KR101469476B1 - backlight unit - Google Patents

Abstract

The present invention relates to a backlight unit capable of reducing the number of light sources and reducing the generation of heat and manufacturing cost while preventing the luminance from being lowered by adjusting the arrangement of the light sources, and more particularly, to a backlight unit having a plurality of light sources And a bottom cover having a light source group formed therein; The interval between adjacent light source groups gradually increases from the central portion of the bottom cover to the edge of the bottom cover.

Backlight unit, luminance, light source group, interval, light emitting diode

Description

Backlight unit {BACKLIGHT UNIT}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight unit, and more particularly, to a backlight unit capable of reducing manufacturing cost by reducing the number of light sources.

A display device includes a light emitting display device such as a cathode ray tube, an organic electro-luminescence display, a plasma display (PDP), and a liquid crystal display, There is a light-receiving-type display device which can not generate light by itself and requires a separate light source.

A typical liquid crystal display device includes two display panels provided with field generating electrodes and a liquid crystal layer having a dielectric anisotropy therebetween. A voltage is applied to the field generating electrode to generate an electric field in the liquid crystal layer, and the intensity of the electric field is controlled by changing the voltage, thereby adjusting the transmittance of light passing through the liquid crystal layer to obtain a desired image. The light at this time may be an artificial light source or a natural light separately.

As a light source for a liquid crystal display device, a plurality of lamps are generally used. As a light source that transmits light evenly to the entire liquid crystal panel from the rear side of the liquid crystal panel, an external electrode fluorescent lamp (EEFL) A fluorescent lamp such as a cold cathode fluorescent lamp (CCFL) or a light emitting diode (LED) is used.

A major advantage of a light emitting diode backlight for a liquid crystal display device which is being actively researched and developed at present is to provide an optimal color tone desired by a user.

However, in such a light emitting diode used as a light source of a backlight unit, the light efficiency is drastically changed by heat. This causes a sensitive balance between the external environment of the liquid crystal display device and the internal heat source, resulting in the collapse of the color balance.

In particular, since a large number of light emitting diodes are provided in the backlight unit of a large-area display device, the above-described problems are further exacerbated. In addition, the manufacturing cost of the backlight unit increases as the number of the light emitting diodes increases.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems described above, and it is an object of the present invention to provide a backlight unit capable of reducing the number of light sources and increasing the reliability of a light source by controlling the arrangement of the light sources, The purpose is to provide.

According to an aspect of the present invention, there is provided a backlight unit including a bottom cover having a plurality of light source groups including a plurality of light sources arranged in one direction, The interval between adjacent light source groups gradually increases from the central portion of the bottom cover to the edge of the bottom cover.

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

First, since the number of light sources can be reduced, heat generated from the light source can be reduced, and manufacturing cost can be reduced.

Secondly, since the interval between the adjacent light source groups gradually increases from the central portion of the bottom cover toward the edge of the bottom cover, the number of light sources included in the light source group can be reduced.

Third, by increasing the interval between the edges of the bottom cover, the light sources are concentrated at the central portion of the bottom cover, thereby enabling low current driving and lowering the power consumption.

Hereinafter, the backlight unit of the present invention will be described in detail with reference to the accompanying drawings.

1st Example

1 is a view illustrating a backlight unit according to a first embodiment of the present invention.

1, the backlight unit according to the first embodiment of the present invention includes a bottom cover 310 (see FIG. 1) in which a plurality of light source groups LG1 to LG12 including a plurality of light sources L arranged in one direction are formed, ); The interval between the adjacent light source groups is gradually increased from the center of the bottom cover 310 toward the edge of the bottom cover 310.

The light source groups LG1 to LG12 include a plurality of light sources L arranged in a line along the longitudinal direction of the short side of the bottom cover 310, that is, the Y axis direction. The light source groups LG1 to LG12 having such a configuration are arranged along the longitudinal direction of the bottom cover 310, that is, along the X axis direction.

As shown in FIG. 1, the intervals dy between the light sources L included in one light source group are all the same.

The number of the light sources L included in each of the light source groups LG1 to LG12 is the same and the light sources L included in each of the light source groups LG1 to LG12 correspond one to one. The light sources L included in the respective light source groups LG1 to LG12 and corresponding to each other are arranged along the X-axis direction.

At this time, the distance between the light sources L included in the adjacent light source groups and corresponding to each other gradually increases from the center of the bottom cover 310 to the edge of the bottom cover 310.

This will be described in more detail as follows.

First, the light source groups LG1 to LG12 include a central light source group positioned at the center of the bottom cover 310; A plurality of first peripheral light source groups positioned between one side edge of the central light source group and the bottom cover 310; And a plurality of second peripheral light source groups positioned between the central light source group and the other edge of the bottom cover 310. [

The central light source group refers to two light source groups located closest to the center of the bottom cover 310 among the plurality of light source groups LG1 to LG12. That is, the central light source group includes a first light source group LG1 positioned closest to one side of the center of the bottom cover 310 and a second light source group LG2 located closest to the other side of the center of the bottom cover 310. [ (LG2).

The first peripheral light source groups refer to third to seventh light source groups LG3 to LG7 positioned between the left side of the first light source group LG1 and the left side edge of the bottom cover 310, The light source groups refer to the eighth to twelfth light source groups LG8 to LG12 located between the right side of the second light source group LG2 and the right side edge of the bottom cover 310. [

Here, the interval between the adjacent central light source groups and the first peripheral light source groups gradually increases from the central portion of the bottom cover 310 to one side edge of the bottom cover 310; The interval between the adjacent central light source groups and the second peripheral light source groups gradually increases from the central portion of the bottom cover 310 to the other edge of the bottom cover 310.

In other words, the interval between the adjacent first, third, fourth, fifth, sixth, and seventh light source groups LG1, LG3, LG4, LG5, LG6, Gradually increases from the central portion to one side edge of the bottom cover 310; The gap between the second, eighth, ninth, tenth, eleventh, and twelfth light source groups LG2, LG8, LG9, LG10, LG11, LG12 adjacent to each other is larger than the distance from the center of the bottom cover 310 And gradually increases toward the other edge of the bottom cover 310.

1, a first distance dx1 between the first light source group LG1 and the third light source group LG3, a third light source group LG3 and a fourth light source group LG4, for example, A third gap dx3 between the fourth light source group LG4 and the fifth light source group LG5 and a fourth gap dx2 between the fifth light source group LG5 and the sixth light source group LG6, and the fifth interval dx5 between the sixth light source group LG6 and the seventh light source group LG7 are different from each other. Specifically, the first interval dx1 between the first light source group LG1 and the third light source group LG3 nearest to the center of the bottom cover 310 is the smallest and the farthest from the center of the bottom cover 310 The fifth interval (dx5) between the seventh light source group LG7 and the sixth light source group LG6 is the largest. In other words, the second spacing dx2 is greater than the first spacing dx1, the third spacing dx3 is greater than the second spacing dx2, and the fourth spacing dx4 is greater than the third spacing dx2, (dx3), and the fifth interval (dx5) is larger than the fourth interval (dx4).

Similarly, the sixth interval dx6 between the second light source group LG2 and the eighth light source group LG8, the seventh interval dx7 between the eighth light source group LG8 and the ninth light source group LG9, (Dx8) between the tenth light source group LG9 and the tenth light source group LG10, the ninth gap dx9 between the tenth light source group LG10 and the eleventh light source group LG11, LG11) and the twelfth light source group (LG12) have different sizes. Specifically, the sixth interval dx6 between the second light source group LG2 and the eighth light source group LG8 nearest to the center of the bottom cover 310 is the smallest, And the tenth interval (dx10) between the twelfth light source group LG12 and the eleventh light source group LG11 is the largest. In other words, the seventh interval dx7 is greater than the sixth interval dx6, the eighth interval dx8 is greater than the seventh interval dx7, Is greater than the spacing (dx8), and the tenth spacing (dx10) is greater than the ninth spacing (dx9).

The first gap dx1 and the sixth gap dx6 are of the same size and the second gap dx2 and the seventh gap dx7 are of the same size and the third gap dx3 and the eighth gap dx8 are equal. The fourth interval dx4 and the ninth interval dx9 have the same size and the fifth interval dx5 and the tenth interval dx10 have the same size.

Of course, the first interval dx1 and the sixth interval dx6 may be set to different sizes, the second interval dx2 and the seventh interval dx7 may be set to different sizes, and the third interval dx3 The fourth interval dx4 and the ninth interval dx9 are set to have different sizes and the fifth interval dx5 and the tenth interval dx10 are set to be different from each other. May be set to different sizes.

The size of such an interval can be increased at a constant rate of increase.

For example, the second spacing dx2 is 0.2 mm greater than the first spacing dx1, the third spacing dx3 is 0.2 mm greater than the second spacing dx2, (Dx3), and the fifth interval (dx5) may be 0.2 mm larger than the fourth interval (dx4). The sixth to tenth intervals dx10 may also increase at an increasing rate as described above.

The interval between the first light source group LG1 and the second light source group LG2 may be the same as the interval between the first light source group LG1 and the third light source group LG3.

The above-mentioned interval means the interval between light sources L located in different light source groups adjacent to each other and corresponding to each other. For example, the first interval dx1 corresponds to one light source L1 positioned in the first light source group LG1 and one light source L1 corresponding to the light source L1 and located in the third light source group LG3, (L2).

Second Example

2 is a view illustrating a backlight unit according to a second embodiment of the present invention.

2, each of the light source groups LG1 to LG12 includes a plurality of light sources L arranged in a row along the longitudinal direction of the long side of the bottom cover 310, that is, along the X axis direction. The light source groups LG1 to LG8 having such a configuration are arranged along the longitudinal direction of the bottom cover 310, that is, the Y-axis direction.

As shown in FIG. 2, the intervals dx between the light sources L included in one light source group are all the same.

The number of the light sources L included in each of the light source groups LG1 to LG8 is the same and the light sources L included in each of the light source groups LG1 to LG8 correspond one to one. The light sources L included in the respective light source groups LG1 to LG8 and corresponding to each other are arranged along the Y-axis direction.

At this time, the distance between the light sources L included in the adjacent light source groups and corresponding to each other gradually increases from the center of the bottom cover 310 to the edge of the bottom cover 310.

This will be described in more detail as follows.

First, the light source groups include a central light source group positioned at the center of the bottom cover 310; A plurality of first peripheral light source groups positioned between one side edge of the central light source group and the bottom cover 310; And a plurality of second peripheral light source groups positioned between the central light source group and the other edge of the bottom cover 310. [

The central light source group refers to two light source groups located closest to the center of the bottom cover 310 among the plurality of light source groups LG1 to LG12. That is, the central light source group includes a first light source group LG1 positioned closest to one side of the center of the bottom cover 310 and a second light source group LG2 located closest to the other side of the center of the bottom cover 310. [ (LG2).

The first peripheral light source groups LG3 through LG5 are positioned between the upper side of the first light source group LG1 and the upper side edge of the bottom cover 310, The light source groups refer to the sixth to eighth light source groups LG6 to LG8 positioned between the lower side of the second light source group LG2 and the lower side edge of the bottom cover 310. [

Here, the interval between the adjacent central light source groups and the first peripheral light source groups gradually increases from the central portion of the bottom cover 310 to the upper edge of the bottom cover 310; The interval between the adjacent central light source groups and the second peripheral light source groups gradually increases from the central portion of the bottom cover 310 to the lower edge of the bottom cover 310.

In other words, the gap between the first, third, fourth, and fifth light source groups LG1, LG3, LG4, LG5 adjacent to each other is smaller than the distance from the center of the bottom cover 310 to one side Increasing gradually towards the edge; As the distance between the adjacent second, sixth, seventh and eighth light source groups LG2, LG6, LG7 and LG8 decreases from the center of the bottom cover 310 to the other edge of the bottom cover 310 Increase.

For example, as shown in FIG. 2, a first distance dy1 between the first light source group LG1 and the third light source group LG3, a third light source group LG3 and a fourth light source group LG4, And the third interval dy3 between the fourth light source group LG4 and the fifth light source group LG5 have different sizes. Specifically, the first interval dy1 between the first light source group LG1 and the third light source group LG3 nearest to the center of the bottom cover 310 is the smallest and the farthest from the center of the bottom cover 310 The third interval dy3 between the fifth light source group LG5 and the fourth light source group LG4 is the largest. In other words, the second spacing dy2 is greater than the first spacing dy1, and the third spacing dy3 is greater than the second spacing dy2.

Similarly, the fourth interval dy4 between the second light source group LG2 and the sixth light source group LG6, the fifth interval dy5 between the sixth light source group LG6 and the seventh light source group LG7, The sixth intervals dy6 between the seventh light source group LG7 and the eighth light source group LG8 have different sizes. Specifically, the fourth interval dy4 between the second light source group LG2 and the sixth light source group LG6 nearest to the center of the bottom cover 310 is the smallest, The sixth interval dy6 between the eighth light source group LG8 and the seventh light source group LG7 is the largest. In other words, the fifth interval dy5 is larger than the fourth interval dy4, and the sixth interval dy6 is larger than the fifth interval dy5.

The first gap dy1 and the fourth gap dy4 are of the same size and the second gap dy2 and the fifth gap dy5 are of the same size and the third gap dy3 and the sixth gap dy6 are the same. Are the same size.

Of course, the first interval dy1 and the fourth interval dy4 may be set to different sizes, the second interval dy2 and the fifth interval dy5 may be set to different sizes, and the third interval dy3 And the sixth interval dy6 may be set to different sizes.

The size of such an interval can be increased at a constant rate of increase.

For example, the second spacing dy2 may be 0.2 mm greater than the first spacing dy1, and the third spacing dy3 may be 0.2 mm greater than the second spacing dx2. The fourth to sixth intervals dy4 to dy6 may also increase at an increasing rate as described above.

The interval between the first light source group LG1 and the second light source group LG2 may be the same as the interval between the first light source group LG1 and the third light source group LG3.

The above-mentioned interval means the interval between light sources L located in different light source groups adjacent to each other and corresponding to each other. For example, the first interval dx1 corresponds to one light source L1 positioned in the first light source group LG1 and one light source L1 corresponding to the light source L and located in the third light source group LG3, (L2).

Third Example

3 is a view illustrating a backlight unit according to a third embodiment of the present invention.

3, the backlight unit according to the third embodiment of the present invention includes a bottom cover 310 (see FIG. 3) having a plurality of light source groups LG1 to LG12 including a plurality of light sources L arranged in one direction, ); The interval between the adjacent light source groups is gradually increased from the center of the bottom cover 310 toward the edge of the bottom cover 310.

The light source groups LG1 to LG12 include a plurality of light sources L arranged in a line along the longitudinal direction of the short side of the bottom cover 310, that is, the Y axis direction. The light source groups LG1 to LG12 having such a configuration are arranged along the longitudinal direction of the bottom cover 310, that is, along the X axis direction.

The number of the light sources L included in each of the light source groups LG1 to LG12 is the same and the light sources L included in each of the light source groups LG1 to LG12 correspond one to one. The light sources L included in the respective light source groups LG1 to LG12 and corresponding to each other are arranged along the X-axis direction.

At this time, the distance between the light sources L included in the adjacent light source groups and corresponding to each other gradually increases from the center of the bottom cover 310 to the edge of the bottom cover 310. A detailed description thereof will be omitted in the description of the first embodiment.

In the meantime, according to the backlight unit according to the third embodiment of the present invention, the interval of the adjacent light sources L included in one light source group increases gradually from the center of the light source group to the edge of the bottom cover 310 do.

3, when the first light source group LG1 includes the first to eighth light sources L1 to L8, the first light source L1 and the third light source L3 are arranged in a matrix, A third interval dy3 between the fourth light source L4 and the fifth light source L5 and a second interval dy2 between the third light source L3 and the fourth light source L4, Have different sizes. The first light source L1 and the second light source L2 positioned closest to the center of the first light source group LG1 among the first to eighth light sources L1 to L8, dy1 is the smallest and the third distance dy3 between the fourth light source L4 and the fifth light source L5 located farthest from the center is the largest. In other words, the second spacing dy2 is greater than the first spacing dy1, and the third spacing dy3 is greater than the second spacing dy2.

Similarly, the fourth interval dy4 between the second light source L2 and the sixth light source L6, the fifth interval dy5 between the sixth light source L6 and the seventh light source L7, And the sixth interval dy6 between the eighth light source L7 and the eighth light source L8 have different sizes. Specifically, the fourth interval dy4 between the second light source L and the sixth light source L positioned closest to the center of the first through eighth light sources L1 through L8 is the smallest, The sixth gap dy6 between the seventh light source L7 and the eighth light source L8 located farthest is the largest. In other words, the fifth interval dy5 is larger than the fourth interval dy4, and the sixth interval dy6 is larger than the fifth interval dy5.

The first gap dy1 and the fourth gap dy4 are of the same size and the second gap dy2 and the fifth gap dy5 are of the same size and the third gap dy3 and the sixth gap dy6 are the same. Are the same size.

Of course, the first interval dy1 and the fourth interval dy4 may be set to different sizes, the second interval dy2 and the fifth interval dy5 may be set to different sizes, and the third interval dy3 And the sixth interval dy6 may be set to different sizes.

In addition, the interval increasing rate between the light sources L included in the adjacent adjacent light source groups and corresponding to each other may be the same as the interval increasing rates of the adjacent light sources L included in one light source group, have.

For example, the spacing increase rate between the light sources L included in the adjacent light source groups and corresponding to each other may be 0.2 mm as described above. The spacing between adjacent light sources L included in one light source group The rate of increase may be 0.2 mm or may have other values.

Fourth Example

4 is a view illustrating a backlight unit according to a fourth embodiment of the present invention.

The backlight unit according to the fourth embodiment of the present invention is similar to the first embodiment shown in Fig. However, the backlight unit according to the fourth embodiment of the present invention, as shown in Fig. And the first light source group LG1 is positioned at the center line dividing the bottom cover 310 into left and right sides.

Since the remaining configuration is the same as that of the first embodiment described above, the description of the remaining configuration is replaced by the description of the first embodiment.

Fifth Example

5 is a view illustrating a backlight unit according to a fifth embodiment of the present invention.

The backlight unit according to the fifth embodiment of the present invention is similar to the second embodiment shown in Fig. However, the backlight unit according to the fifth embodiment of the present invention, as shown in FIG. And the first light source group LG1 is located at the center line dividing the bottom cover 310 into upper and lower portions.

The rest of the configuration is the same as that of the second embodiment described above, so the description of the remaining configuration is replaced with the description of the second embodiment.

6th Example

6 is a view illustrating a backlight unit according to a sixth embodiment of the present invention.

The backlight unit according to the sixth embodiment of the present invention is similar to the third embodiment shown in Fig. However, the backlight unit according to the sixth embodiment of the present invention, as shown in Fig. And the first light source group LG1 is positioned at the center line dividing the bottom cover 310 into left and right sides.

The rest of the configuration is the same as that of the third embodiment described above, so that the description of the remaining configuration is replaced with the description of the third embodiment.

Seventh Example

7 is a view illustrating a backlight unit according to a seventh embodiment of the present invention.

The backlight unit according to the seventh embodiment of the present invention is similar to the first embodiment shown in Fig. However, the backlight unit according to the seventh embodiment of the present invention, as shown in Fig. The light sources L included in the adjacent light source groups form a zigzag arrangement. That is, the light sources L included in the odd-numbered light source group are shifted to be positioned closer to the lower side of the bottom cover 310 than the light sources L included in the even-numbered light source group.

Since the remaining configuration is the same as that of the first embodiment described above, the description of the remaining configuration is replaced by the description of the first embodiment.

Eighth Example

8 is a view illustrating a backlight unit according to an eighth embodiment of the present invention.

The backlight unit according to the eighth embodiment of the present invention is similar to the second embodiment shown in Fig. However, in the backlight unit according to the eighth embodiment of the present invention, as shown in Fig. The light sources L included in the adjacent light source groups form a zigzag arrangement. That is, the light sources L included in the odd-numbered light source group are shifted to be located closer to the right side of the bottom cover 310 than the light sources L included in the even-numbered light source group.

The rest of the configuration is the same as that of the second embodiment described above, so the description of the remaining configuration is replaced with the description of the second embodiment.

9th Example

9 is a view illustrating a backlight unit according to a ninth embodiment of the present invention.

The backlight unit according to the ninth embodiment of the present invention is similar to the third embodiment shown in Fig. However, the backlight unit according to the ninth embodiment of the present invention, as shown in Fig. The light sources L included in the adjacent light source groups form a zigzag arrangement. That is, the light sources L included in the odd-numbered light source group are shifted to be positioned closer to the lower side of the bottom cover 310 than the light sources L included in the even-numbered light source group.

The rest of the configuration is the same as that of the third embodiment described above, so that the description of the remaining configuration is replaced with the description of the third embodiment.

Article 10 Example

10 is a view illustrating a backlight unit according to a tenth embodiment of the present invention.

The backlight unit according to the tenth embodiment of the present invention is similar to the third embodiment shown in Fig. However, the backlight unit according to the tenth embodiment of the present invention is, as shown in Fig. The light sources L included in the adjacent light source groups form a zigzag arrangement. That is, the light sources L included in the odd-numbered light source group are shifted to be located closer to the left side of the bottom cover 310 than the light sources L included in the even-numbered light source group.

The rest of the configuration is the same as that of the third embodiment described above, so that the description of the remaining configuration is replaced with the description of the third embodiment.

Eleventh Example

11 is a view illustrating a backlight unit according to an eleventh embodiment of the present invention.

The backlight unit according to the eleventh embodiment of the present invention is similar to the fourth embodiment shown in Fig. However, the backlight unit according to the eleventh embodiment of the present invention, as shown in Fig. The light sources L included in the adjacent light source groups form a zigzag arrangement. That is, the light sources L included in the odd-numbered light source group are shifted to be positioned closer to the lower side of the bottom cover 310 than the light sources L included in the even-numbered light source group.

Since the remaining configuration is the same as that of the fourth embodiment described above, the description of the remaining configuration is replaced with the description of the fourth embodiment.

Article 12 Example

12 is a view illustrating a backlight unit according to a twelfth embodiment of the present invention.

The backlight unit according to the twelfth embodiment of the present invention is similar to the fifth embodiment shown in Fig. However, the backlight unit according to the twelfth embodiment of the present invention, as shown in Fig. The light sources L included in the adjacent light source groups form a zigzag arrangement. That is, the light sources L included in the odd-numbered light source group are shifted to be located closer to the right side of the bottom cover 310 than the light sources L included in the even-numbered light source group.

Since the remaining configuration is the same as that of the fifth embodiment described above, the description of the remaining configuration is replaced with the description of the fifth embodiment.

Thirteenth Example

13 is a view illustrating a backlight unit according to a thirteenth embodiment of the present invention.

The backlight unit according to the thirteenth embodiment of the present invention is similar to the sixth embodiment shown in Fig. However, in the backlight unit according to the thirteenth embodiment of the present invention, as shown in Fig. The light sources L included in the adjacent light source groups form a zigzag arrangement. That is, the light sources L included in the odd-numbered light source group are shifted to be positioned closer to the upper side of the bottom cover 310 than the light sources L included in the even-numbered light source group.

Since the remaining configuration is the same as that of the sixth embodiment described above, the description of the remaining configuration is replaced with the description of the sixth embodiment.

14th Example

14 is a view illustrating a backlight unit according to a fourteenth embodiment of the present invention.

The backlight unit according to the fourteenth embodiment of the present invention is similar to the sixth embodiment shown in Fig. However, the backlight unit according to the fourteenth embodiment of the present invention, as shown in Fig. The light sources L included in the adjacent light source groups form a zigzag arrangement. That is, the light sources L included in the odd-numbered light source group are shifted to be located closer to the right side of the bottom cover 310 than the light sources L included in the even-numbered light source group.

Since the remaining configuration is the same as that of the sixth embodiment described above, the description of the remaining configuration is replaced with the description of the sixth embodiment.

As described above, the light source L described in the first to fourteenth embodiments can use a light emitting diode (LED) as the point light source L. Specifically, each light source L is a light source L that emits white light. The light source L may be a blue light emitting diode coated with a phosphor on a light emitting surface, and may be a red light emitting diode A diode, a green light emitting diode, and a blue light emitting diode may be used.

Actually, each light source has a package form including the light emitting diode and a circuit structure for driving the light emitting diode.

Meanwhile, in the description of the present invention, the number of the light source groups and the number of the light sources are limited to the specific numerals for the sake of convenience. However, the number of the light source groups and the number of the light sources may vary.

The interval between adjacent light source groups is gradually increased from the central portion of the bottom cover 310 toward the edge of the bottom cover 310 to reduce the number of the light sources L and reduce the luminance to CCFL (Cold Cathode Fluorescent Lamp), so that the manufacturing cost can be reduced and the luminance defect due to the reduction of the number of the light sources L does not occur.

The current supplied to the light sources L is gradually increased from the central portion of the bottom cover 310 to the edge of the bottom cover 310 in order to compensate for the decrease in luminance as the light source L decreases The brightness of the light sources L located at the center of the bottom cover 310 and the brightness of the light sources L located at the edge of the bottom cover 310 may be uniform.

That is, by supplying a higher current to the light sources L located at the edge than the light sources L located at the center, it is possible to compensate for the decrease in luminance due to the decrease of the light source L. [

Article 15 Example

FIG. 15 is a view illustrating a backlight unit according to a fifteenth embodiment of the present invention, and FIG. 16 is a graph illustrating a distance between light sources in one light source group in FIG.

15, a backlight unit according to a fifteenth embodiment of the present invention includes a plurality of light source groups LG1 to LG7 including a plurality of light sources L1 to L24 arranged in one direction, Cover 310; The interval between the adjacent light sources in one light source group gradually increases and decreases gradually from the central portion of the bottom cover 310 to the edge of the bottom cover 310. [

The light source groups LG1 to LG7 include a plurality of light sources L1 to L24 arranged in a row along the longitudinal direction of the long side of the bottom cover 310, that is, along the X axis direction. The light source groups LG1 to LG7 having such a configuration are arranged along the longitudinal direction of the bottom cover 310, that is, the Y-axis direction.

The light sources L1 to L24 included in the adjacent light source groups are arranged in a zigzag pattern. That is, the light sources L included in the odd-numbered light source group are shifted to be located closer to the right side of the bottom cover 310 than the light sources L included in the even-numbered light source group.

The intervals dy between the adjacent light source groups LG1 to LG7 are all the same and the number of the light sources L1 to L24 included in each of the light source groups LG1 to LG12 is the same. Here, the number of the light sources may vary.

In particular, the distance between the light sources L1 to L24 included in one light source group gradually increases from the center of the bottom cover 310 to the edge of the bottom cover 310, and then gradually decreases. This will be described in more detail as follows. Since the intervals between the light sources L1 to L24 in all the light source groups LG1 to LG7 increase or decrease in the same manner, the first light source group LG1 will be exemplarily described. Here, the distance between the light sources L1 to L24 may be a distance between the adjacent light sources or a distance between the center parts of adjacent light sources as described above. In the fifteenth embodiment, the distance between the center parts of the adjacent light sources it means.

The first light source group LG1 includes a central light source unit positioned at the center of the bottom cover 310; A plurality of first ambient light parts positioned between one side edge of the central light source part and the bottom cover 310; And a plurality of second ambient light portions positioned between the central light portion and the other edge of the bottom cover 310. [

The central light source unit refers to two light sources L1 and L2 positioned closest to the center of the bottom cover 310 among the plurality of light sources L1 to L24. That is, the central light source unit includes a first light source L1 positioned closest to one side of the center of the bottom cover 310, a second light source L2 positioned closest to the other side of the center of the bottom cover 310, .

The first ambient light portion refers to the light sources L3 to L13 located between the left side of the central light portion and the left side edge of the bottom cover 310 and the second ambient light portion is located between the right side of the central light portion and the bottom cover 310. [ The light sources L14 to L24 located between the right edges of the light source 310 are referred to as light sources L14 to L24.

Here, the distance between the light sources L1 to L24 increases from the central light source part to the left edge of the bottom cover 310, and then decreases gradually. In addition, the distance between the light sources L1 to L24 increases from the central light source part to the right edge of the bottom cover 310, and gradually decreases.

For example, as shown in FIGS. 15 and 16, the distance between each of the light sources L1 to L24 in one light source group continuously increases from the first light source L1 to the tenth light source L10, 12 light source L12. In addition, the distance between each of the light sources L1 to L24 in one light source group continuously increases from the second light source L2 to the 23rd light source L23, and decreases again as it goes to the 24th light source L24.

17 is a table for comparing and analyzing backlight units having light sources arranged in different ways.

As shown in Fig. 17, an A-type backlight unit, a B-type backlight unit, a C-type backlight unit, and a D-type backlight unit are shown.

The A type backlight unit, the B type backlight unit, the C type backlight unit, and the D type backlight unit all have the light sources L1 to L24 and the bottom cover 310 having the structure as shown in FIG. 15 .

The A type backlight unit is manufactured so that the intervals between the light sources within each light source group are all the same, and the B type, C type, and D type backlight units are formed between the light sources L1 through L24 in each light source group The intervals were made to be different from each other. Here, the C type backlight unit is the backlight unit of the fifteenth embodiment shown in FIG. The B type and D type backlight units are arranged such that the spacing between the light sources L1 to L24 included in one light source group is smaller than the distance between the center of the bottom cover 310 and the bottom cover 310 ), And gradually decrease, but gradually decrease. The B type, the C type, and the D type backlight unit differ from each other in that the size variations of the light source intervals are different from each other.

When the backlight units are sequentially applied to the 47-inch liquid crystal panel, the results of comparing the backlight units based on the image observed on the liquid crystal panel will be described below.

The center point luminance represents the magnitude of the luminance at the center of the liquid crystal panel. The higher the value, the better. Of the A, B, C, and D type backlight units, the B type backlight unit exhibits the highest value in this central luminance test item. That is, in this central luminance test item, the B type backlight unit shows the best result.

The luminance ratio is the ratio between the luminance of the central portion of the A type backlight unit and the luminance of the central portion of the remaining backlight unit as a percentage when the luminance of the central portion of the A type backlight unit is taken as 100. The higher the value is, Among the backlight units of type A, B, C, and D, the backlight unit of type B has the highest value in the luminance ratio test item. That is, in this luminance ratio test item, the B type backlight unit shows the best result.

The luminance uniformity is obtained by dividing the liquid crystal panel evenly into a plurality of display areas and calculating the magnitude of the luminance value of the display area showing the luminance of the highest value with respect to the luminance value of the display area showing the luminance of the lowest value The lowest luminance value). The lower this value is, the better. In this test item, the liquid crystal panel was evenly divided into 128 display areas. Among A type, B type, C type and D type backlight units, the A type backlight unit shows the lowest value in the luminance ratio test item. That is, in this luminance uniformity test item, the A type backlight unit shows the best result.

The surface measurement results show that the luminance uniformity described above is satisfactory. The A type and B type backlight units showed good results, and the C type and D type backlight units showed poor results. PM-1234 means the above surface measuring equipment.

The luminance image is a visual representation of the luminance uniformity. Since the A type and C type backlight units have good luminance uniformity, light of uniform luminance appears on the front face of the display portion of the liquid crystal panel to which these backlight units are applied. However, since the B type and D type backlight units have poor brightness uniformity, light of strong intensity is emitted to the central portion of the display portion of the liquid crystal panel to which these backlight units are applied, and bright lines are generated at the center portion of the display portion.

FIG. 18 is a graph showing the brightness of light emitted from the liquid crystal panel to which the A type, B type, C type, and D type backlight units of FIG. 17 are applied.

The left edge of the liquid crystal panel corresponds to the left edge of the bottom cover 310 and the right edge of the liquid crystal panel corresponds to the right edge of the bottom cover 310. The center of the liquid crystal panel corresponds to the center of the bottom cover 310, Respectively.

According to the above-described test items, the A-type backlight unit has higher luminance uniformity than the C-type backlight unit, but has a lower luminance ratio than the C-type backlight unit. B type and D type backlight units have a problem that a bright line is generated at the center. Therefore, from the results of the above-described respective test items, it can be seen that the C type backlight unit is the most optimized and excellent backlight unit.

Although not shown, the backlight unit according to the first to fourteenth embodiments may have the same features as those of the fifteenth embodiment.

That is, the interval between adjacent light source groups in FIGS. 1 to 14 may gradually decrease from the center of the bottom cover 310 to the edge of the bottom cover 310.

Here, a central light source group positioned at the center of the bottom cover 310; A plurality of first peripheral light source groups positioned between one side edge of the central light source group and the bottom cover 310; And a plurality of second peripheral light source groups positioned between the center light source group and the other edge of the bottom cover 310. [

At this time, the interval between the adjacent central light source groups and the first peripheral light source groups gradually increases and decreases gradually from the central portion of the bottom cover 310 to one side edge of the bottom cover 310; The interval between the adjacent central light source groups and the second peripheral light source groups gradually increases from the center of the bottom cover 310 to the other edge of the bottom cover 310 and gradually decreases.

The central light source group includes a first center light source group positioned closest to one side of the central portion of the bottom cover 310; And a second central light source group positioned closest to the other side of the central portion of the bottom cover 310. [

The light sources included in each light source group are arranged in a line along the short side direction of the bottom cover 310; Wherein each light source group includes the same number of light sources; The intervals between the light sources included in the adjacent light source groups and corresponding to each other gradually increase and decrease from the center of the bottom cover 310 toward the edge of the bottom cover 310; The intervals of the light sources included in one light source group are all the same. Alternatively, the distance between the light sources included in one light source group may gradually increase and decrease as in the fifteenth embodiment.

Alternatively, the light sources included in each light source group are arranged in a line along the long side direction of the bottom cover 310; Wherein each light source group includes the same number of light sources; The interval between the light sources included in the adjacent light source groups and corresponding to each other gradually decreases gradually from the central portion of the bottom cover 310 to the edge of the bottom cover 310.

Alternatively, the light sources included in each light source group are arranged in a line along the direction of the short side of the bottom cover 10; Wherein each light source group includes the same number of light sources; The intervals between the light sources included in the adjacent light source groups and corresponding to each other gradually increase and decrease from the center of the bottom cover 310 toward the edge of the bottom cover 310; The spacing of adjacent light sources included in one light source group gradually increases and decreases gradually from the center of the light source group to the edge of the bottom cover 310. [

In the first to fourteenth embodiments, the distance between the light source groups adjacent to each other may be a distance between the center of the light source belonging to one light source group and the center of the other light source belonging to the other light source group.

The backlight unit thus configured can be mounted on a liquid crystal display device.

Hereinafter, a liquid crystal display equipped with a backlight unit according to the present invention will be described in detail.

FIG. 19 is a view illustrating a liquid crystal display equipped with a backlight unit according to an embodiment of the present invention.

Referring to FIG. 19, a liquid crystal display device according to an embodiment of the present invention includes a backlight unit 300, a liquid crystal panel 390, a support main body 380, and a top cover 400.

The backlight unit 300 may be formed of any one of the backlight units of the present invention as shown in Figs. 1 to 14

The backlight unit 300 includes a bottom cover 310 having both open sides; A plurality of light sources L provided on the bottom surface of the bottom cover 310 and side supports 340a and 340b coupled to both sides of the opened bottom cover 110 to reflect light from the light sources L ).

The light sources L are mounted on a printed circuit board (PCB) 360, and a drive current is supplied from the inverter through the printed circuit board 360 to emit light.

The planar reflection member 330 is formed so that only a light source L that covers the light source L and emits light is formed so as to protrude therefrom by forming a plurality of holes through which the respective light sources L can be inserted do. At this time, the planar reflection member 330 spreads the point light source emitted from the plurality of light sources L widely.

On top of the bottom cover 310, an optical member 350 composed of a diffusion plate and a plurality of optical sheets is positioned. At this time, the diffuser diffuses the light emitted from the plurality of light sources L into the entire area of the liquid crystal panel 100.

The liquid crystal panel 390 includes a transistor array substrate and a color filter array substrate bonded to each other, a spacer (not shown) for keeping the cell gap constant between the two array substrates, and a liquid crystal layer (Not shown).

The color filter array substrate includes a color filter, a common electrode, a black matrix, and the like. Here, the common electrode may be formed on the transistor array substrate.

The transistor array substrate includes a thin film transistor (not shown) formed in a region defined by a plurality of data lines (not shown) and a plurality of gate lines (not shown) and connected to gate lines and data lines, And a liquid crystal cell (not shown).

The support main 380 is coupled to the bottom cover 310 and the top cover 400 having a rectangular frame shape to edge the edge of the liquid crystal panel 390 is assembled to the support main 380 and the bottom cover 310 Respectively.

The bottom cover 310 is formed as a bottom case that engages with the support main body 380 and accommodates the backlight unit 300.

The top cover 400 covers the front edge of the liquid crystal panel 390 disposed on the bottom cover 310 and the side surface of the bottom cover 310. To this end, the top cover 400 includes a flat portion that covers the non-display area, i.e., the edge except the display area of the liquid crystal panel 390, and a side portion that is bent perpendicularly from the flat portion to cover the side surface of the bottom cover 310 .

In order to increase the central brightness of the backlight unit, the positions of the light sources in the first to fifteenth embodiments may be adjusted as follows.

20 to 22 are views for explaining a method of adjusting the positions of light sources.

The backlight unit shown in Fig. 20 is the same as that of Fig. 3 showing the third embodiment described previously.

20, the outermost light sources positioned adjacent to the edge of the bottom cover 310 are spaced apart from the edges of the bottom cover 310 by the size of a or b. Specifically, the center of the outermost light sources Le positioned at the corner of the outermost light sources is spaced apart from the edge of the bottom cover 310 by a in the X-axis direction, And is spaced apart in the axial direction by b. The outermost light sources positioned between the outermost light sources Le positioned at the corner portions are spaced apart from the edges of the bottom cover 310 by a or b.

The magnitude of a or b can be increased to increase the central brightness. Here, a is defined as an X-axis outer gap and b is defined as a Y-axis outer gap.

Increasing the X-axis outer spacing or Y-axis outer spacing means moving the light sources located at the outermost edge toward the center point of the bottom cover. At this time, as the light sources located at the outermost portions move toward the center point of the bottom cover, all the remaining light sources located inside the outermost light sources also move toward the center point. Then, all the light sources L located in the bottom cover move toward the center point of the bottom cover 310. [

That is, as shown in FIG. 21, the light sources L positioned in the first quadrant move downward toward the X-axis center line and move to the left toward the Y-axis centerline. Then, the light sources L positioned in the second quadrant move downward toward the X-axis center line and move to the right toward the Y-axis center line. The light sources L positioned in the third quadrant move upward toward the X-axis center line and move to the right toward the Y-axis center line. The light sources L positioned in the fourth quadrant move upward toward the X-axis center line and move to the left toward the Y-axis center line. As a result, all the light sources L located in the bottom cover 310 are moved toward the center point of the bottom cover 310.

For example, as shown in FIG. 22, if the X-axis outer spacing is further increased by k at a and the Y-axis outer spacing is further increased by b at b, the area of the light source region 800 is reduced. Since the same number of light sources L are provided in the light source area 800 before or after the reduction of the light source area 800, the density of the light sources L after the light source area 800 is reduced is smaller than the density of the light source area 800 Becomes higher than the density of the previous light sources (L). This means that the center luminance increases after the light source area 800 is reduced.

As the X-axis outer spacing and the Y-axis outer spacing increase, the central brightness increases. On the other hand, the brightness of the outer periphery of the bottom cover 310 is lower than that of the center. That is, the center luminance and the luminance uniformity are inversely proportional to each other.

Therefore, the X-axis outer spacing and the Y-axis outer spacing must be adjusted in consideration of the luminance uniformity. In other words, it is preferable to increase the size of the X-axis outer spacing and the Y-axis outer spacing within a proper level of luminance uniformity.

As described above, the luminance uniformity is obtained by equally dividing the liquid crystal panel into a plurality of display regions and dividing the luminance value of the display region showing the luminance of the highest value with respect to the luminance value of the display region showing the luminance of the lowest value Luminance value / lowest luminance value). In the test items as described above, the liquid crystal panel was evenly divided into 128 display areas.

However, in the luminance uniformity test item for setting the X-axis outer spacing and the Y-axis outer spacing, the luminance uniformity is measured by evenly dividing the liquid crystal panel into 17 display areas.

The luminance uniformity measuring method will be described in detail as follows.

First, after preparing any of the backlight units of the first to fifteenth embodiments, the X-axis outer spacing and the Y-axis outer spacing provided in the backlight unit are increased.

Then, the luminance uniformity of the backlight unit is measured. When this measured value is within a preset numerical range, a backlight unit having an increased X-axis outer spacing and a Y-axis outer spacing is normally usable.

 However, if the measured values do not satisfy the numerical range, the X-axis outer spacing and the Y-axis outer spacing must be readjusted.

In addition, the X-axis outer spacing and the Y-axis outer spacing are also affected by the optical distance of the backlight unit. The optical distance of the backlight unit is determined by subtracting the optical distance of the diffusion sheet (the optical member 350 of FIG. 19) from the bottom surface of the bottom cover (the inner surface of the bottom cover on which the printed circuit board 360 of FIG. The seat closest to the bottom cover). The larger the optical distance, the larger the X-axis outer spacing and the Y-axis outer spacing can be set. That is, the optical distance affects the margin of the increment of the X-axis outer spacing and the Y-axis outer spacing.

Such an outer gap adjustment method is also applicable to existing backlight units having the same distance between the light sources (distance in the X-axis direction and distance in the Y-axis direction).

On the other hand, the X-axis outer spacing and the Y-axis outer spacing may be 1/2 of the distance between two adjacent light sources. For example, in the structure of the first embodiment as shown in FIG. 1, the Y-axis outer spacing has a half size with respect to the fixed Y-axis spacing dy. On the other hand, the X-axis outer interval has a size of 1/2 with respect to the fifth or tenth intervals (dx5, dx10) having the largest numerical value. Similarly, in the structure of the second embodiment as shown in FIG. 2, the X-axis outer spacing is 1/2 of the fixed distance xx in the X-axis direction. On the other hand, the Y-axis outer interval has a 1/2 size with respect to the third or sixth intervals dy3 and dy6 having the largest numerical value. The same can be applied to the remaining embodiments.

The backlight unit described in Figs. 20 to 22 can also be applied to the liquid crystal display of Fig.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. Will be clear to those who have knowledge of.

1 is a view illustrating a backlight unit according to a first embodiment of the present invention;

2 is a view illustrating a backlight unit according to a second embodiment of the present invention.

3 is a view illustrating a backlight unit according to a third embodiment of the present invention

4 is a view illustrating a backlight unit according to a fourth embodiment of the present invention

5 is a view illustrating a backlight unit according to a fifth embodiment of the present invention.

6 is a view illustrating a backlight unit according to a sixth embodiment of the present invention.

7 is a view illustrating a backlight unit according to a seventh embodiment of the present invention

8 is a view illustrating a backlight unit according to an eighth embodiment of the present invention

9 is a view illustrating a backlight unit according to a ninth embodiment of the present invention

10 is a view illustrating a backlight unit according to a tenth embodiment of the present invention

11 is a view illustrating a backlight unit according to an eleventh embodiment of the present invention

12 is a view illustrating a backlight unit according to a twelfth embodiment of the present invention

13 is a view illustrating a backlight unit according to a thirteenth embodiment of the present invention

14 is a view illustrating a backlight unit according to a fourteenth embodiment of the present invention

15 is a view illustrating a backlight unit according to a fifteenth embodiment of the present invention

16 is a graph showing the distance between light sources in one light source group in Fig. 15

17 is a table comparing and analyzing backlight units having light sources arranged in different ways

18 is a graph showing the brightness of light emitted from a liquid crystal panel to which the A type, B type, C type, and D type backlight units in Fig. 17 are applied

19 is a view showing a backlight unit according to a sixteenth embodiment of the present invention

20 to 22 are views for explaining a method of adjusting the positions of light sources

Claims (19)

A bottom cover on which a plurality of light source groups including a plurality of light sources arranged in one direction are formed; The distance between adjacent light source groups gradually increases and decreases from the center of the bottom cover toward the edge of the bottom cover; Wherein an interval between adjacent light sources in one light source group gradually increases and decreases from a central portion of the bottom cover toward an edge of the bottom cover. delete delete delete delete delete The method according to claim 1, Wherein a spacing increase / decrease rate of the light sources included in the adjacent light source groups and corresponding to each other is equal to an interval increase / decrease rate of adjacent light sources included in the one light source group. The method according to claim 1, And the increase / decrease ratio of the interval is 0.2 mm. The method according to claim 1, Wherein a spacing increase / decrease rate of the light sources included in the adjacent light source groups and corresponding to each other is different from a spacing increase / decrease rate of adjacent light sources included in the one light source group. The method according to claim 1, Wherein the light sources included in the adjacent light source groups are arranged in a staggered arrangement. delete delete The method according to claim 1, The light source groups include, A central light source group positioned at the center of the bottom cover; A plurality of first peripheral light source groups positioned between one side edge of the central light source group and the bottom cover; A plurality of second peripheral light source groups positioned between the central light source group and the other edge of the bottom cover; The distance between the adjacent central light source groups and the first peripheral light source groups gradually increases and decreases from the central portion of the bottom cover to one side edge of the bottom cover; And, Wherein an interval between the adjacent central light source groups and the second peripheral light source groups gradually increases from the central portion of the bottom cover to the other edge of the bottom cover. 14. The method of claim 13, The central light source group includes: A first central light source group positioned closest to one side of the central portion of the bottom cover; And And a second central light source group positioned closest to the other side of the central portion of the bottom cover. delete delete The method according to claim 1, Wherein the light sources included in each of the light source groups are arranged in a line along a short side direction of the bottom cover; Wherein each light source group includes the same number of light sources; The distance between the light sources included in the other light source groups adjacent to each other and corresponding to each other gradually increases and decreases gradually from the central portion of the bottom cover to the edge of the bottom cover; And, Wherein a distance between adjacent light sources included in one light source group gradually increases and decreases gradually from a center of the light source group to an edge of the bottom cover. The method according to claim 1, Wherein a distance between adjacent light source groups is a distance between a central portion of a light source belonging to one light source group and a center portion of another light source belonging to another light source group. delete

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