KR20030081728A - Apparatus of back light - Google Patents

Abstract

PURPOSE: A back light unit is provided to change arrangement of lamps or structure of a lamp housing to minimize leakage current of the lamps. CONSTITUTION: A back light unit includes a lamp housing(50) and at least one discharge tube(40,42,44) contained in the lamp housing. The discharge tubes have the same parasitic capacitance with the lamp housing. At least one discharge tube has a height different from the height of the other discharge tubes. The lamp housing is rounded. The portion of the bottom face(54) of the lamp housing, which faces at least one discharge tube, is stepped. The discharge tubes are arranged in parallel, and the portion of the bottom face of the lamp housing, which faces at least one discharge tube other than discharge tubes located at both sides of the lamp housing, is stepped.

Description

Backlight device {APPARATUS OF BACK LIGHT}

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") have tended to expand their application ranges due to features such as 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 tube (hereinafter referred to as "CCFL") is used.

CCFL is a light source tube using the Cold EmISsion phenomenon, which is easy to generate low heat, high brightness, long life, and full color. These CCFLs include a light guide type, a direct type type, a reflecting plate type, and the like, and a light source tube suitable for the type of LCD is adopted.

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 AC voltage is applied from an inverter (not shown) to the cathode and the anode of each of the first to third CCFLs 20, 22, and 24, electrons are emitted from the cathode and collide with inert gases inside the glass tube to exponentially. This increases the amount of electrons. 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. .

As described above, when the first to third CCFLs 20, 22, and 24 are driven, the first to third CCFLs 20, depending on the parasitic capacitance or the floating capacity of each of the first to third CCFLs 20, 22, and 24, respectively. Leakage current occurs in each of 22 and 24). 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.

As described above, the 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, the lamp housing 10, and the CCFL is expressed by Equation 1 below.

In Equation 1, [epsilon] s is a permittivity of CCFL and d is a distance from 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 of the lamp housing 10. The parasitic capacitance between the second CCFL 22 and the lamp housing 10 is between the bottom surface of the lamp housing 14. The parasitic capacitance between the third CCFL 24 and the lamp housing 10 is present between the right side wall 16 of the lamp housing 10 and the bottom surface 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 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 such, the parasitic capacitance generated differently in each of the first and second 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. Therefore, leakage current is generated by parasitic capacitance generated differently in each of the first and second CCFLs 20 and 24 and the second CCFL 22 so that the current of each of the first to third CCFLs 20, 22 and 24 is 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.

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

In order to achieve the above object, the backlight device according to an embodiment of the present invention is a lamp housing, at least one or more distance is set in the lamp housing is set so that the parasitic capacitance between the lamp housing and the same; And discharge tubes.

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

In the backlight device, the lamp housing is rounded.

The bottom surface of the lamp housing in the backlight device is characterized in that the step facing the at least one discharge tube.

In the backlight device, the discharge tubes are arranged side by side, and the bottom surface of the lamp housing is characterized in that the part facing the at least one discharge tube except for the discharge tubes disposed at both edges of the lamp housing is stepped.

In the backlight device, the bottom surface of the lamp housing may be stepped 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 AC voltage is applied from an inverter (not shown) to the cathode and the anode of each of the first to third CCFLs 40, 42, and 44, electrons are emitted from the cathode and collide with inert gases inside the glass tube to exponentially. This increases the amount of electrons. 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.

As such, when the first to third CCFLs 40, 42, and 44 are driven, the first to third CCFLs 40, depending on the parasitic capacity or the floating capacity of each of the first to third CCFLs 40, 42, and 44, respectively. Leakage current is generated in each of 42 and 44. 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 form 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 The luminance can be made uniform. Accordingly, the present invention can easily control the current supplied from the inverter to each of the first to third CCFLs 40, 42, and 44.

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 current 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). This increases the amount of electrons. 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, and proceeds to the side and the rear of the first to third CCFLs 70, 72, and 74. It serves to reflect 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).

As such, when the first to third CCFLs 70, 72, and 74 are driven, parasitic capacitances of the first to third CCFLs 70, 72, and 74 may be used to control the first to third CCFLs 70, 72, and 74. In each case, leakage current occurs. 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, C5 and C6 are all the same.

As described above, in the backlight device according to the second embodiment of the present invention, the parasitic capacitances C4, C5, and C6 between the first to third CCFLs 70, 72, and 74 and the lamp housing 60 are described above. By arranging the lamp housing 60 in a triangular form so as to be the same as 1 and 2, and wrapping the first to third CCFLs 70, 72, 74 in the rounded lamp housing 60, Leakage current due to the difference in the parasitic capacitance (C4, C5, C6) between the first to third CCFL (70, 72, 74) and the lamp housing 60 is minimized. In addition, since the parasitic capacitances C4, C5 and C6 between the first to third CCFLs 70, 72 and 74 and the lamp housing 60 are all the same, the first to third CCFLs 70, 72 and 74 are the same. The luminance of can be made uniform. Accordingly, the present invention can easily control the current supplied from the inverter to each of the first to third CCFLs 70, 72, and 74.

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 AC voltage is applied from an inverter (not shown) to the cathode and the anode of each of the first to third CCFLs 90, 92, and 94, electrons are emitted from the cathode and collide with inert gases inside the glass tube to exponentially. This increases the amount of electrons. 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).

As such, 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, leakage current occurs. 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 C3 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 capacitances C4, C5, and C6 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 C4, C5, C6 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 capacitance C7, C8, C9 between each of the first to third CCFLs 90, 92, 94 and the lamp housing 80 is minimized. Further, since the parasitic capacitances C7, C8, and C9 are the same between each of the first to third CCFLs 90, 92, and 94 and the lamp housing 80, 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 from the inverter to each of the first to third CCFLs 90, 92, and 94.

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. As a result, the present invention can easily control the current supplied from the inverter to each of the four CCFLs 102, 104, 106, and 108.

Referring to FIG. 9, a backlight device according to an embodiment of the present invention having a plurality of CCFLs 1111,..., 11n may include a parasitic between the plurality of CCFLs 1111,..., 11n and the lamp housing 110. In order to equalize the capacity, the lamp housing 110 is rounded in the form of a circle, and the plurality of CCFLs 1111,... 11n are connected to the lamp housing 110 along the lamp housing 110 rounded in the form of an arc. Spaced apart to have the same distance. Accordingly, the parasitic capacitance between the plurality of CCFLs 1111,... 11n and the lamp housing 110 becomes the same. Accordingly, the leakage current generated between the lamp housing 110 and the plurality of CCFLs 1111, ..., 11n can be minimized, and the luminance of the plurality of CCFLs 1111, ..., 11n 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 1111, ..., 11n.

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 an exemplary 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 an exemplary embodiment of the present invention arranges a plurality of cold cathode tubes such that parasitic capacitances are the same between the plurality of cold cathode tubes and the lamp housing, thereby preventing leakage current generated between the plurality of cold cathode tubes and the lamp housing. It can be minimized. In addition, the leakage current generated between the plurality of cold cathode tubes 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 tubes and the lamp housing are the same. Therefore, the present invention makes the luminance of the plurality of cold cathode tubes uniform. In addition, the present invention has a structure that can easily control the current supplied to the plurality of cold cathode tubes.

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, And at least one discharge tube accommodated in the lamp housing, the distance from the lamp housing being set so that the parasitic capacitance with the lamp housing is equal to each other. The method of claim 1, At least one discharge tube 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. The method of claim 1, The bottom surface of the lamp housing is characterized in that the step facing the at least one discharge tube is stepped. The method of claim 1, The discharge tubes are arranged side by side, The bottom surface of the lamp housing is a backlight device, characterized in that the step facing the other at least one discharge tube except for the discharge tube disposed at both edges of the lamp housing. The method of claim 4, wherein And a bottom surface of the lamp housing is stepped toward at least one discharge tube except for discharge tubes disposed at both edges of the lamp housing.