KR100804833B1 - Device and method for operating flat fluorescent lamp preventing plasma channeling - Google Patents

Abstract

The present invention relates to a flat fluorescent lamp driving apparatus and a driving method, comprising: a first power supply connected to a first electrode of a flat fluorescent lamp and generating plasma in a lamp length direction inside a discharge space; And a second power source connected to the second electrode and the third electrode and generating a plasma in a thickness direction perpendicular to the lamp length direction.

Accordingly, the flat fluorescent lamp driving apparatus and driving method according to the present invention improve the uniformity of the plasma generated inside the discharge tube of the flat fluorescent lamp to prevent plasma channeling phenomenon in which the plasma is directed in a specific direction. And it can lower the discharge voltage, and provides the effect of improving the brightness and efficiency of the flat fluorescent lamp.

Flat Panel Fluorescent Lamp, Drive Unit, Discharge, Plasma Channeling, LCD Backlight

Description

Device and method for operating flat fluorescent lamp preventing plasma channeling}

Figure 1a is a perspective view showing a flat fluorescent lamp having a conventional partition structure,

FIG. 1B is a cross-sectional view illustrating a cross section of FIG. 1A taken along the X-Y direction,

1C is a cross-sectional view illustrating a cross section taken along the direction X′-Y ′ of FIG. 1A;

2 is a cross-sectional view showing a driving device of a flat fluorescent lamp according to a first embodiment of the present invention,

3 is a cross-sectional view showing a driving device of a flat fluorescent lamp according to a second embodiment of the present invention;

4A and 4B are sectional views showing the driving apparatus of the flat fluorescent lamp according to the third embodiment of the present invention;

5A and 5B are conceptual views conceptually illustrating a power supply of the flat fluorescent lamp driving apparatus according to the present invention.

<Description of the symbols for the main parts of the drawings>

1, 30, 300: flat fluorescent lamp

50, 500: flat fluorescent lamp driving device

10: lower glass 11: upper glass

20: partition 21: fluorescent layer

31, 31 ', 310, 310': first electrode

32, 320: second electrode 33, 330: third electrode

51: first power source 52: second power source

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving apparatus and a driving method of a flat fluorescent lamp capable of preventing plasma channeling, which is a phenomenon of plasma pulling in a discharge tube.

Flat fluorescent lamps are commonly used as a backlight light source for LCD panels such as LCD TVs and monitors. Recently, as the size of LCD panels increases, the importance of flat fluorescent lamps as a light source for backlights is increasing.

Such a flat fluorescent lamp has a problem in that plasma channeling, which is a phenomenon in which plasma is concentrated to a specific position, is severe in that the discharge space is large, and thus there is a problem in that a uniform discharge cannot be realized.

In addition, the flat fluorescent lamp is usually composed of a top glass and a bottom glass, the pressure difference between the inner space and the outer space of the flat fluorescent lamp, the need to have a component that supports the load of the top glass in the lamp interior space do.

In order to solve these problems, the conventional flat fluorescent lamp adopts a structure in which a partition wall is provided between the top glass and the bottom glass.

1A-1C show the structure of such a conventional flat fluorescent lamp.

As shown in FIG. 1A, the flat fluorescent lamp 1 includes a lower glass 10 and an upper glass 11 disposed at a position opposite to the lower glass 10, and each of the upper glass 11 and the lower glass 10. The edges are sealed to form the flat fluorescent lamp 1.

The lower glass 10 is provided with a plurality of partition walls 20 in the longitudinal direction of the flat fluorescent lamp 1, and the partition walls 20 serve as a pillar supporting the load of the upper glass 11. At the same time, a separate discharge space or discharge passage is formed between each partition wall 20.

In the flat fluorescent lamp 1, the fluorescent layer 21 is coated on the lower glass 10, the upper glass 11, and the partition wall 20, and a discharge gas is filled in the discharge space.

FIG. 1B illustrates a cross section of the flat fluorescent lamp 1 of FIG. 1A taken along the X-Y direction, and FIG. 1C illustrates a cross section of the flat fluorescent lamp 1 of FIG. 1A taken along the X'-Y 'direction. As shown in FIG. 1B, the cross section in the lamp longitudinal direction of the flat fluorescent lamp 1 has a rectangular shape formed by the upper glass 11, the lower glass 10, and the partition wall 20, and FIG. 1C. As shown in the cross section in the width direction of the flat fluorescent lamp 1 has a form in which a plurality of partition walls 20 divide the space formed by the upper plate glass 11 and the lower plate glass 10.

The discharge space of the flat fluorescent lamp 1 is formed in the space divided by the upper glass 11, the lower glass 10, and the partition wall 20, as shown in FIGS. 1B and 1C, and the partition wall 20 Thereby, a plurality of discharge passages are formed separately.

Such flat fluorescent lamps usually form electrodes at both ends of upper glass, and apply a high voltage to the electrodes to generate plasma from the discharge gas charged in the discharge space, and the ultraviolet rays generated from the plasma are upper, lower glass and partition walls. Light is generated by exciting the fluorescent layer applied to the film.

However, the driving method of the conventional flat fluorescent lamp 1 as described above is a method of generating a plasma by the discharge in the longitudinal direction of the lamp by connecting one power source to electrodes formed at both ends of the upper glass 11. Generated in the discharge space is not uniformly generated in the discharge space but limited in the longitudinal direction, thereby preventing the occurrence of plasma channeling. As a result, a uniform discharge cannot be obtained in the entire lamp. However, there was a problem that it is difficult to implement a fluorescent lamp of high brightness.

That is, in the case of a flat fluorescent lamp having no partition, such a plasma channeling phenomenon occurs severely in that the discharge space is large. To solve this problem, the flat fluorescent lamp 1 having the partition 20 is conventionally introduced. However, even when the flat fluorescent lamp 1 having the partition wall 20 drives the lamp in a manner of applying a voltage by a single power source as in the prior art, individual discharge passages divided by the partition walls 20 are provided. In the lamp, only the discharge in the longitudinal direction of the lamp is induced, so the plasma channeling phenomenon in each individual discharge path still remains, and there is also a problem that an imbalance occurs between discharges induced in the individual discharge paths.

On the other hand, flat fluorescent lamps have been developed that have a curved serpentine partition without forming the partition in a straight line. However, the plasma channeling phenomenon can be somewhat improved by forming the partition in this manner. In the case of the flat fluorescent lamp, the discharge voltage is increased due to the length of the discharge, and the problem of the increase in the discharge voltage becomes more serious in the case of the large-area flat fluorescent lamp. There is a problem that is practically difficult to use to prevent plasma channeling.

The present invention provides a driving apparatus for preventing a plasma phenomenon in which plasma is not uniformly generated in a discharge space of a flat fluorescent lamp, and improving a uniformity of plasma to implement a flat fluorescent lamp having high brightness and high efficiency. And a driving method.

In order to achieve the above object, a flat fluorescent lamp driving apparatus according to the present invention is a lower plate glass, the upper plate glass disposed at a position facing the lower plate glass, the discharge space formed between the lower plate glass and the upper plate glass, the upper plate glass An apparatus for driving a flat fluorescent lamp comprising a pair of first electrodes formed at both ends of a second electrode, and a second electrode formed on the lower glass, the first power source connected to the first electrode and the second electrode. And a second power source connected thereto, wherein the direction of the plasma generated by the first power source and the direction of the plasma generated by the second power source are perpendicular to each other.

Another flat plate fluorescent lamp driving apparatus according to the present invention is characterized in that the first electrode and the second electrode is characterized in that driving the flat plate fluorescent lamp is formed on the lower plate glass.

In addition, the flat fluorescent lamp driving apparatus according to the present invention may drive a flat fluorescent lamp having a plurality of partitions formed between the top glass and the bottom glass, the third electrode formed on the top glass at intervals from both ends of the top glass; The flat fluorescent lamp provided can also be driven. At this time, it is preferable that a 3rd electrode is a transparent electrode, a mesh type electrode, or a spiral electrode.

Meanwhile, in the flat fluorescent lamp driving apparatus according to the present invention, when the flat fluorescent lamp includes a third electrode, a second power source is connected to the second electrode and the third electrode to generate plasma.

The flat fluorescent lamp driving apparatus according to the present invention discharges the inside of the lamp by driving the lamp by applying power so that the direction of the plasma generated by the first power source and the direction of the plasma generated by the second power source are perpendicular to each other. Plasma is uniformly generated in the space, thereby preventing the plasma channeling phenomenon and providing a high brightness and high efficiency flat fluorescent lamp.

In addition, the flat fluorescent lamp driving apparatus according to the present invention can drive the flat fluorescent lamp with a lower discharge voltage than the conventional driving apparatus by driving the flat fluorescent lamp using two power sources.

Meanwhile, the flat fluorescent lamp driving apparatus according to the present invention may be an internal electrode formed inside the discharge space of the first to third electrodes of the driven flat fluorescent lamp, or may be an external electrode formed outside the discharge space. The second power source has at least one transformer, and the secondary coil of each transformer is preferably connected to the first and second electrodes or the first to third electrodes.

In the flat fluorescent lamp driving apparatus according to the present invention, at least one of the driving voltage, the driving current, the driving frequency, the waveform, the oscillation method, and the switching method of the first power supply and the second power supply is preferably different from each other. The first and second power supplies each have two or more transformers, and the primary and secondary coils of each of the plurality of transformers of each power supply are connected in series or in parallel with each other, and the driving frequency of the first and second power supplies is several tens of kHz. It is preferable that it is to several MHz.

The flat fluorescent lamp driving method according to the present invention is characterized by driving a flat fluorescent lamp using the flat fluorescent lamp device as described above.

Hereinafter, a flat fluorescent lamp driving apparatus and a driving method according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a view showing an embodiment of an electrode form and a driving device of a flat fluorescent lamp according to the present invention.

The configuration of the flat fluorescent lamp 30 shown in FIG. 2 is the same as the flat fluorescent lamp 1 described in FIG. 1 except for the configuration of the electrode, and a description thereof will be omitted.

 Meanwhile, as shown in FIG. 2, electrodes are formed in the flat fluorescent lamp 30 to apply a voltage to drive the flat fluorescent lamp 30. A pair of first electrodes 31 and 31 ′ are formed at both ends of the upper glass 11. It is formed in the form of a strip having a constant width, and the second electrode 32 in the form of a surface electrode is formed on the lower surface of the lower plate 10. In the exemplary embodiment shown in FIG. 2, both the first and second electrodes have the form of external electrodes, but may be internal electrodes formed in the discharge space.

The driving device 50 of the flat fluorescent lamp includes a first power source 51 and a second power source 52, and the first power source 51 is electrically connected to the first electrodes 31 and 31 ′. The second power source 52 is electrically connected to the second electrode 32.

The first and second power sources 51 and 52 are provided with one or more transformers, and FIGS. 5A and 5B are conceptual views illustrating these power sources conceptually.

As shown in Figs. 5A and 5B, the first power source 51 is composed of a primary coil and a secondary coil connected to a power source having a V1 value, and the secondary coil is applied with the same voltage having different polarities at both ends. The middle part is grounded, and both ends are electrically connected to the pair of first electrodes 31 and 31 ', respectively.

On the other hand, the second power source 52 is composed of a primary coil and a secondary coil connected to a power source having a value of V2, one end of the secondary coil is grounded, the other end is electrically connected to the second electrode 32 The same voltage is alternately applied to the second external electrode 32 having the opposite polarity.

The first and second power supplies may be configured with a plurality of transformers as shown in FIGS. 5A and 5B. Thus, when the first and second power supplies include a plurality of transformers, the respective power supplies In the transformers, the primary and secondary coils may be used in series or in parallel, respectively.

Thus, when a plurality of transformers are connected in series or in parallel to form a power supply, the amount of heat generated by the power supply device can be reduced, and the driving of the flat fluorescent lamp can be more easily controlled.

When the first power source 51 applies a voltage to the first electrodes 31 and 31 ′, an electric field is formed in the longitudinal direction of the flat fluorescent lamp, that is, in the direction of the individual discharge passage divided by the partition wall 20. Accordingly, plasma is generated in the direction of the discharge passage of the lamp. In addition, when the second power source 52 applies a voltage to the second electrode 32, an electric field is formed in a thickness direction perpendicular to the length direction of the flat fluorescent lamp, and thus plasma is generated in the thickness direction of the lamp. .

As described above, the driving apparatus 50 of the flat fluorescent lamp according to the present invention simultaneously generates plasma in the direction of the discharge passage of the lamp and the direction perpendicular thereto by using the first and second power sources 51 and 52. Plasma is uniformly generated in each discharge passage of 30), and the occurrence of the plasma channeling phenomenon, which is a phenomenon of being pulled out of the plasma, is prevented.

In addition, the voltage V2 applied to the second power source easily generates a plasma from the lower glass to the upper glass direction even at a lower voltage value than the conventional one. Thus, the voltage V1 applied to the first power source also uses a conventional power source. In the driving apparatus, the driving device can have a lower value than the voltage value applied in the discharge passage direction.

As described above, the flat fluorescent lamp driving apparatus according to the present invention drives the flat fluorescent lamp at a low voltage, thereby improving the ease of generating and maintaining the plasma and improving the discharge efficiency.

FIG. 3 shows another embodiment of a flat fluorescent lamp driving apparatus according to the present invention. The configuration of the driving apparatus 50 itself is similar to that of the driving apparatus 50 shown in FIG. The configuration of the electrodes to which the first and second power sources 51 and 52 are connected is different from the apparatus shown in FIG.

As shown in FIG. 3, the pair of first electrodes 310 and 310 ′ is different from that of the lower plate glass 10 unlike the pair of first electrodes 31 and 31 ′ of the flat fluorescent lamp shown in FIG. 2. It is formed in a band shape having a predetermined width at both ends. That is, both the first electrodes 310 and 310 'and the second electrode 320 of the flat fluorescent lamp 300 are provided on the lower glass 10.

By forming the first electrodes 310 and 310 ′ on the lower glass 10 as described above, the light emitted to the outside by the fluorescent light emission of the lamp is prevented from being blocked by the first electrode.

The driving method of the lamp is the same as that of the driving device 50 shown in FIG. 2, and the plasma is generated in the discharge passage direction of the lamp by the first power source 51 connected to the first electrodes 310 and 310 ′. The plasma is generated in the thickness direction perpendicular to the direction of the discharge passage of the lamp by the second power source 52 connected to the second electrode 320.

On the other hand, in this case, since the first 310, 310 'and the second electrode 320 are all formed in the lower glass 10, the gap between them is too close. Since a leakage phenomenon may occur, the second electrode 320 may be formed at an appropriate interval from the first electrodes 310 and 310 '. Accordingly, the length of the second electrode 320 shown in FIG. 3 in the discharge passage direction of the lamp is shorter than that of the second electrode 32 shown in FIG. 2.

4A and 4B show another embodiment of a flat fluorescent lamp driving apparatus according to the present invention, wherein the third electrodes 33 and 330 are formed on the outer surface of the top glass 11 of the flat fluorescent lamps 30 and 300. In addition, a driving device 500 for driving the formed flat fluorescent lamps 30 and 300 is shown.

FIG. 4A is a configuration in which the third electrode 33 is formed in the flat fluorescent lamp 30 of FIG. 2, and FIG. 4B is a third electrode in the flat fluorescent lamp 300 of FIG. 3. A configuration in which 330 is formed is shown.

The lamp driving device 500 is connected to the first power source 51, the second electrode 32, 320, and the third electrode 33, 330, which are connected to the first electrodes 31, 31 ′, 310, 310 ′. A second power source 52 is provided.

Like the first power source shown in Figs. 2 and 3, the first power source 51 generates plasma in the direction of the discharge path of the lamp inside the individual discharge path, and the second power source 52 is also perpendicular to the lamp discharge path direction. Generate a plasma. In this case, the second power source 52 is not a power source shown in FIG. 5B, but a power source shown in FIG. 5A, and both ends of the secondary coils of the transformer provided in the second power source 52 are respectively formed. The voltage is applied to the second electrodes 32 and 320 and the third electrodes 33 and 330.

On the other hand, the third electrode (33, 330) is formed on the outer surface of the upper glass 11, the result is located on the path of the light is emitted to the outside of the lamp, the problem that can block the light by the fluorescent light emission As such, an electrode of a type that can prevent or minimize the blocking of light is used. In general, it is preferable to use an electrode having a form capable of minimizing light blocking, such as a mesh type electrode or an electrode using a spiral conductive material, or to use a transparent electrode form using a conductive transparent material.

As the first and second power sources used in the flat fluorescent lamp driving apparatus according to the present invention, an apparatus such as an inverter or a converter having a transformer as shown in FIGS. 5A and 5B may be used, and generally, the first and second power sources are used. The output voltages of the two supplies are set differently.

Of course, the output voltages of the first and second power supplies are not limited to having different values, and as part of the circuits of the first power supply and the second power supply are used in common, the output voltage, the driving current, and the driving power of each power supply are shared. The frequency, the waveform, and the like can also be selectively used.

In addition, the driving frequency of the power source provided in the flat panel fluorescent lamp driving apparatus according to the present invention can also be used in the high frequency band of several tens of kHz band.

On the other hand, in the embodiments of the flat fluorescent lamp driving apparatus according to the present invention shown in Figures 2 to 4b described for the drive device for driving a flat fluorescent lamp having a partition therein, according to the present invention The driving device is not limited thereto, and a flat fluorescent lamp having no partition wall therein, a flat fluorescent lamp having a modified partition structure by casting a glass plate, a flat plate lamp having a modified partition structure by casting a glass plate, and an upper plate It is also used for driving all flat lamps developed to date such as flat lamps for discharging.

Flat lamps that are not provided with a partition wall are mainly used as a backlight for a small automobile navigator. When the flat lamp is driven by the flat lamp driving device according to the present invention, as long as the flat lamps are installed at both ends of the flat glass At the same time as the discharge between the pair of electrodes, the discharge between the upper and lower glass plates is induced together.

The present invention can be equally applied to a flat lamp having a modified partition wall structure having a partition wall shape by casting a glass plate to be a top glass, and in the case of a flat lamp inducing discharge between the top and bottom plates, a pair of both ends of the flat plate By installing the electrodes, the discharge in the direction perpendicular to the discharge direction of the upper and lower plates is simultaneously induced.

In the case of a flat lamp which induces a discharge between a plurality of electrodes installed in parallel with a lower plate developed by OSRAM Co., Ltd., another additional discharge is induced in a direction perpendicular to the discharge direction between the electrodes. The flat fluorescent lamp driving apparatus according to the present invention can be used.

According to the flat fluorescent lamp driving apparatus according to the present invention as described above, the plasma generated in the discharge space of the lamp in driving the flat fluorescent lamp by generating a plasma in the lamp longitudinal direction and a direction perpendicular thereto by two power sources, respectively The uniformity of the (uniformity) is improved, thereby preventing the plasma channeling phenomenon that the plasma is concentrated in a specific direction, and provides the effect of improving the brightness of the flat fluorescent lamp.

In addition, the use of two power supplies to drive the flat fluorescent lamp lowers the discharge voltage and provides the effect of improving the discharge efficiency.

Claims (19)

Lower glass, upper glass arranged at a position facing the lower glass, a discharge space formed between the lower glass and the upper glass, a pair of first external electrodes formed at both ends of the upper glass, and the lower glass An apparatus for driving a flat fluorescent lamp comprising a second external electrode formed on, A first power source connected to the first external electrode; And And a second power source connected to the second external electrode. And a direction of the plasma generated by the first power source and a direction of the plasma generated by the second power source are perpendicular to each other. Lower glass, upper glass arranged at a position facing the lower glass, a discharge space formed between the lower glass and the upper glass, a pair of first external electrodes formed at both ends of the lower glass, and the pair An apparatus for driving a flat fluorescent lamp comprising a second external electrode formed on the lower glass at a distance from the first external electrode of, A first power source connected to the first external electrode; And And a second power source connected to the second external electrode. And a direction of the plasma generated by the first power source and a direction of the plasma generated by the second power source are perpendicular to each other. The flat fluorescent lamp driving apparatus according to claim 1 or 2, wherein the flat fluorescent lamp further comprises a plurality of partitions formed between the bottom glass and the top glass.  3. The power supply of claim 1 or 2, wherein each of the first power supply and the second power supply has at least one transformer, and the pair of first external electrodes of the secondary coil of the at least one transformer of the first power supply. And a second external electrode connected to one end of a secondary coil of at least one transformer of the second power source.  The flat fluorescent lamp driving apparatus of claim 4, wherein the first power supply and the second power supply are different from each other in at least one of a driving voltage, a driving current, a driving frequency, a waveform, an oscillation method, and a switching method.  The flat plate of claim 4, wherein each of the first and second power sources includes at least two transformers, and the primary coil and the secondary coil of each of the at least two transformers are connected in series or in parallel with each other. Fluorescent lamp driving device. delete According to claim 1 or 2, wherein the flat fluorescent lamp further comprises a third external electrode formed at intervals from both ends of the upper glass, And the second power source is connected to the second external electrode and the third external electrode to generate plasma in a direction perpendicular to the direction of the plasma generated by the first power source. The flat fluorescent lamp driving apparatus of claim 8, wherein the flat fluorescent lamp further comprises a plurality of partitions formed between the bottom glass and the top glass. The method of claim 8, wherein the first power supply and the second power supply each has at least one transformer, the first external electrode is connected to both ends of the secondary coil of the at least one transformer of the first power source, And second and third external electrodes are connected to both ends of a secondary coil of at least one transformer of the second power source. The flat fluorescent lamp driving device of claim 8, wherein the third external electrode is a transparent electrode, a mesh electrode, or a spiral electrode.  The flat fluorescent lamp driving apparatus of claim 8, wherein the first power supply and the second power supply are different from each other in at least one of a driving voltage, a driving current, a driving frequency, a waveform, an oscillation method, and a switching method. The flat panel of claim 8, wherein each of the first and second power supplies includes at least two transformers, and the primary coil and the secondary coil of each of the at least two transformers are connected in series or in parallel with each other. Fluorescent lamp driving device. delete The flat fluorescent lamp driving apparatus of claim 1 or 2, wherein the first and second external electrodes are external electrodes formed outside the discharge space. delete The flat fluorescent lamp driving apparatus of claim 8, wherein the first to third external electrodes are external electrodes formed outside the discharge space. delete A flat fluorescent lamp driving method, comprising driving a flat fluorescent lamp using the drive device according to claim 1.

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