KR20080051710A - Ultra thin surface light source and backlight unit having the same - Google Patents

Abstract

An ultra thin surface light source apparatus and a back light unit having the same are provided to easily make a module and discharge a surface electrode part included in a surface light source part by connecting the surface electrode part to external devices. An ultra thin surface light source apparatus(200) includes a surface light body, a first surface electrode part and a second surface electrode part, and a pair of electrode lead part. The surface light body has a discharging space. The first surface electrode part and the second surface electrode part are formed on each surface of the first substrate and the second substrate. The first surface electrode part and the second surface electrode part are formed oppositely on the both surfaces of the surface light body. The pair of the electrode lead part is arranged on one side of the surface light source and is connected to each first surface electrode part and second surface electrode part electrically.

Description

ULTRA THIN 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 including a surface electrode unit 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;

Figure 6 is a perspective view showing a surface light source device including an electrode withdrawal unit according to an embodiment of the present invention.

7 is a side view of FIG. 6;

8 is another side view of FIG. 6;

9 is a local perspective view of a surface light source device according to another embodiment of the present invention.

10 is a local perspective view of a surface light source device according to another embodiment of the present invention.

11 and 12 are cross-sectional views showing the electrode lead portion of the clip form according to the present invention.

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

14 is a side view of FIG. 13;

15 is a cross-sectional view showing an electrode unit of a multilayer structure according to the present invention.

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 260: second surface electrode portion

270, 280: electrode withdrawal unit

The present invention relates to an ultra-thin surface light source device and a backlight unit having the same, and in particular, to provide a new surface light source device suitable for a mercury-free lamp.

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 problems remain to increase the size of the surface light source device.

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

Another object of the present invention is to provide a surface light source device having excellent electrical stability and improving discharge failure.

Still another object of the present invention is to provide a surface light source device suitable for a discharge gas excluding mercury.

The present invention provides a flat light source body having a discharge space therein, a first surface electrode portion and a second surface electrode portion formed to face each other on both surfaces of the light source body, and disposed on one side of the light source body. An ultra-thin surface light source device including a pair of electrode lead portions electrically connected to a first surface electrode portion and a second surface electrode portion, respectively.

The electrode lead portions may be disposed at the same positions vertically opposite to both surfaces of the light source body, or may be vertically staggered.

At least one of the first surface electrode portion and the second surface electrode portion may be divided into a plurality of sub electrode portions. In this case, it is preferable that the electrode lead-out unit is electrically connected to each of the plurality of sub-electrode units.

The electrode lead portion may have a form of a conductive layer, a conductive wire, a metal film, or the like formed on one side of the light source body surface, and may be insulated from each other by interposing an insulating structure between the pair of electrode lead portions. The electrode lead-out unit may be a clip structure including a pair of conductive layers that are electrically separated from an inner surface or an outer surface thereof. The clip structure may include an insulating layer therein that insulates a pair of conductive layers.

The light source body may have an internal discharge space sealed by the first substrate and the second substrate, and spacers may be formed in the discharge space to space the first substrate and the second substrate at predetermined intervals. The spacers may be spaced apart from the discharge space in the form of fine pillars, or may be formed in a bar shape or a lattice structure to divide the discharge space into a plurality of sub spaces.

The present invention also provides a flat light source body having a discharge space therein, a first surface electrode portion and a second surface electrode portion formed to face both surfaces of the light source body, and disposed on one side of the light source body. And a pair of electrode extracting portions electrically connected to the first surface electrode portion and the second surface electrode portion, a case accommodating the surface light source device, and a discharge voltage to the surface light source device. Provided is an ultra-thin backlight unit including an inverter to be applied.

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. The pair of surface electrode portions disposed opposite to both surfaces of the light source body are connected to the external driving portion without electrical interference by the electrode drawing portions. Therefore, it is possible to stably drive the surface light source device without short-circuit or poor discharge between the electrodes, and it is advantageous to modularize the backlight unit or the liquid crystal display device. In addition, it is possible to use a gas that excludes mercury as a gas for discharging injected into the discharge space inside the light source body can be applied to environmentally friendly products.

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 (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 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. Alternatively, the two substrates may be heated locally (eg at the edges) to form a light source body that is hermetically sealed.

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 including 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 covering substantially the entire substrate area. The first surface electrode portion or the second surface electrode portion may be divided into a plurality of sub electrode portions as described later.

At least one of the first surface electrode part 250 and the second surface electrode part 260 preferably has an open ratio of 60% or more for exposing 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 spaced apart from each other by the spacer 235. The spacer may be spaced apart from the discharge space in the form of a micro column, or may be formed in a bar shape or a grid structure to divide the discharge space into a plurality of sub spaces. Therefore, the discharge space 240 formed by the first substrate and the second substrate may be divided into one open structure or a plurality of sub spaces.

The gap between the first substrate 210 and the second substrate 220 is very small compared to the substrate area, and the internal space is formed in one open structure, so that it is easy to inject the vacuum exhaust and discharge gas. 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 surface light source device according to the present invention, the electrode portion formed on the surface of the light source body includes a separate electrode drawing portion for electrical connection with an external power supply. The electrode lead-out portion assists the surface electrode portion in the form of a surface electrode to be connected to an external device, and at the same time, serves as an electrical and structural matching portion suitable for modularizing the surface light source device into a backlight unit or a liquid crystal display device.

Referring to FIG. 6, an electrode lead part 270 is electrically connected to one edge of the first surface electrode part. As can be seen in the side view of FIG. 7, the electrode lead-out part 280 is connected to the second surface electrode part. The electrode lead-out portion may have the form of a conductive layer formed of a conductive paste, a conductive wire, a thin metal film, or the like. The position of the electrode lead portion is preferably an edge of the surface of the light source body, and the electrode lead portion may partially overlap with the surface electrode portion.

Each of the electrode lead-out portions 270 and 280 connected to the surface electrode portion is preferably formed on one side of the light source body in terms of electrical connection with the external driver and thinning of the backlight unit. In FIG. 6, the electrode withdrawing portion is formed on one side IV of the light source body, but may be formed on the other side I, II, or III.

In the surface light source device according to the present invention, since the thickness of the light source body is very thin, the spacing between the surface electrode portions is also very small at the millimeter level. Thus, unwanted electrical interference may occur between the electrode lead portions 270 and 280 connected to the surface electrode portion. Since a high voltage is applied to the surface electrode part for driving the surface light source device, electrical interference generated between the electrode lead parts may cause a short circuit or a discharge failure of the electrode part. In order to prevent such electrical interference, the electrode lead portions may be alternately arranged at different positions vertically as shown in FIG. 8. Also in this case, it is preferable to arrange the electrode lead-out portion on the same side of the light source body for ease of design side.

On the other hand, the electrode lead-out portion may be further extended from the light source body in order to facilitate the connection between the surface electrode portion and an external device (for example, a drive such as an inverter). In this case, in order to completely prevent electrical interference between the pair of electrode lead-out portions formed on both surfaces of the light source body, an insulating structure 300 may be interposed between the electrode lead-out portions as shown in FIG. 9.

In addition, in the present invention, as shown in FIG. 10, the electrode lead-out unit may be formed of a structure 310 having a clip shape. The clip structure illustrated in FIGS. 11 and 12 illustratively includes a pair of conductive layers 315 and 316 that are electrically separated from the inner or outer surface of the clip body 312, each of which has a surface electrode portion. Is electrically connected to the In some cases, a conductive paste may be further formed between the conductive layers 315 and 316 and the surface electrode portions 250 and 260. In order to block electrical interference between the pair of conductive layers 315 and 316, the clip structure 310 may include an insulating layer 318 therein.

In the surface light source device according to the present invention, as shown in FIG. 13, the surface electrode part may be divided into a plurality of sub-electrode parts 250a, 250b, 250c and 250d. FIG. 14 shows that the first surface electrode portion and the second surface electrode portion are divided into a plurality of sub electrode portions on both surfaces of the light source body. Such a divided sub-electrode portion may be used to locally drive a discharge, for example, by dividing the discharge space into a virtual sub space. Therefore, intelligent driving of the surface light source device is possible by scan dimming or local dimming.

The electrode lead portions 270a, 270b, 270c, 270d, 280a, 280b, 280c, and 280d are respectively formed in the surface electrode parts 250a, 250b, 250c, 250d, 260a, 260b, 260c, and 260d divided into sub-electrode parts. Preferably, it is advantageous in terms of modularity to form each electrode lead-out portion on the same side of the light source body. A plurality of electrode lead portions opposed to both surfaces of the light source body may be disposed at the same position vertically, respectively, or may be arranged in a staggered form as shown in FIG. 8. In addition, even when a plurality of electrode lead-outs are formed, the insulating structure (300 of FIG. 9), the clip structure 310, and the like in the foregoing embodiment may be applied in a similar manner.

In the surface light source device according to the present invention, the first surface electrode portion 250 and the second surface electrode portion 260 may use a transparent electrode (for example, ITO), or may use a predetermined pattern of electrodes. .

FIG. 15 is a cross-sectional view of an electrode unit according to an exemplary embodiment of the present invention. As illustrated, the lower base layer 252, the electrode pattern 256 formed on the base layer, and the base layer and the electrode pattern are shown. The electrode part of the multilayered structure of the protective layer 254 formed in can be confirmed. In the case of an electrode part including only an electrode pattern, bonding to a glass substrate may be difficult and durability may be degraded, whereas the electrode part of the multilayer structure may be easily bonded to a substrate and ensure durability of the electrode pattern, and various types of electrode patterns may be used. There is an advantage that can be formed. The base layer uses a transparent polymer material as a material resistant to thermal shock, and the electrode material is a material having excellent conductivity of copper, silver, gold, aluminum, nickel, chromium, carbon, or polymer, or a combination of the above materials. Substances can be used. The protective layer uses a transparent polymer material resistant to thermal shock.

The shape of the electrode pattern may be a network structure pattern or a stripe pattern. 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.

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 1000 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. Discharge voltages generated from the inverter 1300 are applied to upper and lower electrode portions 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.

According to the present invention, an ultra-thin surface light source device and a backlight unit are provided. The surface electrode part included in the surface light source device is electrically and stably connected to the external device by the electrode lead-out part to enable stable discharge, and to be easily modularized.

Claims (16)

A flat light source body having a discharge space therein, A first surface electrode portion and a second surface electrode portion formed to face each other on both surfaces of the light source body; A pair of electrode lead portions disposed on one side of the light source body and electrically connected to the first surface electrode portion and the second surface electrode portion, respectively; Ultra-thin surface light source device. The ultra-thin surface light source device according to claim 1, wherein the electrode lead portions are disposed at the same positions vertically opposite to both surfaces of the light source body. The ultra-thin surface light source device according to claim 1, wherein the electrode lead portions are disposed at positions which are opposite to each other and vertically not identical to both surfaces of the light source body. The ultra-thin surface light source device according to claim 1, wherein at least one of the first surface electrode portion and the second surface electrode portion is divided into a plurality of sub-electrode portions. The ultra-thin surface light source device according to claim 4, wherein an electrode lead part is electrically connected to each of the plurality of sub electrode parts. The ultra-thin surface light source device according to claim 1, wherein the electrode lead portion is a conductive layer formed on one side of a light source body surface. The ultra-thin surface light source device according to claim 1, wherein the pair of electrode lead portions are insulated from each other by an insulating structure. The ultra-thin surface light source device according to claim 1, wherein the electrode lead-out unit is a clip structure including a pair of conductive layers electrically separated from each other on an inner surface or an outer surface thereof. The ultra-thin surface light source device according to claim 8, wherein the clip structure includes an insulating layer therein that insulates a pair of conductive layers. The method of claim 1, wherein at least one of the first surface electrode portion and the second surface electrode portion comprises a base layer, an electrode pattern formed on the upper surface of the base layer, and a protective layer formed on the electrode pattern. Ultra-thin surface light source device. The ultra-thin surface light source device of claim 1, wherein the light source body has an internal discharge space sealed by a first substrate and a second substrate, and a plurality of spacers space the first substrate and the second substrate. . The ultra-thin surface light source device according to claim 11, wherein the spacer divides the discharge space into a plurality of subspaces. A planar light source body having a discharge space therein, a first surface electrode portion and a second surface electrode portion formed to face each other on both surfaces of the light source body, and disposed on one side of the light source body to form the first surface. A surface light source device including a pair of electrode drawing portions electrically connected to the electrode portion and the second surface electrode portion, respectively; A case accommodating the surface light source device, and Including an inverter for applying a discharge voltage to the surface light source device Ultra-thin backlight unit. The ultra-thin backlight unit of claim 13, wherein the electrode lead portions are disposed at the same positions vertically opposite to both surfaces of the light source body. The ultra-thin backlight unit of claim 13, wherein the electrode lead portions are disposed at positions not opposite to each other and vertically opposite to both surfaces of the light source body. The ultra-thin backlight unit of claim 13, wherein the pair of electrode lead portions are insulated from each other by an insulating structure.

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