KR100444903B1 - Flat Fluorescent Lamp and Back-light Unit Utilizing Flat Fluorescent Lamp - Google Patents

Abstract

The present invention relates to a backlight unit using a flat lamp, and is provided between a rear substrate and a front substrate made of a transparent material spaced at a predetermined interval by a sealing material on the rear substrate, and installed between the rear substrate and the front substrate. A plurality of partition walls partitioning a discharge space, a phosphor layer applied along a surface of the discharge space partitioned by the partition walls, a plurality of electrodes provided on both of the rear substrate and the front substrate to cause dielectric barrier discharge; A flat lamp comprising an upper portion of an electrode of the rear substrate and a reflective layer covering the entire rear substrate;

A light diffusion part spaced apart a predetermined distance from an upper surface of the front panel of the flat panel lamp to diffuse light emitted from the flat panel lamp; It is configured to include a base member installed through the adhesive layer on the, it is possible to improve the uniformity characteristics of the brightness, and to complement the durability of the lamp when bonding the base member and the flat lamp.

Description

Flat Fluorescent Lamp and Back-light Unit Utilizing Flat Fluorescent Lamp}

The present invention relates to a flat lamp and a backlight unit using the same, and more particularly to a backlight unit using the characteristics of a flat lamp having an electrode structure for generating a dielectric barrier discharge.

In general, flat panel display devices are classified into a light emitting type and a light receiving type, and a light emitting type includes a cathode ray tube, an electroluminescent device, a plasma display panel, and the like, and a light receiving type includes a liquid crystal display.

The liquid crystal display itself does not have a structure that emits light and thus cannot visualize an image unless external light is irradiated. Accordingly, it is possible to install an additional light source, for example, a back light, to observe the image.

The back light source device includes a method of diffusing light irradiated from a cold cathode fluorescent lamp (CCFL) using a light guide plate and a diffusion plate, and a flat type lamp that diffuses light by exciting phosphors by ultraviolet rays. fluorescent lamp method is used.

As shown in FIG. 1, the conventional flat lamp 10 includes a rear substrate 11 and a front substrate 12 bonded to the rear substrate 11 at a predetermined interval by a sealing material 13. It consists of a discharge space is formed. And a phosphor layer 16 formed on the bottom surface of the front substrate 12, a discharge electrode 14 formed in a predetermined pattern on the top surface of the back substrate 11 corresponding to the phosphor layer 16, and And a dielectric layer 15 formed on the top surface of the rear substrate 11 to fill the discharge electrodes 14. The discharge space is filled with a discharge gas made of xenon (Xe), neon (Ne), and the like.

In the conventional flat lamp, the phosphor layer 16 is excited by the ultraviolet light generated by the surface discharge between the electrodes as the power is applied to the discharge electrode 14, and is configured to emit the surface.

However, the conventional flat lamp as described above mainly uses an inert gas such as discharge gas xenon (Xe), neon (Ne), or Xe-Ne, so the AC voltage applied to the discharge electrode 14 is about 2 kV. In addition to being high, the light efficiency is low, below about 30 lm / W. As such, since the fluorescent lamp 10 has low efficiency, in order to obtain more light, the fluorescent lamp 10 needs to widen the area of the discharge space and increase the driving power, thereby increasing the power consumption. In addition, since the discharge gas is an inert gas, the phosphor layer 16 can be excited by the ultraviolet rays of 147 or 173 μm. Therefore, an expensive phosphor raw material should be used instead of the 254 μm ultraviolet phosphor produced in mass production.

On the other hand, conventional mercury-type flat lamps have a meandering long discharge space, and has a structure in which electrodes are disposed at the start and end points of the discharge space. This structure allows a relatively large current to flow in the discharge space, thereby facilitating evaporation of mercury, thereby achieving high efficiency mercury discharge.

However, as the discharge space becomes longer, the discharge start voltage increases. When the discharge demand voltage increases, the lamp stability, current leakage, and electromagnetic wave problems are caused. Also, in recent years, due to the increase in size of the liquid crystal display device, the flat lamp has been enlarged, so that the meandering discharge space is rapidly lengthened.

A planar fluorescent lamp for solving the above problems and a method for manufacturing the same are disclosed in Korean Unexamined Patent Publication No. 2001-0079377.

The disclosed method of manufacturing a flat fluorescent lamp includes heating the flat glass plate to a predetermined temperature capable of forming and forming the heated flat glass plate by using a mold processed to have a plurality of discharge spaces separated by partitions and connected to a discharge passage. Forming a discharge space in the flat glass plate by molding, taking out the molded glass plate having the discharge space formed from the mold, slowly cooling the extracted molded glass plate, and coating a phosphor inside the discharge space of the molded glass plate. Firing, bonding the front cover through a seal paste, evacuating the interior of the discharge space, injecting a discharge gas to seal the exhaust pipe, and installing an electrode for applying a high frequency power to the discharge space. do.

In the above method, an electrode for applying a high frequency power source is disclosed in which an internal electrode provided inside the discharge space or the entire length direction of both sides of the discharge space is provided.

The conventional flat fluorescent lamp configured as described above is very difficult to manufacture because it forms a discharge space by forming a heated glass substrate. In addition, the problem of applying a high voltage to the electrode of the flat fluorescent lamp has been solved, but crosstalk is generated between discharge spaces in which strong discharge occurs in a specific space among the discharge spaces or a phenomenon in which the discharge plasma is severely shaken.

This is because the movement of discharge charges through the inner surface of the opening in which the electrode is located is easy to move without restriction, so that the discharge charges are concentrated in the discharge channel where discharge occurs relatively easily.

Japanese Laid-Open Patent Publication No. 60-216435 discloses another example of a flat lamp. In the flat lamp, partition walls are alternately provided inside a container having an enclosed space to form a meandering discharge space, and electrodes are provided at both ends of the discharge space. Phosphor layers are formed above and below the discharge space. Such a flat lamp has a weak light emission at the edge of the discharge space, so that uniform luminance cannot be obtained, and a high voltage for discharge is required and the electrode is easily deteriorated.

Japanese Patent Application Laid-Open Nos. 09-092208 and 5,903,096 and 5,509,841 disclose surface light source devices having meandering discharge spaces partitioned by partition walls. In particular, US Patent No. 5,509,841 discloses a metal body molded and having a serpentine channel.

An object of the present invention is to solve the above problems, it is possible to lower the discharge start voltage, reduce the power consumption, improve the luminous efficiency, and can obtain a uniform brightness in each area and using a flat lamp It is to provide a backlight unit.

Another object of the present invention is to use a mercury discharge gas and to maintain a stable discharge using a low voltage without isolating each discharge channel, to maximize the light efficiency of the lamp, and to supplement the durability of the lamp flat lamp It is to provide a backlight unit using.

In order to achieve the above object, the present invention, the back substrate, the front substrate of a transparent material spaced at a predetermined interval by a sealing material on the back substrate, and installed between the rear substrate and the front substrate discharge space A plurality of partition walls for partitioning, a phosphor layer applied along a surface of the discharge space partitioned by the partition walls, a plurality of electrodes provided on both of the rear substrate and the front substrate to cause dielectric barrier discharge, and the rear substrate. A light diffusion unit including a flat lamp having an upper part of an electrode and a reflective layer covering the entire back substrate thereof, a light diffusing part configured to diffuse light irradiated from the flat lamp at a predetermined interval on the front substrate of the flat lamp; An insulating layer provided under the reflective layer of the flat panel lamp through the adhesive layer, and a bottom plate provided with the adhesive layer under the insulating layer. It is configured to include a switch member.

According to the backlight unit using the flat lamp according to the present invention, the luminance is improved by forming a reflective layer and openings are formed in the electrode to increase the width of the electrode to lower the discharge start voltage and adjust the plasma discharge region to improve the uniformity of the luminance. The base member and the flat lamp can be joined to complement the durability of the lamp.

1 is a cross-sectional view of a conventional flat lamp,

2 is a cross-sectional view showing a backlight unit according to the present invention;

3 is an exploded perspective view of a lamp of the backlight unit according to the present invention;

4 is a cross-sectional view taken along the line A-A of FIG.

5A to 5C are cross-sectional views illustrating an embodiment of a partition wall of a lamp of a backlight unit according to the present invention;

6A to 6E are plan views illustrating electrode embodiments of the lamp of the backlight unit according to the present invention.

Explanation of symbols on the main parts of the drawings

20: flat lamp 21: rear substrate

22: front substrate 23: sealing material

24: partition 25: phosphor layer

26, 26 ', 27, 27': electrode 28: reflective layer

29: metal piece 31: light diffusion unit

32: insulating layer 33: base member

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

2 is a cross-sectional view illustrating a backlight unit according to the present invention, FIG. 3 is an exploded perspective view of a lamp of the backlight unit according to the present invention, and FIG. 4 is a cross-sectional view taken along line A-A of FIG.

As shown in FIG. 2, the backlight unit according to the present invention includes a flat lamp 20, a light diffusion unit 31 for diffusing light emitted from the flat lamp 20, and the flat lamp. The insulating layer 32 and the base member 33 provided in the lower part of 20 are comprised.

As shown in FIGS. 3 and 4, the flat lamp 20 includes a back substrate 21, a front substrate 22, a partition wall 24, a phosphor layer 25, and electrodes 26, 26 ′, 27. 27 ') and a reflective layer 28 are included.

The flat lamp 20 is provided with a front substrate 22 through a sealing material 23 on the rear substrate 21, and divides the discharge space between the rear substrate 21 and the front substrate 22. A plurality of partition walls 24 are in close contact with the front substrate and alternately installed at predetermined intervals, and a plurality of electrodes 26, 26 ′, 27, on both the back substrate 21 and the front substrate 22. 27 ') is installed. The phosphor layer 25 is coated along the discharge space partitioned by the partition wall 24, and the reflective layer 28 is formed to cover the back substrate 21. Here, the front substrate 22 is preferably made of a transparent material that can transmit light well to the outside.

As shown in FIG. 3, the partition wall 24 is installed between the rear substrate 21 and the front substrate 22 and extends from an edge of the rear substrate 21 and the front substrate 22. The discharge space is partitioned and a channel for applying the phosphor layer 25 is formed. The partition wall 24 is provided such that the odd rows 24 'are closely attached to one side and the even rows 24 " are closely attached to the other side so that they are continuously arranged in a zigzag form (alternatively) to form a discharge space. Here, one end portions of the partition wall 24 are preferably spaced apart from the edge by a predetermined distance, and the width of the upper surface of the partition wall 24 is preferably 2 mm or less in order to minimize the non-light emitting area. It is preferable that the pitch of 24 or the space of the discharge space partitioned by the partition 24 is set to 5 to 15 mm.

5A to 5C, the partition wall 24 may have a different shape depending on the rear substrate 21 and the front substrate 22. That is, the partition wall 24 may be manufactured integrally like the rear substrate 21 by sandblasting or laser etching or softening the back substrate 21 and pressing or reducing pressure as shown in FIG. 5A. As shown in 5b, the front substrate 22 may be integrally manufactured.

In addition, the partition wall 24 may be manufactured by separating the first partition wall 24a integrally formed with the rear substrate 21 and the second partition wall 24b integrally formed with the front substrate as shown in FIG. 5C. . Here, it is preferable that the first partition 24a and the second partition 24b are manufactured so that they can be alternately arranged alternately.

As shown in FIG. 3, the phosphor layer 25 is coated along the surface of the discharge space partitioned by the rear substrate 21, the front substrate 22, and the partition wall 24. As shown in FIGS. 5A to 5C, the phosphor layer 25 is applied to both sides of the rear substrate 21 and the partition wall 24 in consideration of the transmission of the phosphor layer on which the excited light is applied to the front substrate 22. The thickness T2 of the phosphor layer applied on the front substrate 22 is thinner than the thickness T1 of the phosphor layer. Preferably, the phosphor layer 25 applied to the back substrate 21, the front substrate 22, and the partition wall 24 is thinly coated to 25 μm or less.

In the discharge space partitioned by the partition wall 24, a rare gas such as mercury (Hg), argon (Ar), neon (Ne) helium (He), krypton (Kr), or xenon (Xe) alone or Ne-Ar or Discharge gas containing mixed gas such as He-Ar, Ne-Xe is injected. In addition, it is preferable to use ultraviolet rays of mercury or xenon as a main source of phosphors constituting the phosphor layer 25.

Meanwhile, a metal piece 29 impregnated with mercury is disposed along one side of the discharge space partitioned by the partition wall 24 to supply mercury to the discharge gas injected into the discharge space. And 27 and 27 'are provided on both outer surfaces of the rear substrate 21 and the front substrate 22 corresponding to both end sides of the discharge space partitioned by the partition wall 24 for plasma discharge.

As shown in FIG. 3, the electrodes 26 and 26 ′ are symmetrically formed with a band electrode on both outer surfaces of the rear substrate 21. Here, the electrodes 27 and 27 'provided on the front substrate 22 are also constituted by strip electrodes. In addition, the electrodes 26, 26 ', 27, and 27' may have a relatively wider width than the conventional one so as to narrow the intervals in opposite directions.

As illustrated in FIGS. 3 and 6A, a plurality of floating electrodes 26a may be disposed between the electrodes 26 and 26 ′. In this case, since the floating electrode 26a of the independent type is intermittently interposed in the discharge space, voltage is induced by the power applied to the electrodes 26 and 26 'to generate discharge. As a result, the electrodes 26 and 26 'can be left at the same time and discharge can be started at a relatively low voltage, thereby achieving a more stable discharge.

As illustrated in FIGS. 6B to 6E, the electrodes 26 and 26 ′ may be configured to form stripe, square, and circular openings 26b, 26c, and 26d in the electrode body. Here, the openings 26b, 26c, and 26d become larger in the direction facing each other from the outside, that is, the areas per unit surface area of the electrodes 26, 26 'of the back substrate 21 are gradually opposite. Preferably, the openings 26b, 26c, and 26d are made smaller in size from the inner side to the outer side. The shape of the openings 26b, 26c, and 26d is not limited by the above-described embodiment.

As shown in FIGS. 2 and 3, the reflective layer 28 covers the upper portion of the electrode 26 of the rear substrate 21 and the entire rear substrate 21. Here, the reflective layer 28 is preferably used by mixing a white ceramic material containing Al ₂ O ₃ , TiO ₂ , WO ₃ and the like having high light reflection efficiency with a glass material, and the thickness of the reflective layer 28 is 20. It is preferable to apply so that it may apply in more than micrometer, and to have sufficient reflection efficiency and insulation function.

As shown in FIG. 2, the light diffusion unit 31 has a primary function of diffusing light generated by excitation of the phosphor from the flat lamp 20, and a non-light emitting area by the partition wall 24. It has a secondary function that makes it invisible. The light diffusion unit 31 is composed of a transparent plate 31a for transmitting the light of the flat lamp 20 and a diffuser plate 31b which is installed in contact with the transparent plate 31a to diffuse light. have. Here, the diffusion plate 31b is preferably made of a diffusive acrylic plate.

The light diffusion portion 31 is installed at a distance L from the upper surface of the flat lamp 20 to the upper surface of the diffusion plate 31b at the pitch or the partition 23 of the pitch P of the partition wall. It is preferable to make it 1/2 to 2 times the pitch of the channel partitioned by this.

The insulating layer 32 is formed on the bottom of the reflective layer 28 via an adhesive layer 32a to insulate the lower portion of the flat lamp 20. Here, the adhesive layer 32a can be firmly fixed even in a heat generating state by the discharge of the flat lamp 20, and is preferably made of a material having heat resistance.

The base member 33 is installed on the bottom surface of the insulating layer 32 via an adhesive layer 32b to prevent damage due to bending or external impact of the flat lamp. Here, it is preferable that the base member 33 is made of a metal plate material, and it is preferable to arrange the projection of the lattice structure or to use a casting so that warpage does not occur.

Referring to the operation of the flat panel backlight unit according to the invention configured as described above are as follows.

In order to drive the surface light source device, an AC or pulse waveform voltage is applied to the electrodes 26 and 27. When the voltage is applied in this way, an electric field is formed on the surface corresponding to the electrodes 26 and 27 of the flat lamp 20. The formed electric field accelerates the space charge in the discharge space, and the accelerated free electrons ionize the discharge gas to increase the number of space charges exponentially to form a plasma. Mercury is gasified and ionized by the heat generated by the plasma, and the excited mercury atoms are stabilized by receiving space charge energy in the plasma state to generate ultraviolet rays of 254 μm.

The ultraviolet rays generated during the discharge excite the phosphors of the phosphor layer 25 applied to each discharge space and convert them into visible light. At this time, the unique discharge between the channels can be maintained only when the upper end of each partition wall 24 is in close contact with the front substrate 22. If the upper end of the partition wall 24 does not guarantee the close contact, the discharge crosstalk between the channels is seriously generated due to the characteristics of the plasma in which the discharge is formed along the minimum electrical resistance space, thereby concentrating the current to only one discharge channel. As a result, a situation in which the overall lighting is impossible may occur.

In the operation as described above, since the discharge space partitioned by the partition wall 24, that is, a metal piece 29 impregnated with mercury is installed in the channel, mercury is supplied to maintain the partial pressure of mercury in the discharge space. . In particular, since the electrode 26 has a relatively wide width and has openings 26b, 26c, and 26d, a plasma discharge region can be formed relatively wide, and the openings 26b, 26c, and 26d face each other. Since it is gradually enlarged in the direction, it is possible to fundamentally solve the nonuniformity of the plasma discharge due to the voltage difference due to the proximity of the electrode 26.

In the structure having the floating electrode 26a, the distance between the electrodes becomes close by the floating voltage, and discharge can be performed even at a low voltage.

In addition, in the method of mixing both the structure having the openings 26b, 26c, and 26d and the structure having the floating electrode 26a, the design of the electrode can be made easier, and the discharge distortion caused by the surface electric field of the electrode itself is remarkably. Reduced brightness can be reduced dramatically when lit. In particular, according to the experiments of the present inventors, since the distance between the electrodes can be substantially narrowed, the discharge start voltage was lowered by 30% or more, and the light emission distribution was adjusted by changing the shape and the opening of the electrode pattern.

In addition, by using a material of white color of the material of the electrode to be able to reflect the visible light generated from the flat lamp to the front possible to improve the light efficiency by 2%. In addition, the reflective layer covering the outside of the electrode material and the entire back substrate may improve the light efficiency of the flat lamp by minimizing the loss of visible light generated from the flat lamp to the back of the lamp. In particular, the experiments of the present inventors confirmed that the light efficiency is improved by 6% or more depending on the material arrangement of the reflective layer.

The light emitted by the flat lamp 20 is irradiated through the transparent plate 31a and the diffuser plate 31b of the light diffusion unit 31 supported by the base member 33. The flat lamp Since the distance from (20) to the diffuser plate was 1/2 to 2 times the length of the barrier rib pitch, it was possible to remove the speckles in which the luminance of the channel portion was relatively higher than that of the barrier rib portion.

As described above, in the backlight unit using the flat panel lamp of the present invention, an opening may be formed in the electrode to increase the width of the electrode, thereby lowering the discharge start voltage and adjusting the plasma discharge region, thereby improving the uniformity of the luminance. By combining the flat lamp with the base member through the adhesive layer / insulation layer / adhesion layer, it is possible to minimize the light loss to the back to improve the light efficiency and to supplement the durability of the lamp.

Claims (14)

Back board, A front substrate made of a transparent material spaced apart at predetermined intervals by a sealing material on the rear substrate; A plurality of partition walls installed between the rear substrate and the front substrate to be in close contact with the front substrate so as to partition a discharge space and installed alternately (zigzag) ; A phosphor layer applied along the surface of the discharge space partitioned by the partition wall; A first electrode provided in a band shape so as to be symmetrical to both sides of an outer surface of the front substrate ; A band-shaped second electrode provided on both sides of the outer surface of the rear substrate so as to be parallel to the first electrode, and having an opening formed therein; And a reflective layer formed by mixing a white ceramic material with a glass material so as to cover an upper portion of the electrode of the rear substrate and the entire rear substrate thereof . The method of claim 1, The partition wall is a flat lamp, characterized in that integrally molded with the back substrate. The method of claim 1, The partition wall is a flat lamp, characterized in that formed of the same transparent material as the front substrate and integrally with the front substrate. The method of claim 1, And the partition wall comprises a first partition wall integrally formed with the rear substrate and a second partition wall integrally formed with the front substrate. delete delete The method of claim 1, And a plurality of floating electrodes are disposed between the electrodes of the rear substrate. The method of claim 1, Flat panel lamp, characterized in that a plurality of the opening is formed of one of the stripe, circle, square . The method of claim 8 , The opening of the electrode is a flat lamp, characterized in that gradually formed from the inner side to the outer side. The method of claim 1, The reflective layer has Al ₂ O ₃ , TiO ₂ , WO _3, etc. as a main component, and has a thickness of 20 μm or more, and is applied to a flat lamp. Back board, A front substrate made of a transparent material spaced apart at predetermined intervals by a sealing material on the rear substrate; A plurality of partition walls installed between the rear substrate and the front substrate to be in close contact with the front substrate so as to partition a discharge space and installed alternately (zigzag) ; A phosphor layer applied along the surface of the discharge space partitioned by the partition wall; A first electrode provided in a band shape so as to be symmetrical to both sides of an outer surface of the front substrate ; A band-shaped second electrode provided on both sides of the outer surface of the rear substrate so as to be parallel to the first electrode, and having an opening formed therein; A flat lamp comprising a reflective layer formed by mixing a white ceramic material with a glass material so as to cover an upper portion of an electrode of the rear substrate and the entire back substrate ; A light diffusion unit spaced apart from the upper substrate by a predetermined distance on the front substrate of the flat lamp to diffuse light emitted from the flat lamp; An insulating layer provided under the reflective layer of the flat lamp via an adhesive layer; And A base member installed under the insulating layer through an adhesive layer; Backlight unit using a flat lamp comprising a. The method of claim 11, And the light diffusing unit comprises a transparent plate for transmitting the light of the flat plate lamp and a diffuser plate disposed in contact with the transparent plate to diffuse the light. The method of claim 11, The light diffusing unit is a backlight unit using a flat panel lamp, characterized in that made of an acrylic plate having a diffusing property. The method of claim 11, The pitch of the discharge space partitioned by the partition wall is a backlight unit using a flat lamp, characterized in that 5 to 15mm.