KR20070118504A - Complex electrode with diffusion layer, surface light source with diffusion layer mounted thereon and backlight unit having the same - Google Patents

Abstract

A complex electrode with a diffusion layer, an FFL(Flat Fluorescent Lamp) with a diffusion layer mounted thereof and a backlight unit having the same are provided to realize an ultra-slimmed backlight unit without necessity of a separate diffusion member according as the diffusion layer is attached and integrated to a substrate which emits light and prevent efficiency of light, which the FFL emits, from being deteriorated by a dark portion of a surface light source itself caused by a spacer or a surface electrode. An FFL includes a first substrate(210), a second substrate(220), a sealing member(230) first and second surface electrodes(250,260), and a diffusion layer(300). The second substrate is opposite to the first substrate at predetermined intervals. The sealing member is formed in the edge between the first substrate and the second substrate and seals the inner space formed by the first substrate and the second substrate. The first and second surface electrodes are separately formed in the whole surface of the first substrate and the second substrate. The diffusion layer is attached to a substrate which emits light in the first substrate and the second substrate.

Description

A composite electrode including a diffusion layer, a surface light source device including an attachment diffusion layer, and a backlight unit having the same TECHNICAL FIELD

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;

Figure 6 is a cross-sectional view showing an electrode portion of a multi-layer structure according to the present invention.

7 and 8 are plan views showing another example of the electrode pattern of the electrode unit according to the present invention.

9 is a perspective view showing a light emitting region and a dark portion of the surface light source device according to the present invention.

10 is a schematic perspective view showing an attachable diffusion layer according to the present invention.

11 is a cross-sectional view showing a surface light source device including an attachable diffusion layer according to the present invention.

12 is an enlarged view of a portion B of FIG. 11;

FIG. 13 is a cross-sectional view illustrating a surface light source device including an attachable diffusion layer according to another exemplary embodiment of the present invention. FIG.

14 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 part 260: second surface electrode part

300: diffusion layer 350: adhesive layer

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.

Accordingly, 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.

Other objects and features of the present invention will be presented in more detail in the following detailed description.

According to the present invention, a first substrate, a second substrate facing the first substrate at predetermined intervals, and an inner side formed at an edge between the first substrate and the second substrate are formed by the first substrate and the second substrate. A sealing member for sealing a space, and first and second surface electrode portions formed on the entire surfaces of the first and second substrates, respectively, and are attached to the substrate from which light is emitted from among the first and second substrates. It provides a surface light source device comprising a diffusion layer.

The diffusion layer is preferably a mixed structure in which organic or inorganic diffuser glass beads are dispersed in a resin matrix. The size and amount of the organic or inorganic diffuser glass beads can be appropriately adjusted within a range that does not impair the luminous efficiency of the surface light source device.

The diffusion layer may be inserted between the first substrate and the first surface electrode portion or the second substrate and the second surface electrode portion, and may be attached on the first surface electrode portion or the second surface electrode portion.

The surface of the first surface electrode portion or the second surface electrode portion may further include an adhesive layer to firmly bond with the substrate or the diffusion layer.

In the surface light source device according to the present invention, a plurality of spacers are formed between the first substrate and the second substrate or a plurality of protrusions are integrally formed on an inner surface of the first substrate or the second substrate to form an inverted space therein. do.

At least one of the first and second surface electrode parts may include a base layer, an electrode pattern formed on an upper surface of the base layer, and a protective layer formed on the electrode pattern. In this case, it is preferable that the base layer and the protective layer are transparent to visible light. The electrode part may include a mesh structure or a stripe-shaped electrode pattern. The material of the electrode unit may be any one selected from copper, silver, gold, aluminum, ITO, Ni, Cr, carbon-based conductive material, conductive polymer. Preferably, at least one of the first and second surface electrode portions has an opening ratio of 60% or more to expose the first substrate or the second substrate.

In the surface light source device according to the present invention, the first substrate, the second substrate, and the sealing member form an internal discharge space having an open structure, and preferably discharge gas limited to mercury is injected into the discharge space. However, the discharge gas is not particularly limited.

The present invention also provides a first substrate and a second substrate forming a sealed discharge space, first and second surface electrode portions respectively formed on the entire surface of the first substrate and the second substrate, and a substrate on which light is emitted. A surface light source device including a diffusion layer attached to the side; A case accommodating the surface light source device; And an inverter configured to apply a voltage to the first and second surface electrode units.

The present invention also provides a composite light source for a surface light source comprising a diffusion layer in which an organic or inorganic diffusion material is dispersed in a resin matrix and an electrode layer attached to one surface of the diffusion layer.

In the surface light source device according to the present invention, since the diffusion layer is attached to and integrated with the substrate on which the light is emitted, a separate diffusion member is not required, thereby enabling an ultra-thin backlight unit. Further, the light emitted from the surface light source device can be prevented from deteriorating in efficiency due to the dark area of the surface light source itself due to the spacer or the surface electrode portion.

On the other hand, in the surface light source device and the backlight unit according to the present invention, 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 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.

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 the thickness of about 3mm, preferably 0.5 ~ 1.5mm 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 divided by partition walls as in the conventional surface light source device. Instead of the discharge space, 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 form a surface light source device using a gas other than mercury, for example, xenon, argon, neon, other inert gas, or a mixture 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.

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, 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. 6 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 disposed on the electrode layer 256. The electrode part of the multilayered structure of the protective layer formed in this 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.

7 and 8 illustrate an example of the electrode pattern of the plate-shaped electrode of the present invention, and each shows a pattern of a network structure or a stripe shape, and patterns of other shapes, for example, circles, ellipses, and polygons, are regularly Patterns arranged in such a manner may also be used.

In the surface light source device according to the present invention, since the discharge space is not partitioned by the partition wall, the ratio of the dark area is smaller than that of the conventional multi-discharge channel type surface light source device as shown in FIG. Area has a big advantage. However, the surface light source device according to the present invention also cannot avoid the presence of a dark portion to some extent. For example, referring to FIG. 9, a sealing portion 230 ′ is present at an edge of the first substrate 210. In addition, in the light emitting area, the effective effective light emitting area 210 'is slightly reduced by the spacer area 235'.

The present invention further includes a diffusion layer separately to reduce dark areas inevitably generated in the surface light source device and to improve the overall brightness characteristics. The present invention does not include such a diffusion layer as an additional element like a diffusion member in a conventional backlight unit, but provides a diffusion layer integrated directly attached to the surface light source device.

As shown in FIG. 10, the diffusion layer 300 is preferably a mixed structure in which the organic or inorganic diffuser glass beads 320 are dispersed in the resin layer 310. The resin layer functions as a matrix of organic or inorganic diffuser glass beads, and the organic or inorganic diffuser glass beads are evenly dispersed in the resin layer. The size or amount of the organic or inorganic diffuser glass beads may be optimized in consideration of the luminous efficiency of the surface light source device.

11 illustrates an example of a surface light source device in which a diffusion layer is integrated. In the present embodiment, the diffusion layer 300 is formed on the upper surface of the first substrate 210 from which light is emitted, and the first surface electrode part 250 is formed thereon. The organic or inorganic diffuser glass beads 320 of the diffusion layer 300 improve scattering and diffusion of light emitted from the surface light source device, thereby improving luminance uniformity of the surface light source device, and in particular, reducing dark areas inevitably generated to reduce light emission efficiency. Can be maximized. In addition, since there is no need for a separate diffusion member, there is an advantage of reducing the volume of the backlight unit.

As shown in the enlarged view of FIG. 12, a separate adhesive layer 350 may be formed on the bottom surface of the first surface electrode part 250 to further strengthen the bonding with the diffusion layer 300. A pressure sensitive adhesive (PSA) resin or the like may be used as the adhesive layer.

In the present invention, a composite structure having a diffusion layer having an organic or inorganic diffusion material dispersed in a resin matrix on one surface of an electrode layer may be applied to a light source body of a surface light source. In this case, an adhesive layer may be further included on one surface of the electrode layer, and the structure of the electrode layer may have a complex structure including a base layer, an electrode pattern, and a protective layer as described above.

FIG. 13 is a surface light source device according to another embodiment of the present invention. Unlike FIG. 11, a diffusion layer 300 is formed on an upper surface of the first surface electrode part 250. The first surface electrode portion is in contact with the first substrate via the adhesive layer 350. In this embodiment, since the diffusion layer is formed at the top of the surface light source device, more uniform luminance can be obtained by scattering and diffusing light passing through the electrode portion.

The diffusion layer 300 shown in FIGS. 11 and 13 is preferably formed in a subsequent process after completing the light source body of the surface light source device. Alternatively, it may be possible to form the diffusion layer together in the forming process of the first substrate 210.

When the surface from which light is emitted is the second substrate 220, the diffusion layer may be formed in contact with one surface of the second surface electrode part 260 on the second substrate side. In addition, the surface light source device including the attachment diffusion layer according to the present invention has a structure in which a plurality of spacers are formed between the first substrate and the second substrate, or a plurality of protrusions are integrally formed on the inner surface of the first substrate or the second substrate. Applicable to both.

14 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, 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 surface light source 200 does not require a separate diffusion plate, a diffusion sheet, a prism sheet, etc., because the diffusion layer is attached to the surface, but in some cases, an additional optical member is included to change the characteristics of the emitted light. Do not exclude

The upper case 1100 is coupled to the lower case 1200 to support the surface light source 200. 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.

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, since a diffusion layer is attached to and integrated with the substrate from which light is emitted, an additional diffusion member is not required, thereby enabling an ultra-thin backlight unit. In addition, the light emitted from the surface light source device due to the dark portion of the surface light source itself due to the spacer or the surface electrode portion can prevent the efficiency from being lowered.

In addition, according to the present invention, the inside of the surface light source device forms a discharge space of one open structure, it is possible to use a gas that excludes mercury as a discharge gas injected into the discharge space can be applied to environmentally 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.

Claims (18)

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; First and second surface electrode portions formed on the entire surface of the first substrate and the second substrate, respectively, And a diffusion layer attached to a side of the substrate from which the light is emitted from the first substrate and the second substrate. Surface light source device. The surface light source device according to claim 1, wherein the diffusion layer has a mixed structure in which an organic or inorganic diffusion material is dispersed in a resin matrix. The surface light source device of claim 2, wherein the diffusion layer is an organic or inorganic diffusion material. The surface light source device according to claim 1, wherein the diffusion layer is inserted between the first substrate and the first surface electrode portion or the second substrate and the second surface electrode portion. The surface light source device according to claim 1, wherein the diffusion layer is attached on the first surface electrode portion or the second surface electrode portion. The surface light source device of claim 1, further comprising an adhesive layer attached to a surface of the first surface electrode portion or the second surface electrode portion. The surface light source device of claim 1, wherein a plurality of spacers are formed between the first substrate and the second substrate. The surface light source device of claim 1, wherein a plurality of protrusions are integrally formed on an inner surface of the first substrate or the second substrate. The ultra-thin surface of claim 1, wherein at least one of the first and second surface electrode portions comprises a base layer, an electrode pattern formed on an upper surface of the base layer, and a protective layer formed on the electrode pattern. Light source device. 10. The surface light source device according to claim 9, wherein the base layer and the protective layer are transparent to visible light. The surface light source device of claim 1, wherein the electrode unit comprises an electrode pattern such as a pattern in which circles, ellipses, polygons, and the like are regularly arranged, a mesh structure pattern, or a stripe pattern. The method of claim 1, wherein the electrode unit is formed of any one material selected from copper, silver, gold, aluminum, nickel, chromium, ITO, carbon-based conductive material, conductive polymer, and a composite material thereof. Surface light source device. The surface light source device according to claim 1, wherein at least one of the first and second surface electrode portions has an opening ratio of 60% or more to expose the first substrate or the second substrate. The surface light source device of claim 1, 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 first substrate and a second substrate forming a sealed discharge space, first and second surface electrode portions respectively formed on the entire surfaces of the first and second substrates, and a diffusion layer attached to the substrate from which light is emitted. A surface light source device comprising; A case accommodating the surface light source device; And And an inverter configured to apply voltage to the first and second surface electrode parts. Ultra-thin backlight unit. A composite electrode for a surface light source, comprising a diffusion layer in which an organic or inorganic diffusion material is dispersed in a resin matrix, and an electrode layer attached to one surface of the diffusion layer. The composite electrode for a surface light source according to claim 16, further comprising an adhesive layer formed on one surface of the electrode layer. The composite electrode of claim 16, wherein the electrode layer comprises a base layer, an electrode pattern formed on an upper surface of the base layer, and a protective layer formed on the electrode pattern.

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