KR20080054926A - Backlight assembly - Google Patents

Abstract

A backlight assembly is provided to use a light source package having high-efficiency LED(Light Emitting Diode) chips and low-efficiency LED chips as a light source unit to prevent color smudging caused by a luminance difference in lights emitted from the light source unit. A backlight assembly(60) includes a light source unit(661), an optical member(62), and a mold frame(65). The light source unit includes a plurality of light source packages(A). Each of the light source packages includes a plurality of high-efficiency LED(Light Emitting Diode) chips and a plurality of low-efficiency LED chips. The optical member is arranged on the light source unit. The mold frame houses the light source unit and the optical member.

Description

Backlight Assembly {BACKLIGHT ASSEMBLY}

1 is an exploded perspective view of a backlight assembly according to a first embodiment of the present invention;

2 is a combined perspective view of a backlight assembly according to a first embodiment of the present invention;

3 is an enlarged view of a portion A of FIG. 2 in the backlight assembly according to the first embodiment of the present invention;

4 is an enlarged view of a portion A of FIG. 2 in the backlight assembly according to the second embodiment of the present invention;

5 is an enlarged view of a portion A of FIG. 2 in the backlight assembly according to the third embodiment of the present invention;

6 is an enlarged view of a portion A of FIG. 2 in the backlight assembly according to the fourth embodiment of the present invention;

7 is an enlarged view of a light source unit in a backlight assembly according to a fifth embodiment of the present invention;

8 is an exploded perspective view of a display device including a backlight assembly according to an exemplary embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

50: panel unit 51: TFT panel

53: color filter panel 60: backlight assembly

61: top chassis 62: optical sheet

64 diffuser 65 mold frame

66: light source assembly 661: light source unit

663: printed circuit board

The present invention relates to a backlight assembly, and more particularly, to a backlight assembly capable of improving color unevenness due to a difference in luminance of light generated from a light source unit.

Liquid crystal displays are light-receiving elements that do not emit light by themselves, and are largely divided into a liquid crystal display panel for displaying a screen and a backlight assembly for supplying light thereto. The backlight assembly includes a light source for emitting light. As a light source, a cold cathode flourescent lamp (CCFL) or an external electrode flourescent lamp (EEFL) is used. Recently, a light emitting diode (LED) is used instead of the lamp. .

Unlike cold cathode fluorescent lamps, light-emitting diodes do not contain mercury and are eco-friendly and color reproducibility is 104% higher than that of NTSC.

However, in the backlight assembly using the light emitting diode, the center portion where the light emitting diode is disposed is high in light efficiency while the other portions are inferior in light efficiency as compared to the center portion. In order to secure high display quality characteristics, a backlight assembly using a light emitting diode may be configured as a high-efficiency product. However, due to cost problems, only a high-efficiency product is not available, so a high-efficiency and low-efficiency product is used as a light source.

Differences in the efficiency of light emitting diodes constituting the light source unit reduce the color reproducibility of the backlight assembly and cause color spots on the screen of the display device.

The technical problem of the present invention is to provide a backlight assembly which can improve the occurrence of color unevenness on the screen due to the difference in luminance of light generated by the light source unit.

In order to achieve the above object, a backlight assembly according to the present invention includes a light source unit including a plurality of light source packages, an optical member disposed on the light source unit, a light source unit and a mold frame for accommodating the optical member, Each includes a plurality of high efficiency LED chips and low efficiency LED chips.

Here, the plurality of high-efficiency light emitting diode chips and low-efficiency light emitting diode chips constituting the light source package are spaced at the same distance from one center point to form a circle and are arranged at equal intervals. Can be arranged.

In addition, the plurality of high-efficiency LED chips and the low-efficiency LED chips constituting the light source package may be linearly arranged at equal intervals, and the high-efficiency LED chips and the low-efficiency LED chips may be alternately arranged.

In addition, the plurality of high-efficiency light emitting diode chips and the low-efficiency light emitting diode chips constituting the light source package may be arranged in a matrix form at equal intervals, and the high efficiency light emitting diode chips and the low efficiency light emitting diode chips may be alternately arranged.

In addition, the plurality of high-efficiency LED chips and the low-efficiency LED chips constituting the light source package may be arranged at equal intervals in a triangle, and the high-efficiency LED chips and the low-efficiency LED chips may be alternately arranged.

In addition, one light source package may be a light source unit including all of a red light emitting diode chip, a green light emitting diode chip, and a blue light emitting diode chip.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 10. These embodiments of the present invention are merely for illustrating the present invention, but the present invention is not limited thereto.

1 shows a backlight assembly according to a first embodiment of the present invention, FIG. 2 shows a combination thereof, and FIG. 3 shows an enlarged portion A of FIG. 2.

The backlight assembly 60 shown in FIG. 1 shows a direct type backlight assembly mainly used for large display devices such as LCD TVs. The structure of the backlight assembly 60 shown in FIG. 1 is merely for illustrating the present invention, but the present invention is not limited thereto. Therefore, the present invention can also be applied to backlight assemblies having other structures.

The backlight assembly 60 is formed by combining a plurality of optical sheets 62, a diffusion plate 64, a plurality of light source assemblies 66, and the like. The backlight assembly 60 also includes a top chassis 61 and a mold frame 65 to secure them. The top chassis 61 and the mold frame 65 serve to fix the components of the backlight assembly 60. In the exemplary embodiment of the present invention, the structure of the backlight assembly 60 in which the plurality of light source assemblies 66 are fixed by the mold frame 65 is taken as an example, but the present invention is not limited thereto.

The light source assembly 66 includes a light source unit 661 that emits light and a printed circuit board 663 that mounts and drives the light. The plurality of light source assemblies 66 are accommodated in the mold frame 66 and arranged in the X-axis direction. Although not shown in FIG. 1, a plurality of wires are installed on the rear surface of the mold frame 65 to interconnect the plurality of light source assemblies 66. The content of the wiring connection can be easily understood by those of ordinary skill in the art, so a detailed description thereof will be omitted. The wire is drawn out from the light source assembly 66 and connected to an inverter (not shown) installed at the bottom of the bottom chassis 67. The inverter applies a driving voltage obtained by converting external power to the light source assembly 66.

2 and 3, when the light source assembly 66 including the light source unit 661 mounted with the light emitting diode is further enlarged, the light source unit 661 according to the first embodiment of the present invention is a light source. Each of the red, green, and blue light emitting diodes constituting the unit 661 is composed of a light source package A composed of a plurality of light sources. Hereinafter, each of the red, green, and blue light emitting diodes will be referred to as a light source package A for convenience.

Referring to FIG. 3, the light source package A includes a plurality of high efficiency LED chips and low efficiency LED chips. The light source package A according to the first embodiment of the present invention is a light source package A by mixing a light emitting diode chip having a low luminous efficiency and a light emitting efficiency with a high luminous efficiency at a predetermined ratio instead of a low price. Configure Accordingly, the luminous efficiency can be improved compared to the cost. In general, when one light emitting diode is used as a unit for implementing one color, a difference in efficiency of each light emitting diode is represented as a difference in efficiency of the color. On the other hand, when the light source package A is manufactured using m high efficiency LED chips and n low efficiency LED chips as in the first embodiment of the present invention, (m + n average luminance values) * (m + n) Since the luminance of the light source package A is reduced, the dispersion of the luminance characteristics between the respective light source packages A will be reduced. Accordingly, the color reproducibility of the backlight assembly is deteriorated due to the difference in efficiency of the light emitting diode, and the problem of color unevenness on the screen of the display device can be improved.

3, the light source package A according to the first embodiment of the present invention is a plurality of high-efficiency LED chip and low-efficiency LED chip spaced at the same distance from one center point to form a circular and arranged at equal intervals The high efficiency LED chip and the low efficiency LED chip are alternately arranged.

Light emitted from the light source assembly 66 is uniformly diffused while passing through the diffuser plate 64. The light source assembly 66 is spaced apart from the light source assembly 66 and the diffusion plate 64 by a predetermined distance in order to prevent the generation of bright lines by the light source assembly 66. The light diffused while passing through the diffusion plate 64 passes through the plurality of optical sheets 62 and the brightness thereof is improved. Since many prism sheets are included in many optical sheets 62, the linearity of light can be improved. Light which ensures uniformity and high brightness is supplied in an upper direction (Z-axis direction) of the backlight assembly 60.

The light source assembly 66 is fixed to the opening 651 formed in the mold frame 65 from the outside of the mold frame 65. The light source assembly 66 may be firmly fixed to the mold frame 65 using screws 665. Alternatively, the light source assembly 66 may be fixed to the mold frame 65 using an adhesive or the like. After fixing the light source assembly 66, the light source assembly 66 is covered by the bottom chassis 67. The bottom chassis 67 is fixed to the outside of the mold frame 67 to protect the light source assembly 66 from external impact, and may not use the bottom chassis 67 as necessary.

Hereinafter, another embodiment of the present invention will be described, and details overlapping with the first embodiment will be omitted.

Referring to FIG. 4, in the light source package A according to the second embodiment of the present invention, a plurality of high-efficiency light emitting diode chips and low-efficiency light emitting diode chips form a straight line and are arranged at equal intervals. Diode chips are alternately arranged. As in the above-described embodiment, since the light source package A is composed of a plurality of high efficiency light emitting diode chips and low efficiency light emitting diode chips, the distribution of luminance characteristics between each light source package A will be reduced. Therefore, the color reproducibility of the backlight assembly is lowered, and the problem of color unevenness on the screen of the display device can be improved.

Referring to FIG. 5, in the light source package A according to the third embodiment of the present invention, a plurality of high-efficiency light emitting diode chips and low-efficiency light emitting diode chips form a matrix and are arranged at equal intervals. Low efficiency light emitting diode chips are arranged alternately. As in the above-described embodiment, since the light source package A is composed of a plurality of high efficiency light emitting diode chips and low efficiency light emitting diode chips, the distribution of luminance characteristics between each light source package A will be reduced. Therefore, the color reproducibility of the backlight assembly is lowered, and the problem of color unevenness on the screen of the display device can be improved.

Referring to FIG. 6, the light source packages A according to the fourth exemplary embodiment of the present invention have a triangle and are arranged at equal intervals, and the high efficiency LED chip and the low efficiency LED chip are alternately arranged. As in the above-described embodiment, since the light source package A is composed of a plurality of high efficiency light emitting diode chips and low efficiency light emitting diode chips, the distribution of luminance characteristics between each light source package A will be reduced. Therefore, the color reproducibility of the backlight assembly is lowered, and the problem of color unevenness on the screen of the display device can be improved.

In the above-described first to fourth embodiments of the present invention, the light source package A is one example of implementing one color, and the configuration may be variously modified.

As an example, the light source package A according to the fifth embodiment of the present invention shown in FIG. 7 is composed of three colors R, G, and B. FIG. That is, the light source package A including the plurality of high efficiency LED chips and the low efficiency LED chips includes all of the red, green, and blue LED chips. Similarly, in the light source package A according to the fourth embodiment of the present invention, since the light source package A is composed of a plurality of high efficiency light emitting diode chips and low efficiency light emitting diode chips, the distribution of luminance characteristics between each light source package A is reduced. Will be reduced. Therefore, the color reproducibility of the backlight assembly is lowered, and the problem of color unevenness on the screen of the display device can be improved.

8 illustrates a display device including a backlight assembly according to a first embodiment of the present invention.

Here, the liquid crystal display panel can be used as the panel unit 50. It is merely illustrative of the present invention and the present invention is not limited thereto.

The display device 100 includes a panel unit 50 and a backlight assembly 60. Another top chassis 68 is used to stably fix the panel unit 50 on the backlight assembly 60. The panel unit assembly 40 includes a panel unit 50, a driver integrated circuit package (driver IC package) 43, 44, and a printed circuit board 41, 42. The driver IC package may be a chip on film (COF) or a tape carrier package (TCP). The printed circuit boards 41 and 42 may be housed on the side of another top chassis 68.

The panel unit 50 includes a TFT panel 51 composed of a plurality of TFTs (thin film transistors), a color filter panel 53 positioned on the TFT panel 51, and liquid crystals injected between the panels. City). Polarizing plates are attached to the upper part of the color filter panel 53 and the lower part of the TFT panel 51 to polarize the light passing through the panel unit 50.

The TFT panel 51 is a transparent glass substrate on which a thin film transistor on a matrix is formed, a data line is connected to a source terminal, and a gate line is connected to a gate terminal. In the drain terminal, a pixel electrode made of transparent indium tin oxide (ITO) as a conductive material is formed.

When electrical signals are input from the printed circuit boards 41 and 42 to the gate line and the data line of the panel unit 50 described above, electrical signals are input to the gate terminal and the source terminal of the TFT, and these electrical signals Depending on the input, the TFT is turned on or turned off so that an electrical signal necessary for pixel formation is output to the drain terminal.

On the other hand, the color filter panel 53 is arrange | positioned on the TFT panel 51 facing it. The color filter panel 53 is a panel in which RGB pixels, which are color pixels in which a predetermined color is expressed while light passes, are formed by a thin film process, and a common electrode made of ITO is coated on the entire surface thereof. When power is applied to the gate terminal and the source terminal of the TFT and the thin film transistor is turned on, an electric field is formed between the pixel electrode and the common electrode of the color filter panel 53. By this electric field, the arrangement angle of the liquid crystal injected between the TFT panel 51 and the color filter panel 53 is changed, and the light transmittance is changed according to the changed arrangement angle to obtain a desired pixel.

The printed circuit boards 41 and 42, which receive image signals from the outside of the panel unit 50 and apply driving signals to the gate lines and the data lines, respectively, may include the respective driving IC packages 43 attached to the panel unit 50. 44). In order to drive the display device 100, the gate printed circuit board 41 transmits a gate driving signal, and the data printed circuit board 42 transmits a data driving signal. That is, the gate driving signal and the data driving signal are applied to the gate line and the data line of the panel unit 50 through the respective driving IC packages 43 and 44. A control board (not shown) is installed on the back of the backlight assembly 60. The control board is connected to the data printed circuit board 42 to convert the analog data signal into a digital data signal, and then supplies it to the panel unit 50.

Although the above-described embodiment of the present invention has been described with an example of a light emitting diode as a light source, it is merely to illustrate the present invention, and the present invention is not limited thereto, and the backlight uses a plurality of light sources as a unit for implementing color. It can be widely applied to the assembly.

As described above, the backlight assembly according to the present invention uses a light source package formed by mixing a high efficiency and a low efficiency light emitting diode chip as a light source unit, whereby color unevenness is generated on the screen due to a difference in luminance of light generated from the light source unit. It can be improved.

Claims (6)

A light source unit including a plurality of light source packages, An optical member disposed on the light source unit, A mold frame accommodating the light source unit and the optical member Including, The light source package may include a plurality of high efficiency light emitting diode chips and a low efficiency light emitting diode chip, respectively. In claim 1, The plurality of high-efficiency light emitting diode chips and the low-efficiency light emitting diode chips constituting the light source package are spaced at the same distance from one center point to form a circular shape and are arranged at equal intervals. Arranged backlight assembly. In claim 1, The plurality of high efficiency light emitting diode chips and the low efficiency light emitting diode chips constituting the light source package are linearly arranged at equal intervals, and the high efficiency light emitting diode chip and the low efficiency light emitting diode chip are alternately arranged. In claim 3, The plurality of high efficiency light emitting diode chips and the low efficiency light emitting diode chips constituting the light source package are arranged in a matrix form at equal intervals, and the high efficiency light emitting diode chip and the low efficiency light emitting diode chip are alternately arranged. In claim 1, The plurality of high efficiency light emitting diode chips and the low efficiency light emitting diode chips constituting the light source package are triangularly arranged at equal intervals, and the high efficiency light emitting diode chip and the low efficiency light emitting diode chip are alternately arranged. The method according to any one of claims 1 to 5, And one light source package is a light source unit including all of a red light emitting diode chip, a green light emitting diode chip, and a blue light emitting diode chip.

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