KR20080001930A - Backlight unit - Google Patents

Abstract

A backlight unit is provided to increase the restriction area of first and second common electrode lines by having first and second sub ribs, thereby reducing humming noise effectively. A backlight unit comprises plural light emitting lamps, first and second lower structures, a common electrode, and first(45a) and second upper structures. The plural light emitting lamps are disposed at regular intervals on the upper part of a cover bottom. The first and second lower structures are formed in a direction along the lower part of both ends of the light emitting lamps. The common electrode is formed in a direction on the upper part of the first and second lower structures. The first and second upper structures have main ribs(46) and sub ribs(46a,46b) capable of restricting the common electrode in a horizontal direction and are formed in a direction in an area corresponding to between the light emitting lamps.

Description

Backlight unit

1 is a perspective view of a conventional direct backlight unit

2 is a partial perspective view of a backlight unit for applying the present invention

3 is a partial perspective view showing the inside of the upper mechanism of FIG.

4A is a partial perspective view of a backlight unit according to an embodiment of the present invention.

Figure 4b is a partial perspective view showing the inside of the upper mechanism according to an embodiment of the present invention

Explanation of symbols on the main parts of the drawings

40: cover bottom 41: light emitting lamp

42a: first external electrode 43: common electrode

44a: first lower mechanism 45a: first upper mechanism

46: main rib 46a, 46b: first and second sub ribs

47: fastening portion 48a, 48b: first, second common electrode line

49: stopper

The present invention relates to a backlight unit, and more particularly, to a backlight unit suitable for reducing humming noise generated at a common electrode when dimming a backlight unit having an external electrode light emitting lamp.

CRT (Cathode Ray Tube), one of the commonly used display devices, is mainly used for monitors such as TVs, measuring devices, and information terminal devices.However, due to the weight and size of the CRT itself, Could not respond actively to demands.

Therefore, in the trend of miniaturization and weight reduction of various electronic products, CRT has a certain limit in weight and size, and is expected to replace the liquid crystal display (LCD) and gas discharge using electro-optic effects. Plasma Display Panels (PDPs) and Electro Luminescence Displays (ELDs) using electroluminescent effects are used. Among them, research on liquid crystal displays is being actively conducted.

In order to replace the CRT, liquid crystal display devices having advantages such as small size, light weight, and low power consumption have been actively developed. Recently, the liquid crystal display device has been developed enough to perform a role as a flat panel display device. As it is used for a monitor of a desktop computer and a large information display device, the demand for a liquid crystal display device is continuously increasing.

Since most of the liquid crystal display devices are light-receiving devices that display images by controlling the amount of light coming from the outside, a separate light source for illuminating the LCD panel, that is, a backlight unit, is necessary.

In general, a backlight unit used as a light source of a liquid crystal display device is a method of disposing a cylindrical light emitting lamp, and is divided into an edge method and a direct method.

In the double-edge method, the lamp unit is installed on the side of the light guide plate for guiding the light, and the lamp unit covers a lamp emitting light, a lamp holder inserted at both ends of the lamp to protect the lamp, and an outer circumferential surface of the lamp, and one side It is provided with a lamp reflector plate fitted to the side of the light guide plate to reflect the light emitted from the lamp toward the light guide plate.

The edge method in which the lamp unit is installed on the side of the light guide plate is applied to a relatively small liquid crystal display device such as a monitor of a laptop computer and a desktop computer, and has good uniformity of light and a long service life. It is advantageous to thin the liquid crystal display device.

On the other hand, the direct type method has been developed mainly as the size of the liquid crystal display device has increased to 20 inches or more. will be.

The direct method is mainly used for a large screen liquid crystal display device requiring high luminance because the light utilization efficiency is higher than that of the edge method.

However, the liquid crystal display device adopting the direct method is used as a large monitor or a television, so it takes longer to use than a laptop computer and the number of lamps is larger, so the liquid crystal of the direct method is lower than the edge type liquid crystal display device. It is more likely that a lamp that will not turn on will appear due to the failure and life of the lamp in the display.

In addition, in the edge method in which the lamp units are installed on both side surfaces of the light guide plate, due to the life and failure of the lamp, for example, when one lamp is not turned on, only the brightness of the screen is lowered. However, in the direct method, since a plurality of lamps are installed at the bottom of the screen, for example, due to the life and failure of the lamp, if one lamp does not light up, the part where the lamp is not lit becomes significantly darker than the other part. The part that does not appear immediately on the screen.

For this reason, since the lamp is frequently replaced in the direct type liquid crystal display device, the direct type liquid crystal display device should have an easy structure for disassembling and assembling the lamp unit.

Hereinafter, a direct type backlight unit according to the prior art will be described with reference to the accompanying drawings.

1 is a perspective view of a conventional direct backlight unit.

As shown in FIG. 1, the conventional backlight unit includes a plurality of light emitting lamps 11 arranged at regular intervals with external electrodes 10a and 10b at both ends of the outside of the tube on the cover bottom 15. ; A common electrode (13) formed in a gripper type to apply a voltage to the electrodes (10a, 10b) across the light emitting lamp (11) and to fix the light emitting lamp (11); It consists of first and second lower mechanisms 14a and 14b formed in one direction under both ends of the light emitting lamps 11 to seat the common electrode 13.

The common electrode 13 is integrally arranged in one direction to apply the same voltage to both ends of the plurality of light emitting lamps 11.

As described above, the light emitting lamps 11 having the external electrodes 10a and 10b at both ends of the tube are simultaneously controlled by the voltage applied through the common electrode 13.

The backlight unit including the external electrode light emitting lamp adjusts dimming by applying a burst mode inverter for the purpose of improving CR and changing luminance.

The dimming control is to turn off the light emitting lamp at a cycle of about 150 to 240 Hz, and repeat the operation of the light emitting lamp. When the AC power is repeatedly applied to the common electrode 13 at the same frequency, the dimming control is performed. In addition, vibration also occurs in the common electrode to which power is applied.

Since a frequency that can be perceived by a human is approximately 20 Hz to 20000 Hz, when vibration is generated by applying a voltage to the common electrode at a frequency as described above, a humming noise that can be perceived by a human is generated.

The present invention has been made to solve the above problems, in particular, to provide a backlight unit suitable for reducing the humming noise (humming noise) generated in the common electrode when dimming the backlight unit having an external electrode light emitting lamp. have.

The backlight unit according to the present invention for achieving the above object comprises a plurality of light emitting lamps arranged at regular intervals on the cover bottom; First and second lower mechanisms formed in one direction along lower ends of the light emitting lamps; A common electrode formed in one direction on the first and second lower mechanisms; In the region corresponding to the light emitting lamps, the first lip and the second lip having a main lip and a sub lip configured to constrain the common electrode are configured in one direction.

In this case, the main lip is arranged in a horizontal direction with the light emitting lamp, the sub-lip is characterized in that it extends in the left and right directions at both ends of the main lip in a direction perpendicular to the main lip.

The common electrode may include a plurality of gripper type fastening parts spaced apart from each other to restrain both ends of the light emitting lamps, and first and second common electrode lines formed at both sides of the fastening part to connect the fastening parts; A stopper formed at an end of the second common electrode line on which the end of each light emitting lamp is seated and a plurality of holes formed at a portion to which a screw is to be fastened, in order to prevent right and left biasing of the light emitting lamp when assembling the light emitting lamp. It consists of.

The main lip is configured so that both ends thereof extend to the first and second common electrode lines of the common electrode, and the first and second sub ribs horizontally press the first and second common electrode lines. Consists of.

Further, light scattering means such as a diffusion sheet and a diffusion plate that scatter light emitted from the light emitting lamp is further disposed on the upper side of the light emitting lamp.

Prior to describing the configuration according to the embodiment of the present invention having the above characteristics, a brief description of the backlight unit for preventing the humming noise for application to the present invention will be given below.

FIG. 2 is a partial perspective view of a backlight unit for applying the present invention, and FIG. 3 is a partial perspective view showing the inside of the upper mechanism of FIG. 2.

As shown in FIGS. 2 and 3, the backlight unit for applying the present invention has a first external electrode 20a and a second external electrode (not shown) at both ends of the tube on the top of the cover bottom 30. A plurality of light emitting lamps 21 arranged at regular intervals and a gripper type for applying a voltage to the first and second external electrodes on both ends of the light emitting lamp 21 and fixing the light emitting lamp 21. A first lower mechanism 24a and a second lower mechanism (not shown) formed in one direction under both ends of the light emitting lamps 21 to seat the common electrode 23, and the common electrode 23. In an upper portion corresponding to the first and second lower mechanisms, the first upper mechanism 25a and the second upper mechanism (not shown) are configured.

The common electrode 23 is seated in one direction on top of the first lower mechanism 24a and the second lower mechanism.

A plurality of ribs 26 are provided in the first upper mechanism 25a and the second upper mechanism to fix the common electrode 23.

In this case, the ribs 26 are formed in a line shape at portions corresponding to the light emitting lamps 21.

When the first upper mechanism 25a and the second upper mechanism configured as described above are fastened to the upper portion of the first lower mechanism 24a and the second lower mechanism, the lip of the first upper mechanism 25a and the second upper mechanism ( The end of the rib 26 fixes the common electrode 23 while forcibly pressing the common electrode 23 disposed on the upper portion of the first lower mechanism 24a and the second lower mechanism.

As described above, in the backlight unit, both ends of the ribs 26 formed in the first upper mechanism 25a and the second upper mechanism are pressed against the common electrode 23 from the top. In addition, the vibration generated from the first and second lower mechanisms and the common electrode when the power for dimming is applied is reduced.

However, the above configuration in which the common electrode is pressed using only both ends of the rib has a limitation in reducing the humming noise caused by the vibration generated in the first and second lower mechanisms and the common electrode.

Accordingly, the present invention proposes a configuration that can more effectively reduce the humming noise generated from the common electrode.

Hereinafter, a backlight unit according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

4A is a partial perspective view of a backlight unit according to an embodiment of the present invention, and FIG. 4B is a partial perspective view showing the inside of an upper mechanism according to an embodiment of the present invention.

In the backlight unit according to the exemplary embodiment of the present invention, as illustrated in FIGS. 4A and 4B, the first external electrode 42a and the second external electrode (not shown) are disposed at both ends of the tube on the cover bottom 40. And a plurality of light emitting lamps 41 arranged at regular intervals, and applying voltage to the first external electrode 42a and the second external electrode at both ends of the light emitting lamp 41 and fixing the light emitting lamp 41. A common electrode 43 having a fastening portion 47 formed in a gripper type, and a first lower portion formed in one direction at both ends of the light emitting lamps 41 to seat the common electrode 43. The instrument 44a and the second lower instrument (not shown), and the first upper instrument 45a and the second upper instrument (not shown) configured at an upper portion corresponding to the first lower instrument 44a and the second lower instrument. It consists of.

Although not shown in the drawing, the first lower mechanism 44a and the second lower mechanism are further provided with grooves between the light emitting lamps 41.

The common electrode 43 is mounted in one direction on top of the first lower mechanism 44a and the second lower mechanism.

In detail, the common electrode 43 includes a plurality of fastening parts 47 formed with a slit and spaced apart from each other to restrain the first and second external electrodes at both ends of each light emitting lamp 41; The first and second common electrode lines 48a and 48b formed at both sides of the coupling part 47 to connect the coupling parts 47 and each of the light emitting lamps 41 to prevent the left and right of the light emitting lamp 41 from being assembled. Fixing the stopper 49 and the common electrode 43 which are formed in the vertical direction at the end of the outer common electrode line on which the end of the light emitting lamp 41 is seated, and the first and second lower mechanisms. It consists of a plurality of holes (not shown) formed in the portion to be screwed for. In the above, the fastening part 47 is formed to surround the light emitting lamp 41 in a gripper type, and two or more slits are formed in the middle thereof, so that the fastening part 47 may be caused by a processing tolerance rather than a single plate. The contact failure with the light emitting lamp 41 can be reduced, and the electrical continuity / conductivity can be improved by maximizing the contact area with the light emitting lamp 41.

In addition, a plurality of mains are arranged in one direction at regular intervals to fix the common electrode 43 in the first upper mechanism 45a and the second upper mechanism corresponding to the light emitting lamps 41. A rib 46 and first and second sub-lips 46a and 46b extending from the left and right directions at both ends of the main lip 46 in a direction perpendicular to the main lip 46 are formed.

In this case, the main ribs 46 are formed so that both ends thereof extend to the first and second common electrode lines 48a and 48b of the common electrode 43, and the first and second sub ribs 46a and 46b. ) Is configured to press the first and second common electrode lines 48a and 48b horizontally.

When the first and second upper mechanisms configured as described above are fastened to the upper portions of the first and second lower mechanisms, the main ribs 46 of the first upper mechanism 45a and the second upper mechanism (not shown) are provided. And the common electrode 43 is fixed by forcibly pressing the common electrode 43 in the direction of the arrow shown in FIG. 4A of the first and second sub ribs 46a and 46b.

As described above, the first and second sub ribs 46a and 46b are further provided to increase the restraint region of the first and second common electrode lines 48a and 48b which are components of the common electrode 43. do. By increasing the restraint regions of the first and second common electrode lines 48a and 48b as described above, the humming noise due to the vibration generated from the common electrode 43 when the power for dimming is applied can be reduced more effectively. It becomes possible.

In addition, although not shown in the drawing, a diffusion sheet scatters the light emitted from the light emitting lamp 41 so that a uniform light source distribution is formed on the display surface of the liquid crystal panel above the light emitting lamp 41. And light scattering means such as a diffusion plate.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the above embodiments, but should be defined by the claims.

The backlight unit according to the present invention as described above has the following effects.

When the power supply for dimming the backlight unit having the external electrode light emitting lamp is applied, vibration generated from the common electrode and the resulting humming noise can be reduced more effectively.

Claims (6)

A plurality of light emitting lamps arranged on the cover bottom at regular intervals; First and second lower mechanisms formed in one direction along lower ends of the light emitting lamps; A common electrode formed in one direction on the first and second lower mechanisms; And a first upper part and a second upper part configured in one direction, the main lip and the sub lip configured to constrain the common electrode in a horizontal direction in a region corresponding to the light emitting lamps. The method of claim 1, The main lip is arranged in a horizontal direction with the light emitting lamp, The sub lip is a backlight unit, characterized in that extending in left and right directions at both ends of the main lip in a direction perpendicular to the main lip. The method of claim 1, The common electrode may include a plurality of gripper-type fastening portions formed to be spaced apart from each other to restrain both ends of the light emitting lamps; First and second common electrode lines formed at both sides of the coupling part to connect the coupling parts; A stopper formed at an end of the second common electrode line on which an end of each of the light emitting lamps is seated, in order to prevent right and left biasing of the light emitting lamps during assembly of the light emitting lamps; Backlight unit, characterized in that consisting of a plurality of holes formed in the part to be screwed. The method according to claim 1 or 3, And the main lip is configured such that both ends thereof extend to the first and second common electrode lines of the common electrode. The method according to claim 1 or 3, And the first and second sub ribs are configured to horizontally press the first and second common electrode lines. The method of claim 1, And a light scattering means such as a diffusion sheet and a diffusion plate that scatter light emitted from the light emitting lamp above the light emitting lamp.

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