KR20080013179A - Flat electrode, surface light source and backlight unit having the same - Google Patents

Abstract

A flat electrode, a surface light source, and a backlight unit having the light source are provided to improve brightness uniformity of the backlight unit by adding a conductive micro wire pattern inside a high molecular base layer and a protective layer. Micro conductive wires(256') are patterned on the same plane to form a flat electrode for a surface light source. The micro conductive wires are apart from each other by a constant distance. A thickness of the conductive wire lies between 1mum and 1mm. The conductive wire is made of a material selected from the group consisting of SUS, Al, Cu, Ag, Zn, and Au. A distance between the conductive wires lies between 0.5 and 1mm. The conductive wire is formed on a base layer(252). A protective layer(254) is formed on the conductive wire.

Description

Flat electrode, surface light source device and backlight unit including the same {FLAT ELECTRODE, SURFACE LIGHT SOURCE AND BACKLIGHT UNIT HAVING THE SAME}

1 is a perspective view showing an example of a surface light source device.

2 is a perspective view showing a surface light source device according to the present invention.

Figure 3 is a side view showing a surface light source device according to the present invention.

4 is a sectional view taken along the line X-X 'of FIG.

5 is an enlarged view of a portion A of FIG. 4;

6 to 9 are perspective views showing an example of the manufacturing process of the flat electrode of the present invention.

10 is a cross-sectional view taken along the line Y-Y 'of FIG.

11 to 13 are plan views showing various examples of the electrode pattern of the electrode unit according to the present invention.

14 is a sectional view showing another embodiment of a surface light source device according to the present invention.

FIG. 15 is an enlarged view of a portion B of FIG. 14; FIG.

16 is an exploded perspective view showing a backlight unit including the surface light source device of the present invention.

*** Explanation of symbols for the main parts of the drawing ***

200: surface light source device 210: first substrate

220: second substrate 230: sealing member

235: spacer 240: discharge space

250: first surface electrode portion 252: base layer

254: protective layer 256 ': conductive wire

260: second surface electrode portion 270: interlayer

The present invention relates to a flat panel electrode, a surface light source device having the same, and a backlight unit having the same, and provides a new surface light source device suitable for mercury-free lamps as a surface light source device employing a flat electrode that is easy to manufacture and excellent in mechanical properties. do.

The liquid crystal display displays an image by using electrical and optical characteristics of the liquid crystal. Liquid crystal displays have the advantages of being very small in volume and light in weight compared to cathode ray tubes (CRTs). As a result, they are widely used in portable computers, communication devices, liquid crystal television receivers, and aerospace industries. .

The liquid crystal display device includes a liquid crystal controller for controlling liquid crystal and a rear light source for supplying light to the liquid crystal. The liquid crystal controller includes a pixel electrode disposed on the first substrate, a common electrode disposed on the second substrate, and a liquid crystal interposed between the pixel electrode and the common electrode. The pixel electrode is formed in plural in correspondence with the resolution, and the common electrode is made of one and facing the pixel electrode. A thin film transistor (TFT) is connected to each pixel electrode to apply a pixel voltage having a different level, and a reference voltage of the same level is applied to the common electrode. The pixel electrode and the common electrode are made of a transparent material having conductivity.

Light supplied from the rear light source sequentially passes through the pixel electrode, the liquid crystal, and the common electrode. 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, the rear light source of the liquid crystal display is mainly used a cold cathode fluorescent lamp (CCFL) having a rod shape or a light emitting diode (LED) having a dot shape. Cold cathode ray tube 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 ray tube type lamps or light emitting diodes have poor brightness uniformity. Accordingly, a rear light source having a cold cathode ray tube lamp or a light emitting diode as a light source is an optical member such as a light guide panel (LGP), a diffusion member, a prism sheet, or the like to increase luminance uniformity. (optical member) is required. As a result, a liquid crystal display using a cold cathode ray tube lamp or a light emitting diode 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. Referring to FIG. 1, the conventional surface light source device 100 includes a light source body 110 and electrodes 160 provided on outer surfaces of both edges of the light source body 110. The light source body 110 includes first and second substrates disposed to face each other at predetermined intervals. A plurality of partitions 140 are disposed between the first and second substrates to partition the space between the first and second substrates into a plurality of discharge channels 120. A sealing member (not shown) is disposed between the edges of the first and second substrates to isolate the discharge channels 120 from the outside. Discharge gas is injected into the discharge space 150 inside the discharge channel.

In order to discharge-drive the surface light source device, an electrode is applied to the first substrate and the second substrate or one of the two substrates so that the electrodes have the same area per discharge channel in the form of a strip of strips or in the form of island electrodes. Therefore, when the surface light source device is driven using an inverter, all the front channels are discharged in the same manner.

The surface light source device has a problem in that luminance uniformity is not good because the light emission characteristics vary depending on the position of the discharge channel. In addition, there is a problem that a dark portion is generated by channeling due to interference between adjacent channels between a plurality of discharge channels.

In particular, the existing surface light source device contains mercury (Hg) as a discharge gas, which is not only environmentally problematic, but also increases the luminance stabilization time when driving at low temperatures, and the temperature variation of the surface light source itself due to the temperature sensitivity of mercury. As a result, there is a problem in that the luminance uniformity is lowered. In addition, many solutions remain for the enlargement of the surface light source device.

It is an object of the present invention to provide a novel surface light source device suitable for large area.

Another object of the present invention is to provide a surface light source device and a backlight unit which are excellent in brightness and luminance uniformity and which are thin.

Still another object of the present invention is to provide a flat electrode which is not only easy to manufacture as an electrode unit for a surface light source device but also has excellent mechanical properties and greatly improved durability.

The present invention provides a flat electrode for a surface light source, characterized in that the fine conductive wire is formed patterned at regular intervals on the same plane.

The conductive wire is formed on the upper surface of the base layer, it is preferable to further include a protective layer on the wire. Since the wire pattern is protected by the base layer and the protective layer, not only the durability of the flat electrode is improved, but also the adhesion to the substrate is easy, and the formation of a large area flat plate electrode in the form of a plate or sheet is easy.

In addition, the present invention is formed on the edge between the first substrate, the second substrate facing the first substrate at a predetermined interval, and the first substrate and the second substrate is formed by the first substrate and the second substrate A sealing member for sealing an inner space to be formed, and a surface electrode part formed on at least one surface of the first substrate and the second substrate, wherein fine conductive wires are patterned and formed at regular intervals on the same plane. Provided is a surface light source device.

In addition, the present invention is a sealed discharge space formed of the first substrate and the second substrate, and formed on at least one surface of the first substrate and the second substrate, the fine conductive wire pattern at regular intervals on the same plane Provided is a backlight unit including a surface light source device including a surface electrode unit, a case accommodating the surface light source device, and an inverter for applying a voltage to the first and second surface electrode units.

The surface light source device and the backlight unit according to the present invention can have an ultra-thin structure of extremely thin overall thickness. In addition, the enclosed space formed by the first substrate, the second substrate and the sealing member forms an internal discharge space having an open structure, and a gas excluding mercury may be used as the discharge gas injected into the discharge space. It can be applied to eco-friendly products. In addition, since the discharge space is not partitioned by the partition wall, the luminance and luminance uniformity of the light emitted to the entire surface of the substrate are excellent.

In particular, the present invention proposes a composite electrode in which a conductive microfiber wire pattern is included in the polymer base layer and the protective layer as a flat plate electrode suitable for a surface light source device, thereby simultaneously ensuring ease of manufacture and durability. The flat plate electrode may enable efficient discharge in an ultra-thin surface light source device having an open structure and may improve luminance and luminance uniformity.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

2 is a perspective view showing the surface light source device 200 according to an embodiment of the present invention, Figure 3 is a side view.

The surface light source device 200 includes a planar first substrate 210 and a planar second substrate 220 having the same shape. The first substrate 210 and the second substrate 220 is preferably a transparent thin glass substrate, each thickness is not particularly limited, but a thickness of about 1 ~ 2 mm, preferably 1 mm or less is suitable.

A fluorescent layer may be coated on the inner surfaces of the first substrate 210 and the second substrate 220, and a reflective film may be further formed on one of the first substrate and the second substrate. The first substrate 210 and the second substrate 220 face each other at predetermined intervals, and a sealing member 230 such as a frit is inserted into an edge thereof to form a sealed space.

In the surface light source device according to the present invention, a large area flat plate electrode is formed on an outer surface of a light source body formed by a first substrate and a second substrate. FIG. 4 is a cross-sectional view taken along line X-X 'of FIG. 2, and FIG. 5 is an enlarged view of portion A of FIG. 4, and as illustrated, the outer surfaces of the first and second substrates 210 and 220 are respectively formed. The first surface electrode portion 250 and the second surface electrode portion 260 are formed. The first surface electrode part 250 and the second surface electrode part 260 are formed of a surface electrode having a flat plate shape substantially covering the entire substrate area.

At least one of the first surface electrode portion 250 and the second surface electrode portion 260 preferably has an open ratio of 60% or more to expose the substrate to increase the transmittance of light emitted by the discharge from the light source body. Do.

The first substrate 210 and the second substrate 220 are flat, and the interior defined by the first substrate, the second substrate, and the sealing member is partitioned by the partition wall as in the conventional surface light source device. Instead of individual discharge spaces, the discharge space 240 of one open structure is formed. The spacing between the first substrate and the second substrate is very small compared to the substrate area, and the internal space is formed in one open structure, so that the vacuum exhaust and discharge gas can be easily injected. In addition, it is suitable to construct a surface light source device using a gas other than mercury, for example, xenon, argon, neon, other inert gas, or a mixed gas thereof, as a discharge gas.

The vertical space of the discharge space 240 between the first substrate 210 and the second substrate 220 may be determined by the spacer 235. The number and spacing of the spacers 235 may be determined in a range that does not impair the luminance characteristics of the light emitted from the surface light source device. In addition, by forming a part of the top plate may be artificially added to the characteristics of the spacer.

Alternatively, the height of the discharge space 240 may be defined by protrusions (not shown) integrally formed on the inner surface of the first substrate or the second substrate.

In the surface light source device according to the present invention, as the first surface electrode portion 250 or the second surface electrode portion 260, a flat plate electrode patterned with a conductive microfiber wire having a fine thickness is used. The conductive wire may be patterned at regular intervals on the same plane to form a variety of patterns such as a circle, an ellipse, or a polygonal array, a mesh structure, or a stripe structure.

The thickness of the conductive wire is preferably in the form of microfibers in the range of 1 ㎛ ~ 1 mm, the material of the conductive wire may be selected from SUS, Al, Cu, Ag, Zn, Au. Flat electrode for a surface light source, characterized in that the conductive metal.

It is preferable that the distance between the conductive wire and the adjacent wire is in the range of 0.5 to 1 mm, and the luminance of the surface light source device is excellent in this range.

In the planar electrode of the surface light source device according to the present invention, it is preferable that the conductive wire is formed on the upper surface of the base layer, and the multilayer structure further includes a protective layer on the wire. Since the wire pattern is protected by the base layer and the protective layer, not only the durability of the wire pattern is improved, but also the bonding of the flat electrode to the substrate is easy, and the formation of a large area flat plate electrode in the form of a plate or sheet is easy.

The base layer and the protective layer may be made of a polymer material that is transparent to visible light.

6 to 10 illustrate an example of a flat electrode manufacturing process of the present invention. First, as shown in FIG. 6, a base layer 252 that is transparent to visible light is prepared. The size of the base layer is made substantially the same as the area of the surface light source device.

Next, the conductive wire 256 ′ is patterned on the base layer 252 at predetermined intervals (FIG. 7). Conductive wires may be prepared in individual units, and each wire may be disposed on the base layer 252, but a single wire may be formed, for example, in a zigzag form, and then, as shown in FIG. It is advantageous in the process to form the wire in a form arranged at predetermined intervals.

The base layer and the protective layer are advantageous to eliminate the movement of the conductive wire using a material that can be attached by heat.

Finally, the protective layer 254 is formed on the wire pattern to complete the flat electrode. FIG. 10 is a cross-sectional view taken along the line Y-Y 'of FIG. 9, where conductive wires 256 ′ are disposed at predetermined intervals between the base layer 252 and the protective layer 254.

Alternatively, the conductive wire may be cut after bonding the base layer and the protective layer.

The plate electrode having a multilayer structure including such a wire pattern may be formed on the upper surface and the lower surface of the surface light source device or may be formed only on one surface thereof.

On the other hand, it is preferable that the multi-layered flat electrode formed as described above is attached to the first substrate and / or the second substrate after manufacturing the light source body including the first substrate and the second substrate. For example, a first flat substrate and a second flat substrate are prepared, a phosphor is coated on inner surfaces of the first and second substrates, and an edge surface of at least one of the first and second substrates. A sealing member is formed on the first substrate, and the first substrate and the second substrate are joined to form a sealed discharge space. Attaching the multilayer electrode to the outer surface of the first substrate or the second substrate of the completed light source body avoids the sintering process in the process of forming the light source body. It becomes wider and the increase in resistance of the electrode part can be avoided.

The wire pattern of the plate electrode used in the surface light source device of the present invention can be applied in various forms. For example, a pattern of a network structure as shown in FIG. 11 or a stripe pattern shown in FIGS. 12 and 13 may be used. Discharge characteristics of the surface light source device are varied by different electrode pattern shapes of the first surface electrode portion 250 and the second surface electrode portion 260 formed on the first substrate 210 and the second substrate 220, respectively. It can change.

14 is a cross-sectional view illustrating an ultra-thin surface light source device 200 ′ according to another embodiment of the present invention, and FIG. 15 is an enlarged view of portion B of FIG. 14. Unlike the previous embodiment, the intermediate layer 270 is further added between the outer surface of the light source body including the first substrate 210 and the second substrate 220 of the surface light source device and the electrode portions 250 and 260. You can see that.

In particular, the intermediate layer 270 is a transparent polymer material having excellent transmittance with respect to visible light, and preferably a material resistant to mechanical impact, thermal stability, and heat shock. The material of the intermediate layer used is acrylic acid, methacrylic acid, butyl acrylate, methyl methacrylate, 2-ethylhexyl acrylate, acrylic ester, styrene, vinyl ether, vinyl, vinylidene halide, N-vinyl pyrrolidone Allyl esters of ethylene, C3 or higher alpha-olefins, allyl amines, saturated monocarboxylic acids and amides thereof, propylene, 1-butene, 1-pentene, 1-hexene, 1-decene, allyl amine, allyl acetate, allyl propionate At least one ethylenically unsaturated selected from the group consisting of allyl lactate, amides thereof, mixtures thereof, 1,3-butadiene, 1,3-pentadiene, 1,4-pentadiene, cyclopentadiene and hexadiene isomers Polymers of monomers; Or carboxymethylcellulose and derivatives thereof having a lower carboxyl substitution degree of about 0.7, hydroxyethylcellulose, ethyl hydroxyethylcellulose, methylcellulose, methyl hydroxypropylcellulose, hydroxypropylcellulose, poly (acrylic acid) and alkali metal salts thereof , Ethoxylated starch derivatives, sodium and other alkali metal polyacrylates, water soluble starch glues, gelatin, water soluble alginates, casein, agar, natural and synthetic gums, partially and fully hydrolyzed poly (vinyl alcohol), poly Effective in stabilizing latex systems, selected from the group consisting of acrylamide, poly (vinylpyrrolidone), poly (methyl vinylether-maleic anhydride), guar and derivatives thereof, gelatin and casein and having a molecular weight of less than about 75,000 Decompression comprising an aqueous emulsified latex system containing a positive water soluble protective colloid Pressure sensitive adhesive compositions and the like can be used.

The intermediate layer is formed in a range of 10 μm to 1 mm, and has a space between the first substrate 210 and the first surface electrode portion 250 and a space between the second substrate 220 and the second surface electrode portion 260. It can form in at least one of them. By appropriately adjusting the thickness of the intermediate layer, the distance between the first surface electrode portion 250 and the second surface electrode portion 260 may be adjusted. For example, as shown in FIG. 15, the distance H1 between the first electrode portion determined by the first substrate 210 and the second substrate 220 is Ht due to the thickness H2 of the intermediate layer 270. Can be increased. As a result, the space | interval between electrode parts can be controlled and the discharge characteristic or efficiency of a surface light source device can be changed.

In addition, by interposing the intermediate layer 270 between the substrates 210 and 220 and the electrode parts 250 and 260, the bonding force of the substrate and the electrode part may be increased, and the electrode part of the multilayered structure may not be the multilayer part in the embodiment. It is also possible to use an electrode portion including only the electrode pattern.

In addition, by changing the material and thickness of the intermediate layer it is possible to efficiently control the heat generated from the electrode (250, 260).

Features and detailed structures of the surface light source device including the intermediate layer 270 may further include features of the surface light source device including the electrode part having the multilayer structure described above, and a detailed description thereof will be omitted.

16 is an exploded perspective view showing a backlight unit including the ultra-thin surface light source device according to the present invention. As shown, the backlight unit includes a surface light source 200, upper and lower cases 1100 and 1200, an optical sheet 900, and an inverter 1300. The lower case 1200 includes a bottom portion 1210 and a plurality of sidewall portions 1220 extending to form an accommodation space from an edge of the bottom portion 1210 to accommodate the surface light source 200. The surface light source 200 is accommodated in the storage space of the lower case 1200.

The inverter 1300 is disposed on the rear surface of the lower case 1200 and generates a discharge voltage for driving the surface light source 200. The discharge voltage generated from the inverter 1300 is applied to the electrode portion of the surface light source 200 through the first and second power lines 1352 and 1354, respectively. The optical sheet 900 may include a diffuser plate for uniformly diffusing the light emitted from the surface light source 200, a prism sheet for imparting linearity to the diffused light, and the like. The upper case 1100 is coupled to the lower case 1200 to support the surface light source 200 and the optical sheet 900. The upper case 1100 prevents the surface light source 200 from being separated from the lower case 1200.

Unlike the illustrated figure, the upper case 1100 and the lower case 1200 may be formed as one integrated case. On the other hand, the backlight unit according to the present invention may not include the optical sheet 900 because the brightness and luminance uniformity of the surface light source device is excellent.

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.

The present invention secures ease of manufacture and durability at the same time by proposing a composite electrode containing a conductive microfiber wire pattern inside the polymer base layer and the protective layer as a flat plate electrode suitable for a surface light source device. The flat plate electrode may enable efficient discharge in an ultra-thin surface light source device having an open structure and may improve luminance and luminance uniformity.

Claims (17)

A flat electrode for a surface light source, wherein the fine conductive wires are patterned and formed on the same plane at regular intervals. The flat electrode of claim 1, wherein the conductive wire has a thickness in a range of 1 μm to 1 mm. The flat electrode of claim 1, wherein the conductive wire is made of a conductive metal selected from SUS, Al, Cu, Ag, Zn, and Au. The flat panel electrode of claim 1, wherein the conductive wire has a distance from an adjacent wire of 0.5 to 1 mm. The flat electrode of claim 1, wherein the conductive wire is formed on an upper surface of the base layer, and a protective layer is further formed on the wire. The flat panel electrode for a surface light source according to claim 5, wherein the base layer and the protective layer are transparent to visible light. The flat plate electrode of claim 1, wherein the wire pattern has a form in which circles, ellipses, or polygons are regularly arranged, a mesh structure, or a stripe structure. The flat electrode for a surface light source according to claim 1, wherein the wire pattern has an opening ratio of 60% or more exposed by portions other than the pattern. The first substrate, A second substrate facing the first substrate at predetermined intervals; A sealing member formed at an edge between the first substrate and the second substrate to seal an internal space formed by the first substrate and the second substrate; It is formed on at least one surface of the first substrate and the second substrate, the fine conductive wire includes a surface electrode portion is formed by patterning at regular intervals on the same plane Surface light source device. 10. The surface light source device according to claim 9, wherein the conductive wire has a distance of 0.5 to 1 mm from an adjacent wire. The surface light source device of claim 9, wherein the conductive wire is formed on an upper surface of the base layer, and further includes a protective layer on the wire. The surface light source device of claim 9, further comprising an intermediate layer formed in a space between the first substrate and the second substrate and the surface electrode part. The surface light source device according to claim 12, wherein the intermediate layer is transparent to visible light. The surface light source device according to claim 12, wherein the intermediate layer has a thickness in a range of 10 µm to 1 mm. 10. The surface light source device according to claim 9, wherein at least one spacer is inserted between the first substrate and the second substrate. The surface light source device of claim 9, wherein the first substrate, the second substrate, and the sealing member form an internal discharge space having an open structure, and a discharge gas excluding mercury is injected into the discharge space. A surface electrode in which a closed discharge space formed of a first substrate and a second substrate and a surface of at least one of the first and second substrates are formed and fine conductive wires are patterned at regular intervals on the same plane. A surface light source device comprising a part, A case accommodating the surface light source device, and And an inverter configured to apply voltage to the first and second surface electrode parts. Backlight unit.

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