KR101382744B1 - Display device - Google Patents

Abstract

A display device is started. The display device includes a display panel; And a plurality of light sources disposed under the display panel, wherein the optical axes of the light sources are inclined with respect to the bottom surface of the display panel.

Description

Display device {DISPLAY DEVICE}

The embodiment relates to a display device.

In general, liquid crystal displays (LCDs) have tended to be gradually widened due to their light weight, thinness, and low power consumption. According to this trend, liquid crystal display devices are used in office automation equipment, audio / video equipment, and the like. The liquid crystal display device displays a desired image on the screen by controlling the amount of transmitted light according to a video signal applied to a plurality of control switches arranged in a matrix form.

Since the liquid crystal display device is not a self-luminous display device, a backlight unit for providing light to the back of a liquid crystal display panel on which an image is displayed is provided.

A liquid crystal panel including a color filter substrate and an array substrate interposed between the color filter substrate and the array substrate, and a backlight unit for emitting light to the liquid crystal panel .

The backlight unit used in such a liquid crystal display device can be generally divided into an edge type backlight unit or a direct type backlight unit.

The edge type backlight unit includes a light guide plate and light emitting diodes. The light emitting diodes are disposed on the side surface of the light guide plate, and the light guide plate guides the light emitted from the light emitting diode through total reflection or the like and emits toward the liquid crystal panel.

The direct type backlight unit does not use a light guide plate, and the light emitting diodes are disposed on the rear surface of the light guide plate. Accordingly, the light emitting diodes emit light toward the rear surface of the liquid crystal panel.

Such a backlight unit must emit light uniformly toward the liquid crystal panel. That is, efforts are being made to improve the luminance uniformity of the liquid crystal display device.

Embodiments provide a display device having improved luminance uniformity and which can be easily manufactured.

In one embodiment, a display device includes: a display panel; And a plurality of light sources disposed under the display panel, wherein the optical axes of the light sources are inclined with respect to the bottom surface of the display panel.

In one embodiment, a display device includes: a display panel; A first circuit board disposed under the display panel and extending in one direction; And a second circuit board disposed side by side on the first circuit board. A plurality of first light sources connected to the first circuit board; And a plurality of second light sources connected to the second circuit board, wherein the first circuit board and the second circuit board are inclined with respect to the display panel.

The display device according to the embodiment inclines the optical axis of the light sources with respect to the display panel. That is, the light sources emit light in a direction inclined to the lower surface of the display panel. In this case, the light sources are arranged in rows in a direction substantially parallel to the first direction. Further, the light sources may be densely arranged in the first direction and less densely arranged in the second direction, which is perpendicular to the first direction.

In this case, since the light sources irradiate light in a direction inclined to the lower surface of the display panel, the luminance of the region between the columns of the light sources may be prevented from being lowered. The light sources are arranged in a first row and a second row, and the light sources of the first row and the light sources of the second row are irradiated with light between the first row and the second row in a direction inclined to the display panel. have.

Accordingly, the phenomenon in which the luminance between the first column and the second column is lowered is prevented, and the light from the light sources has an improved luminance uniformity and can be incident on the display panel.

That is, the display device according to the embodiment may have a high luminance uniformity as a whole, even if the number of columns in which the light sources are arranged is reduced. That is, even if the distance between the columns of the light sources is increased, since the light sources irradiate the light obliquely to the display panel, the luminance uniformity can be improved as a whole.

Therefore, the display device according to the embodiment can reduce the number of rows of the light sources and reduce the number of circuit boards to be used. Therefore, the display device according to the embodiment can be easily manufactured at a low cost.

1 is an exploded perspective view showing a liquid crystal display device according to an embodiment.
FIG. 2 is a cross-sectional view showing a section cut along AA 'in FIG. 1; FIG.
3 is a diagram illustrating a process of irradiating light to a liquid crystal display panel and optical sheets.
4 is a plan view illustrating a printed circuit board and light emitting diodes.

In the description of the embodiments, it is described that each panel, sheet, member, guide, unit or the like is formed "on" or "under" of each panel, sheet, member, In this case, "on" and "under " all include being formed either directly or indirectly through another element. In addition, the upper or lower reference of each component is described with reference to the drawings. The size of each component in the drawings may be exaggerated for the sake of explanation and does not mean the size actually applied.

1 is an exploded perspective view showing a liquid crystal display device according to an embodiment. FIG. 2 is a cross-sectional view illustrating a cross section taken along line AA ′ in FIG. 1. 3 is a diagram illustrating a process of irradiating light to a liquid crystal display panel and optical sheets. 4 is a plan view illustrating a printed circuit board and light emitting diodes.

1 to 4, the liquid crystal display according to the embodiment includes a liquid crystal display panel 20 and a backlight unit 10. The liquid crystal display panel 20 displays an image. Although not shown in detail, the liquid crystal display panel 20 is bonded to a thin film transistor (TFT) substrate and a color filter substrate to maintain a uniform cell gap facing each other, and a liquid crystal interposed between the two substrates. Layer. The thin film transistor substrate includes a plurality of gate lines, a plurality of data lines intersecting the plurality of gate lines, and a thin film transistor (TFT) formed at an intersection of the gate lines and the data lines.

A gate driving printed circuit board (PCB) 21 for supplying a scan signal to the gate line and an data driving PCB for supplying a data signal to the data line are provided at an edge of the liquid crystal display panel 20. circuit board 22 is provided.

The gate and data driving PCBs 21 and 22 are electrically connected to the liquid crystal display panel 20 by a chip on film (COF). Here, the COF may be changed to a TCP (Tape Carrier Package).

In addition, the liquid crystal display according to the embodiment surrounds the panel guide 24 supporting the liquid crystal display panel 20 and the edge of the liquid crystal display panel 20 and is coupled to the panel guide 24. 23).

The backlight unit 10 is configured in a direct manner provided in a large liquid crystal display device of 20 inches or more. The backlight unit 10 includes a bottom cover 11, a plurality of printed circuit boards 110 and 120, a plurality of light emitting diodes 210 and 220, and optical sheets 300, 400, and 500.

The bottom cover 11 has a box shape with an upper surface opened, and accommodates the printed circuit boards 110 and 120. In addition, the bottom cover 11 supports the optical sheets 300, 400, and 500 and the liquid crystal display panel 20.

The bottom cover 11 may be made of metal or the like. For example, the bottom cover 11 may be formed by bending or bending a metal plate. That is, the printed circuit boards 110 and 120 are accommodated in a space that is bent or curved.

In addition, the bottom surface of the bottom cover 11 may have a high reflectance. That is, the bottom itself of the bottom cover 11 may perform a reflective sheet function. Unlike this, although not shown in the drawing, a reflective sheet may be separately provided inside the bottom cover 11.

The printed circuit boards 110 and 120 are disposed inside the bottom cover 11. The printed circuit boards 110 and 120 may be driving substrates for driving the light emitting diodes 210 and 220. The printed circuit board 30 is electrically connected to the light emitting diodes 210 and 220. That is, the light emitting diodes 210 and 220 may be mounted on the printed circuit board 30.

As illustrated in FIGS. 1, 2, and 4, the printed circuit boards 110 and 120 may have a shape extending in a first direction. In more detail, the printed circuit boards 110 and 120 may extend in the first direction in parallel with each other. The printed circuit boards 110 and 120 may have a band shape extending in the first direction.

The printed circuit boards 110 and 120 may be two or more. For example, the printed circuit boards 110 and 120 may include a first printed circuit board 110 and a second printed circuit board 120. Alternatively, the printed circuit boards 110 and 120 may be three or more. The number of printed circuit boards 110 and 120 may vary depending on the area of the liquid crystal display panel 20.

The first printed circuit board 110 and the second printed circuit board 120 are arranged side by side with each other. In more detail, the first printed circuit board 110 and the second printed circuit board 120 may be disposed in parallel to each other.

The length of the first printed circuit board 110 and the second printed circuit board 120 may vary depending on the width of the liquid crystal display panel 20. Widths of the first printed circuit board 110 and the second printed circuit board 120 may be about 5 mm to about 3 cm.

The printed circuit boards 110 and 120 are electrically connected to the light emitting diodes 210 and 220, and supply driving signals to the light emitting diodes 210 and 220. Reflective layers may be coated on upper surfaces of the printed circuit boards 110 and 120 to improve performance of the backlight unit 10. That is, the reflective layer may reflect the light emitted from the light emitting diodes 210 and 220 upward.

The light emitting diodes 210 and 220 generate light by using an electrical signal applied through the printed circuit board 30. That is, the light emitting diodes 210 and 220 are light sources for generating light. More specifically, each light emitting diode 20 is a point light source, and each of the light emitting diodes 20 is gathered to form a surface light source. Here, the light emitting diodes 210 and 220 are light emitting diode packages including a light emitting diode chip.

The light emitting diodes 210 and 220 are mounted on the printed circuit boards 110 and 120. The light emitting diodes 210 and 220 may emit white light. Alternatively, the light emitting diodes 210 and 220 may emit blue light, green light, and red light evenly.

As shown in FIGS. 1 to 4, the light emitting diodes 210 and 220 may include a plurality of first light emitting diodes 210 and a plurality of second light emitting diodes 220.

The first light emitting diodes 210 are disposed on the first printed circuit board 110. The first light emitting diodes 210 may be mounted on the first printed circuit board 110. In more detail, the first light emitting diodes 210 may be arranged in a row in the first direction. That is, the first light emitting diodes 210 may be mounted in a line on the first printed circuit board 110. In addition, the first light emitting diodes 210 may be spaced apart from each other at regular intervals D1.

The second light emitting diodes 220 are disposed on the second printed circuit board 120. The second light emitting diodes 220 may be mounted on the second printed circuit board 120. In more detail, the second light emitting diodes 220 may be arranged in a row in the first direction. That is, the second light emitting diodes 220 may be mounted on the second printed circuit board 120 in a row. In addition, the second light emitting diodes 220 may be spaced apart from each other at regular intervals D2.

As shown in FIGS. 1 and 4, the first light emitting diodes 210 may be arranged in a first row, and the second light emitting diodes 220 may be arranged in a second row. The first row and the second row are arranged side by side.

An interval D1 between the first light emitting diodes 210 is smaller than an interval D3 between the first column and the second column. For example, the spacing D3 between the first column and the second column is about 1.3 to about 10 times, more specifically, about 1.5 times the spacing D1 between the first light emitting diodes 210. To about 3 times, more specifically, about 2 times to about 2.5 times.

In addition, the spacing D2 between the second light emitting diodes 220 is also smaller than the spacing D3 between the first column and the second column. For example, the spacing D3 between the first column and the second column is about 1.3 to about 10 times, more specifically, about 1.5 times the spacing D2 between the second light emitting diodes 220. To about 3 times, more specifically, about 2 times to about 2.5 times.

The printed circuit boards 110 and 120 are inclined with respect to the liquid crystal display panel 20. In more detail, top surfaces of the printed circuit boards 110 and 120 are inclined with respect to the bottom surface of the liquid crystal display panel 20. In more detail, the printed circuit boards 110 and 120 may have a shape extending in the first direction, and at the same time, may be inclined in a short axis direction, that is, in a width direction. That is, the printed circuit boards 110 and 120 may be tilted at a predetermined angle with respect to the rotation axis in the first direction.

In addition, the printed circuit boards 110 and 120 are inclined to the optical sheets 300, 400, and 500. The printed circuit boards 110 and 120 may be inclined with respect to the bottom surfaces of the optical sheets 300, 400, and 500.

An angle θ2 between the printed circuit boards 110 and 120 and the liquid crystal display panel 20 may be about 5 ° to about 85 °. In more detail, the angle θ2 between the printed circuit boards 110 and 120 and the liquid crystal display panel 20 may be about 20 ° to about 40 °.

The first printed circuit board 110 and the second printed circuit board 120 may be inclined symmetrically with each other. That is, the first printed circuit board 110 may be tilted so that the top surface of the first printed circuit board 110 faces the central portion of the liquid crystal display panel 20. In addition, the second printed circuit board 120 may be inclined such that the top surface of the second printed circuit board 120 faces the central portion of the liquid crystal display panel 20.

The printed circuit boards 110 and 120 may be inclined by the inclined members 111 and 121. The inclined members 111 and 121 may have a wedge shape. That is, the inclined members 111 and 121 may include an inclined surface for tilting the printed circuit boards 110 and 120.

The inclined members 111 and 121 are interposed between the bottom surface of the bottom cover 11 and the printed circuit boards 110 and 120. The first inclined member 111 is interposed between the first printed circuit board 110 and the bottom cover 11, and the second inclined member 121 is the second printed circuit board 120 and the bottom cover. It is interposed between (11).

In addition, the optical axis OA of the light emitting diodes 210 and 220 is inclined with respect to the liquid crystal display panel 20. That is, as the printed circuit boards 110 and 120 are inclined with respect to the liquid crystal display panel 20, the optical axes OA of the light emitting diodes 210 and 220 are also inclined.

The optical axes OA of the light emitting diodes 210 and 220 are inclined with respect to the bottom surface of the liquid crystal display panel 20. In addition, the optical axis OA of the light emitting diodes is inclined with respect to the optical sheets 300, 400, and 500. An angle θ1 between the optical axis OA of the light emitting diodes 210 and 220 and the bottom surface of the liquid crystal display panel 20 may be about 5 ° to about 85 °. In more detail, the angle θ1 between the optical axis OA of the light emitting diodes 210 and 220 and the bottom surface of the liquid crystal display panel 20 may be about 50 ° to about 70 °. Here, the light emitted from the light emitting diodes 210 and 220 may have optical characteristics of line symmetry based on the optical axis OA of the light emitting diodes 210 and 220.

In addition, the backlight unit 10 may further include lens units disposed corresponding to the light emitting diodes 210 and 220, respectively. The lens units may receive light emitted from the light emitting diodes 210 and 220 to control the luminous flux. The lens units may change the luminous flux of light emitted from the light emitting diodes 210 and 220 to a larger direction angle. The lens units may cover the light emitting diodes 210 and 220, respectively.

The optical sheets 300, 400, and 500 are disposed on the light emitting diodes 210 and 220. The optical sheets 300, 400, and 500 may be disposed on the bottom cover 11. The optical sheets 300, 400, and 500 may cover the light emitting diodes 210 and 220.

The optical sheets 300, 400, and 500 improve characteristics of light passing through the optical sheets 300, 400, and 500. The optical sheets 300, 400, and 500 include a diffusion sheet 300, a first prism sheet 400, and a second prism sheet 500.

The diffusion sheet 300 is disposed on the light emitting diodes 210 and 220. The diffusion sheet 300 covers the light emitting diodes 210 and 220. In more detail, the diffusion sheet 300 may cover the light emitting diodes 210 and 220 as a whole.

Light emitted from the light emitting diodes 210 and 220 is incident on the diffusion sheet 300. Light from the light emitting diodes 210 and 220 may be diffused by the diffusion sheet 300.

As shown in FIGS. 2 and 3, the diffusion sheet 300 may include a plurality of diffusion patterns having a shape extending in one direction. The diffusion patterns may be optical patterns that diffuse light from the light emitting diodes 210 and 220.

The direction in which the diffusion patterns extend may be substantially the same as the first direction. In more detail, the angle between the direction in which the diffusion patterns extend and the first direction may be about 0 ° to about 5 °. In more detail, the diffusion patterns may extend in the first direction. That is, the diffusion patterns may extend in parallel with the first row and the second row. In addition, the diffusion patterns may extend in parallel with the first printed circuit board 110 and the second printed circuit board 120.

The pitch of the diffusion patterns may be about 10 μm to about 200 μm. In addition, the width of the diffusion patterns may be about 1 μm to about 100 μm. In addition, the diffusion patterns may have a height of about 0.1 μm to about 100 μm.

The first prism sheet 400 is disposed on the diffusion sheet 300. The first prism sheet 400 may include a pattern having a pyramid shape. The first prism sheet 400 may improve the straightness of the light from the diffusion sheet 300.

The second prism sheet 500 is disposed on the first prism sheet 400. The second prism sheet 500 may include a pattern having a pyramid shape. The second prism sheet 500 may further improve the straightness of the light from the first prism sheet 400.

As shown in FIG. 3, the liquid crystal display panel 20 may be divided into a first region R1 and a second region R2. The first region R1 and the second region R2 may be defined by a straight line extending in the first direction and passing through a central portion of the liquid crystal display panel 20. That is, the liquid crystal display panel 20 may be divided into the first region R1 and the second region R2 by the straight line. That is, the liquid crystal display panel 20 may be accurately divided into the first region R1 and the second region R2.

In this case, the first light emitting diodes 210 and the first printed circuit board 110 are disposed in the first region R1, and the second light emitting diodes 220 and the second printed circuit board ( 120 may be disposed in the second region R2.

In this case, the first light emitting diodes 210 may radiate light toward a central portion of the liquid crystal display panel 20. That is, light of the first light emitting diodes 210 may be a region corresponding to the first light emitting diodes 210 and the first printed circuit board 110, and the second light emitting diodes 220 and the second light emitting diodes. 2 may face the region R3 between the regions corresponding to the printed circuit board 120.

Similarly, the second light emitting diodes 220 may radiate light toward a central portion of the liquid crystal display panel 20. That is, the light of the second light emitting diodes 220 may be a region corresponding to the first light emitting diodes 210 and the first printed circuit board 110 and the second light emitting diodes 220 and the second light emitting diodes. 2 may face the region R3 between the regions corresponding to the printed circuit board 120.

As such, light from the first light emitting diodes 210 and the second light emitting diodes 220 may pass through the optical sheets 300 and 400 and be incident to the liquid crystal display panel 20. have.

In this case, since the first light emitting diodes 210 and the second light emitting diodes 220 irradiate light toward a central portion of the liquid crystal display panel 20, the first and second columns of light emitting diodes 210 and the second light emitting diodes 220 are disposed between the first and second columns. Even if the interval is widened, the luminance of the area between the first column and the second column can be prevented from being lowered.

That is, light from the first light emitting diodes 210 and light from the second light emitting diodes 220 may be appropriately overlapped and incident on the region between the first column and the second column.

Accordingly, in the liquid crystal display according to the embodiment, the light emitting diodes 210 and 220 may be disposed more densely in the first direction and less densely in the second direction. In this case, since the first light emitting diodes 210 and the second light emitting diodes 220 are inclined, the overall luminance uniformity may be improved or maintained.

Accordingly, the liquid crystal display according to the embodiment can reduce the number of columns of the light emitting diodes 210 and 220. That is, in the liquid crystal display according to the embodiment, the light emitting diodes 210 and 220 are disposed anisotropically without being disposed at equal intervals regardless of the direction. The luminance unevenness that may be caused by the anisotropic arrangement of the light emitting diodes 210 and 220 is compensated by the tilting of the light emitting diodes 210 and 220, and the liquid crystal display according to the embodiment has a uniform brightness as a whole. It can have That is, the light passing through the diffusion sheet 300 is incident on the liquid crystal display panel 20 with a uniform luminance as a whole.

That is, the liquid crystal display according to the embodiment may have a high luminance uniformity as a whole even if the number of columns in which the light emitting diodes 210 and 220 are disposed is reduced. That is, even if the distance between the columns of the light emitting diodes 210 and 220 increases, the luminance uniformity may be improved by the arrangement of the light emitting diodes 210 and 220.

Therefore, the liquid crystal display according to the embodiment can reduce the number of columns of the light emitting diodes 210 and 220 and can reduce the number of printed circuit boards 110 and 120 used. Therefore, the liquid crystal display according to the embodiment can be easily manufactured at low cost.

In the present embodiment, the light emitting diodes are described as being arranged in two rows, but are not limited thereto. Two rows of light emitting diodes may be inclined to be symmetrical to each other in the first region, and two rows of light emitting diodes may be inclined to be symmetrical to each other in the second region. In addition, depending on the size of the liquid crystal display panel, the number of columns of the light emitting diodes may be further increased.

In addition, the features, structures, effects and the like described in the embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects and the like illustrated in the embodiments can be combined and modified by other persons skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims (12)

Display panel; And
A plurality of light sources disposed under the display panel;
A diffusion sheet disposed between the display panel and the light sources;
A circuit board connected to the light sources;
A bottom cover accommodating the circuit board; And
It includes a wedge-shaped inclined member located between the bottom cover and the circuit board,
The optical axis of the light sources are inclined with respect to the lower surface of the display panel by the inclined member,
And the diffusion sheet includes a plurality of diffusion patterns arranged to be parallel to the circuit board. The display device of claim 1, wherein an angle between a lower surface of the display panel and an optical axis of the light sources is 5 ° to 85 °. The display device of claim 2, wherein an angle between a lower surface of the display panel and an optical axis of the light sources is 50 ° to 70 °. delete The display device of claim 1, wherein an angle between the circuit board and the display panel is 20 ° to 40 °. The display device of claim 1, wherein the circuit board extends in a first direction. The method of claim 1, wherein the light sources are
A plurality of first light sources arranged in a first row in a first direction; And
And a plurality of second light sources arranged in a second row side by side in the first column. The display device of claim 7, wherein the display panel is divided into a first area and a second area by a straight line extending in the first direction.
The straight line is positioned in the middle of the display panel;
The first light sources are disposed in the first area,
The second light sources are disposed in the second area. The display device of claim 7, wherein the optical axis of the first light sources faces an area between the area corresponding to the first light sources and the area corresponding to the second light sources of the display panel.
And an optical axis of the second light sources toward an area between the area corresponding to the first light sources and the area corresponding to the second light sources. The display device of claim 7, wherein a distance between the first column and the second column is 1.3 to 10 times larger than a distance between the first light sources. Display panel;
A first circuit board disposed under the display panel and extending in one direction; And
A second circuit board arranged side by side on the first circuit board;
A plurality of first light sources connected to the first circuit board;
A plurality of second light sources connected to the second circuit board;
A diffusion sheet disposed between the display panel and the first and second light sources;
A bottom cover accommodating the first and second circuit boards;
A first wedge-shaped inclined member positioned between the bottom cover and the first circuit board; And
A second wedge-shaped inclined member positioned between the bottom cover and the second circuit board,
The first circuit board and the second circuit board are inclined with respect to the display panel by the first and second inclined members.
And the diffusion sheet includes a plurality of diffusion patterns arranged in parallel with the first and second circuit boards. The method of claim 11, wherein the angle between the first circuit board and the display panel is 20 ° to 40 °,
And the first circuit board and the second circuit board are inclined with each other.

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