KR20090058719A - 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 plurality of discharge channels are divided into one block by a predetermined number, and a first electrode to which a voltage is applied to each block. And a second electrode disposed on the same plane as the first electrode and separated along the longitudinal direction of the discharge channels, and having a second electrode to which a voltage is applied to each column, so that not only scan driving but also local dimming is possible. Provided is a surface light source device and a backlight unit having an electrode structure.

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 type electrode structure divided into a plurality of blocks to enable scan driving and local dimming, 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 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 improving brightness and extending lamp life by providing a surface discharge electrode structure capable of local dimming as well as scan driving.

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 a second electrode disposed on the same plane as the first electrode and separated in a longitudinal direction of the discharge channels, and a second electrode applied with a voltage for each column. There is a characteristic.

The first electrodes are arranged to be separated at regular intervals along the length direction of the discharge channel, and the plurality of first electrodes forming one block is connected by the first connection electrode.

The first connection electrode is formed at regular intervals along the length direction of the discharge channel in a direction orthogonal to the discharge channel, and the first connection electrodes constituting one block are connected by the inlet electrode.

The second electrodes may be separated at regular intervals along the length direction of the discharge channel, and the second electrodes corresponding to each column may be connected by the second connection electrodes along the length direction of the discharge channel.

The second connection electrodes are arranged at regular intervals between the first connection electrodes in a direction orthogonal to the discharge channel, and the second connection electrodes forming one row are connected to each other.

At least one of the first electrode and the second electrode may have a plurality of branch electrodes formed to protrude in a direction in which the two electrodes face each other, and a plurality of convex portions convexly formed may be formed.

The surface light source device according to the second exemplary embodiment of the present invention includes 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 plurality of discharge spaces. The first electrode is divided into one block, and a plurality of columns are arranged on the same plane as the first electrode and are separated along the longitudinal direction of the discharge space, and the voltage is applied to each column. It has a feature including a second electrode to be.

According to an embodiment of 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 a plurality of discharge channels are partitioned into one block by a predetermined number, and each block A surface light source device including a first electrode to which a voltage is applied, and a second electrode disposed on the same plane as the first electrode and separated in a longitudinal direction of the discharge channels, and a second electrode to which voltage is applied to each column. And a chassis for 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.

In addition, the surface discharge type electrode structure can be improved to enable local dimming as well as scan driving, to improve brightness, and to prolong the life of the lamp.

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 that forms a discharge space into which discharge gas is injected, and electrode units 200 and 300 that apply 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 parts 200 and 300 may be formed in a block-shaped form so that a certain number of discharge channels 140 may be bundled into one block B and scan may be performed by applying a voltage to each block B. FIG. have.

In addition, the electrode parts 200 and 300 may be divided at regular intervals in the longitudinal direction of the discharge channel 140 to locally apply a voltage along the longitudinal direction of the discharge channel, thereby forming a local dimming drive.

For example, the electrode parts 200 and 300 may be divided into four blocks B1 to B4 so that the seven discharge channels 140 are bundled into one block B and the plurality of discharge channels 140 are divided into four. have. In addition, the electrode parts 200 and 300 may be divided into sixteen in the longitudinal direction of the discharge channel 140 as an example. Therefore, 64 parts of the surface discharges are divided by the electrode parts 200 and 300 to locally control luminance.

The number of discharge channels and the number of blocks partitioned into one block B may vary depending on 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, are formed to be parallel to the longitudinal direction of the discharge channel 140, and are divided at regular intervals, and are formed on the second substrate 130. ) And a second electrode 300 corresponding to the other edge of the discharge channel 140 and formed in parallel with the first electrode 200 at regular intervals and divided at regular intervals along the longitudinal direction of the discharge channel. do.

The first electrode 200 is arranged to be divided at regular intervals along the longitudinal direction of the discharge channel, the first electrodes 200 partitioned into one block B is connected by the first connection electrode 210. do.

The first electrodes 200 are preferably configured in pairs such that electrodes having the same polarity may be disposed at opposite edges of the discharge channels 140 adjacent to each other of the discharge channels 140.

The first connection electrode 210 is provided in plural so that the first electrodes 200 corresponding to each column of the first electrodes 200 divided along the longitudinal direction of the discharge channel 140 are connected. The first connection electrodes 210 divided into one block of the first connection electrodes 210 are connected to one by the induction electrode 220 to receive a voltage.

The second electrode 300 is disposed in parallel with the first electrode 200 and formed on the other side of the discharge channel 140 to generate a discharge between the first electrode 200 and the first electrode 200. In this case, the second electrodes 300 are disposed in pairs between the first electrodes 200.

The second electrode 300 is formed to be divided at regular intervals along the length direction of the discharge channel 140, and arranged in a plurality of rows along the length direction of the discharge channel 140 of the second electrodes 300. The second electrodes 300 corresponding to the respective columns of the second electrodes 300 are connected by the second connection electrode 310.

Here, the first connection electrodes 210 are formed in a direction orthogonal to the longitudinal direction of the discharge channel 140 and arranged at regular intervals in the longitudinal direction of the discharge channel 140. The second connection electrodes 210 are formed to be orthogonal to the length direction of the discharge channel 140 and are disposed between the first connection electrodes 210.

As such, the first electrodes 200 forming one block are connected by the first connection electrode 210 so that a voltage is applied to each block, and the second electrodes 300 corresponding to the respective columns are connected to the second connection. Since the voltage is applied to each column connected by the electrode 310, local dimming may be performed while performing scan driving.

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 plan view showing an electrode structure according to another embodiment of the present invention.

The electrode structure according to the second embodiment is the same as the electrode structure described in the above embodiment, but is formed to protrude at a predetermined interval to the positive electrode of at least one of the first electrode 200 and the second electrode 300. Electrodes 320 are formed.

That is, the branch electrodes 320 are formed at regular intervals on the side of the first electrode 200 and the second electrode 300 facing each other to determine the distance between the first electrode 200 and the second electrode 300. It is possible to reduce the starting voltage by bringing the initial discharge closer to each other.

As such, the branch electrodes 320 may be formed to protrude on the side of the electrode or may be integrally formed with the electrode.

6 is a plan view showing an electrode structure according to another embodiment of the present invention.

The electrode structure according to the third embodiment is the same as the electrode structure described in the above embodiment, except that at least one electrode of the first electrode 400 and the second electrode 410 has the convex portion 450 repeatedly. It has a structure that is formed.

Here, the convex portion 450 is formed in a convex shape of the electrode, and the block portion 450 has a form in which two electrodes protrude convexly in a lateral direction facing each other.

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.

7 is a perspective view of a surface light source device according to a second embodiment of the present invention, and FIG. 8 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). In addition, the first electrode 610 divides a predetermined number of discharge spaces into one block and applies a voltage to each block to perform scan driving, and the second electrode 620 is spaced at a predetermined interval in the longitudinal direction of the discharge space. It is composed of a plurality of columns to be divided, so that local dimming can be performed by applying a voltage for each column.

9 is an exploded perspective view illustrating 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 plan view showing an electrode structure according to another embodiment of the present invention.

6 is a plan view showing an electrode structure according to another embodiment of the present invention.

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

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

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

Claims (15)

A light source body having 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 one block by a predetermined number and applying a voltage to each block; And a second electrode disposed on the same plane as the first electrode and arranged in a plurality of rows separated along a longitudinal direction of discharge channels, and having a voltage applied to each column. 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 first electrode and the second electrode are surface discharge type electrodes formed on the surface of the second substrate at predetermined intervals. The method of claim 1, The first electrode is disposed to be separated at a predetermined interval along the longitudinal direction of the discharge channel, the plurality of first electrodes forming a block is connected to the surface light source device, characterized in that by the first connection electrode. The method of claim 4, wherein The first connection electrode is formed at regular intervals along the longitudinal direction of the discharge channel in a direction orthogonal to the discharge channel, and the first connection electrodes forming one block are connected by an introduction electrode. . The method of claim 4, wherein The second electrode is a surface light source device, characterized in that the second electrode corresponding to each column of the plurality of rows separated along the longitudinal direction of the discharge channel is connected by a second connection electrode. The method of claim 6, And the second connection electrodes are disposed at regular intervals between the first connection electrodes in a direction orthogonal to the discharge channel, and the second connection electrodes forming one row are connected to each other. The method of claim 1, The surface light source device of claim 1, wherein the first electrode and the second electrode are alternately arranged one by one. The method of claim 1, At least one of the first electrode and the second electrode is a surface light source device characterized in that it has a plurality of branch electrodes are formed so that the two electrodes protrude in a direction facing each other. The method of claim 1, At least one of the first electrode and the second electrode is a surface light source device, characterized in that a plurality of convex portions are formed convexly formed in a direction facing each other. 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; A first electrode partitioning the plurality of discharge spaces into one block by a predetermined number and applying a voltage to each block; And a second electrode disposed on the same plane as the first electrode and separated in a longitudinal direction of the discharge space, and having a second voltage applied to each column. The method of claim 12, The first electrode may be disposed to be separated at regular intervals along the length direction of the discharge space, and the plurality of first electrodes forming one block may be connected by a first connection electrode. The method of claim 12, The second electrode may be arranged to be separated at a predetermined interval along the longitudinal direction of the discharge channel, and the second electrodes corresponding to each column in the longitudinal direction of the discharge channel may be connected by a second connection electrode. Device. A light source body having a first substrate and a second substrate having a plurality of discharge channels formed thereon, a first electrode partitioning the plurality of discharge channels into a predetermined number of blocks, and applying a voltage to each block; A surface light source device disposed in the same plane as the electrodes and arranged in a plurality of rows separated along the longitudinal direction of the discharge channels, the surface light source device including a second electrode to which a voltage is applied for each column; A chassis accommodating the surface light source device; And And an inverter configured to apply a voltage to the electrode unit.

Images