KR20090055850A - Surface light source and backlight unit having the same - Google Patents

Abstract

The present invention provides a light source body including a first substrate and a second substrate on which a plurality of discharge channels are formed, a first electrode partitioning the plurality of discharge channels into a single block by a predetermined number, and applying a voltage to each block; The present invention provides a surface light source device and a backlight unit having the same, the second electrode being configured to perform an optimal scan driving.

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 surface discharge electrode structure partitioned into a plurality of blocks to facilitate scan driving, 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.

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 having a surface discharge type electrode structure capable of performing an optimal scan driving by applying a voltage for each block and a backlight unit having the same.

It is still another object of the present invention to provide a surface light source device and a backlight unit capable of optimizing a surface discharge electrode structure to improve luminance and to prevent interblock and channeling.

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; The electrode unit is configured to apply a voltage to each other to perform an optimized scan driving.

One of the first substrate and the second substrate has a shape in which the substrate itself is formed so that a plurality of discharge channels are formed, and the electrode portion is formed of a surface discharge type electrode formed at a predetermined interval on the surface of the substrate.

A first electrode comprising a plurality of sub-electrodes disposed in each of the outermost sides of a block and a pair of sub-electrodes disposed in the center and connecting electrodes connecting the sub-electrodes; And a second electrode including a pair of sub-electrodes arranged in pairs at predetermined intervals between the sub-electrodes and a connecting electrode connecting the sub-electrodes.

According to the present invention, a backlight unit includes a light source body including a first substrate and a second substrate on which a plurality of discharge channels are formed, and the plurality of discharge channels are divided into one block by a predetermined number and a voltage is applied to each block. And a surface light source device including an electrode portion, a case accommodating the surface light source device, and an inverter for applying a voltage to the electrode portion.

The present invention configured as described above can use a discharge gas free of mercury can provide an environment-friendly surface light source device.

In addition, the surface light source device of the present invention has an advantage of performing an optimal scan driving by binding a predetermined number of discharge channels into blocks and applying a voltage to each block.

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 parts 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.

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 a discharge space 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. 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 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 (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.

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 according to the temperature deviation.

As illustrated in FIGS. 3 and 4, the electrode parts 200 and 300 may be surface discharge type electrodes 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 units 200 and 300 may be formed in a block-type form so as to bundle a predetermined number of discharge channels 140 into one block B and apply a voltage to each block B.

For example, the electrode parts 200 and 300 may be divided into six blocks B1 to B6 so that the four discharge channels 140 may be bundled into one block B and the plurality of discharge channels may be divided into six. The number of discharge channels and the number of blocks divided into one block B 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 (B), the first electrode 200 is arranged at a predetermined interval by a pair, one end of the plurality of first electrodes is the first connection electrode 220 integrally Connected.

Here, the first electrodes 210 disposed at both outermost sides of one block B 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 320 is integrally connected to ends of the second electrodes 300.

Here, the first connection electrode 220 and the second connection electrode 320 are electrically connected to each other with different intervers.

As such, the electrode unit may have a structure in which the first electrodes 200 and the second electrodes 300 are alternately arranged in pairs, and the plurality of first electrodes 200 includes the first connection electrode 220. ) May be integrally connected, and the plurality of second electrodes 300 may be integrally connected to the second connection electrode 320.

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 electrode structures of one block described above are arranged in plural at regular intervals so that a voltage is applied to each block to perform scan driving.

Here, the distance between the first electrode 200 and the second electrode 300 maintains an optimized distance that can increase the discharge efficiency using the positive light region and minimize the starting voltage. In addition, the distance between the block and the neighboring block may prevent inter-blocking or channeling during discharge through scan driving, and maintain an optimized distance to remove the dark portion.

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.

5 is a perspective view of a surface light source device according to a second embodiment of the present invention, and FIG. 6 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.

Surface discharge type electrode parts 610 and 620 are formed on a surface of one of the first and second substrates 510 and 520. In some cases, the electrode parts 610 and 620 may be formed on both the first substrate 510 and the second substrate 520.

The electrode parts 610 and 620 may have the same electrode part as the structure of the electrode part (the electrode part illustrated in FIGS. 3 and 4) described in the above embodiment. Therefore, a detailed description of the first electrode and the second electrode structure will be omitted.

As described above, in the surface light source device according to the second embodiment, the discharge space between the planar first substrate 510 and the second substrate 520 is the same as the discharge channel described in the embodiment by the partition wall 530. It is divided into a plurality of discharge spaces 540, the first electrode 610 and the second electrode 620 is formed in both edges of each discharge space 540 in parallel with the longitudinal direction of the discharge space (540). The first electrode 610 and the second electrode 620 divide a predetermined number of discharge spaces into one block and apply a voltage to each block to perform scan driving.

7 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 200 by wires 810, respectively, and electrically connected to the plurality of second electrodes 300 and wires 820, respectively. Is generated and supplied to the electrodes 200 and 300 to drive the surface light source device 100.

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 illustrating an electrode structure according to an exemplary embodiment of the present invention.

4 is an enlarged view of a portion A of FIG. 3.

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 (14)

A light source body having a first substrate and a second substrate on which a plurality of discharge channels are formed; And a electrode unit for dividing the plurality of discharge channels into one block by a predetermined number and applying a voltage to each block. 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, And the electrode part is a surface discharge type electrode formed at a predetermined interval on a surface of the second substrate. The method of claim 1, And the electrode portion is disposed at a predetermined interval parallel to the longitudinal direction of the discharge channel. The method of claim 1, The electrode unit constituting the one block surface light source device, characterized in that the first electrode and the second electrode are alternately arranged at a predetermined interval. The method of claim 1, The electrode unit constituting the one block is a surface light source device, characterized in that the first electrode and the second electrode are arranged in pairs. The method of claim 1, The electrode unit includes a plurality of first electrodes disposed at each of the outermost sides of a block and arranged in pairs at the center, and a plurality of second electrodes arranged in pairs at predetermined intervals between the first electrodes. Become, And a plurality of first electrodes constituting a block are connected by a first connection electrode, and a plurality of second electrodes constituting a block are connected by a second connection electrode. 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 first substrate and a second substrate, the inside of which is divided into a plurality of discharge spaces and formed in a flat plate shape; And a electrode unit for dividing the plurality of discharge spaces into one block by a predetermined number and applying a voltage to each block. The method of claim 9, The electrode unit is a surface light source device, characterized in that formed on the surface of any one of the first substrate and the second substrate in the form of a plate parallel to the longitudinal direction of the discharge space. The method of claim 9, The electrode unit includes a plurality of first electrodes arranged in pairs and a second electrode arranged in pairs between the first electrodes. The method of claim 11, And a plurality of first electrodes constituting the one block are connected to the first connection electrode, and second electrodes constituting the one block are connected to the second connection electrode. A surface light source including 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 dividing the plurality of discharge channels into a block by a predetermined number and applying a voltage to each block. Device; 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 13, The electrode unit includes a plurality of first electrodes arranged in pairs, and a second electrode arranged in pairs between the first electrodes, And a plurality of first electrodes constituting the one block are connected to the first connection electrode, and second electrodes constituting the one block are connected to the second connection electrode.

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