block.

It is still another object of the present invention to provide a surface light source device capable of minimizing a current bleeding phenomenon during scan driving to prevent phosphor deterioration and to improve image quality uniformity.

In accordance with another aspect of the present invention, a surface light source device 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 unit for separating discharge channels into blocks and applying a voltage to each block. And a communication hole for communicating between the discharge channels, and the communication hole for communicating between the discharge channels separated into blocks among the plurality of communication holes is provided at a portion without an electrode.

One of the first substrate and the second substrate is formed by forming the substrate itself so that a plurality of discharge channels are formed, and the electrode unit divides a predetermined number of discharge channels into one block and four or more to divide the discharge channels into four or more. It is composed of blocks.

In accordance with another aspect of the present invention, there is provided a surface light source device including a light source body having a flat plate type first substrate and a second substrate having a plurality of discharge spaces partitioned by partition walls, and a discharge space divided into blocks, and a voltage for each block. And a communication hole formed in the partition wall so as to communicate between the discharge spaces, and a communication hole for communicating between the discharge spaces divided into blocks among the plurality of communication holes is installed in a portion without the electrode. It is characterized by.

The backlight unit 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, an electrode portion for separating discharge channels into blocks, and applying a voltage to each block, and between the discharge channels. And a communication hole for communicating between discharge channels separated by blocks among the plurality of communication holes, the communication hole including a surface light source device installed in a portion without an electrode, a case accommodating the surface light source device, and an electrode. And an inverter for applying a voltage to the unit.

The surface light source device of the present invention configured as described above has an advantage of performing an optimal scan driving by dividing a discharge space into a plurality of discharge channels and separating an electrode into a plurality of blocks to apply a voltage for each block.

In addition, the surface light source device of the present invention can use a discharge gas free of mercury can provide an environmentally friendly surface light source device.

In addition, the surface light source device of the present invention by installing a communication hole for communicating between the discharge channels divided into blocks of the communication holes for communicating each discharge channel in the absence of the electrode to minimize the current phenomena between blocks during the scan drive to minimize the phosphor There is an advantage that can prevent deterioration and improve image quality uniformity.

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, Figure 3 is a surface light source device according to an embodiment of the present invention Top view of the.

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 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.

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 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.

A fluorescent layer (not shown) is coated on an inner surface of the first substrate 120 to form a discharge space, and a reflective layer (not shown) and a fluorescent layer (not shown) are disposed on an inner surface of the discharge channel 140 formed on the second substrate 130. ) 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.

As shown in FIG. 4, the electrode parts 200 and 300 are formed of a surface discharge electrode formed only on the surface of any one of the first substrate 120 and the second substrate 130. The electrode parts 200 and 300 are preferably formed on the outer surface of the second substrate 130 formed in a flat plate shape. The electrode unit may be formed in a block-shaped form to bundle a predetermined number of discharge channels 140 into one block and apply a voltage to each block.

For example, the electrode parts 200 and 300 bundle two or more (more preferably four) discharge channels into one block, and four or more (more preferably, six or more) so that a plurality of discharge channels are divided into four or more. It is preferable to divide into blocks B1 to B6. The number of discharge channels and the number of blocks divided into one block may vary according to the screen size of the display, the width or shape of the discharge channel, or the size of the surface light source device.

The electrode parts 200 and 300 correspond to one edge of the discharge channel 140 and are formed on the surface of the second substrate 130 in parallel with the longitudinal direction of the discharge channel 140 and the discharge channel ( The second electrode 300 corresponds to the other edge of the 140 and formed in parallel with the first electrode 200 at a predetermined interval.

Looking at the electrode structure corresponding to one block, the first electrode 200 is disposed at a predetermined interval by a pair, one end of the plurality of first electrodes is connected to the first connection electrode 210 integrally. Here, the first electrodes 200 disposed at both outermost sides of one block may be disposed one by one.

The second electrode 300 is disposed in plural pairs between the first electrodes 200, and the second connection electrode 310 is integrally connected to ends of the second electrodes 300.

The first connection electrode 210 and the second connection electrode 310 are electrically connected to different interposers, respectively.

In addition, the electrode unit may use an electrode structure having any structure in which a plurality of first electrodes and a plurality of second electrodes are bundled into one block to apply a voltage in each block unit.

The first connection electrode 210 is formed at one edge of the second substrate 130 in a direction orthogonal to the first electrode 200, and the second connection electrode 310 is formed at the other edge of the second substrate 130. It is formed in a direction orthogonal to the second electrode 300. In addition, the end portion of the first connection electrode 210 and the second electrode 300 and the end portion of the second connection electrode 310 and the first electrode 200 are maintained at a predetermined interval so that discharge occurs.

Accordingly, a portion E without an electrode is formed at the end of the first electrode 200 disposed at the outermost side of each block B. FIG. That is, a portion E without an electrode is formed at one edge between the block B1 and the block B2.

Communication holes 400 and 410 are formed between the discharge channels 140 to communicate impurities between the discharge channels to discharge impurities in the discharge channels 140 to the outside and to inject discharge gas into the discharge channels.

The communication hole 410 for communicating between the discharge channels 140 separated into blocks among the plurality of communication holes is installed in the portion E without the electrode described above.

The communication hole 400 communicating between the discharge channels 140 forming one block is preferably installed at the center of the discharge channel 140, but any position of the discharge channel other than the center of the discharge channel 140 is provided. Can also be installed.

As such, since the communication hole 410 communicating between the discharge channels divided into blocks is installed in the portion E without the electrode, cross talk that may be generated by the electrode during scan driving may be minimized. It becomes possible.

In addition, since the communication hole 410 communicating between discharge channels separated by blocks is formed at one edge of the substrate instead of the effective surface of the screen on which the image is displayed, it is possible to maintain uniformity of image quality and suppress phosphor degradation. You can do it.

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, chromium, Any one material selected from ITO, a carbon-based conductive material, a conductive polymer, or a composite material thereof may be used.

Various types of discharge gas may be selected as the discharge gas injected into the discharge channel 140, but preferably, a gas that excludes mercury, such as xenon, argon, neon, other inert gas, or a mixture 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.

5 is a cross-sectional view of a 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.

Electrodes for generating a discharge voltage are formed on the surfaces of the first and second substrates 510 and 520, and the electrode portions 550 and 560 bundle a predetermined number of discharge spaces 540 into one block and for each block. It may be formed in a separate form in block units to apply a voltage.

Like the electrode parts 200 and 300 described in the above embodiment, the electrode parts 550 and 560 have a portion E having no electrode at one edge between the block B1 and the block B2. Since the structures of the electrode parts 550 and 560 are the same as those of the electrode parts 200 and 300 described in the embodiment, detailed descriptions thereof will be omitted.

In the partition wall 530, communication holes 580 and 590 are formed to communicate between the discharge spaces, and the communication holes communicating between the discharge spaces 540 partitioned by blocks among the communication holes are portions E without electrodes. Is installed on.

In addition, the communication holes 580 connecting the discharge spaces 540 forming one block may be installed at any position such as the center or the edge of the discharge spaces. 8 is an exploded perspective view showing a backlight unit related 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 first electrode 200 and the wire 810, and electrically connected to the second electrode 300 and the wire 820 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.

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

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

4 is a plan view showing the electrode structure of the surface light source device according to an embodiment of the present invention.

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

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

7 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; An electrode unit separating the discharge channels into blocks and applying a voltage to each block; It includes a communication hole for communicating between the discharge channels, The communication hole for communicating between the discharge channels separated into blocks among the plurality of communication holes is installed in the area where the electrode is absent. The method of claim 1, Any one of the first substrate and the second 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 substrate is a surface light source device, characterized in that the portion without the electrode is formed at one edge between the block and the block. The method of claim 1, The communication hole for connecting between the plurality of discharge channels divided into one block is provided in the center of the discharge channel, the surface light source device. 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. A light source body having a flat plate type first substrate and a second substrate having a plurality of discharge spaces partitioned by partition walls; An electrode unit for separating the discharge space into blocks and applying a voltage to each block; It includes a communication hole formed in the partition wall to communicate between the discharge space, A communication hole for communicating between discharge spaces separated by blocks among the plurality of communication holes is installed in a portion where no electrode. The method of claim 6, The substrate is a surface light source device, characterized in that the portion without the electrode is formed at one edge between the block and the block. A light source body having a first substrate and a second substrate on which a plurality of discharge channels are formed, an electrode unit for separating the discharge channels into blocks, applying a voltage to each block, and communicating between the discharge channels A communication hole including a ball, wherein the communication hole communicating between discharge channels separated into blocks among the plurality of communication holes includes a surface light source device installed at a portion without an electrode; A case accommodating the surface light source device; And And an inverter configured to apply a voltage to the electrode unit. The method of claim 8, The electrode unit is formed on both sides of the discharge channel in the horizontal direction and the longitudinal direction of the discharge channel, the surface of the light source device, characterized in that the electrode is formed at one edge of the block separated.

Images