KR20090061280A - Surface light source and backlight unit having the same - Google Patents

Abstract

A surface light source and backlight unit having the same is provided to reduce the power consumption by forming the first driving electrode and the second driver electrode. The first substrate(120) and the second substrate(130) are formed of the transparent flat plate glass. The sealing member(140) is interposed in the edge of the second substrate and the first substrate and the discharge space(160). The spacer(150) is interposed inside the discharge space. The discharge gas is injected in the discharge space of the light source body. The electrode is formed between the first substrate and the second substrate and applies the discharge voltage in the discharge gas. The driving electrode causing the initial discharge in the first electrode and the second electrode is formed.

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 drive electrode 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 has a discharge space in which discharge gas is injected. The light source body includes a first substrate and a second substrate. The first substrate and the second substrate are sealed at their edges to have a discharge space between the first substrate and the second substrate, and a plurality of spacers are provided in the discharge space to maintain a gap between the first substrate and the second substrate. Let's do it.

As the electrode, a surface discharge electrode composed of a first electrode and a second electrode provided on one surface of at least one of the first substrate and the second substrate is used. When a discharge voltage is applied to the discharge gas through the electrode, visible light is generated, and the generated visible light is emitted through the substrate.

The conventional surface discharge electrode uses a positive column to increase efficiency, and in order to use the positive electrode, the distance between the first electrode and the second electrode should be increased. However, when the distance between the first electrode and the second electrode is far, the start voltage and the sustain voltage become high, thereby increasing the power consumption and using a switching device of an expensive driver.

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

An object of the present invention is to provide a surface light source device and a backlight unit having the same by using a driving electrode to reduce the power consumption by reducing the starting voltage and to use a switching device of a relatively inexpensive driver.

The surface light source device according to an embodiment of the present invention lowers the starting voltage by including a light source body forming a discharge space and an electrode formed on the surface of the light source body and having at least one driving electrode formed on one side thereof.

The electrode includes a plurality of pairs of first and second electrodes arranged at regular intervals, and the driving electrode is branched from at least one first driving electrode and a second electrode branched from the first electrode, and the first drive. At least one second driving electrode disposed to face each other is composed of.

According to an embodiment of the present invention, a backlight unit includes a light source body forming a discharge space, a surface light source device including an electrode formed on a surface of the light source body and having at least one driving electrode formed on one side thereof, and a surface light source device. And a case for housing and an inverter for applying a voltage to the electrode.

In the surface light source device of the present invention configured as described above, a first driving electrode and a second driving electrode having a shorter distance than a distance between the first electrode and the second electrode are formed on the first electrode and the second electrode, thereby starting voltage and discharging. Lower voltages reduce power consumption and allow the use of relatively inexpensive switching devices for driving.

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 surface light source device 100 shown in FIG. 1 includes a light source body 110 forming a discharge space in which discharge gas is injected, and an electrode 200 applying 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 flat glass substrate.

The first substrate 120 and the second substrate 130 are disposed to face each other at predetermined intervals, and the sealing member 140 is interposed therebetween to form a discharge space 160 sealed therein.

The sealing member 140 may be formed as a separate member from the first substrate 120 and the second substrate 130 to be bonded or fused between the first substrate 120 and the second substrate 130. The first substrate 120 or the second substrate 130 may be integrally formed on one edge of the first substrate 120 or the second substrate 130 to be bonded or fused to the other edge.

A fluorescent layer is coated on the inner surface of the first substrate 120 or the second substrate 130, and a reflective layer is formed on the inner surface of the second substrate 130 or the first substrate 120 facing the reflective substrate. A fluorescent layer is formed on it.

The spacer 150 is interposed in the discharge space 160 to maintain the gap of the discharge space 160. The spacer 150 may be bonded to or integrally formed with the first substrate 120 and the second substrate 130. Thus, for example, an embodiment in which the spacer 150 is integrally formed with the first substrate 120 by molding the first substrate 120 may be possible.

The spacer 150 is preferably made of a material having transparency to visible light.

The spacer 150 is in an island form. Therefore, the interior defined by the first substrate 120 and the second substrate 130 forms a single discharge space 160 having one open structure. The distance between the first substrate 120 and the second substrate 130 is very small compared to the substrate area, and is formed in a single space, so that the vacuum exhaust and discharge gas are easily injected.

However, the present invention is not limited thereto, and in some embodiments, the inner space of the light source body 100 may be partitioned into a plurality of discharge spaces by partition walls.

Discharge gas is injected into the discharge space 160 of the light source body 110.

As the discharge gas, various kinds of discharge gas may be selected, but preferably, a gas excluding mercury such as xenon, argon, neon, other inert gas, or a mixture 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 provides an advantage that can minimize the problem that the brightness uniformity of the surface light source device in accordance with the temperature deviation.

The electrode 200 is formed on at least one surface of the first substrate 120 and the second substrate 130 to apply a discharge voltage to the discharge gas. When a discharge voltage is applied to the discharge gas, ultraviolet rays are generated by the discharge of the discharge gas. The generated ultraviolet rays excite the fluorescent layer to generate visible light, and the generated visible light is transmitted forward through the substrate.

At least, when an electrode is formed on the emission side substrate 120 of visible light, the electrode has an open ratio of 60% or more to expose the substrate in order to increase the transmittance of light emitted by the discharge from the light source body 110. It is preferable.

The electrode 200 may use a transparent electrode (eg, ITO), may use other conductive materials, and preferred materials include copper, silver, gold, aluminum, nickel, chromium, ITO, carbon-based conductive materials, and conductive polymers. , Or any one material selected from a composite material of these may be used.

The electrode 200 may be formed by directly printing an electrode pattern on the surface of the light source body 110. Alternatively, after forming an multilayer film by attaching an electrode pattern to an insulating film, the multilayer film may be a light source. It may be attached to the surface of the body (110).

The electrode 200 may be a surface discharge electrode that is formed on one surface of at least one of the first substrate 120 and the second substrate 130 to cause surface discharge.

As shown in FIG. 3, the surface discharge electrode 200 includes a plurality of first electrodes 210 and a second electrode disposed at a distance on the surface of the substrate 120 to facilitate the use of positive columns. And a driving electrode 300 branching from the first electrode and the second electrode to lower the starting voltage Vf and the sustain voltage Vs.

As shown in FIG. 3, the first electrode 210 and the second electrode 220 have a structure in which two first electrodes 210 and two second electrodes 220 are alternately arranged at a predetermined interval. It may have a. In this case, since only one surface of the first electrode 210 and the second electrode 220 are disposed to face each other, discharge occurs only on one surface of the first electrode 210 and the second electrode 220.

Each of the first electrode 210 and the second electrode 220 may be connected to the lead-out portion to receive the discharge voltage at the same time, and may be separately connected to the power supply.

The distance between the first electrode 210 and the second electrode 220 is preferably maintained at least 8mm to facilitate the use of a positive pole. In this case, when the distance between the first electrode 210 and the second electrode 220 is greater than 8mm, the start voltage and the sustain voltage become high. To solve this problem, the first electrode 210 and the second electrode 220 are solved. Drive electrode 300 causing an initial discharge.

The driving electrode 300 includes a first driving electrode 310 connected to the first electrode 210 and a second driving electrode connected to the second electrode 220 and disposed to face the first driving electrode 310. 320.

The distance between the first driving electrode 310 and the second driving electrode 320 is disposed closer than the distance between the first electrode 210 and the second electrode 220. In addition, both ends of the first electrode 210 and the second electrode 220 may be formed in the first driving electrode 310 and the second driving electrode 320, and the first electrode 210 and the second electrode may be formed. It may be formed at one end of the electrode 220.

The first driving electrode 310 and the second driving electrode 320 may be formed in an “L” shape to face each other, and in addition, the first electrode 210 and the second electrode (eg, a “T” shape) may be disposed. 220 may be applied to any shape that is connected to each other and arranged facing each other.

The first driving electrode 310 and the second driving electrode 320 may be formed in at least one intermediate side in some cases other than the ends of the first electrode 210 and the second electrode 220. In addition, the first driving electrode 310 and the second driving electrode 320 may be used for not only an external electrode but also an internal electrode.

As such, since the distance between the first driving electrode 310 and the second driving electrode 320 is close, an initial discharge occurs at a low starting voltage at an initial stage, and the length direction of the first electrode 210 and the second electrode 220 occurs. The discharge occurs along the diffusion. Therefore, the starting voltage can be lowered from about 1.7 kv to about 1.2 kv, and thus the holding voltage can be lowered as compared with the existing.

As another embodiment, as shown in FIG. 4, the first electrode 410 and the second electrode 420 are alternately disposed on the surface of the light source body 110 so as to have an overall interdigitated structure. Can be formed. In this case, since both surfaces of the first electrode 410 and the second electrode 420 are disposed to face each other, discharge occurs at both surfaces of the first electrode 410 and the second electrode 420.

The driving electrode 430 applied to the electrode of the other embodiment includes two first driving electrodes 440 branched from both ends of one first electrode 410 to both sides, and the first driving electrode 440. The second driving electrodes 450 may be disposed to face each other and branch to both sides of the second electrode 420.

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

The surface light source device according to the second embodiment may be disposed to face each other, and the first and second substrates 510 and 520 may have a structure formed in a predetermined shape to form a plurality of discharge channels 530. The first electrode 540 and the second electrode 550 are formed on one surface of at least one of the first substrate 510 and the second substrate 520 to cause surface discharge.

The first substrate 510 disposed on the upper side and formed to form a plurality of discharge channels 530 is formed, and the second substrate 520 disposed on the lower side is formed in a flat plate shape to form a first electrode. It is preferable that the 540 and the second electrode 550 are formed at a predetermined interval.

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 510 and the second substrate 520 may be joined by a sealing member 560 such as a frit, or may be directly fused using a heating means such as a laser. The first electrode 540 and the second electrode 550 are formed on the surface of the second substrate 520 in parallel with the longitudinal direction of the discharge channel 530, respectively, and are located at positions corresponding to both sides of the discharge channel 530. Each is arranged. In this case, electrodes having the same polarity are disposed on two side surfaces of the neighboring discharge channels 530 to prevent interference between the electrodes.

In addition, the surface light source device according to the second exemplary embodiment of the present invention is branched from the surfaces of the first electrode 540 and the second electrode 550 facing each other to lower the start voltage Vf and the sustain voltage Vs. It further includes electrodes 560 and 570.

Since the driving electrodes 560 and 570 have the same structure as the driving electrode 300 described in the above embodiment, description thereof will be omitted. That is, the electrode structure shown in FIG. 3 may be applied to the electrode structure according to the second embodiment, and the electrode structure shown in FIG. 4 may be applied.

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

The surface light source device according to the third embodiment may be disposed to face each other, and the first and second substrates 510 and 520 may be formed in a predetermined shape so as to form a plurality of discharge channels 530. And a first electrode 610 formed on the surface of the first substrate 510 and disposed on one side of the discharge channel 530, and formed on the surface of the second substrate 520 and the other side of the discharge channel 530. The second electrode 620 is disposed on the first electrode 610 to cause a discharge in a diagonal direction.

At least one of the first electrode 610 and the second electrode 620 is formed with driving electrodes 630 and 640 to lower the starting voltage Vf and the sustain voltage Vs.

The driving electrode branches from both ends of the first electrode 610 and branches from both ends of the first driving electrode 630 and the second electrode 620 to be formed on the surface of the discharge channel 530. The second driving electrode 640 is formed on the surface of the substrate 520.

Here, the structure of the first driving electrode 630 and the second driving electrode 640 may be applied to the structure of the driving electrode 300 shown in Figure 3, the structure of the driving electrode 300 shown in Figure 4 is applied Can be.

In the surface light source device according to the third exemplary embodiment configured as described above, since the distance between the first driving electrode 630 and the second driving electrode 640 is close, initial discharge occurs at a low starting voltage and the first electrode 610 is initially generated. ) And the second electrode 620 discharge in a diagonal direction.

8 is an exploded perspective view showing a backlight unit related 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, any one of the surface light source devices described in the embodiment and the second embodiment is used.

The optical sheet 400 is disposed on the top surface of the surface light source device 100. The optical sheet 400 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 400 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 120 and the wire 810, and electrically connected to the second electrode 130 and the wire 820 to generate a high potential discharge voltage. The surface light source device 100 is driven by supplying it to 170.

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 showing the electrode structure of the surface light source device according to an embodiment of the present invention.

4 is a plan view showing another electrode structure of the surface light source device according to the present invention.

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

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

7 is a partial cross-sectional view of a surface light source device according to a third embodiment of the present invention.

8 is an exploded perspective view of a backlight unit according to an example of the present invention.

Claims (12)

A light source body forming a discharge space; A main electrode formed on the surface of the light source body; And a driving electrode branched from one side of the main electrode to generate an initial discharge. The surface light source device of claim 1, wherein the main electrodes are surface discharge electrodes including a plurality of first and second electrodes alternately alternately arranged. The display device of claim 2, wherein the driving electrode comprises at least one first driving electrode branched from the first electrode, and at least one second driving electrode branched from the second electrode and disposed to face the first driving electrode. Surface light source device characterized in that the. The surface light source device of claim 3, wherein the first driving electrode and the second driving electrode are branched at opposite surfaces of the first electrode and the second electrode, respectively. The surface light source device of claim 2, wherein the driving electrode is formed at both ends of the first electrode and the second electrode, respectively. The surface light source device of claim 3, wherein a distance between the first driving electrode and the second driving electrode is smaller than a distance between the first electrode and the second electrode. The surface light source device of claim 2, wherein the driving electrode is formed in an “L” shape. The method of claim 1, The light source body includes a first substrate formed to form a plurality of discharge channels, and a second substrate in the form of a plate attached to the first substrate. The method of claim 8, And the main electrode and the driving electrode are formed on a surface of the second electrode having a flat plate shape. The method of claim 8, The main electrode includes a first electrode formed on the surface of the first substrate in the longitudinal direction of the discharge channel, and a second electrode formed on the surface of the second substrate and disposed in a diagonal direction with the first electrode. A first driving electrode is formed in the second electrode, and a second driving electrode is formed in the second electrode. A surface light source device including a light source body forming a discharge space, a main electrode formed on a surface of the light source body, and a driving electrode branched from one side of the main electrode to generate an initial discharge; A case accommodating the surface light source device; And And a inverter for applying a voltage to the electrode. The method of claim 11, And the driving electrode is formed at at least one end of both ends of the main electrode, and the distance between the driving electrodes is shorter than the distance between the main electrodes.

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