KR20080098767A - Discharging elerctrode for surface light source, surface light source and backlight unit having the same - Google Patents

Abstract

A discharging electrode for a surface light source, and a surface light source and a backlight unit having the same are provided to reduce the heating by decreasing an electrode area and improve discharging efficiency. A discharging electrode for a surface light source includes: a first electrode(260) and a second electrode(270) which are arranged alternately at a portion of a light source body; and plural first protrusions(264a,274a) and plural second protrusions(264b,274b) which are protruded in the opposite directions of the first electrode and the second electrode. The first protrusions and the second protrusions are arranged alternately.

Description

Discharge electrode for surface light source device, surface light source device and backlight unit including the same {DISCHARGING ELERCTRODE FOR SURFACE LIGHT SOURCE, SURFACE LIGHT SOURCE AND BACKLIGHT UNIT HAVING THE SAME}

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

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

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

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

5 is a cross-sectional view taken along the line Y-Y 'of FIG. 3;

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

7 is a plan view showing an electrode unit according to the present invention applied to a surface light source device.

8 is a schematic view showing a plasma discharge generated in the surface light source device of the present invention.

9 is an enlarged view showing the discharge protrusion formed on the sub-electrode of the discharge electrode of the present invention.

10 is a schematic view showing the interval between the sub-electrode of the discharge electrode of the present invention.

11 is a schematic view showing another embodiment of the discharge protrusion of the discharge electrode of the present invention.

12 is an exploded perspective view of 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 260: first electrode portion

264: sub electrode 264a, 274a: first projection

270: second electrode portion 274: sub-electrode

264b, 274b: second projection

The present invention relates to a surface light source device and a backlight unit, and proposes a discharge electrode having a plurality of discharge protrusions in order to increase discharge efficiency and discharge stability of the surface light source device.

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. 1 and 2, an example of a surface light source device 100 having a plurality of discharge channels is illustrated. The surface light source device 100 includes a light source body 110 and electrode units 160 provided on outer surfaces of both edges of the light source body 110.

The light source body 110 includes a first substrate 112 and a second substrate 114 disposed to face each other at a predetermined interval. A plurality of partition walls 140 are disposed between the first substrate and the second substrate to divide the space between the first substrate and the second substrate into a plurality of discharge channels 120. A sealing member 130 is disposed between the edges of the first substrate 112 and the second substrate 114 to isolate the discharge channels 120 from the outside. Discharge gas is injected into the discharge space 150 inside the discharge channel 120.

In order to drive the surface light source device, a pair of electrode portions 160 having a band shape are formed on the first substrate 112 and / or the second substrate 114.

In such a surface light source device, a pair of electrode portions are substantially spaced apart from each other, and thus there is a limit to the use of various discharge gases having different discharge mechanisms. In addition, the substrate must be formed to form a channel, and if uniformity of discharge between channels is not secured, there is a problem that luminance uniformity of the entire surface light source device is lowered.

Recently, as the liquid crystal display device becomes larger and larger, the demand for a large area light source device is rapidly increasing. Accordingly, new technologies need to be developed for a light source body structure, an electrode structure, and a discharge gas suitable for a large area of the surface light source device. .

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

In addition, another object of the present invention is to provide a surface light source device and a backlight unit with improved discharge efficiency.

In addition, another object of the present invention is to provide a surface light source device having excellent discharge stability and reduced heat generation during driving.

In order to achieve the above object, the present invention proposes a discharge electrode for a surface light source device in which a plurality of discharge protrusions protruding from a plurality of stripe type electrode surfaces are formed integrally.

In detail, the present invention includes a first electrode portion and a second electrode portion which are arranged crosswise on at least one surface of the light source body, wherein the first electrode portion and the second electrode portion are provided with a plurality of first protrusions protruding in opposite directions. It includes a second projection, the first projection provides a discharge electrode for a surface light source device, characterized in that the second projection is arranged alternately.

The first electrode portion and the second electrode portion may include a plurality of strip-shaped sub-electrodes, and the sub-electrodes may be disposed in a mutually interdigitated structure.

The first protrusion and the second protrusion may be formed to have a width wider than the thickness. This form is effective for elliptical plasma discharge in the discharge space inside the surface light source device.

The present invention also includes a light source body having a discharge space therein, and a first electrode portion and a second electrode portion which are arranged on at least one surface of the light source body, wherein the first electrode portion and the second electrode portion It provides a surface light source device characterized in that it comprises a plurality of first projections and second projections protruding in the opposite direction, wherein the first projections are arranged alternately with the second projections.

In addition, the present invention includes a light source body having a discharge space therein, and a first electrode portion and a second electrode portion which are arranged crosswise on at least one surface of the light source body, wherein the first electrode portion and the second electrode portion A first housing including a plurality of first protrusions and second protrusions protruding in opposite directions, wherein the first protrusion includes an electrode unit interposed with the second protrusion, and the light source body; And an inverter configured to apply a voltage to the electrode unit.

According to the present invention, the inter-electrode interference can be minimized during discharge, and the electrode area can be reduced to reduce heat generation, and thus no additional heat dissipation means is required. In addition, uniform and stable discharge is possible in the surface light source device, thereby improving brightness and improving brightness uniformity. In particular, it can be effectively applied to a large area light source device.

3 is a perspective view showing a flat surface light source device 200 according to an embodiment of the present invention. The surface light source device 200 includes a planar first substrate 210 and a planar second substrate 220 having the same shape as the light source body.

The surface light source device has a sealed discharge space therein, and a surface electrode at least locally covering the surface is formed on one surface (for example, the surface 210 'of the first substrate).

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. The area of the first substrate 210 and the second substrate 220 may be changed according to the size of the backlight or the liquid crystal display device to which it is applied.

A fluorescent layer (not shown) may be applied to the inner surfaces of the first substrate 210 and the second substrate 220, and a reflective film (not shown) may be further formed on any one of the first substrate and the second substrate. The first substrate 210 and the second substrate 220 are opposed to each other at predetermined intervals, and as shown in FIG. 4, a sealing member 230 such as a frit is inserted into the edge of the internal discharge space ( 240). Alternatively, as shown in FIG. 5, the edges of both substrates may be directly fused by heating to form a sealed internal discharge space 240. The discharge space may include a plurality of island-shaped spacers.

The interior defined by the first substrate 210 and the second substrate 220 may form a discharge space 240 of one open structure. Alternatively, as shown in FIG. As a result, the discharge space 240 may be divided into a plurality of subspaces. The partitioned discharge space is advantageous for the divided driving of the surface light source device as described later. The partition wall 250 may be separately inserted between the first substrate 210 and the second substrate 220, or may be formed by molding one surface of the two substrates to partially protrude.

The gap between the first substrate 210 and the second substrate 220 is very small compared with the entire area of the substrate, so that it is very easy to inject the vacuum discharge and discharge gas into the internal discharge space. 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.

In the present invention, a discharge electrode is formed on at least one surface of the light source body of the planar surface light source device shown in FIG. Referring to FIG. 7, a plurality of band-shaped electrodes are disposed at predetermined intervals.

The discharge electrode includes a first electrode part 260 to which a first voltage is applied and a second electrode part 270 to which a second voltage is applied. The first voltage and the second voltage may be in phase or different from each other.

The first electrode part 260 and the second electrode part 270 include a plurality of band-shaped sub electrodes 264 and 274, and the sub electrode 264 of the first electrode part 260 is a second electrode. The sub-electrodes 274 of the unit 270 are disposed to intersect with each other in the same plane, and are formed in an interdigitated structure as a whole. The first electrode and the second electrode may be formed in a linear conductive band or a conductive pattern.

Alternatively, the first electrode part 260 and the second electrode part 270 are formed on different surfaces of the light source body, respectively, or both the first electrode part 260 and the second electrode part 270 on both sides of the light source body. ) May be formed.

As illustrated in FIG. 7, the plurality of sub electrodes 264 and 274 may be electrically connected to each other by the common lead portions 262 and 272. Unlike illustrated, voltage may be applied to each sub-electrode separately, and in this case, the surface light source device may be locally driven.

A plurality of protrusions are formed in the plurality of sub-electrodes 264 and 274 of the first electrode part 260 and the second electrode part 270 perpendicular to the longitudinal direction. The protrusion includes first protrusions 264a and 274a protruding in a first direction and second protrusions 264b and 274b protruding in a direction opposite to the first direction.

The first protrusions 264a and 274a and the second protrusions 264b and 274b are formed to have a staggered structure. In addition, the first protrusion 264a of the sub-electrode 264 of the first electrode 260 and the second protrusion 274b of the sub-electrode 274 of the second electrode 270 face each other. The second protrusion 264b of the sub-electrode 264 of the first electrode 260 and the first protrusion 274a of the sub-electrode 274 of the second electrode 270 face each other. Such a structure can prevent mutual interference between the first protrusions 264a and 274a and the second protrusions 264b and 274b when the surface light source device is driven, thereby preventing the discharge from becoming unstable and decreasing the luminance uniformity. In addition, the plasma discharges D1 and D2 interleaved with each other, as shown in FIG. 8, rather than a checkerboard lattice-shaped plasma discharge in the surface light source device internal discharge space, thereby ensuring uniformity and stability of discharge. have.

In the present invention, the protrusions that are alternately protruded from the side in the width direction of the strip-shaped sub-electrode are preferably the same shape with each other, and it is effective to maintain the uniformity of discharge to be formed at the same intervals.

Referring to FIG. 9, the sub-electrode 264 of the first electrode unit is enlarged, and the first protrusion 264a and the second protrusion 264b are formed on the side surface of the sub-electrode 264 in a rectangular shape having straight sides and end portions thereof. You can see that. The first projections 264a and the second projections 264b are formed in a flat shape having a width larger than the height, which is suitable for the formation of the elliptical plasmas D1 and D2 shown in FIG. 8.

Width (a) of the sub-electrode 264 may vary depending on the area of the surface light source device or the electrode material, preferably in the range of 50㎛ ~ 2mm. The shape of the first protrusion 264a and the second protrusion 264b may be optimally designed in consideration of the uniformity and stability of the discharge while minimizing interference between the plurality of protrusions. The thickness in the direction perpendicular to the length of the sub-electrodes of the first and second protrusions 264a and 264b, that is, the height b, is preferably 0.5 to 2 times the width of the sub-electrode a. In addition, the width c of the first protrusion 264a and the second protrusion 264b in a direction parallel to the length of the sub-electrode is preferably 2 to 3 times the width of the sub-electrode a.

On the other hand, the spacing between sub-electrodes is also very important in terms of brightness and discharge stability of the surface light source device. If the spacing between the sub-electrodes is too small, the luminance may be degraded or the inter-electrode interference may be severe on the surface of the light source device exit surface. On the other hand, if the spacing between the sub-electrodes is too large, the discharge may not be uniform or the amount of discharge may be low. have. Therefore, as shown in FIG. 10, the spacing between the sub electrodes is suitably 3 to 15 mm based on the spacing w between the projections 264b and 274a facing each other.

In the present invention, the first protrusions 264a and 274a and the second protrusions 264b and 274b protruding from the side surface of the sub-electrode are preferably straight sides, but the ends may not be straight. . For example, as shown in Fig. 11, when the ends of the projections 264a 'and 274b' are arc-shaped, they are effective for forming a circular to elliptical plasma discharge.

The discharge electrode of the present invention may be formed by a method such as printing the individual sub-electrode pattern directly on the surface of the light source body, otherwise the multilayer film is formed after attaching the electrode pattern to an insulating film to form a multilayer film It may be attached to the surface. In addition, the discharge electrode for the surface light source device according to the present invention may be applied to a light source body including a plurality of discharge channels shown in FIG. 1 as well as the flat light source body of FIG. 3.

12 is an exploded perspective view showing a backlight unit including the 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 100. The surface light source 100 is accommodated in the storage space of the lower case 1200. A reflector (not shown) may be additionally disposed below the surface light source 100, and a reflector may not be employed.

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 electrodes 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.

The present invention has been exemplarily described through the preferred embodiments, but the present invention is not limited to such specific embodiments, and various forms within the scope of the technical idea presented in the present invention, specifically, the claims. May be modified, changed, or improved.

As described above, according to the present invention, the interference between the electrodes can be minimized during discharge, and since the electrode area is reduced to reduce heat generation, no additional heat dissipation means is required. In addition, uniform and stable discharge is possible in the surface light source device, thereby improving brightness and improving brightness uniformity.

Claims (17)

A first electrode part and a second electrode part which are arranged crosswise on at least one surface of the light source body, The first electrode portion and the second electrode portion includes a plurality of first projections and second projections protruding in opposite directions, wherein the first projections are arranged alternately with the second projections Discharge electrode for surface light source device. The discharge electrode of claim 1, wherein the first electrode part and the second electrode part comprise a plurality of band-shaped sub-electrodes, and the sub-electrodes are arranged in a mutually interdigitated structure. The discharge electrode for a surface light source device according to claim 1, wherein the first protrusion and the second protrusion are formed to have a width wider than a thickness. The discharge electrode for a surface light source device according to claim 1, wherein the first projection and the second projection have a straight side and end. The discharge electrode for a surface light source device according to claim 1, wherein the first protrusion and the second protrusion have a straight side and an arc at an end thereof. The discharge electrode for a surface light source device according to claim 1, wherein an interval between the protrusions facing each other is 3 to 15 mm. The discharge electrode for a surface light source device according to claim 1, wherein each of the first electrode portion and the second electrode portion includes a plurality of sub-electrodes. 8. The discharge electrode for a surface light source device according to claim 7, wherein the sub electrode has a width of 50 µm to 2 mm. The discharge electrode for a surface light source device according to claim 7, wherein the thickness of the first protrusion and the second protrusion in the direction perpendicular to the length of the sub electrode is 0.5 to 2 times the width of the sub electrode. The discharge electrode for a surface light source device according to claim 7, wherein the width of the first protrusion and the second protrusion in a direction parallel to the length of the sub electrode is two to three times the width of the sub electrode. The discharge electrode for a surface light source device according to claim 1, wherein each of the first electrode portion and the second electrode portion includes a plurality of sub electrodes and a common lead portion electrically connecting the sub electrodes. A light source body having a discharge space therein, A first electrode part and a second electrode part which are arranged crosswise on at least one surface of the light source body, The first electrode portion and the second electrode portion includes a plurality of first projections and second projections protruding in opposite directions, wherein the first projections are arranged alternately with the second projections Surface light source device The surface light source device of claim 12, wherein the surface light source devices are driven by a plurality of elliptical plasma discharges that are alternately disposed. The surface light source device of claim 12, wherein the light source body comprises a flat first substrate and a second substrate. The surface light source device of claim 14, wherein a plurality of spacers are formed in the light source body. The surface light source device of claim 14, wherein the light source body has a plurality of partition walls formed therein. A light source body having a discharge space therein, A first electrode portion and a second electrode portion intersecting at least one surface of the light source body, wherein the first electrode portion and the second electrode portion have a plurality of first protrusions and second protrusions protruding in opposite directions; Includes, the first projection and the electrode portion which is alternately arranged with the second projection, A case accommodating the light source body; And And an inverter configured to apply a voltage to the electrode unit.

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