KR20060055590A - Surface light source and back light assembly using the same - Google Patents

Abstract

In the surface light source device having a thin thickness, the discharge space defined by the first substrate and the second substrate is divided into a plurality of discharge spaces by partition walls having receiving grooves for accommodating the mercury getter at an end contacting the second substrate. Divided into. In order to inject the discharge gas into the discharge spaces, the light source body including the first substrate and the second substrate is exposed to a vacuum atmosphere to evacuate the discharge spaces, and then discharge gas is injected into the discharge spaces. Subsequently, after discharging the discharge spaces injected with the discharge gas, the mercury getter is heated to inject mercury gas into the sealed discharge spaces. In this case, the partition wall portion and the first substrate are integrally manufactured by molding, and the receiving groove is integrally manufactured. The light source body is manufactured by disposing a mercury getter in the receiving groove and then bonding the second substrate to the first substrate. By embedding the mercury getter in the partition wall portion, the thickness of the surface light source device can be reduced, and a surface light source device and a backlight unit having uniform luminance can be provided.

Surface light source

Description

Surface light source device and back light unit using same {SURFACE LIGHT SOURCE AND BACK LIGHT ASSEMBLY USING THE SAME}

1 is a cross-sectional view of a surface light source device for explaining a mercury injection method disclosed in the prior art.

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

3 is a cross-sectional view taken along the line I _1- I ₂ of FIG. 2.

FIG. 4 is an enlarged cross-sectional view of part I ₃ of FIG. 3.

FIG. 5 is an exploded perspective view showing a backlight unit having the surface light source device shown in FIG. 2.

<Explanation of symbols for main parts of the drawings>

100: surface light source device 105: discharge space

110: light source body 120: first substrate

121: discharge part 125: partition wall part

126 ： Accommodation groove 127 ： Auxiliary groove

128: fluorescent pattern 130: second substrate

132: reflection layer 134: fluorescent part                 

135: sealing member 140: getter

150 electrode 300 backlight unit

360: upper case 370: lower case

380: optical sheet 390: inverter

392: first power line 394: second power line

The present invention relates to a surface light source device and a backlight unit having the same. More particularly, the present invention relates to a surface light source device and a backlight unit that emit light in the form of a plane.

In general, liquid crystals (LC) have both electrical and optical characteristics. The arrangement of the liquid crystal is changed in correspondence with the direction of the electric field by the electrical properties, and the transmittance of light is changed in response to the arrangement by the optical properties.

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 CRTs, etc. As a result, they are widely used in portable computers, communication devices, liquid crystal television receivers, and aerospace industries.

In order to control the liquid crystal, a liquid crystal display device requires a liquid crystal controlling part for controlling the liquid crystal and a light supplying part for supplying light to the liquid crystal.

The liquid crystal control part 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.

The light supply part supplies light to the liquid crystal of the liquid crystal control part. Light 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 is greatly influenced by the luminance and luminance uniformity of the light supply part. In general, the higher the luminance and the uniformity of the luminance, the better the display quality.

The light supply part of the conventional liquid crystal display device mainly uses a cold cathode fluorescent lamp (CCFL) having a rod shape or a light emitting diode (LED) having a dot shape. Cold cathode ray tube type lamp has a high brightness, long life, and has the advantage of having a very low heat generation compared to incandescent lamps. On the other hand, the light emitting diode has advantages of low power consumption and high brightness. However, the conventional cold cathode ray tube lamps or light emitting diodes have a disadvantage in that the luminance uniformity is weak. Therefore, a light supply part having a cold cathode ray tube lamp or a light emitting diode as a light source may have an optical member such as a light guide panel (LGP), a diffusion member, and a prism sheet to increase luminance uniformity. (optical member) is included. 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. In order to solve this problem, a planar light source device has been proposed. The surface light source device can be largely divided into a partition independent type and a partition integral type.

The partition independent surface light source device includes a first and a second substrate. A plurality of partitions are disposed between the first and second substrates. The partitions are arranged in parallel at equal intervals to form a plurality of discharge spaces between the first and second substrates. A sealing member is disposed between the edges of the first and second substrates to isolate the discharge spaces from the outside. On the other hand, the sealing member is bonded to the first and second substrates via a sealing frit. Discharge gases are injected into the discharge spaces, and electrodes for applying a voltage to the discharge gas are disposed on or around the outer peripheral surfaces of both edges of the first and second substrates.

On the other hand, in the partition integrated surface light source device, the partitions are integrally formed on the first substrate or the second substrate. In this case, the sealing member is not used, and the plurality of discharge spaces are formed by directly joining the partition walls arranged at the outer side to the first substrate or the second substrate through the sealing frit.

The discharge voltage is applied to the electrodes of the surface light source device having the above configuration, the barrier discharge is generated in the discharge spaces, and the ultraviolet rays generated by the discharge excite the fluorescent layer to generate visible light. Hereinafter, a method of injecting mercury disclosed in the related art will be described.                         

1 is a cross-sectional view of a surface light source device for explaining a mercury injection method disclosed in the related art.

Referring to FIG. 1, the surface light source device 10 includes a first substrate 11 and a second substrate 12 disposed to face each other at a predetermined interval. A plurality of partition walls 20 are arranged in parallel at equal intervals between the first substrate 11 and the second substrate 12, and the sealing member is formed along the circumference of the first substrate 11 and the second substrate 12. (22) is formed. Here, the space shielded from the outside by the first and second substrates 11 and 12 and the sealing member 22 becomes the discharge space 17. Electrodes 40 are formed on both sides of the first and second substrates 11 and 12, respectively.

A hole 15 is formed at one end of the second substrate 12, and an exhaust tip 30 for injecting discharge gas and mercury gas into the discharge spaces 17 is connected to the hole 15. When the discharge space 17 is shielded from the outside by the first and second substrates 11 and 12, the gas in the discharge spaces 17 is discharged to the outside using the exhaust tip 30. That is, the discharge spaces 17 are formed in a vacuum state. Subsequently, after the discharge gas is supplied to the discharge spaces 17 through the exhaust tip 30, the getter 31 is inserted into the exhaust tip 30. After the exhaust tip 30 is cut while the getter 31 is inserted, the exhaust tip 30 remaining in the second substrate 12 is melted to seal the hole 15. In this case, the getter 31 remains on the second substrate 12 by the molten exhaust tip 30. Next, when the getter 31 is heated using high frequency, the getter 31 is activated and mercury gas is discharged from the getter 31. As a result, the discharge gas and the mercury gas are supplied to the discharge spaces 17.

The conventional mercury injection method as described above leaves the exhaust tip 30 on the second substrate in order to enter the mercury or vacuum getter into the light source body. Therefore, the thickness of the surface light source device 10 also increases by the thickness of the remaining exhaust tip 30. Indeed, the thickness of the exhaust tip 30 remaining on the second substrate in the surface light source production line is about 10 to 20 mm. This is a serious limiting factor in achieving the purpose of the surface light source device 10 presented to improve the thickness of the cold cathode ray tube lamp.

One object of the present invention is to provide a surface light source device that can improve the luminescence of the lamp and can have a thin thickness.

Still another object of the present invention is to provide a backlight unit having the surface light source device.

In accordance with an aspect of the present invention, a surface light source device includes a light source body having partition walls for forming a plurality of discharge spaces, and an electrode for applying a voltage to the discharge spaces. In this case, the partition part is integrally formed with the groove | channel which receives a getter.

In order to achieve the object of the present invention, a back light unit according to another embodiment includes a surface light source device according to the embodiment, an upper and lower case for accommodating the surface light source device, and interposed between the surface light source device and the upper case. And an inverter for applying a discharge voltage to the electrode for driving the optical sheet and the surface light source device.

According to the embodiment of the present invention as described above, by forming a groove for accommodating the getter in the partition wall, it is possible to remove the exhaust tip remaining in the light source body in order to accommodate the getter. Therefore, the thickness of the surface light source device can ultimately greatly reduce the thickness of the backlight unit.

Hereinafter, a surface light source device and a backlight unit using the same according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited or limited by the following embodiments.

Example 1

2 is a perspective view showing a surface light source device according to a first embodiment of the present invention, Figure 3 is a cross-sectional view taken along the line I _1- I ₂ of Figure 2, Figure 4 is an enlarged portion I ₃ of FIG. It is sectional drawing shown.

2 and 4, the surface light source device 100 according to the present embodiment includes a light source body 110 and an electrode 150 provided with a plurality of discharge spaces 105. The light source body 110 includes a first substrate 120 and a second substrate 130, and the first substrate 120 is disposed on the second substrate 130. The electrode 150 is disposed at both ends of the first and second substrates 120 and 130 to cover all the discharge spaces 105.

The second substrate 130 has a rectangular flat plate shape and is made of a transparent or translucent substrate. The second substrate 130 transmits visible light and blocks ultraviolet rays. Preferably, the second substrate 130 is a glass substrate. However, a UV absorbing substrate having a higher UV blocking rate than glass may be used as the second substrate 130. The reflective layer 132 and the fluorescent layer 134 are sequentially formed on the upper surface of the second substrate 130. The first substrate 120 is disposed on the second substrate 130 to define discharge spaces from the outside.

The first substrate 120 has a shape bent in a zigzag shape along the vertical direction, and is made of a transparent or translucent substrate like the second substrate 130. As shown in FIG. 3, the longitudinal cross-section of the first substrate 120 has a shape in which a plurality of semi-ellipses similar to trapezoids are continuously connected. However, unlike this, the first substrate 120 may be formed such that the longitudinal section has various shapes such as a semicircle, a triangle, a square, and the like. The first substrate 120 may be an emission surface from which light generated in the discharge spaces 105 is emitted.

The first substrate 120 is divided into a plurality of discharge parts 121 and a plurality of partition walls 125. The discharge parts 121 are spaced apart from the second substrate 130 to form discharge spaces 105. The fluorescent pattern 122 is formed on an inner surface of the first substrate 120 exposed to the discharge spaces 105. The discharge parts 121 are arranged in parallel with each other and have an approximately arcuate pillar shape. The partition part 125 connects adjacent discharge parts 121 to each other. That is, the first substrate 120 is formed by alternately connecting the discharge part 121 and the partition wall part 125.

The partition portion 125 has a thin and long flat plate shape in parallel with the discharge portion 121. In this case, the end portion 124 of the partition wall portion 125 has a width of about 3 to 5 mm and is in contact with the second substrate 130. In more detail, the end portion 124 of the partition portion 125 abuts the fluorescent layer 134 on the second substrate 130. In the present embodiment, the width of the barrier rib portion 125 is preferably about 3 to 5 mm in order to prevent drift and the occurrence of dark portions, but this may be selectively changed.                     

Receiving grooves 126 for receiving getters 140 are formed at the end portions 124 of the partition walls 125. Receiving groove 126 is sized to accommodate at least one getter 140. Receiving groove 126 is substantially irrelevant to any position formed at the end 124 of the partition wall portion 125.

The receiving groove 126 is preferably formed integrally with the partition wall (125). There are various ways in which the accommodation groove 126 may be integrally formed in the partition 125. For example, the receiving groove 126 may be integrally formed through a molding process using a mold.

The receiving groove 126 is formed in the direction opposite to the fluorescent layer 134 at the center of the end 124. More developmentally, auxiliary holes 127 are formed at both sides of the receiving groove 126. The auxiliary holes 127 partially open both sides of the partition 125 to communicate the receiving groove 126 with the discharge spaces 105. In addition, the receiving groove 126 may be formed in all of the partitions 125, and the formation position in the partitions 125 may be selectively changed.

Preferably, the discharge part 121 and the partition wall part 125 of the first substrate 120 are integrally formed. For example, a first substrate having a plurality of discharge parts 121 and a plurality of partition walls 125 may be formed by heating the plate-shaped base substrate to a predetermined temperature and then molding the base substrate through a mold having a desired shape. 120).

The first substrate 120 is coupled to the second substrate 130. In this case, the sealing member 135 is interposed between the first substrate 120 and the second substrate 130.

As the sealing member 135, frit which is a mixture of glass and metal which has a melting | fusing point lower than glass is typical, but this invention is not limited by this. In addition, since the location of the sealing member 135 for bonding the first substrate 120 and the second substrate 130 may be variously selected, the present invention is not limited thereto.

The discharge spaces 105 communicate with each other by a connection passage 129 formed on the rear surface of the first substrate 120. Therefore, the discharge gas injected into any one or more discharge spaces 105 is then moved to the other discharge spaces 105 through the connection passage 129, and eventually discharge gas with a uniform gas pressure in all the discharge spaces 105. Is distributed. It will be apparent to those skilled in the art that the connecting passage 129 for communicating the discharge spaces 105 may be variously modified or removed, and thus the present invention is not limited thereto.

The discharge spaces 105 are injected with various kinds of discharge gases for plasma discharge. For example, a mixed gas including mercury (Hg), neon (Ne), argon (Ar), xenon, or krypton may be used as the discharge gas. In this case, it is preferable that a discharge gas is injected into the discharge spaces 105 at a pressure of about 50 torr. Assuming that the internal pressure of the discharge spaces 105 is about 50 torr, the internal pressure of the discharge spaces 105 is relatively much less than the external atmospheric pressure of about 760 torr. Due to this pressure difference, the pressure applied to the discharge spaces 105 from the outside becomes relatively very high, and the first substrate 120 is in close contact with the second substrate 130. Therefore, the end portion 124 of the partition portion 125 of the first substrate 120 is in close contact with the fluorescent layer 134. As a result, the getter 140 disposed in the accommodation groove 126 does not flow into the discharge spaces 105.

The electrodes 150 are formed at both ends of the first and second substrates 120 and 130 in the direction perpendicular to the longitudinal direction of the discharge spaces 105, respectively, and overlap the discharge spaces 105. The electrode 150 is formed on at least one outer surface of the outer surface of the first substrate 120 and the outer surface of the second substrate 130. Alternatively, the electrode 150 may be formed on the inner surface of the first substrate 120 or the second substrate 130.

The electrode 150 has a high conductivity, for example, any one of metal materials such as copper (Cu), nickel (Ni), silver (Ag), gold (Au), aluminum (Al), and chromium (Cr). It is formed by a method of spray coating a metal powder (metal powder) consisting of the above metal material. Alternatively, the electrode 150 may be formed by attaching a conductive aluminum tape or by attaching a conductive metal material using a conductive adhesive such as silver paste. The electrode 150 generates plasma in the discharge spaces 105 by a discharge voltage applied from the outside.

Charge generated in the discharge spaces 105 by the electrode 150 collides with the discharge gas, and in this process, non-visible light is generated from the discharge gas. The invisible light is changed into visible light through the fluorescent layer and the fluorescent patterns 134 and 128 exposed to the discharge spaces 105 and is emitted through the first substrate 120. In this case, the fluorescent pattern 128 formed on the first substrate 120 is essential and may be formed on the second substrate 130 or the sealing member 135 in consideration of the luminance of the entire surface light source device.

The fluorescent layer and the fluorescent patterns 134 and 128 convert into invisible light visible light such as ultraviolet light. The thickness of the fluorescent layers and the fluorescent patterns 134 and 128 is preferably about 10 μm. The fluorescent layer and the fluorescent patterns 134 and 128 are made of a mixture of red fluorescent material, green fluorescent material, and blue fluorescent material. The color of visible light emitted through the fluorescent layer and the fluorescent patterns 134 and 128 is changed according to the mixing ratio of the red, green and blue fluorescent materials. For example, in order to emit white visible light from the fluorescent layers and the fluorescent patterns 134 and 128, red, green, and blue fluorescent materials are respectively mixed in the same weight ratio. Hereinafter, the receiving groove 126 will be described in detail.

The receiving groove 126 is used to receive the getter 140 for improving luminous efficiency or vacuum degree. There are many kinds of getters 140 that can be accommodated in the accommodation grooves 126. Representative examples include a mercury getter and a vacuum getter. Receiving groove 126 is substantially irrelevant to any getter 140 is accommodated, at least one getter 140 is accommodated in the receiving groove 126. In the present embodiment, only the mercury getter is described, but this does not limit or limit the present invention.

When high energy such as high frequency is applied to the getter 140, the getter 140 is activated by the high energy and mercury gas is released. In this case, the getter 140 preferably contains solidified mercury.

The mercury gas generated by activating the getter 140 is discharged from the receiving groove 126 into the discharge spaces 105 through the auxiliary holes 127 formed at both sides of the partition wall 125.

The auxiliary holes 127 are not necessarily formed on the side of the partition wall 125 in order to allow the mercury gas generated from the getter 140 to flow into the discharge spaces 105. In general, since the fluorescent layer 134 contacting the end portion 124 of the partition portion 125 is made of a porous material, when the mercury gas pressure inside the receiving groove 126 increases, the mercury gas is removed from the receiving groove 126. It flows out to the discharge spaces 105.

As described above in the related art, in the conventional surface light source device 10, the exhaust tip 30 has to be left in order to accommodate the getter 31. Thereby, the thickness increase of the surface light source device 10 was inevitable. However, the surface light source device 100 according to the present exemplary embodiment may greatly reduce the thickness of the surface light source device 100 by forming the receiving groove 126 for accommodating the getter 140 in the partition wall 125. . Hereinafter, one method for manufacturing the surface light source device according to the present embodiment will be described. However, it should be noted that the surface light source device may be manufactured by other methods besides the following method.

Example 2

5 is an exploded perspective view showing a backlight unit having a light source device according to Embodiment 1 of the present invention.

Referring to FIG. 5, the backlight unit 300 according to the present embodiment includes the surface light source device 100, the upper and lower cases 360 and 370, the optical sheet 380, and the inverter 390 according to the first embodiment. do.

Since the surface light source device 100 has substantially the same configuration as in the first embodiment, the description of the surface light source device 100 will be omitted.

The lower case 370 includes a bottom portion 372 and a plurality of sidewalls 384 extending from the edge of the bottom portion 372 to form an accommodation space for accommodating the surface light source device 100. The surface light source device 100 is accommodated in the storage space of the lower case 370.

The inverter 390 is disposed on the rear surface of the lower case 370 and generates a discharge voltage for driving the surface light source device 100. The discharge voltage generated from the inverter 390 is applied to the electrodes 150 of the surface light source device 100 through the first and second power lines 392 and 394, respectively.

The optical sheet 380 may include a diffuser plate (not shown) for uniformly diffusing the light emitted from the surface light source device 100, and a prism sheet (not shown) for imparting straightness to the diffused light.

The upper case 360 is coupled to the lower case 370 to support the surface light source device 100 and the optical sheet 380. The upper case 360 prevents the surface light source device 100 from being separated from the lower case 370.

Meanwhile, a liquid crystal display panel (not shown) for displaying an image may be disposed on the upper case 360.

As described above, according to the present invention, the thickness of the surface light source device can be substantially reduced by embedding a getter in the partition wall for dividing the discharge space into a plurality of discharge spaces. Therefore, it is possible to manufacture a surface light source device that can improve the light emitting degree of the lamp and can have a thin thickness. Furthermore, the power consumption of the surface light source device may be reduced, and the weight of the liquid crystal display may be reduced.

As described above, although described with reference to the preferred embodiments of the present invention, those skilled in the art various modifications and variations of the present invention without departing from the spirit and scope of the present invention described in the claims below You will understand that it can be changed.

Claims (5)

A light source body having a partition for forming a plurality of discharge spaces, the groove having a groove accommodating a getter in the partition; And And an electrode for applying a voltage to the discharge spaces. The method of claim 1, wherein the light source body comprises a first substrate and a second substrate facing each other at a predetermined interval, The barrier rib is formed integrally with the first substrate to be in contact with the second substrate. The surface light source device of claim 2, wherein the groove is integrally formed on the first substrate. The surface light source device of claim 2, wherein the light source body further includes a sealing member formed along a circumference of the first substrate and the second substrate to seal between the first substrate and the second substrate. A surface light source device having a partition for forming a plurality of discharge spaces, the surface light source device including a light source body in which a groove for acquiring a getter is formed and an electrode for applying a voltage to the discharge spaces; Upper and lower cases accommodating the surface light source device; An optical sheet interposed between the surface light source device and the upper case; And And an inverter for applying a discharge voltage for driving the surface light source device to the electrode.

Images