KR100855491B1 - Apparatus of back light - Google Patents

Abstract

The present invention relates to a backlight device that can minimize the leakage current of the lamp by changing the arrangement of the lamp or the structure of the lamp housing.

According to an embodiment of the present invention, a backlight device includes a lamp housing and one or a plurality of discharge tubes accommodated in the lamp housing with a distance from the lamp housing set such that parasitic capacitances of the lamp housing are the same. A portion of the bottom surface of the housing is characterized in that the portion facing the discharge tube is stepped.

By this arrangement, the present invention arranges the plurality of cold cathode fluorescent lamps so that the parasitic capacitance between the plurality of cold cathode fluorescent lamps and the lamp housing is the same, thereby minimizing leakage current generated between the plurality of cold cathode fluorescent lamps and the lamp housing. can do. In addition, it is possible to minimize the leakage current generated between the plurality of cold cathode fluorescent lamps and the lamp housing by projecting the bottom surface of the lamp housing to a predetermined height so that the parasitic capacitance between the plurality of cold cathode fluorescent lamps and the lamp housing are the same. Therefore, the present invention makes the luminance of a plurality of cold cathode fluorescent lamps uniform. In addition, the present invention has a structure that can easily control the current supplied to a plurality of cold cathode fluorescent lamps.

Description

Backlight device {APPARATUS OF BACK LIGHT}             

1 is a cross-sectional view showing a conventional backlight device.

FIG. 2 shows a backlight device for driving the CCFL shown in FIG. 1; FIG.

3 is an equivalent circuit diagram of a backlight device for driving the CCFL shown in FIG.

4 is a cross-sectional view showing the parasitic capacitance between the lamp housing and the CCFL.

5 is a cross-sectional view of a backlight device according to a first embodiment of the present invention.

6 is a cross-sectional view illustrating a backlight device according to a second embodiment of the present invention.

7 is a cross-sectional view illustrating a backlight device according to a third embodiment of the present invention.

8 is a cross-sectional view of a backlight device having a plurality of CCFLs according to another embodiment of the present invention.

9 is a cross-sectional view of a backlight device having a plurality of CCFLs and a rounded lamp housing in a circular shape according to another embodiment of the present invention.

10 is a cross-sectional view illustrating a backlight device including a lamp housing having a plurality of CCFLs and protrusions according to another exemplary embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

10, 50, 60, 80, 100, 110, 120: lamp housing

14, 16, 82, 86: both side walls of the lamp housing

20,22,24,40,42,44,70,72,74,90,92,94,102,104,106,108: CCFL

84: bottom surface of the lamp housing

87: projection of the lamp housing

The present invention relates to a backlight device, and more particularly to a backlight device to minimize the leakage current of the lamp by changing the arrangement of the lamp or the structure of the lamp housing.

Liquid crystal displays (hereinafter, referred to as "LCDs") are becoming increasingly wider in scope due to their light weight, thinness, and low power consumption. According to this trend, LCDs are used for office automation equipment, audio / video equipment, and the like. On the other hand, the LCD is controlled to display the desired image on the screen by adjusting the transmission amount of the light beam according to the image signal applied to the plurality of control switches arranged in a matrix form.

Since the LCD is not a self-luminous display device, a light source such as a back light is required. As a light source used for the backlight, a cold cathode fluorescent lamp (hereinafter referred to as "CCFL") is used.

CCFL is a light source using the cold cathode emission (electron emission caused by a strong electric field applied to the surface of the cathode), it is easy to generate low heat, high brightness, long life, full color. The CCFL includes a light guide type, a direct type type, a reflective plate type, and the like, and a light source having a suitable type is adopted according to the requirements of the LCD.

Such CCFLs use multiple CCFLs as backlights depending on the size of the LCD.

Referring to FIG. 1, a conventional backlight device includes first to third CCFLs 20, 22, and 24 arranged side by side to generate light, and first to third CCFLs 20, 22, and 24 arranged side by side. ) Is provided with a lamp housing (10).

Each of the first to third CCFLs 20, 22, and 24 includes a glass tube, inert gases inside the glass tube, and a cathode and an anode installed at both ends of the glass tube. Inert gas is filled in the glass tube, and phosphor is coated on the inner wall of the glass tube.

When an alternating voltage is applied to the cathode and anode of each of the first to third CCFLs 20, 22, and 24, an AC voltage is applied from an inverter (not shown), electrons are emitted from the cathode and collide with inert gases inside the glass tube to exponentially The amount of electrons increases. As the electrons flow through the inside of the glass tube, the inert gas is excited by the electrons, and ultraviolet rays are emitted. The ultraviolet rays collide with the luminescent phosphor applied to the inner wall of the glass tube to emit visible light.

The lamp housing 10 prevents light leakage of visible light emitted from each of the first to third CCFLs 20, 22, and 24, and proceeds to the side and the rear of the first to third CCFLs 20, 22, and 24. It serves to reflect visible light to the front.

As such, the conventional backlight device generates visible light by applying an alternating voltage to each of the first to third CCFLs 20, 22, and 24, and advances the generated light to the front surface by the lamp housing 10. .

When the first to third CCFLs 20, 22 and 24 are driven, the first to third CCFLs 20 and 22 may be set by parasitic or floating capacities of the first to third CCFLs 20, 22 and 24, respectively. , 24) leakage current occurs in each. The parasitic capacitance of each of the first to third CCFLs 20, 22, and 24 may vary depending on the distance from the lamp housing 10.

This parasitic capacitance will be described with reference to FIGS. 2 and 3. First, as shown in FIG. 2, the CCFL generates light by a current supplied from the inverter Vs through the capacitor CB. When the CCFL is driven as shown in FIG. 3, the parasitic capacitance CS generated between the CCFL and the lamp housing 10 is represented by Equation 1 below.

In Equation 1, ε s is the permittivity of the CCFL, d is the distance to the lamp housing (10). Due to the parasitic capacitance CS between the CCFL and the lamp housing 10, the current supplied to the CCFL is represented by Equation 2.

In Equation 2, IS is a current supplied to the CCFL, and VL is a voltage supplied from the inverter to the CCFL. The current IS supplied to the CCFL through Equation 2 is inversely proportional to the parasitic capacitance CS. That is, when the same voltage is supplied from the inverter to the CCFL, the current supplied to each of the plurality of CCFLs shown in FIG. 4 depends on the parasitic capacitance CS of each of the CCFLs.

Referring to FIG. 4, the parasitic capacitance between the first CCFL 20 and the lamp housing 10 is between the left side wall 14 of the lamp housing 10 and the bottom surface 12 of the lamp housing 10. . Parasitic capacitance between the second CCFL 22 and the lamp housing 10 is present between the bottom surface 12 of the lamp housing 14. The parasitic capacitance between the third CCFL 24 and the lamp housing 10 is between the right side wall 16 of the lamp housing 10 and the bottom surface 12 of the lamp housing 10.

The parasitic capacitance present between each of the first and third CCFLs 20 and 24 and the left sidewall 14 and the right sidewall 16 of the lamp housing 10 is the first capacitance C1 and the first to third The parasitic capacitance between each of the CCFLs 20, 22, 24 and the bottom surface 12 of the lamp housing 10 is the second capacitance C2. Accordingly, the parasitic capacitance of the first CCFL 20 has the first capacitance C1 and the second capacitance C2, and the parasitic capacitance of the second CCFL 22 has the second capacitance C2. The parasitic capacitance of the third CCFL 24 has a first capacitance C1 and a second capacitance C2.

As described above, the parasitic capacitance generated differently in each of the first and third CCFLs 20 and 24 and the second CCFL 22 may be difficult to control or cannot be controlled by the structure of the lamp housing 10. There is this. Accordingly, leakage current is generated by parasitic capacitances generated differently in the first and third CCFLs 20 and 24 and the second CCFLs 22, respectively, so that the currents of the first to third CCFLs 20, 22 and 24 are each different. Deviation and luminance deviation occur.

Accordingly, an object of the present invention is to provide a backlight device that can minimize the leakage current of the lamp by changing the arrangement of the lamp or the structure of the lamp housing.

In order to achieve the above object, a backlight device according to an embodiment of the present invention is one or a plurality of the lamp housing and the lamp housing is set so that the distance between the lamp housing is set so that the parasitic capacitance of the lamp housing is the same. Discharge tubes are provided, and a part of the bottom surface of the lamp housing is characterized in that the portion facing the discharge tube is stepped.

In the backlight device, one or more of the discharge tubes may have a different height from the discharge tubes.

In the backlight device, the lamp housing is rounded.                     

In the backlight device, the discharge tubes are arranged side by side, and a part of the bottom surface of the lamp housing is characterized by stepped portions facing one or more discharge tubes except for discharge tubes disposed at both edges of the lamp housing.

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In the backlight device, a part of the bottom surface of the lamp housing may protrude toward at least one discharge tube except for discharge tubes disposed at both edges of the lamp housing.

Other objects and features of the present invention in addition to the above objects will be apparent from the description of the embodiments with reference to the accompanying drawings.

A preferred embodiment of the present invention will be described with reference to FIGS. 5 to 10.

Referring to FIG. 5, the backlight device according to the first exemplary embodiment of the present invention may include first to third CCFLs 40, 42, and 44 arranged in a triangle to generate light, and first to third CCFLs 40. , 42, 44 are mounted and have a lamp housing 50 surrounding the first to third CCFLs 40, 42, 44.

Each of the first to third CCFLs 40, 42, and 44 includes a glass tube, inert gases inside the glass tube, and a cathode and an anode provided at both ends of the glass tube. Inert gas is filled in the glass tube, and phosphor is coated on the inner wall of the glass tube.                     

When an alternating voltage is applied to the cathode and anode of each of the first to third CCFLs 40, 42, and 44, an AC voltage is applied from an inverter (not shown), electrons are emitted from the cathode and collide with inert gases in the glass tube to exponentially The amount of electrons increases. As the electrons flow through the inside of the glass tube, the inert gas is excited by the electrons, and ultraviolet rays are emitted. The ultraviolet rays collide with the luminescent phosphor applied to the inner wall of the glass tube to emit visible light.

The lamp housing 10 prevents light leakage of visible light emitted from each of the first to third CCFLs 40, 42, and 44, and proceeds to the side and the rear of the first to third CCFLs 40, 42, and 44. It serves to reflect visible light to the front.

As described above, the backlight device according to the first exemplary embodiment of the present invention generates visible light by applying an alternating voltage to each of the first to third CCFLs 40, 42, and 44 arranged in a triangular shape, and generates the generated light. It is advanced to the front by the lamp housing 50.

When the first to third CCFLs 40, 42 and 44 are driven, the first to third CCFLs 40 and 42 may be set by parasitic capacitance or stray capacitance of each of the first to third CCFLs 40, 42 and 44. , 44) leakage current occurs in each. The parasitic capacitance of each of the first to third CCFLs 40, 42, and 44 depends on the distance from the lamp housing 50.

As such, the first to third CCFLs 40, 42, 44 to equalize the parasitic capacitance of each of the first, second, and third CCFLs 40, 42, 44 that vary depending on the distance from the lamp housing 50. Each is arranged in the lamp housing 50 in the form of a triangle. That is, the first and third CCFLs 40 and 44 and the second CCFL 42 have steps.

In detail, the first CCFL 40 is disposed adjacent to the left wall 56 of the lamp housing 50. As a result, the first CCFL 40 has a parasitic capacitance C1 between the left walls 56 of the lamp housing 50, and the parasitic capacitances between the bottom surfaces 54 of the lamp housing 50 are far from each other. It is destroyed. The second CCFL 42 is disposed between the first and third CCFLs 40 and 44 and adjacent the bottom surface 54 of the lamp housing 50. As a result, the second CCFL 42 has a parasitic capacitance C2 between the bottom surface 54 of the lamp housing 50, and a parasitic between the left wall 56 and the right wall 52 of the lamp housing 50. Capacity is extinguished because of its distance. In addition, the third CCFL 44 is disposed adjacent to the right wall 52 of the lamp housing 50. As a result, the third CCFL 44 has a parasitic capacitance C3 between the right wall 52 of the lamp housing 50, and the parasitic capacitance between the bottom surface 54 of the lamp housing 50 is far from each other. It is destroyed.

Therefore, the distance between the lamp housing 50 and each of the first to third CCFLs 40, 42, 44 are all the same, so that the lamp housing 50 and the first to third CCFLs 40, 42, 44 are the same. Parasitic capacitances C1, C2, and C3 are all the same.

As described above, in the backlight device according to the first embodiment of the present invention, the parasitic capacitances C1, C2, and C3 between the first to third CCFLs 40, 42, and 44 and the lamp housing 50 are described above. By arranging the lamp housing 50 in a triangular manner so as to be equal to 1 and 2, the parasitic capacitances C1, C2, C3 between each of the first to third CCFLs 40, 42, 44 and the lamp housing 50 The leakage current due to the difference is minimized. In addition, since the parasitic capacitances C1, C2, C3 between the first to third CCFLs 40, 42, 44 and the lamp housing 50 are all the same, the first to third CCFLs 40, 42, 44 are the same. The luminance of can be made uniform. Accordingly, the present invention can easily control the current supplied to each of the first to third CCFLs 40, 42, and 44 from the inverter.

Referring to FIG. 6, the backlight device according to the second exemplary embodiment of the present invention may include first to third CCFLs 70, 72, and 74 arranged in a triangular shape to generate light, and first to third CCFLs 70. , 72, 74 are mounted and have a circular lamp housing 60 for enclosing the first to third CCFLs 70, 72, 74.

Each of the first to third CCFLs 70, 72, and 74 includes a glass tube, inert gases inside the glass tube, and a cathode and an anode provided at both ends of the glass tube. Inert gas is filled in the glass tube, and phosphor is coated on the inner wall of the glass tube.

When an alternating voltage is applied to the cathodes and anodes of each of the first to third CCFLs 70, 72, and 74, an AC voltage is applied from an inverter (not shown). The amount of electrons increases. As the electrons flow through the inside of the glass tube, the inert gas is excited by the electrons, and ultraviolet rays are emitted. The ultraviolet rays collide with the luminescent phosphor applied to the inner wall of the glass tube to emit visible light.

The lamp housing 60 prevents light leakage of visible light emitted from each of the first to third CCFLs 70, 72, and 74 to the side and the back of the first to third CCFLs 70, 72, and 74. It reflects the traveling visible light to the front.

As described above, the backlight device according to the second exemplary embodiment of the present invention generates visible light by applying an AC voltage to each of the first to third CCFLs 70, 72, and 74 arranged in a triangular form, and generates the generated light. It is advanced to the front by the lamp housing (60).

Each of the first to third CCFLs 70, 72 and 74 by parasitic capacitance of each of the first to third CCFLs 70, 72 and 74 when the first to third CCFLs 70, 72 and 74 are driven. Leakage current occurs at The parasitic capacitance of each of the first to third CCFLs 70, 72, and 74 may vary depending on the distance from the lamp housing 60.

In order to equalize the parasitic capacitance of each of the first to third CCFLs 70, 72, and 74 depending on the distance to the lamp housing 60, each of the first to third CCFLs 70, 72, and 74 is a triangle. It is disposed in the lamp housing 60 in the form, the lamp housing 60 is rounded to surround the first to third CCFL (70, 72, 74).

Thus, the distance between the lamp housing 60 and each of the first to third CCFLs 70, 72, 74 is all the same. As such, the distance between the lamp housing 60 and each of the first to third CCFLs 70, 72, and 74 is the same, so that the parasitic between the lamp housing 60 and the first to third CCFLs 70, 72, and 74 is the same. The capacities C4, C6 and C5 are all the same.

As described above, in the backlight device according to the second embodiment of the present invention, the parasitic capacitances C4, C6, and C5 between the first to third CCFLs 70, 72, and 74 and the lamp housing 60 are described above. The first and third CCFLs 70, 72, and 74 are wrapped in the lamp housing 60 in a triangular shape and the rounded lamp housing 60 to be the same by 1 and 2. The leakage current due to the difference in the parasitic capacitances C4, C6, and C5 between the third CCFLs 70, 72, and 74 and the lamp housing 60 may be minimized. In addition, since the parasitic capacitances C4, C6, C5 between the first to third CCFLs 70, 72, 74 and the lamp housing 60 are all the same, the first to third CCFLs 70, 72, 74 are the same. The luminance of can be made uniform. Accordingly, the present invention can easily control the current supplied to each of the first to third CCFLs 70, 72, and 74 from the inverter.

Referring to FIG. 7, a backlight device according to a third exemplary embodiment of the present invention may include first to third CCFLs 90, 92, and 94 arranged side by side to generate light, and first to third CCFLs 90, respectively. 92 and 94 are mounted and have a lamp housing 80 for enclosing the first to third CCFLs 90, 92 and 94.

Each of the first to third CCFLs 90, 92, and 94 includes a glass tube, inert gases inside the glass tube, and a cathode and an anode installed at both ends of the glass tube. Inert gas is filled in the glass tube, and phosphor is coated on the inner wall of the glass tube.

When an alternating voltage is applied to the cathode and anode of each of the first to third CCFLs 90, 92, and 94, an AC voltage is applied from an inverter (not shown). The amount of electrons increases. As the electrons flow through the inside of the glass tube, the inert gas is excited by the electrons, and ultraviolet rays are emitted. The ultraviolet rays collide with the luminescent phosphor applied to the inner wall of the glass tube to emit visible light.

The lamp housing 80 prevents light leakage of visible light emitted from each of the first to third CCFLs 90, 92, and 94, and proceeds to the side and the rear of the first to third CCFLs 90, 92, and 94. It serves to reflect visible light to the front.

As described above, the backlight device according to the third embodiment of the present invention generates visible light by applying an alternating current voltage to each of the first to third CCFLs 90, 92, and 94 arranged side by side, and generates the generated light. It is advanced to the front by the housing (80).

When the first to third CCFLs 90, 92, and 94 are driven, parasitic capacitances of the first to third CCFLs 90, 92, and 94 may be used to determine the first to third CCFLs 90, 92, and 94. In each case, a leakage current is generated. The parasitic capacitance of each of the first to third CCFLs 90, 92, and 94 may vary depending on the distance from the lamp housing 80.

As such, in order to make the parasitic capacitance of each of the first to third CCFLs 90, 92, and 94 varying according to the distance from the lamp housing 80, the first to third CCFLs 90, The bottom surface 84 of the lamp housing 80 adjacent the second CCFL 92 of 92, 94 projects toward the second CCFL 92. This protruding protrusion 87 has a bent portion 85 and a horizontal portion 83. At this time, the bent portion 85 may be bent in a vertical or predetermined slope.

 Accordingly, the distance between the lamp housing 80 and each of the first to third CCFLs 90, 92, and 94 is the same. That is, the first CCFL 90 is disposed adjacent to the left wall 86 of the lamp housing 80. As a result, the first CCFL 90 has a parasitic capacitance C7 between the left wall 86 of the lamp housing 80, and the parasitic capacitance between the bottom surfaces 84 of the lamp housing 80 is far apart. It is destroyed. The second CCFL 92 is disposed between the first and third CCFLs 90, 94 and is disposed adjacent to the protrusion 87 of the lamp housing 80. Due to this, the second CCFL 92 has a parasitic capacitance C9 between the horizontal surfaces 83 of the protrusions 87 protruding from the bottom surface 84 of the lamp housing 80, and the left side of the lamp housing 80. The parasitic capacitance between the wall 86 and the right wall 82 is extinguished because of the distance. In addition, the third CCFL 94 is disposed adjacent the right wall 82 of the lamp housing 80. Because of this, the third CCFL 94 has a parasitic capacitance C8 between the right side wall 82 of the lamp housing 80, because the parasitic capacitance between the bottom surface 84 of the lamp housing 80 is far apart. It is destroyed.

Therefore, the distance between the lamp housing 80 and each of the first to third CCFLs 90, 92, and 94 is the same, so that the distance between the lamp housing 80 and the first to third CCFLs 90, 92, and 94 is the same. Parasitic doses C7, C9, and C8 are all the same.

As described above, in the backlight device according to the third embodiment of the present invention, the first to third CCFLs 90, 92, and 94 are disposed in parallel to the lamp housing 80, and each of the first to third CCFLs 90 is disposed in parallel. 92, 94, and the bottom surface of the lamp housing 80 adjacent to the second CCFL 92 such that the parasitic capacitances C7, C9, C8 between the lamp housing 80 are the same by Equations 1 and 2 described above. By projecting 84 to a predetermined height, the leakage current due to the difference in parasitic capacitances C7, C9, C8 between each of the first to third CCFLs 90, 92, 94 and the lamp housing 80 is minimized. In addition, since the parasitic capacitances C7, C9 and C8 between each of the first to third CCFLs 90, 92 and 94 and the lamp housing 80 are all the same, the first to third CCFLs 90, 92 and 94 are the same. The luminance of can be made uniform. Accordingly, the present invention can easily control the current supplied to each of the first to third CCFLs 90, 92, and 94 from the inverter.

Meanwhile, according to the large screen of the liquid crystal panel, the backlight device uses at least four CCFLs. Each of these multiple CCFLs is disposed in the lamp housing such that parasitic capacitances between the lamp housings are the same, as shown in FIGS. 8 to 10.

Referring to FIG. 8, in the backlight device having four CCFLs 102, 104, 106 and 108, two of the four CCFLs 102, 104, 106 and 108 are adjacent to both side walls of the lamp housing 100. The CCFLs 102 and 108 have a step with the other two CCFLs 104 and 108. That is, the two CCFLs 102, 108 adjacent to the edge of the lamp housing 100 are placed at the bottom of the lamp housing 100 so that the parasitic capacitances between the CCFLs 102, 104, 106, 108 and the lamp housing 100 are the same. It is spaced a predetermined distance from the plane. Accordingly, the parasitic capacitances of each of the lamp housing 100 and the four CCFLs 102, 104, 106, and 108 are the same, thereby minimizing leakage current as described above, and the respective CCFLs 102, 104, 106, and 108. Can be made uniform. Thus, the present invention can easily control the current supplied to each of the four CCFLs 102, 104, 106, and 108 from the inverter.

Referring to FIG. 9, a backlight device according to an embodiment of the present invention having a plurality of CCFLs 1111,..., 111n is a parasitic between the plurality of CCFLs 1111,..., 111n and the lamp housing 110. In order to equalize the capacity, the lamp housing 110 is rounded in the shape of a circle, and the plurality of CCFLs 1111,... 111n are rounded with the lamp housing 110 along the lamp housing 110 rounded in the shape of an arc. Spaced apart to have the same distance. Accordingly, the parasitic capacitance between the plurality of CCFLs 1111,..., 111n and the lamp housing 110 becomes the same. Therefore, it is possible to minimize the leakage current generated between the lamp housing 110 and the plurality of CCFLs 1111,..., And 111n, and to uniformize the luminance of the plurality of CCFLs. . For this reason, the present invention can easily control the current supplied from the inverter to each of the plurality of CCFLs 1111, ..., 111n.

Referring to FIG. 10, a backlight device according to an exemplary embodiment of the present invention having a plurality of CCFLs 1211,..., 121n is a parasitic between the plurality of CCFLs 1211,..., 121n and the lamp housing 120. In order to equalize the capacities, a plurality of CCFLs 1211, ..., 121n are disposed side by side, and a lamp housing 120 surrounding them is disposed at both ends of the plurality of CCFLs 1211, ..., 121n. Except for the CCFLs 1211 and 121n, the bottom surface adjacent to the plurality of CCFLs 1212, ..., 121n-1 has a protrusion 124 protruding to a predetermined height. At this time, the protrusion 124 of the lamp housing 120 protrudes to be equal to the separation distance of the CCFLs 1211 and 121n adjacent to both side walls of the lamp housing 120. Accordingly, the parasitic capacitance between the lamp housing 120 having the protrusion 124 and the plurality of CCFLs 1211,..., 121n becomes equal. Accordingly, the leakage current generated between the lamp housing 120 and the plurality of CCFLs 1211,..., 121n can be minimized, and the luminance of the plurality of CCFLs 1211,..., 121n can be made uniform. . For this reason, the present invention can easily control the current supplied from the inverter to each of the plurality of CCFLs 1211, ..., 121n.

Meanwhile, in the backlight device according to the embodiment of the present invention, three or more CCFLs are disposed in the lamp housing, but the present invention is not limited thereto, and one or two CCFLs may be disposed in the lamp housing in the same manner as the above-described technical concept. have. That is, in the backlight device according to the embodiment of the present invention, at least one CCFL is stored in the lamp housing at a distance from the lamp housing so that the parasitic capacitance with the lamp housing is the same.

As described above, the backlight device according to the embodiment of the present invention is arranged by arranging a plurality of cold cathode fluorescent lamps so that the parasitic capacitance between the plurality of cold cathode fluorescent lamps and the lamp housing, the plurality of cold cathode fluorescent lamps and lamp housings The leakage current generated in the liver can be minimized. In addition, the leakage current generated between the plurality of cold cathode fluorescent lamps and the lamp housing may be minimized by protruding the bottom surface of the lamp housing to a predetermined height such that the parasitic capacitances between the plurality of cold cathode fluorescent lamps and the lamp housing are the same. Therefore, the present invention makes the luminance of the plurality of cold cathode fluorescent lamps uniform. In addition, the present invention has a structure that can easily control the current supplied to a plurality of cold cathode fluorescent lamps.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (6)

Lamp housing, A distance from the lamp housing is set so that the parasitic capacitance with the lamp housing is equal to each other, and one or a plurality of discharge tubes housed in the lamp housing; And a part of the bottom surface of the lamp housing facing the discharge tube is stepped. The method of claim 1, One or a plurality of discharge tubes of the discharge tube is characterized in that the arrangement height is different from the discharge tube. The method of claim 1, And the lamp housing is rounded. delete The method of claim 1, The discharge tubes are arranged side by side, And a portion of the bottom surface of the lamp housing facing one or more discharge tubes except for the discharge tubes disposed at both edges of the lamp housing. The method of claim 1, And a part of a bottom surface of the lamp housing protrudes toward at least one discharge tube except for discharge tubes disposed at both edges of the lamp housing.

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