KR20090062424A - Surface light source and backlight unit having the same - Google Patents

Abstract

A surface light source device and a backlight unit including the same are provided to prevent a channeling phenomenon by minimizing interference between adjacent blocks in a scan driving process. A surface light device is comprised of a light source body, and an electrode(200,300). The light source body includes a first substrate and a second substrate. One of the first substrate and the second substrate is formed to have a plurality of discharge channels. The electrode unit partitions the discharge space to the plurality of blocks. The electrode unit applies the voltage to each block. The distance between adjacent blocks is above 4 mm.

Description

Surface light source device and backlight unit having the same {SURFACE LIGHT SOURCE AND BACKLIGHT UNIT HAVING THE SAME}

The present invention relates to a surface light source device having a surface discharge electrode structure partitioned into a plurality of blocks to facilitate scan driving, and a backlight unit having the same.

The liquid crystal display displays an image by using electrical and optical characteristics of the liquid crystal. Since the liquid crystal part of the liquid crystal display is a light receiving element that does not generate light by itself, it separately requires a rear light source, that is, a backlight.

Light supplied from the rear light source sequentially passes through the pixel electrode, the liquid crystal, and the common electrode of the liquid crystal display. In this case, the display quality of the image passing through the liquid crystal largely depends on the luminance and luminance uniformity of the rear light source. In general, the higher the luminance and the uniformity of the luminance, the better the display quality.

Conventionally, a rear light source of a liquid crystal display device has been mainly used a cold cathode fluorescent lamp (CCFL) or a light emitting diode (LED). Cold cathode fluorescent lamp has the advantage of high brightness, long life, and very low heat generation compared to incandescent lamps. On the other hand, the light emitting diode has the advantage of high power consumption but excellent brightness. However, cold cathode fluorescent lamps or light emitting diodes have poor luminance uniformity. Therefore, existing back light sources require optical members such as a light guide panel (LGP), a diffusion member, a prism sheet, and the like to increase luminance uniformity. As a result, the liquid crystal display has a problem in that the volume and weight of the optical member are greatly increased.

As a back light source for a liquid crystal display, a flat fluorescent lamp (FFL) in the form of a flat plate has been proposed.

The conventional surface light source device comprises a light source body and an electrode.

The light source body includes a first substrate and a second substrate that are disposed to face each other and are formed in a flat plate type, and have a discharge space in which discharge gas is injected. The edges of the first substrate and the second substrate are sealed to seal the discharge space.

Phosphors are coated on the surfaces of the first substrate and the second substrate, and when the discharge voltage is applied to the discharge gas by the electrodes, ultraviolet rays are generated by the discharge of the discharge gas. The generated ultraviolet rays excite the phosphor to generate visible light, and the generated visible light is transmitted forward through the substrate.

Currently, in order to improve the image quality of a large area liquid crystal display device and to realize a clearer and more natural display quality, the surface light source device needs a technology for locally controlling the luminance of the surface light source device used as a backlight.

In addition, due to the harmfulness of mercury, which is mainly used as the discharge gas, there is a demand for the development of an environment-friendly surface light source device that can use a discharge gas without mercury.

An object of the present invention is to provide a surface light source device that can use a discharge gas free of mercury.

Another object of the present invention is to provide a surface light source device having a surface discharge type electrode structure capable of performing an optimal scan driving by applying a voltage for each block and a backlight unit having the same.

It is still another object of the present invention to provide a surface light source device and a backlight unit which can prevent interblock and channeling by minimizing interference between adjacent blocks during scan driving.

The surface light source device according to the exemplary embodiment of the present invention includes a light source body having a first substrate and a second substrate having a discharge space, and an electrode unit for dividing the discharge space into a plurality of blocks and applying a voltage to each block. And the distance between adjacent blocks can be maintained at 4 mm or more to minimize interference between adjacent blocks.

One of the first substrate and the second substrate has a feature that the substrate itself is formed so that a plurality of discharge channels are formed, and the plurality of discharge channels are divided into one block by a predetermined number by the electrode unit.

The backlight unit according to the exemplary embodiment of the present invention includes a light source body having a first substrate and a second substrate having a discharge space, and an electrode unit for dividing the discharge space into a plurality of blocks and applying a voltage to each block. And a distance between adjacent blocks is 4 mm or more, a case for housing the surface light source device, and an inverter for applying a voltage to the electrode portion.

The present invention configured as described above can use a discharge gas free of mercury can provide an environment-friendly surface light source device.

In addition, the surface light source device of the present invention has an advantage of performing an optimal scan driving by binding a predetermined number of discharge channels into blocks and applying a voltage to each block.

In addition, the surface light source device of the present invention can minimize the interference between adjacent blocks during scan driving by optimizing the distance between blocks disposed adjacent to each other, thereby preventing the channeling or channeling, thereby improving the reliability of the lamp and the inverter. There is an advantage.

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

1 is a perspective view of a surface light source device according to an embodiment of the present invention, Figure 2 is a cross-sectional view of the surface light source device according to an embodiment of the present invention.

The illustrated surface light source device 100 includes a light source body 110 that forms a discharge space into which discharge gas is injected, and electrode units 200 and 300 that apply a discharge voltage to the discharge gas. The light source body 110 includes a first substrate 120 and a second substrate 130. The first substrate 120 and the second substrate 130 are preferably formed of a transparent glass substrate. The first substrate 120 and the second substrate 130 are disposed to face each other, and one of the two substrates 120 and 130 has a structure formed in a predetermined shape to form a plurality of discharge channels 140.

In the present exemplary embodiment, the first substrate 120 disposed at the upper side to emit light has a structure formed to form a plurality of discharge channels 140, and the second substrate 130 disposed at the lower side is formed in a flat plate shape. do. In the drawing, the discharge channel 140 is formed on the first substrate 120 but is not limited thereto. The discharge channel is formed on the second substrate 130 or the first substrate 120 and the second substrate 130 are not limited thereto. It can be molded to everything.

Discharge channels 140 are formed in plural at regular intervals in the transverse or longitudinal direction of the substrate. In addition, the discharge channel 140 may be applied to any shape that can form a discharge space such as an elliptical shape, a semicircle shape, a polygonal shape, and the like.

The first substrate 120 is formed with a plurality of discharge channels 140 at equal intervals, and is attached to the upper surface of the second substrate 130. Accordingly, the molded portion of the first substrate 120 in contact with the second substrate 130 serves as a partition wall for partitioning each discharge space 160 and also serves as a spacer for maintaining the discharge space.

Such a substrate forming type does not require a separate spacer for supporting a discharge space between the first substrate and the second substrate, thereby simplifying the manufacturing process and having strength that can sufficiently cope with the impact stress of the surface light source device.

Edges of the first substrate 12O and the second substrate 130 may be joined by a sealing member 180 such as a frit, or may be directly fused using a heating means such as a laser. In addition, a sealing member such as a frit may be formed at a portion where the first substrate 120 and the second substrate 130 contact each other (a portion formed to form a discharge channel of the first substrate and an upper surface of the second substrate). May be bonded together, or may be directly fused using a heating means such as a laser.

A fluorescent layer (not shown) is coated on an inner surface of the first substrate 120 to form a discharge space, and a reflective layer (not shown) and a fluorescent layer (not shown) are disposed on an inner surface of the discharge channel 140 formed on the second substrate 130. ) May be applied respectively. In addition, an MgO coating layer may be formed on the inner surface of the discharge channel 140 to prevent phosphor deterioration due to ion collision.

Various types of discharge gas may be selected as the discharge gas injected into the discharge space 160, but preferably, a gas excluding mercury such as xenon, argon, neon, other inert gas, or a mixed gas thereof is used.

In particular, when a discharge gas excluding mercury is used, it not only provides an environmentally friendly advantage, but also shortens the luminance stabilization time even when driving at low temperature. In addition, due to the temperature sensitivity of the mercury, it is possible to minimize the luminance uniformity of the surface light source device according to the temperature deviation.

As illustrated in FIGS. 3 and 4, the electrode parts 200 and 300 may be surface discharge type electrodes formed only on the surface of any one of the first substrate 120 and the second substrate 130. The electrode parts 200 and 300 are preferably formed on the outer surface of the second substrate 130 formed in a flat plate shape. The electrode parts 200 and 300 may be formed in a form separated into block units B1 to B6 to bundle a predetermined number of discharge channels 140 into one block B and apply a voltage to each block.

The electrode parts 200 and 300 may be directly coated on the surfaces of the first substrate 120 and the second substrate 130, and may be formed by attaching a stripe-type wire or band-shaped conductive tape.

The electrode parts 200 and 300 may use transparent electrodes (eg, ITO), other conductive materials may be used, and preferred materials include copper, silver, gold, aluminum, nickel, chromium, ITO, carbon-based conductive materials, and conductive materials. Any one material selected from polymers or composite materials thereof may be used.

The electrode parts 200 and 300 may be divided into four or more blocks. Preferably, the electrode parts 200 and 300 may be divided into six blocks B1 to B6 so that the four discharge channels are bundled into one block and the plurality of discharge channels are divided into six. have.

The number of discharge channels and the number of blocks divided into one block B may vary according to the screen size of the display, the width or shape of the discharge channel, or the size of the surface light source device.

The electrode parts 200 and 300 correspond to one edge of the discharge channel 140 and are formed on the surface of the second substrate 130 in parallel with the longitudinal direction of the discharge channel 140 and the discharge channel ( The second electrode 300 corresponds to the other edge of the 140 and formed in parallel with the first electrode 200 at a predetermined interval.

The plurality of first electrodes 200 are arranged in pairs at a predetermined interval, and the first electrodes 200 forming one block are connected by the first connection electrode 210. The first connection electrode 210 is formed at one edge of the substrate, and ends of the first electrodes 200 are connected and electrically connected to the inverter to receive a voltage.

The plurality of second electrodes 300 are arranged in pairs at predetermined intervals between the first electrodes, and the second electrodes forming one block are connected by the second connection electrode 310. The second connection electrode 310 is formed at the other edge of the substrate, the ends of the second electrodes 300 are connected, and are electrically connected to the inverter to receive a voltage.

As such, the electrode unit may have a structure in which the first electrodes 200 and the second electrodes 300 are alternately arranged in pairs, and the plurality of first electrodes 200 forming one block may include a first The second electrodes 310 that are integrally connected to the connection electrode 210 and form one block may have a structure that is integrally connected to the second connection electrode 310.

In addition, the electrode unit may use an electrode structure having any structure in which a plurality of first electrodes and a plurality of second electrodes are bundled into one block to apply a voltage in each block unit.

The electrode structures of one block described above are arranged in plural at regular intervals so that a voltage is applied to each block to perform scan driving.

The distance H between one block B1 and another adjacent block B2 is preferably maintained at least 4 mm so as to minimize interference between adjacent blocks during scan driving.

That is, if the distance between adjacent blocks (H) is 4mm or less, vibration or trimming occurs due to the interference of adjacent blocks (B1, B2) during scan driving, and the distance between adjacent blocks (H) is prevented. ) Should be kept more than 4mm. More preferably, the distance between the blocks is maintained about 4mm ~ 6mm.

In this case, the width T of the first electrode 200 and the second electrode 300 is preferably maintained at about 1.5 mm to 2.5 mm, and the distance P between the first electrode and the second electrode is defined as the positive column region. It is preferable to maintain 10 mm or more so as to increase the used discharge efficiency.

As described above, the surface light source device according to the present invention can minimize the interference caused by the adjacent blocks during scan driving by optimizing the distance between the blocks constituting the electrode portion and the adjacent blocks, thereby preventing the smashing or trembling. Display screens can be implemented and inverters and lamps can improve reliability.

5 is a perspective view of a surface light source device according to a second embodiment of the present invention, and FIG. 6 is a cross-sectional view of the surface light source device according to a second embodiment of the present invention.

The light source body 500 according to the second embodiment includes a first substrate 510 and a second substrate 520 formed of a transparent flat glass substrate.

The first substrate 510 and the second substrate 520 are disposed to face each other with a predetermined interval therebetween, and the partition 530 partitioning the discharge space 540 into a plurality of discharge spaces 540 isolated from each other. ) Is installed. The partition wall 530 may be integrally molded with the substrate and may be molded separately from the substrate and attached to the surface of the substrate.

Surface discharge type electrode parts 610 and 620 are formed on a surface of one of the first and second substrates 510 and 520. In some cases, the electrode parts 610 and 620 may be formed on both the first substrate 510 and the second substrate 520.

The electrode parts 610 and 620 may have the same electrode part as the structure of the electrode part (the electrode part illustrated in FIGS. 3 and 4) described in the above embodiment. Therefore, a detailed description of the first electrode and the second electrode structure will be omitted.

7 and 8 are graphs showing output waveforms of an inverter during scan driving of a surface light source device according to an embodiment of the present invention.

FIG. 7 is a graph showing an output waveform of an inverter when the distance between blocks of an electrode portion is 4 mm or less. It can be seen that an interference portion I between adjacent blocks is generated when the distance between adjacent blocks disposed is 4 mm or less.

8 is a graph showing the output waveform of the inverter when the distance between blocks of the electrode unit is 4 mm or more, and it can be seen that interference between blocks disposed adjacent to each other does not occur.

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

As shown, the backlight unit includes the surface light source device 100 described above, the bottom chassis 600, the fixed frame 700 and the inverter 800.

The bottom chassis 600 accommodates the surface light source device 100.

As the surface light source device 100, the surface light source device described above is used.

The optical sheet 900 is disposed on the top surface of the surface light source device 100. The optical sheet 900 may be composed of a diffusion sheet and a prism sheet.

The fixing frame 700 is coupled to the bottom chassis 600 to fix the optical sheet 900 to be disposed on the top surface of the surface light source device 100.

In the LCD, a liquid crystal panel is positioned in front of the fixed frame 700.

The inverter 800 is electrically connected to the first electrode 200 and the wire 810 constituting one block, and is electrically connected to the second electrode 300 and the wire 820 constituting one block. The surface light source device 100 is driven by generating a high potential discharge voltage and supplying the discharge voltage to the electrodes 200 and 300.

Although described above with reference to preferred embodiments of the present invention, those skilled in the art or those skilled in the art without departing from the spirit and scope of the invention described in the claims to be described later Various modifications and variations can be made in the present invention without departing from the scope thereof.

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

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

3 is a plan view illustrating an electrode structure according to an exemplary embodiment of the present invention.

4 is an enlarged view of a portion A of FIG. 3.

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

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

7 and 8 are graphs showing the inverter output waveform of the surface light source device according to the present invention.

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

Claims (9)

A light source body having a first substrate and a second substrate having a discharge space; The discharge space is divided into a plurality of blocks, and includes an electrode unit for applying a voltage for each block, And the distance between the adjacent blocks is 4 mm or more. The method of claim 1, Any one of the first substrate and the second substrate is a surface light source device, characterized in that the substrate itself is formed so that a plurality of discharge channels are formed. The method of claim 2, The plurality of discharge channels are partitioned into one block by a predetermined number by the electrode unit. The method of claim 1, And the electrode portion is divided into four or more blocks. The method of claim 1, The electrode unit constituting the one block is a surface light source device, characterized in that the first electrode and the second electrode are arranged in pairs. The method of claim 5, The width of the first electrode and the second electrode is a surface light source device, characterized in that 1.5mm ~ 2.5mm. The method of claim 5, And a distance between the first electrode and the second electrode is 10 mm or more. The method of claim 1, The surface light source device, characterized in that the discharge gas in which mercury is removed is injected into the discharge space. A light source body having a first substrate and a second substrate having a discharge space, and an electrode portion for dividing the discharge space into a plurality of blocks and applying a voltage to each block, and the distance between adjacent blocks is 4 mm or more. A surface light source device; A case accommodating the surface light source device; And an inverter configured to apply a voltage to the electrode unit.

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