JP2002008408A - Fluorescent lamp, backlight, and operating method for backlight - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescent lamp having uniform luminance, which is thin and capable of operating with a low frequency, a backlight having high luminance and efficiency, and the operating method for the backlight. SOLUTION: In a backlight (20), a plurality of fluorescent lamps (22) having external electrodes (23) formed in both ends of glass tubes, are arranged in outward portions in a light guide plate. Otherwise AC power is applied from the outside to the fluorescent lamps arranged between a reflector (21) and a diffuser (25). Otherwise, the fluorescent lamps are arranged in an appointed interval between upper and lower substrates which a phosphor layer is applied to, and the electrode which AC power is applied to, is formed on outer or inner surfaces in the upper and lower substrates. The fluorescent lamp can operate in connected with one power supply by a parallel connecting method, and serves as a bulkhead and is self-luminous, thereby achieving uniform luminance and thinning of the backlight. The backlight operates with the low frequency by a squarewave from a switching inverter, thereby achieving high luminance and efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent lamp including an external electrode, a backlight using the same, and a method of driving the same, and more particularly, to an external electrode fluorescent lamp in which external electrodes are provided at both ends of an electrodeless fluorescent lamp. And a backlight driving method for electrically connecting a plurality of fluorescent lamps.

[0002]

2. Related Art In general, flat panel display devices are roughly classified into a self-luminous type and a passive type. The self-luminous type includes a flat panel cathode ray tube, a plasma display panel, an electroluminescent element, a fluorescent display, and a light emitting diode, and the passive type includes a liquid crystal display.

The liquid crystal display is a passive flat panel display device which cannot form an image by self-emission and forms an image by externally incident light, and therefore has a problem that it is difficult to see an image in a dark place. In order to solve such a problem, a backlight is provided on the back of the liquid crystal display to irradiate light so that an image can be viewed even in a dark place. The general requirements for backlights are high brightness, high efficiency, uniform brightness, long life, low profile,
Low weight, low price, etc. In the case of notebook personal computers, high-efficiency long-life lamps are required to reduce power consumption, and high luminance is required for backlights for monitors and TVs.

As a backlight, a cold cathode fluorescent lamp (C
A method of disposing a CFL) and a flat panel fluorescent lamp method in which upper and lower substrates coated with a phosphor are assembled are widely used. The CCFL can be classified into an edge light type using a light guide plate (plastic light guide) and a direct light type arranged in a plane according to the arrangement of a light source on a display surface. However, the CCFL according to the prior art is 30,000.
Since the lamp operates at a high luminance of about 0 cd / m ² , the life of the lamp becomes a problem. In particular, in the edge light method, the CCFL emits light with high luminance, but the luminance of the panel is low.
It is not suitable for panels for large screens. In the direct light type, CCFLs cannot be connected in parallel and driven by a single inverter, and the number of CCFLs arranged on a plane is limited to optimize the brightness of the panel.
The arrangement interval between CCFLs increases. For this reason, a reflector having a special structure is required, and the distance between the diffuser and the lamp is increased in order to obtain uniform brightness, so that the panel becomes thicker.

In the flat panel fluorescent lamp system, since the internal pressure of the upper and lower substrates to be assembled is lower than the atmospheric pressure,
In order to prevent breakage of the glass substrate, the thickness of the substrate must be made sufficiently large, and as a result, there is a disadvantage that the weight becomes heavy. In addition, in the flat panel fluorescent lamp system, a ball-shaped or cross-shaped spacer and a partition are provided between the upper and lower substrates in order to increase the area of the screen. The problem of heat generation with efficiency is exacerbated. When a partition is used, the stripe pattern of the partition appears on the screen, so that uniformity of luminance cannot be maintained.

Accordingly, it is necessary to develop a backlight which guarantees high brightness and high efficiency of a liquid crystal display, which has been increasing in size, and which has a long life and a light weight. SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide an external electrode fluorescent lamp in which an external electrode is formed on an electrodeless glass tube, which is superposed and driven by a parallel connection method. It is an object of the present invention to provide a backlight including a possible external electrode fluorescent lamp and a driving method thereof.

[0007] The electrode structure of the conventional external electrode fluorescent lamp (EEFL) is various, such as a belt-shaped one, a metal cap joined to a glass tube, and a glass tube whose both ends are inflated. (FIG. 15). EEFL is CCF
L has a longer life than L, but generally EEFL is several MHz
EMI by high frequency to obtain high brightness by high frequency driving
There was a problem, a problem of low efficiency, and a problem of the high-frequency power supply device, and it could not be adopted as a light source of the backlight.

FIG. 15 illustrates a conventional embodiment of an external electrode fluorescent lamp to be compared with the present invention. FIG.
(A) is a belt-shaped external electrode, in which a plurality of pairs of belt electrodes are installed in a glass tube cylinder, and the length of each belt electrode is reduced so that it can be driven by a high frequency of MHz or more. I have. Belt shape E in FIG.
The EFL has an advantage that an electrode can be provided in a middle portion of the glass because the electrode is provided in the cylinder of the glass tube. Recently, a backlight is constructed by a method in which a belt-shaped external electrode fluorescent lamp is disposed directly below a reflector, and the backlight is driven at a high frequency of several MHz to achieve a high luminance of several 10,000 cd / m ^2. Of the external electrode fluorescent lamp was obtained. In particular, when performing such high-frequency driving, if the length of the glass tube is long, it is helpful to install a belt-like electrode in the middle part of the glass tube, but this is necessary to make the panel uniform and thin. However, there is a problem in realizing uniformity and thinning because the brightness of the electrode portion is reduced. Further, driving by high frequency basically has a problem of electromagnetic interference (EMI), a problem of low efficiency, and a problem that a high-frequency power supply device cannot be miniaturized. This is described in Japanese Patent Laid-Open No. 60-25 / 1985.
No. 488 (February 13, 1985), Korean Patent Application No. 10
-1999-0052964 and Japanese Patent Application No. 10-
No. 336926 (November 27, 1998).

FIG. 15B shows a form in which a metal capsule is joined to the tip of a glass tube, and is characterized in that a ferroelectric substance is applied inside the metal capsule. This is disclosed in U.S. Pat. No. 2,624,858 (June 6, 1953). The method shown in FIG. 15B is adopted when the diameter of the glass tube is large. That is, when the thickness of the glass tube is thick,
Because there is a capacitive voltage drop due to the glass tube itself,
Although such a method can be adopted, the joint portion is easily damaged due to a difference in thermal expansion coefficient between the glass tube and the metal. However, in the case of a fine tube having an outer diameter of 2.6 mm and a thickness of 0.5 mm or less, such as a cold cathode tube generally used in an existing backlight, the electric capacity due to the glass thickness is reduced. Since the voltage drop is small, there is no reason to adopt a method of joining the metal capsule and the glass tube.

FIGS. 15C and 15D show a structure in which both ends of the glass tube form a space wider than the intermediate portion for the purpose of high luminance and high efficiency. This is disclosed in U.S. Pat. No. 1,612,387 (November 28, 1926) and U.S. Pat. No. 1,676,790 (July 10, 1928). When the space at both ends of the glass tube is widened as described above, the brightness and efficiency of the lamp increase, but it is difficult to adopt such a structure for a thin glass tube.

The external electrode of the present invention is applied to a fine tube having an outer diameter of several millimeters, and there are various types based on an end cap type electrode enclosing both ends of a sealed glass tube. An end-cap type electrode that wraps a cylindrical surface including the edge surfaces at both ends of a glass tube is advantageous in realizing high brightness and high efficiency compared to a belt-shaped electrode that simply wraps only a cylindrical surface. According to the experimental results of the present applicant, higher luminance is obtained as the electrode length in the glass tube direction is longer. However, if the length of the electrode is long, the effective light emitting surface is reduced, and the edge portion where the panel does not emit light is wide because the electrode portion is wide when employed in a backlight. Therefore, from the viewpoint that the length of the electrode can be shortened as much as possible, the end cap type is more advantageous than the belt type. In the present invention, there is no particular reason for forming the belt-shaped electrode in the middle portion in the glass tube direction. On the other hand, the method to widen the space at both ends of the glass tube,
It is difficult to adopt in the manufacturing process of micro tubes. In the present invention, the electrode length at both ends of the glass tube is predetermined, and when adopted as a backlight light source of an edge light type or a direct light type, unlike a straight metal capsule, a method of bending the tip of the glass tube is employed. By doing so, the length of both electrodes is appropriately selected to minimize the non-light-emitting edge region, thereby obtaining high luminance and high efficiency.

Another aspect of the present invention provides a backlight driving method employing an external electrode fluorescent lamp, and in particular, a driving circuit for realizing uniformity of luminance, high luminance and high efficiency of a large-area backlight. Is provided. A known example of driving a cold cathode fluorescent lamp employed in a conventional backlight is disclosed in Korean Patent Publication No. 1998-02.
No. 8921 is well disclosed.

FIG. 16 is a circuit diagram showing a CCFL drive IC for an LCD panel and peripheral circuits according to the known example, and shows a lamp drive IC 10 having a plurality of input / output pins.
0 and main power circuit section 120 with half-bridge circuit
And a lamp 140. On the other hand, the lamp driving IC
100 is a first pin 1 connected to an input voltage terminal, a second pin 2 connected to a predetermined minimum frequency terminal, a third pin 3 connected to a predetermined maximum frequency terminal, and a ground voltage terminal. A connected fourth pin 4, a fifth pin 5 connected to a feedback voltage terminal, and a sixth pin 6 connected to a predetermined comparison terminal.
And a seventh pin 7 connected to a predetermined internal high-voltage terminal, and an eighth pin 8 connected to a predetermined external control signal terminal and for turning on and off the IC circuit.

Further, the main power circuit section 120 is constituted by a half-bridge circuit which responds to an output signal of a predetermined pin of the lamp driving IC 100 and comprises a plurality of passive elements. Power circuit section 120
Is configured to be driven in accordance with a predetermined output signal. The CCFL adopting the LCD backlight as in the above-mentioned known example is supplied with power by an inverter. The principle of such an inverter is to use a step-up transformer to obtain a high voltage necessary for starting and maintaining the discharge of the CCFL using a low AC voltage of several tens KHz obtained from an LC resonance type inverter. At this time, the output waveform of the inverter is in the form of a sine wave. Such an LC resonance type inverter has advantages that the device is relatively simple and the efficiency is high. On the other hand, CCFLs cannot be connected in parallel and driven by one inverter. Therefore, a backlight combined with a light guide plate employing CCFLs or a direct type backlight requires an inverter corresponding to the number of CCFLs.

On the other hand, a direct-light type backlight in which a plurality of external electrode fluorescent lamps are arranged in an edge region of a light guide plate (plastic light guide) or a plane of the light guide plate is driven by one inverter by mutually connecting EEFLs in parallel. It is possible. The reason is that since the EEFL electrode is not exposed to the discharge space, the actual current does not flow into the electrode, the wall charges collect on the electrode portions on both sides, and the discharge at both ends of the lamp is interrupted by the formation of a reverse voltage due to the wall charges. Then, after another lamp is discharged and wall charges are formed in the same manner, the other lamps are sequentially discharged, so that a plurality of lamps emit light by one inverter. But CC
The method of driving the EEFL using an inverter that outputs a sine wave used for driving the FL cannot control wall charges effectively, so that the brightness and efficiency are extremely lower than those of a single tube EEFL. . In addition, when a plurality of EEFLs are connected in parallel and driven by such an inverter, the high voltage application time in one cycle is limited, so that the EEFL that emits light is emitted.
The number of L is limited, and therefore, in the case of a backlight in which a large number of EEFLs are arranged on a plane, uniformity of luminance cannot be realized.

As described above, tens of K driving the CCFL
Since the EEFL cannot be driven by a low-frequency LC resonance type inverter, it has been difficult to realize a backlight employing the EEFL. In addition, the conventional E by a high frequency of several MHz
The driving of the EFL is difficult to overcome the problems of EMI, low efficiency, and downsizing of the high frequency power supply.

[0017]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide an external electrode fluorescent lamp in which an external electrode is formed in an electrodeless glass tube or an external electrode outside of a light guide plate. To provide a backlight including a fluorescent lamp that can be driven by being placed in one side or overlapping on a reflector and connected in parallel, and achieving uniform brightness, high brightness, and high efficiency of the backlight It is intended to provide a driving method for performing the above.

[0018]

SUMMARY OF THE INVENTION The present invention provides a 100 KHz
The following low-frequency driving realizes a high-luminance and high-efficiency external electrode fluorescent lamp and constitutes a backlight including the same. Generally, a fluorescent lamp is driven by an LC resonance type inverter, but in the present invention, by driving the external electrode fluorescent lamp by a switching inverter circuit that outputs a rectangular pulse wave, it is more than twice as large as the LC resonance type inverter drive. Brightness and efficiency have been achieved. That is, LCD
-Several tens of thousands in a single tube of an external electrode fluorescent lamp with an outer diameter of 2.6 mm commonly used for backlights
High luminance of cd / m ² and high efficiency of several tens of lm / W or more were achieved. In particular, according to the experimental results of the applicant, EEFL achieved higher efficiency than CCFL at a luminance of about 10,000 cd / m ² . Therefore, it is useful to employ the EEFL as a light source of the backlight if the EEFL is operated at the luminance having the highest efficiency by utilizing such characteristics of the EEFL. In particular, the present invention
Compared to CCFLs, they have a longer life, are easier to manufacture an electrodeless lamp, and have the advantage that they can be driven by a single inverter by connecting a plurality of external electrode fluorescent lamps in parallel.

In the present invention, the external electrode fluorescent lamp is CC
Like the FL, it can be used in an edge light system and a direct light system. Another object of the present invention is to provide a light-emitting partition type fluorescent lamp in which a plurality of fluorescent lamps on which external electrodes are formed are arranged between upper and lower substrates on which phosphor layers are formed and used as partitions. Another object of the present invention is to provide a backlight employing such a fluorescent lamp. The present invention has been conceived to solve the problem of driving a backlight employing an external electrode fluorescent lamp and the problem of driving a large-area backlight manufactured by arranging a plurality of backlights on a plane.
It is an object of the present invention to provide a driving method for realizing high luminance uniformity and high luminance and high efficiency of a large-area backlight.

In order to achieve the above object, a fluorescent lamp according to the present invention comprises a glass tube in which discharge gas is injected, a phosphor layer is applied to an inner peripheral wall and both ends are sealed, and an L-shaped, C-shaped, An end cap type external electrode formed in a spiral shape or a bent shape such as a wave shape and wrapping both ends of the glass tube is provided. The backlight of the present invention includes a light guide plate, an external electrode fluorescent lamp provided around the light guide plate, and a switching inverter circuit connected to the external electrode and applying a rectangular wave signal of 100 KHz or less. The external electrode fluorescent lamp includes a glass tube in which a discharge gas is injected, a phosphor layer is coated on an inner peripheral wall, and both ends of the glass tube are sealed, and an end cap type external electrode surrounding both ends of the glass tube. The external electrode fluorescent lamp includes a plurality of external electrode fluorescent lamps connected in parallel.

A backlight according to another aspect of the present invention includes a plurality of external electrode fluorescent lamps connected in parallel, and a rectangular wave of 100 KHz or less connected to an electrode connecting line of the plurality of external electrode fluorescent lamps. A switching inverter for applying a signal. The external electrode fluorescent lamp includes a glass tube in which a discharge gas is injected, a phosphor layer is coated on an inner peripheral wall, and both ends are sealed, and an end cap type external electrode surrounding both ends of the glass tube. The backlight further includes a reflector, and a light guide plate having a diffusion groove in which the external electrode fluorescent lamp is installed, wherein the reflector has a wavy shape surrounding the external electrode fluorescent lamp, and the external electrode fluorescent lamp. Are arranged along a triangular saw-shaped groove.

In a backlight according to still another aspect of the present invention, a glass tube in which a discharge gas is injected, a phosphor layer is applied to an inner peripheral wall and both ends are sealed, and a plurality of the glass tubes are connected to each other. A socket-like multiple capsule electrode structure having a plurality of external electrodes in parallel, a reflector, a diffusion plate, and 100K connected to the socket-like multiple capsule electrode structure.
And a switching inverter for applying a rectangular wave signal of less than Hz. The external electrode fluorescent lamp includes a glass tube in which a discharge gas is injected, a phosphor layer is coated on an inner peripheral wall, and both ends are sealed, and a cap-shaped external electrode that surrounds both ends of the glass tube.

A backlight according to another aspect of the present invention includes an external electrode fluorescent lamp, a reflective plate, a diffuser, and an external electrode fluorescent lamp arranged so that external electrode portions overlap each other in the transverse direction to the middle of the panel. 100KH connected to the electrode
a switching inverter for applying a rectangular wave signal of z or less. The external electrode fluorescent lamp includes a glass tube in which a discharge gas is injected and a phosphor layer is applied to an inner peripheral wall and both ends of the glass tube are sealed, and a cap-shaped external electrode wrapping both ends of the glass tube. Is a conductive transparent electrode material.

A backlight according to another aspect of the present invention has an upper substrate having an upper phosphor layer applied to a lower surface thereof, and a lower phosphor layer provided on an upper surface thereof so as to face the upper substrate. A lower substrate, an edge support interposed between the upper substrate and the lower substrate, and hermetically sealing the two substrates; and an external electrode fluorescent lamp installed at a predetermined distance above the lower substrate. And electrodes respectively formed on both outer surfaces of the upper and lower substrates and connected to an electrode connection line to which an AC type power supply is applied, and a switching inverter connected to the electrodes and applying a rectangular wave signal of 100 KHz or less. And a discharge gas injected into the internal space when the upper and lower substrates are sealed.
The external electrode fluorescent lamp is a glass tube in which a discharge gas is injected, a phosphor layer is applied to an inner peripheral wall and both ends are sealed,
Including a capsule-shaped external electrode surrounding both ends of the glass tube,
The external electrode fluorescent lamp is not connected to the electrode and is installed in a floating state inside the upper substrate and the lower substrate.

A backlight according to another aspect of the present invention includes an upper substrate having a lower surface coated with an upper phosphor layer;
A lower substrate disposed opposite to the upper substrate and having an upper surface coated with a lower phosphor layer, an edge support base interposed between the upper substrate and the lower substrate to hermetically seal both substrates, A multi-layer structure in which an upper plate electrode and a lower plate electrode each having a surface on which a ferroelectric substance is applied and a groove for coupling a glass tube is formed at a predetermined interval is coupled to each other and disposed at both ends of a lower substrate inside the flat panel. A capsule-shaped electrode structure, glass tubes respectively connected in parallel to grooves of the multi-capsule electrode structure provided at both ends of a lower substrate inside the flat panel, and connected to the multi-capsule electrode structure Electrode connection line, and 10
A switching inverter for applying a rectangular wave signal of 0 KHz or less and a discharge gas injected into an internal space when the upper substrate and the lower substrate are sealed. A discharge gas is injected into the glass tube, a phosphor layer is applied to an inner peripheral wall, and both ends are sealed.

The switching inverter forms a bridge circuit with the first, second, third and fourth FETs. DC is applied to the drains of the first and third FETs, the sources of the second and fourth FETs are grounded,
The source of the first FET is connected to the drain of the second FET, the source of the third FET is connected to the drain of the fourth FET, and the connection point of the first and second FETs is A step-up transformer is connected between the connection point of the third and fourth FETs. The square wave output from the switching inverter includes overshooting.

[0027] A driving method for driving a backlight in which a plurality of outer tube electrode fluorescent lamps are connected in parallel includes a step of dividing the plurality of fluorescent lamps into a plurality of predetermined regions; Connecting the external electrodes of the fluorescent lamps to the same electrode connection lines, connecting the switching inverters outputting rectangular waves to the electrode connection lines connected to the regions, respectively, and the same gates for the switching inverters. Applying a signal, and supplying the inverting rectangular wave to the electrode connection line in response to the gate signal.

The switching inverter forms a bridge circuit with the first, second, third and fourth FETs. DC is applied to the drains of the first and third FETs, and the sources of the second and fourth FETs are grounded.
The source of the third FET is connected to the drain of the second FET, the source of the third FET is connected to the drain of the fourth FET, and the connection point of the first and second FETs is connected to the third FET.
And a connection point of the fourth FET and a step-up transformer.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a fluorescent lamp according to an embodiment of the present invention and a backlight employing the same will be described in detail with reference to the accompanying drawings. FIG. 1 illustrates a fluorescent lamp 10 according to an example of the present invention. Referring to the drawings, the fluorescent lamp 10 has a cylindrical glass tube 11.
including. Both ends of the glass tube 11 are sealed after the phosphor 12 is applied and a mixed discharge gas such as an inert gas or mercury is injected. The cross section of the glass tube 11 is not limited to a circle, but may be a flat elliptical circle or a multi-cylinder shape bent integrally.

In FIG. 1A, end cap-shaped external electrodes 13 are formed on both ends of a linear outer peripheral surface at both ends of a sealed glass tube 11, respectively. According to the experimental results of the applicant, the length of the cap of the external electrode portion should be sufficiently ensured to achieve high brightness and high efficiency. Therefore, an external electrode is formed by lengthening the cap electrode or bending both ends of the glass tube. At this time, there are various shapes such as an L-shape, a C-shape, a spiral shape, and a waveform as shown in FIG. Such a bent external electrode may be formed by directly bending the end portion of a straight glass tube, or separately manufacturing a bent glass tube on which an electrode is installed, and applying both ends of the straight glass tube coated with a phosphor. It is manufactured by the method of joining to.

The external electrode 13 is formed of a conductive material, but has a shape that completely surrounds the end of the glass tube 11, and no phosphor is applied to the inside of the glass tube corresponding to the external electrode. A method for forming such an external electrode 13 is as follows.
There may be various methods such as a form of a cap made of a metal material, a method of attaching a metal tape, and a method of dipping both ends of the glass tube 11 into a metal solution. The external electrode 13 is preferably made of a conductive material having low electric resistance, such as aluminum, silver, and copper.

In the present invention, when the length of the glass tube is long, end caps are provided at both ends of the glass tube, but it is not necessary to provide a belt-like electrode at an intermediate portion of the glass tube. The reason for this is that the longer the glass tube and the longer the distance between both electrodes, the more advantageous the EEFL brightness and efficiency. Also,
The belt-shaped electrode is disadvantageous in terms of luminance and efficiency as compared with the end cap type electrode, and is disadvantageous in making the electrode thin because the luminance becomes non-uniform depending on the electrode portion installed in the middle of the glass.

On the other hand, the glass tube 11 is coated with a ferroelectric material on the inner side corresponding to the external electrode 13 or separately coated with a dielectric material in order to increase the life and the generation of secondary electrons. Can be adopted at both ends inside the glass tube that is hermetically sealed later. In addition to applying a ferroelectric, magnesium oxide, calcium oxide, or the like can be applied to serve as a protective film and facilitate electron emission.

FIG. 2 illustrates an edge light type backlight according to a first embodiment of the present invention. As shown, the EEFL can be arranged around the light guide plate in various ways. The external electrode fluorescent lamp of the present invention can be adopted in the edge light type similarly to the cold cathode fluorescent lamp because of the use of the end cap type electrode and the bent electrode structure as shown in FIG. This is because a high-brightness and high-efficiency lamp can be realized by the adopted driving method. The lamp of the present invention is installed at a plurality of edges on the light guide plate and is basically connected in parallel and driven by one inverter, but the lamps can be installed at both ends of the light guide plate and all edges. Also, a plurality of pieces can be provided at each end.

FIG. 3 shows an EEF according to a second embodiment of the present invention.
5 illustrates a light-type arrangement directly under L. The present embodiment is characterized in that EEFLs are connected in parallel and driven by a switching inverter to achieve high efficiency and uniformity of luminance. In the case of a fine tube having an outer diameter of 2.6 mm, the luminance is about 10%. High efficiency can be obtained at 2,000 cd / m ² . In the case of a high-luminance surface light source having a panel luminance of 10,000 cd / m ² or more due to the direct arrangement of the EEFL, a special reflector structure is used to make the lamp interval appropriate and to improve the reflectance. To achieve high efficiency backlight.

In principle, all lamps arranged on the reflector are connected in parallel and driven by a single inverter. The arrangement method is to arrange linear EEFLs at appropriate intervals as shown in FIG. 3 (a), to stand an L-shaped electrode on a plane as shown in FIG. 3 (b), or to form an L-shaped electrode as shown in FIG. The electrodes lie on a plane to minimize non-light emitting areas at the edges of the electrode portions.
FIG. 4A shows a system in which a long lamp is bent at the end of the panel and is arranged. Such a system is employed for the purpose of increasing the luminous efficiency of the lamp. As shown in FIG. 4B, a method of inserting an electrodeless lamp into a socket-type multiple capsule electrode structure can also be adopted.

FIG. 4C shows an arrangement of EEFLs for forming a very large backlight. In this case, a plurality of EEFLs are arranged in the longitudinal direction of the lamp, but in order to prevent a sharp decrease in luminance from the electrode portion, the electrode surface is coated with a reflector or the electrode itself is made of a transparent electrode material. Then, in order to compensate for the brightness decrease in the portion where the electrode portions of the lamp overlap, a reflector is additionally applied to the electrode surface in the middle of the panel, or the electrode located in the middle is formed of a conductive transparent electrode material, Minimize brightness reduction.

FIG. 5 shows a backlight employing an EEFL direct-type arrangement according to the second embodiment. Referring to the drawing, a reflector 21 is provided on the backlight 20, and a fluorescent lamp 22 is installed on an upper surface of the reflector 21. As described above, the fluorescent lamp 22 is an external electrode fluorescent lamp (EEFL) in which a phosphor is applied to the inner peripheral surface and external electrodes 23 made of a conductive material are formed at both ends of the outer peripheral surface. . The fluorescent lamp 22
In order to maintain the uniformity of the luminance, a plurality of are arranged on the upper surface of the reflection plate 21 at regular intervals and in close contact with each other.

In order to electrically connect the fluorescent lamps 22 to each other, the external electrodes 23 are electrically connected to each other, and the electrode connecting wires 24 are connected to the outermost external electrodes 23a, respectively. Extending from the outermost outer electrode. Thus, when an AC power supply is applied to the fluorescent lamps 22, all the fluorescent lamps 22 can be driven in a parallel manner.

A diffusion plate 25 is provided above the fluorescent lamp 22 so as to face the reflection plate 21. In order to prevent the image of the fluorescent lamp 22 from appearing, it is preferable to separate the diffusion plate from the fluorescent lamp 22 by an appropriate distance from the viewpoint of improving the uniformity of luminance. Here, the distance between the diffusion plate 25 and the fluorescent lamp 22 is the same as that of the fluorescent lamp 2.
Corresponding to a diameter of 2. For example, if the diameter of the fluorescent lamp 22 is 2.6 mm, the distance between the fluorescent lamp 22 and the diffusion plate 25 is about 2.6 mm. As a result, the minimum thickness is about 5.2m
m.

According to the experiment of the applicant, the outer diameter is 2.6 m.
The backlight 30 adopting the EEFL of m has a luminance of 10,000 cd / m ² or more and an efficiency of 50 lm / m ^2.
W or more, and no high heat was generated. In particular, EEFL
The longer the length of the panel in the lamp direction, the higher the brightness and the higher the efficiency. FIG.
9 shows a backlight according to a second embodiment of the present invention relating to the shape of an EFL and a reflector. FIG. 6A shows a case where the lamps are arranged at intervals of about the lamp diameter, and the EEFL is simply arranged on the plane reflector. In this case, the backlight intends to obtain a higher brightness than the brightness of the single lamp as shown in FIG. 6 (b), 7
7 (a) and FIG. 7 (b), the luminance of the panel is intended to be smaller than the luminance of a single lamp, and the lamps are arranged at intervals of several times the outer diameter of the lamp. In such a case, a table having a triangular cross section is provided on the reflector as shown in FIG. 6B to increase the reflectance, or a concave mirror reflector is provided as shown in FIG. 7A. In addition, as shown in FIG. 7B, a method of inserting a lamp into a groove provided in the light guide plate and providing a reflector and a diffuser to increase the uniformity of the brightness with the reflector can be adopted. According to the experimental results of the applicant, EEFL having an outer diameter of 2.6 mm is arranged on the reflector at intervals of about 15 mm, and the distance between the lamp and the diffuser is 25 mm, and the luminance is 1000 cd / m ² or more. A highly efficient backlight of 50 lm / W or more was realized.

FIG. 8 shows a backlight 30 according to a third embodiment of the present invention before being assembled.
8 shows the state after the backlight 30 of FIG. 8 has been assembled. Referring to FIGS. 8 and 9, the backlight 30 includes the upper substrate 31 and the upper substrate 31.
And a lower substrate 32 installed so as to be opposed. An upper phosphor layer 33 is formed on the lower surface of the upper substrate 31. A lower phosphor layer 34 is also formed on the upper surface of the lower substrate 32.

The fluorescent lamp 3 is provided above the lower substrate 32.
5 are provided at predetermined intervals. The fluorescent lamp 35 includes the upper substrate 31 and the lower substrate 3.
2 serves to support both substrates when they are combined,
In addition, it plays a role as a partition. The fluorescent lamp 35
In accordance with the features of the present invention, external electrodes 36 made of a conductive material are provided at both ends of the outer peripheral surface of the present invention.

In order to supply power to the backlight 30, an upper electrode 37 and a lower electrode 38 are provided along outer surfaces of corresponding sides of the assembled upper substrate 31 and lower substrate 32, respectively. The upper electrode 37 and the lower electrode 38 are made of a conductive metal material, and cover a part of the outer surfaces of the upper substrate 31 and the lower substrate 32 in a lid shape. At this time, it is advantageous to increase the formation area of the lower electrode 38 to obtain a stable discharge. Therefore, it is preferable to apply the lower electrode 38 to the lower surface of the lower substrate 32 as much as possible.

An edge support 39 is provided between the upper substrate 31 and the lower substrate 32 along the edges of the substrates to seal the substrates and maintain airtightness. With the edge support 39 interposed between the upper substrate 31 and the lower substrate 32, a discharge gas is injected into the backlight 30 before sealing. The upper electrode 37 and the lower electrode 3
8 can be separately formed on the substrates 31 and 32, and then both electrodes can be energized on both sides of the substrates 31 and 32, respectively. Can also be provided.

The upper electrode 37 and the lower electrode 38 have electrode connection lines 30 connected to both sides of the substrates 31 and 32, respectively.
0 supplies power. On the other hand, the fluorescent lamp 3
The external electrode 36 formed on the electrode 5 is not directly connected to the upper electrode 37 and the lower electrode 38 but is arranged in a floating state, and is discharged by a method induced by electric power supplied to both electrodes 37 and 38. Is to be generated. The external electrode 36 can be eliminated in some cases, but providing it is useful for obtaining a stable discharge.

The backlight 3 having the above structure
When power is supplied to the external electrode fluorescent line 35 through the electrode connection line 300, the external electrode fluorescent lamp 35 is separately manufactured and disposed between the upper substrate 31 and the lower substrate 32, and serves as a partition. Self-luminous. In the present invention, FIGS. 8 and 9 show a basic form of a partition panel light emitting type flat panel lamp. Such a lamp is convenient for applying a voltage to a flat panel external electrode. Due to the voltage drop, the driving voltage increases. In order to improve such a point, it is possible to adopt a method in which a metal electrode coated with a dielectric is installed inside the flat panel. That is, as shown in FIG. 10, after a multi-capsule electrode structure for mounting an electrodeless fluorescent tube is installed, a method in which an electrode connecting wire is pulled out to connect a lamp to a power source can be selected.

At this time, a ferroelectric material is applied to all surfaces of the multi-capsule electrode structure so that a direct current does not directly flow into the electrodes during discharge. As shown in the figure, the upper and lower portions (upper and lower electrodes) are separately manufactured so that the ferroelectric material can be easily applied to the inside of the groove, and the ferroelectric material is applied to all surfaces. The electrode fluorescent lamp is mounted in the groove, and the upper and lower electrodes are connected.

In a conventional backlight, when a fluorescent lamp is used as a partition, the partition is dark and the brightness uniformity cannot be maintained. However, according to a feature of the present invention, the fluorescent lamp 35 can also emit light by itself. Brightness uniformity is obtained. At the same time, since the fluorescent lamp 35 plays the role of a partition, the thickness of the glass of the upper and lower substrates 31 and 32 can be reduced, which is advantageous for weight reduction and large area.

Hereinafter, an inverter according to another embodiment of the present invention for driving a backlight having an EEFL of an edge light type and a direct light type according to the above embodiment will be described, and a method of driving the inverter and its operation will be described. explain in detail. A switching inverter according to an embodiment of the present invention is a combination of a switching circuit and a step-up transformer, and a power supply outputs a square wave suitable for driving a plurality of parallel-connected external electrode fluorescent lamps, and outputs a frequency and The output waveform conditions can be easily adjusted,
There is an overshooting part in the output waveform.

The split drive system according to another embodiment of the present invention is applied to a large-area backlight having an EEFL planar arrangement or a large-area flat panel lamp employing an AC type discharge by coating electrodes with a dielectric layer. You. In this divisional driving method, a large area is divided into several regions, and each region is driven by an in-phase waveform, thereby reducing the size of the driving device and realizing stable high-speed driving.

FIG. 11 shows signal waveforms applied to a switching inverter and a gate according to an embodiment of the present invention. This device is designed to effectively drive a plurality of parallel-connected EEFLs. The circuit features of the device include an LC resonant inverter used to drive an existing CCFL and an LC resonant inverter. In contrast, a high-voltage rectangular wave is output by a combination of four high-speed FETs serving as switches and a step-up transformer. Further, the frequency of the output rectangular wave, the voltage maintenance ratio, and the like can be easily controlled by adjusting each FET gate signal in the form shown in FIG. The operation principle of the switching inverter of the present invention is as follows. In a state where DC is applied to the FET provided at the upper end of the circuit and the drains of the gates A and C, a gate signal having the shape shown in FIG. 11 is applied to each FET. And each FET
, The gates A and D are simultaneously turned on and then turned off, and the gates C and B operate similarly. At this time, since the step-up transformers are connected to the output terminals of the left and right FETs, current flows alternately through the primary coils of the step-up transformers while each FET is in the ON state. Accordingly, a high-voltage rectangular wave output is generated in the secondary coil of the step-up transformer as shown in FIG. The characteristic of this output waveform is that, unlike a sine wave, the voltage rise time is short and has a constant voltage maintenance section. Further, due to the characteristics of the coil, a transient overshooting voltage is generated in a section where the voltage changes abruptly.

Hereinafter, the operation of the inverter will be described in detail. The output voltage waveform in the form of a square wave generated from the switching inverter is different from the existing LC resonance type inverter due to its characteristics. Even with only one switching inverter, a plurality of EEFLs connected in parallel are stable with uniform brightness. Can be operated. The reason is that, unlike the sine wave, the voltage maintaining section of the rectangular wave is constant. Then, a rectangular wave is simultaneously applied to EEFL,
When the FL is turned on, the applied voltage maintains a constant discharge voltage unlike the sine wave, so that even if each EEFL lamp is sequentially turned on within one cycle of the applied voltage, the lighting degree of each lamp is uniform. To maintain a constant light emission uniformity. Another reason is that the voltage rise time of the rectangular wave is shorter than that of a sine wave of the same frequency. After being sequentially turned on and off by the initially applied voltage, space charges and excited molecules remain inside the lamp tube, of which the space charges were formed around the electrodes during the first discharge. An electric field formed between the wall charges gradually recombine with the wall charges. The movement of such space charges and excited molecules depends on the strength of the electric field applied to the tube and its temporal change.In the case of a sine wave, however, the slope of the voltage rise is always smaller than that of a rectangular wave of the same frequency, A voltage is applied for a relatively long time before the second discharge is started, during which a kind of combination of space charge and wall charge formed during the first discharge due to the electric field formed by the applied voltage. The wall charge erasure phenomenon appears. As a result, the amount of wall charges is reduced, which results in a reduction in a voltage section in which a stable discharge can be maintained, that is, a reduction in a sustain voltage margin. The intensity of the discharge also decreases, and the luminance and the efficiency decrease. However, the rectangular wave output from the switching inverter according to the present invention has a voltage rising time relatively shorter than a sine wave, and the applied voltage exceeds the discharge starting voltage before the space charge is recombined with the wall charge, thereby causing a discharge. You can start. In addition, the effect of the steep voltage rising gradient enables instantaneous and quick movement of space charge, which increases effective collisions between space charge and neutral and excited molecules, thereby increasing the generation of secondary electrons. And an additional effect of increasing the discharge to increase the sustain voltage margin is achieved.

The overshooting voltage appearing at the rising or falling portion of the output waveform of the switching inverter shown in FIG. 12 facilitates the start of discharge and has the effect of making it possible to omit separate adjustment of the output voltage after the start of discharge. is there. The magnitude of this overshooting voltage depends on the output transformer and the electric capacity of the EEFL.
This is a value of the order, and decreases to less than 3% while the discharge is maintained after the start of the discharge. That is, the effect of the overshooting voltage appears only before the discharge starts. The reason for having such characteristics is that the EEFL has a property of a capacitive load and a property of a resistive load from the pure capacitive load before the start of discharge to the capacity of the resistive load after the start of discharge, and the vibration damping effect by the resistance component occurs. It is. After all, the effect of facilitating the start of the discharge of the overshooting voltage is exerted only before the start of the discharge. Generally, the discharge tube is A
Although it is a C type or a DC type, the discharge starting voltage is higher than the sustaining voltage. If there is an overshooting voltage in the output waveform, the applied voltage for starting discharge can be lowered only in that portion. For example, if the discharge starting voltage of a certain discharge tube is 1.3 kV and the overshooting portion of the applied voltage waveform is 30%, the discharge can be started with an average output voltage of 1 kV. Especially EE
The longer the length of the FL tube, the higher the firing voltage,
When using long tubes, waveforms with overshooting are advantageous. Another important effect is that a voltage adjustment process generally performed after the start of discharge can be omitted. In fact, when using waveforms without overshooting,
A method is adopted in which a voltage required for starting discharge is applied, and when the discharge starts, the voltage is artificially lowered for reasons such as adjusting the life and brightness of the discharge tube. In the switching inverter, the maximum voltage value differs by about 20 to 30% before and after the start of discharge due to the presence of the overshooting voltage. Therefore, after the start of discharge, the voltage is automatically adjusted to the level of the maintenance voltage, and the voltage is separately adjusted. There is no need to attach equipment.

A self-discharge effect that increases efficiency and brightness appears. Self-discharge is a unique phenomenon that appears only in an AC discharge tube, and the strength of the wall voltage induced by the wall charge formed by the discharge is high. When the voltage is higher than the discharge starting voltage, a discharge occurs between the wall charges when the externally applied voltage decreases to reach zero potential. FIG. 12 shows a rectangular wave generated by the switching inverter and a self-discharge phenomenon that occurs when the square wave is applied to the EEFL. When self-discharge occurs, the discharge current and the number of times of light emission in each voltage waveform cycle are twice that when no self-discharge occurs, and the intensity is slightly smaller than when no self-discharge occurs. This is because the wall charges are partially erased by the occurrence of self-discharge. The occurrence of such self-discharge has the effect of increasing efficiency and brightness.

Still another embodiment of the present invention is a large area backlight divided drive system. A backlight having a small area configured by arranging the EEFLs on a plane can be driven by a single switching inverter. However, the larger the area, the larger the power consumption, and the larger the boost transformer used for the inverter. Therefore, it becomes difficult to manufacture a small-sized switching inverter.
Furthermore, if the length of the line for applying a voltage is long, problems such as signal interference and impedance matching occur, causing uneven brightness. To solve the problem in such a case, as shown in FIG. 14, the entire backlight is divided into regions of an appropriate size, and the divided regions are switched inverters that consistently generate voltage waveforms of the same phase. Is adopted. here,
The reason why the output waveforms of the respective switching inverters should be in phase is that if the phases are different from each other, there is a possibility that a leakage phenomenon may occur in an adjacent portion between the divided regions. In the method in which the output waveform of each switching inverter is in phase,
In each region, the FET for performing high-speed switching of the switching inverter and the boosting transformer are connected independently, and one gate signal is connected to each FET.
Commonly used for At this time, since one circuit for generating a gate signal is shared, it is more cost-effective than using a plurality of switching inverters. is there.

Although the present invention has been described with reference to the embodiments illustrated in the drawings, the embodiments are only illustrative and that various modifications and variations of the embodiments may be made by one of ordinary skill in the art. Obviously, other equivalent embodiments are possible, and thus the true technical scope of the present invention is:
It should be determined by the technical idea described in the claims.

[0058]

As described above, in the backlight including the external electrode fluorescent lamp of the present invention and the driving method thereof,
Since the external electrodes are provided at both ends of the outer peripheral surface of the fluorescent lamp and the fluorescent lamp is arranged in a plane, the following effects can be obtained. First, the manufacture of the fluorescent lamp is simple because the electrodes of the fluorescent lamp are formed outside.
High brightness and high efficiency are realized by adopting a linear end cap method or a method of bending both ends of the glass tube in order to make the length of both ends of the glass tube sufficient. In addition, the fluorescent lamps are arranged at the edges of the light guide plate or are superimposed on a plane, so that the fluorescent lamps can be connected to one power supply in a parallel connection manner and driven by this power supply, thereby achieving high brightness and high efficiency. In addition, a thin backlight which is easy to manufacture is realized.

Secondly, since the fluorescent lamp plays the role of a partition and emits light by itself, uniformity of luminance can be maintained, and by using the fluorescent lamp as a partition, thin upper and lower substrates can be adopted. Become. This makes it possible to manufacture a large-area surface light source that ensures uniform brightness. Third, since the backlight constituted by arranging a plurality of outer tube electrode fluorescent lamps is driven at a low frequency of several tens KHz,
The problem of MI can be avoided.

Fourthly, the switching inverter of the present invention, which combines a high-speed FET and a step-up transformer, outputs a high-voltage rectangular wave and generates an overshooting voltage, so that high-speed driving with uniform luminance can be performed. It is possible, and the discharge starting voltage can be naturally lowered, and the self-discharge effect can be obtained. With such an effect, high luminance and high efficiency can be obtained.

Fifth, according to the inverter of the present invention manufactured by sharing the gate signal of the FET element and independently connecting only the step-up transformer in order to divide and drive the display screen with a large screen backlight and drive the display screen. The same-phase voltage is applied to each of the divided screens to prevent leakage between adjacent divided areas, thereby stabilizing the discharge and making the luminance of the large-area backlight uniform. Further, the length of a line to which a voltage is applied can be reduced, and the problems of signal interference and impedance matching can be avoided, so that it is effective to realize uniform luminance. Then, the size of the step-up transformer can be reduced, and a small inverter can be obtained by sharing the gate signal generator.

Further, according to the switching inverter of the present invention, (i) a plurality of EEFLs connected in parallel can be driven at high speed by one inverter so as to have uniform luminance.
i) The discharge starting voltage can be reduced by the presence of the overshooting voltage, and (iii) the brightness and efficiency can be increased by the self-discharge action.

[Brief description of the drawings]

FIG. 1A is a perspective view illustrating an end-cap type linear external electrode fluorescent lamp according to an embodiment of the present invention;
(B) is a perspective view illustrating a curved external electrode fluorescent lamp according to an example of the present invention.

FIG. 2 is a view illustrating a backlight arrangement method in which an external electrode fluorescent lamp according to a first embodiment of the present invention is arranged at an end of a light guide plate.

FIG. 3 (a) is a diagram illustrating an arrangement of a linear end cap type fluorescent lamp of a direct type backlight according to a second embodiment of the present invention, and FIG. 3 (b) is a direct type according to a second embodiment of the present invention; FIG. 7C is a diagram illustrating an arrangement method of a bent electrode fluorescent lamp of a backlight, and FIG. 9C is a diagram illustrating another arrangement method of a bent electrode fluorescent lamp of a direct backlight according to a second embodiment of the present invention.

FIG. 4A is a view illustrating an arrangement method of an elongated fluorescent lamp bent in an edge region of a direct type backlight according to a second embodiment of the present invention, and FIG.
FIG. 3C is a diagram illustrating a connection method of a direct backlight with a superimposed capsule according to the embodiment, and FIG. 4C is a diagram illustrating a superposition arrangement of a direct backlight for a large screen in a lamp direction according to a second embodiment of the present invention. is there.

FIG. 5 is an exploded perspective view illustrating a direct backlight according to a second embodiment of the present invention;

FIG. 6A is a diagram illustrating an arrangement method of a reflector and a fluorescent lamp of a direct type backlight according to a second embodiment of the present invention, and FIG. 6B shows another arrangement method of the reflector and the fluorescent lamp. FIG.

FIG. 7A is a diagram showing another arrangement method of a reflector and a fluorescent lamp, and FIG. 7B is a diagram showing another arrangement method of a reflector and a fluorescent lamp.

FIG. 8 is an exploded perspective view illustrating a partition-emission type backlight according to a third embodiment of the present invention before being assembled.

9 is a partially cutaway perspective view illustrating a state after assembly of the backlight in FIG. 8;

FIG. 10 is a conceptual view of an electrode structure illustrating a coupling method of a multiple capsule electrode and an electrodeless fluorescent lamp installed in a flat panel fluorescent lamp of a partition wall emission type backlight according to a third embodiment of the present invention.

FIG. 11 is a diagram illustrating a switching inverter and signal waveforms applied to a gate according to an embodiment of the present invention.

FIG. 12 is a diagram illustrating a change in a switching inverter output waveform before and after a discharge is started according to an embodiment of the present invention.

FIG. 13 is a diagram illustrating a magnetic discharge phenomenon in rectangular wave driving according to an embodiment of the present invention.

FIG. 14 is a schematic diagram illustrating in-phase split driving for driving a large-area backlight according to another embodiment of the present invention.

FIG. 15 is a diagram illustrating a conventional external electrode fluorescent lamp.

FIG. 16 shows a conventional CCFL drive IC for an LCD panel.
FIG. 3 is a circuit diagram showing a peripheral circuit.

[Explanation of symbols]

 10, 22, 35 Fluorescent lamp 11 Glass tube 12 Phosphor 13, 23, 23a, 36 External electrode 20, 30 Backlight 21 Reflector 24, 300 Electrode connection line 25 Diffusion plate 31 Upper substrate 32 Lower substrate 33 Upper phosphor layer 34 lower phosphor layer 37 upper electrode 38 lower electrode 39 edge support A, B, C, D gate

Continuation of the front page (31) Priority claim number 2000-83512 (32) Priority date December 28, 2000 (2000.12.28) (33) Priority claiming country Korea (KR) (72) Inventor Choi Galactic Republic of Korea Republic of Korea Seoul Special City No. 366, Jungggye-dong, Robara-ku, Rip apartment 110-dong, 502 No.502 F-term (reference) 3K072 AB02 AC01 AC11 BC02 GA02 GB18 5G435 AA03 AA16 AA18 BB12 BB15 EE26 EE29 FF03 FF06 FF08 GG24 GG26

Claims (22)

[Claims] 1. A glass tube that is sealed after a discharge gas is injected, a phosphor layer applied to an inner peripheral wall of the glass tube, and both ends of the outer peripheral surface of the glass tube. And an external electrode formed of a conductive material. 2. A glass tube in which a discharge gas is injected, a phosphor layer is coated on an inner peripheral wall, and both ends are hermetically sealed. The glass tube has a bent shape such as an L-shape, a C-shape, a spiral shape, or a corrugated shape. And an end cap type external electrode formed so as to surround the both ends of the glass tube. 3. A reflector, and a plurality of reflectors arranged on the upper surface of the reflector, wherein a phosphor layer is applied to an inner peripheral wall of each glass tube, and a fluorescent layer is applied to both ends of the outer peripheral surface of the glass tube. A back, comprising: a plurality of fluorescent lamps formed with external electrodes made of a conductive material so as to surround both ends; and a diffusion plate disposed above the fluorescent lamps and opposed to the reflection plate. Light. 4. The fluorescent lamp according to claim 1, wherein the external electrodes are electrically connected to each other, and an external electrode of an outermost fluorescent lamp of the fluorescent lamps is connected to an electrode connection line to which an AC power supply is applied. The backlight according to claim 3, characterized in that: 5. An upper substrate having an upper phosphor layer applied to a lower surface thereof, a lower substrate disposed opposite to the upper substrate and having a lower phosphor layer applied to an upper surface thereof, An edge support that is interposed between the lower substrate and hermetically seals the two substrates, and is installed at a predetermined distance from the lower substrate, and is applied to an inner peripheral wall of the glass tube; A fluorescent lamp having a phosphor layer and external electrodes formed at both ends to surround both ends of the outer peripheral surface of the glass tube, and external electrodes made of a conductive material; and on both outer surfaces of the upper substrate and the lower substrate, respectively. A backlight connected to an electrode connection line to which an AC type power supply is applied. 6. The backlight according to claim 5, wherein the fluorescent lamp is not connected to the electrode and is installed in a floating state inside the upper substrate and the lower substrate. 7. A light guide plate, a fluorescent lamp provided around the light guide plate, and a switching inverter connected to an external electrode for applying a rectangular wave signal of 100 KHz or less, wherein the fluorescent lamp comprises a discharge gas. A backlight comprising: a glass tube into which a phosphor layer is applied to an inner peripheral wall and both ends of which are sealed; and an end cap-type external electrode surrounding both ends of the glass tube. 8. The backlight according to claim 7, wherein the fluorescent lamp includes a plurality of external electrode fluorescent lamps connected in parallel. 9. A plurality of external electrode fluorescent lamps connected in parallel, an electrode connecting line connecting end cap type external electrodes of the plurality of external electrode fluorescent lamps in parallel, a reflecting plate, and a diffusing plate. A switching inverter connected to the electrode connection line to apply a rectangular wave signal of 100 KHz or less, wherein the external electrode fluorescent lamp is filled with a discharge gas, has a phosphor layer applied to an inner peripheral wall thereof, and has both ends sealed. A backlight comprising: a stopped glass tube; and the end cap-type external electrodes surrounding both ends of the glass tube. 10. The backlight according to claim 9, wherein the reflector further comprises a plurality of tripods disposed between the external electrode fluorescent lamps. 11. The backlight according to claim 9, wherein the reflection plate has a wavy shape surrounding the external electrode fluorescent lamp. 12. A light guide plate having a diffusion groove in which the external electrode fluorescent lamp is installed, wherein the reflector has a triangular saw shape, and the external electrode fluorescent lamp is disposed along the triangular saw groove. 10. The backlight according to claim 9, wherein the backlight is used. 13. A socket-type multiplex comprising a glass tube in which a discharge gas is injected, a phosphor layer is coated on an inner peripheral wall and both ends are sealed, and a plurality of external electrodes to which the glass tube is connected in parallel. A capsule electrode structure, a reflecting plate, a diffusion plate, and one connected to the socket-type multiple capsule electrode structure.
A switching inverter for applying a rectangular wave signal of 00 KHz or less. 14. A rectangular wave of 100 KHz or less connected to an external electrode, a fluorescent plate, a diffuser, and an external electrode, wherein the external electrode portions are alternately arranged in the middle of the panel so that the external electrode portions overlap each other in a transverse direction. A switching inverter for applying a signal, the external electrode fluorescent lamp, a glass tube in which a discharge gas is injected, a phosphor layer is applied to an inner peripheral wall and both ends are sealed,
A backlight comprising: a capsule-shaped external electrode surrounding both ends of the glass tube. 15. The external electrode of the external electrode fluorescent lamp according to claim 1, wherein the external electrode is a conductive transparent electrode material.
4. The backlight according to 4. 16. An upper substrate having an upper phosphor layer applied to a lower surface thereof, a lower substrate disposed opposite to the upper substrate and having an upper surface coated with a lower phosphor layer, the upper substrate and the lower substrate An edge support base interposed between the first and second substrates and hermetically sealing the two substrates; an external electrode fluorescent lamp installed at a predetermined distance above the lower substrate; and An electrode formed on both outer surfaces of both sides of the lower substrate and connected to an electrode connection line to which an AC power supply is applied; a switching inverter connected to the electrode to apply a rectangular wave signal of 100 KHz or less; A discharge gas injected into an internal space when sealing the lower substrate, wherein the external electrode fluorescent lamp is injected with a discharge gas and a phosphor layer is applied to an inner peripheral wall; Backlight end is characterized in that it comprises a capsular external electrodes surrounding the opposite ends of the glass tube and the glass tube was sealed. 17. The fluorescent lamp as claimed in claim 16, wherein the external electrode fluorescent lamp is installed in the upper substrate and the lower substrate in a floating state without being connected to the electrode.
The backlight described in 1. 18. An upper substrate having a lower surface coated with an upper phosphor layer, a lower substrate disposed opposite to the upper substrate and having a lower phosphor layer applied on an upper surface, the upper substrate and the lower substrate An upper plate electrode and a lower plate each having a surface on which a ferroelectric material is applied and grooves formed with a glass tube are formed at predetermined intervals, respectively, which are interposed between the first and second substrates and seal the two substrates. An electrode and a multi-capsule electrode structure installed at both ends of the lower substrate; and a multi-capsule electrode structure installed in both ends of the lower substrate in parallel with grooves of the multi-capsule electrode structure, respectively. A glass tube, a switching inverter connected to an electrode connection line and applying a rectangular wave signal of 100 KHz or less, and injected into an internal space when sealing the upper substrate and the lower substrate. And a discharge gas, wherein the glass tube is filled with the discharge gas, a phosphor layer is applied to an inner peripheral wall, and both ends are sealed. 19. The switching inverter forms a bridge circuit with first, second, third and fourth FETs, DC is applied to drains of the first and third FETs, and the second and third FETs are connected to each other. The source of the fourth FET is grounded,
The source of the first FET is connected to the drain of the second FET, and the source of the third FET is connected to the fourth FET.
8. A step-up transformer is connected between a connection point of the first and second FETs and a connection point of the third and fourth FETs. The backlight described in 1. 20. The backlight according to claim 7, wherein the rectangular wave output from the switching inverter includes overshooting. 21. A driving method for driving a backlight in which a plurality of outer tube electrode fluorescent lamps are connected in parallel, wherein: a step of dividing the plurality of fluorescent lamps into a plurality of predetermined regions; Connecting the external electrodes of the fluorescent lamp to the same electrode connection line, applying the same gate signal to each of the switching inverters, and the switching inverters having the same phase in response to the gate signal. Supplying to the electrode connection lines. 22. The switching inverter forms a bridge circuit with first, second, third and fourth FETs, DC is applied to drains of the first and third FETs, and the second and third FETs are connected to each other. The source of the fourth FET is grounded,
The source of the first FET is connected to the drain of the second FET, and the source of the third FET is connected to the fourth FET.
22. A step-up transformer is connected between the connection point of the first and second FETs and the connection point of the third and fourth FETs. 3. The backlight driving method according to 1.