KR102080276B1 - Back Light Unit and Liquid Crystal Display Device using the same - Google Patents

Abstract

The present invention is a light source; A light guide plate facing the light source; An optical sheet formed on the light guide plate; And a reflecting plate formed under the light guide plate, wherein the light guide plate has a first side facing the light source and functioning as a light incident surface, a second side facing the first side, a lower surface facing the reflecting plate, and the A top surface which faces the bottom surface and functions as a light emitting surface, wherein a plurality of protrusion patterns are formed on a bottom surface of the light guide plate, and each of the plurality of protrusion patterns is a first side formed of a portion of the bottom surface; The cross-sectional structure includes a second side extending from one end of one side and a third side extending from the other end of the first side, wherein the second side is a side close to the light source, and the third side is A far side, wherein the second angle between the first side and the third side is smaller than the first angle between the first side and the second side Byte unit, and provides a liquid crystal display device using the same.

Description

Back light unit and liquid crystal display device using the same

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device having a light guide plate type backlight unit.

Liquid crystal display devices have a wide range of applications ranging from notebook computers, monitors, spacecraft, aircraft, etc. to the advantages of low power consumption and low power consumption.

The liquid crystal display device includes a lower substrate, an upper substrate, and a liquid crystal layer formed between the two substrates, and the arrangement of the liquid crystal layers is adjusted according to the presence or absence of an electric field, and accordingly the light transmittance is adjusted to display an image. .

Unlike other spontaneous flat panel displays, such liquid crystal displays are non-light-emitting, and thus a backlight unit is mounted as a light source behind the liquid crystal panel. Such a backlight unit is largely classified into a direct type type and a light guide plate type.

In the direct type, the lamp is disposed on the lower front of the liquid crystal panel so that the light emitted from the lamp is directly transferred to the liquid crystal panel. In the light guide plate, the lamp is disposed on the lower side of the liquid crystal panel. It's the way it goes.

Hereinafter, a conventional liquid crystal display device having a light guide plate type backlight unit will be described with reference to the drawings.

1 is a schematic cross-sectional view of a conventional liquid crystal display device.

As can be seen in FIG. 1, a conventional liquid crystal display device includes a backlight unit 1 and a liquid crystal panel 2.

The backlight unit 1 includes a light guide plate 10, a light source 20, an optical sheet 30, and a reflecting plate 40.

The light guide plate 10 changes the movement path of the light so that the light emitted from the light source 20 can move toward the liquid crystal panel 2. As described above, a protrusion pattern 11 is formed on the lower surface of the light guide plate 10 to change the movement path of the light. The protruding pattern 11 has a circular dot structure.

The light source 20 is disposed to face one side of the light guide plate 10. The light source 20 is made of a light emitting diode or a fluorescent lamp.

The optical sheet 30 serves to uniformly inject the light passing through the upper surface of the light guide plate 10 into the liquid crystal panel 2. Such an optical sheet 30 consists of two prism sheets and one diffusion sheet.

The reflector 40 is disposed under the light guide plate 10 to reflect light passing through the bottom surface of the light guide plate 10 to re-inject into the light guide plate 10.

The liquid crystal panel 2 includes a lower substrate 50, an upper substrate 60, and a liquid crystal layer (not shown) formed between both substrates 50 and 60.

In the conventional liquid crystal display device, the light emitted from the light source 20 is reflected from the protruding pattern 11 having a circular dot structure provided in the light guide plate 10 to the liquid crystal panel 2. The path is changed. However, when the conventional light guide plate 10 is used, the amount of light reflected by the circular dot structure is limited, and thus there is a limit in improving the light efficiency.

The present invention has been devised to solve the above problems, and an object of the present invention is to provide a backlight unit and a liquid crystal display device using the same, which can further improve light efficiency.

The present invention, in order to achieve the above object; A light guide plate facing the light source; An optical sheet formed on the light guide plate; And a reflecting plate formed under the light guide plate, wherein the light guide plate has a first side facing the light source and functioning as a light incident surface, a second side facing the first side, a lower surface facing the reflecting plate, and the A top surface which faces the bottom surface and functions as a light emitting surface, wherein a plurality of protrusion patterns are formed on a bottom surface of the light guide plate, and each of the plurality of protrusion patterns is a first side formed of a portion of the bottom surface; The cross-sectional structure includes a second side extending from one end of one side and a third side extending from the other end of the first side, wherein the second side is a side close to the light source, and the third side is A far side, wherein the second angle between the first side and the third side is smaller than the first angle between the first side and the second side It provides a byte unit.

The present invention also includes a backlight unit and a liquid crystal panel formed on the backlight unit, wherein the backlight unit comprises: a light source; A light guide plate facing the light source; An optical sheet formed on the light guide plate; And a reflecting plate formed under the light guide plate, wherein the light guide plate has a first side facing the light source and functioning as a light incident surface, a second side facing the first side, a lower surface facing the reflecting plate, and the A top surface which faces the bottom surface and functions as a light emitting surface, wherein a plurality of protrusion patterns are formed on a bottom surface of the light guide plate, and each of the plurality of protrusion patterns is a first side formed of a portion of the bottom surface; The cross-sectional structure includes a second side extending from one end of one side and a third side extending from the other end of the first side, wherein the second side is a side close to the light source, and the third side is And a second angle between the first side and the third side is smaller than a first angle between the first side and the second side. Provides a display device.

According to the present invention as described above has the following effects.

According to the present invention, a protruding pattern formed on a lower surface of the light guide plate is formed to have a triangular cross-sectional structure or a square cross-sectional structure, and includes a first angle between a first side formed of a portion of the lower surface of the light guide plate and a second side close to the light source. In contrast, by forming a small second angle between the first side of the lower surface of the light guide plate and the third side away from the light source, the amount of light propagated to the upper surface of the light guide plate may be increased, thereby improving light efficiency.

1 is a schematic cross-sectional view of a conventional liquid crystal display device.
2 is a schematic cross-sectional view of a liquid crystal display according to an exemplary embodiment of the present invention.
FIG. 3A illustrates a cross section of the light guide plate and the optical sheet according to the exemplary embodiment of the present invention, and FIG. 3B illustrates a bottom surface of the light guide plate according to the exemplary embodiment of the present invention.
4 is a cross-sectional view of a light guide plate according to another embodiment of the present invention.
5 is a cross-sectional view of a light guide plate according to another embodiment of the present invention.
FIG. 6A illustrates a cross section of a light guide plate according to still another embodiment of the present invention, and FIG. 6B illustrates an upper surface of a light guide plate according to another embodiment of the present invention.
FIG. 7A illustrates a cross section of a light guide plate according to still another embodiment of the present invention, and FIG. 7B illustrates a top surface of the light guide plate according to another embodiment of the present invention.
8 is a cross-sectional view of a light guide plate according to another embodiment of the present invention.
9 illustrates a cross section of an optical sheet according to an embodiment of the present invention.
10 illustrates a bottom surface of a light guide plate according to another embodiment of the present invention.
FIG. 11A illustrates a bottom surface of a light guide plate according to another exemplary embodiment of the present invention, FIG. 11B is a cross-sectional view taken along line AA of FIG. 11A, and FIG. It is sectional drawing of the BB line of a).
12 (a) to 12 (c) are views for explaining a method of designing a liquid crystal display according to an exemplary embodiment of the present invention.
13 illustrates a bottom surface of a light guide plate according to another embodiment of the present invention.
14 is a schematic view of a bottom surface of a light guide plate according to another embodiment of the present invention.
15 is a schematic diagram of a bottom surface of a light guide plate according to another embodiment of the present invention.
16 is a schematic view of a bottom surface of a light guide plate according to another embodiment of the present invention.

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

2 is a schematic cross-sectional view of a liquid crystal display according to an exemplary embodiment of the present invention.

As can be seen in FIG. 2, the liquid crystal display according to the exemplary embodiment of the present invention includes a backlight unit 1 and a liquid crystal panel 2.

The backlight unit 1 includes a light guide plate 100, a light source 200, an optical sheet 300, and a reflector plate 400.

The light guide plate 100 is disposed to face the light source 200 so as to change a movement path of the light so that the light emitted from the light source 200 may move toward the liquid crystal panel 2.

The light guide plate 100 faces the light source 200 and faces the first side surface 100a which functions as a light incident surface, a second side surface 100b facing the first side surface 100a, and the reflective plate 400. And an upper surface 100d which faces the lower surface 100c and functions as a light emitting surface while facing the lower surface 100c. The height of the first side surface 100a and the height of the second side surface 100b may be the same. Accordingly, the light guide plate 100 may be formed of a plate having the same thickness as a whole.

A protruding pattern 110 is formed on the lower surface 100c of the light guide plate 100 to change a movement path of light. A detailed configuration of such a protruding pattern 110 will be described later.

The light source 200 is disposed to face the first side surface 100a of the light guide plate 100. The light source 200 may be made of a point light source such as a light emitting diode or may be made of a line light source such as a fluorescent lamp.

The optical sheet 300 is formed on the light guide plate 100. The optical sheet 300 serves to uniformly inject light passing through the upper surface 100d of the light guide plate 100 into the liquid crystal panel 2. The optical sheet 300 may be formed of a prism sheet. More specifically, the optical sheet 300 may be formed of an inverted prism sheet formed such that the prism structure faces the upper surface 100d of the light guide plate 100.

The reflective plate 400 is formed under the light guide plate 100. The reflective plate 400 serves to re-inject light passing through the lower surface 100c of the light guide plate 100 into the light guide plate 100.

The liquid crystal panel 2 includes a lower substrate 500, an upper substrate 600, and a liquid crystal layer (not shown) formed between both substrates 500 and 600.

Although not shown, a gate line and a data line defining a pixel region are formed on the lower substrate 500 to cross each other, and a pixel electrode is formed in the pixel region. In addition, a black matrix is formed on the upper substrate 600 to prevent light leakage, and color filters of red (R), green (G), and blue (B) are formed between the black matrices. Specific configurations of the lower substrate 500 and the upper substrate 600 may include a driving mode of the liquid crystal panel 2, for example, a twisted nematic (TN) mode, a vertical alignment (VA) mode, and an in plane (IPS). Depending on the switching mode, the FFS (Fringe field switching) mode, and the like, various forms known in the art may be changed.

3 (a) shows a cross section of the light guide plate 100 and the optical sheet 300 according to an embodiment of the present invention, Figure 3 (b) of the light guide plate 100 according to an embodiment of the present invention The lower surface 100c is shown. The light guide plate 100 illustrated in FIG. 3A corresponds to a cross section of the A-A line of FIG. 3B.

As shown in FIGS. 3A and 3B, a protruding pattern 110 is formed on the lower surface 100c of the light guide plate 100.

As shown in FIG. 3A, the protruding pattern 110 is formed in a triangular cross-sectional structure on the lower surface 100c of the light guide plate 100. In more detail, the protruding pattern 110 has a portion of the lower surface 100c of the light guide plate 100 as the first side 110a and a second side extending from one end of the first side 110a. 110b and a third side 110c extending from the other end of the first side 110a to meet the second side 110b. The second side 110b is a side close to the light source 200 and the third side 110c is a side far from the light source 200.

In this case, the second angle θ2 between the first side 110a and the third side 110c is smaller than the first angle θ1 between the first side 110a and the second side 110b. Set it. The light emitted from the light source 200 is reflected from the third side 110c and travels toward the upper surface 100d of the light guide plate 100. The second angle θ2 is changed to the first angle θ1. When the size is set smaller than that of the light guide plate 100, the amount of light traveling to the upper surface 100d of the light guide plate 100 may be increased. In particular, the second angle θ2 may be greater than 0 ° and smaller than 10 °, and preferably, 1 ° or more and 5 ° or less, which may be advantageous for increasing the amount of light that proceeds to the upper surface 100d of the light guide plate 100.

As shown in FIG. 3B, the plurality of protruding patterns 110 are spaced apart from each other at predetermined intervals in the horizontal and vertical directions on the lower surface 100c of the light guide plate 100, and the protruding patterns 110. Each consists entirely of rectangular, in particular rectangular, planar structures.

Referring again to FIG. 3A, an optical sheet 300 is formed on the top surface 100d of the light guide plate 100. The optical sheet 300 may be formed of an inverted prism sheet formed such that a prism pattern faces the top surface 100d of the light guide plate 100.

The inverted prism sheet changes a light propagation path so that light emitted through the upper surface 100d of the light guide plate 100 is perpendicular to the liquid crystal panel. At this time, as can be seen in Figure 1 described above, in the prior art, although two prism sheets were required on the upper surface of the light guide plate 10, in the present invention, the light guide plate 100 having the protrusion pattern 110 as described above is provided. By applying, the directionality of light emitted through the upper surface of the light guide plate 10 is improved, so that one reverse prism sheet can be used as the optical sheet 300. Although not shown, a diffusion sheet or a Dual Brightness Enhancement Film (DBEF) may be further formed on an upper surface of the inverse prism sheet.

4 is a cross-sectional view of a light guide plate 100 according to another embodiment of the present invention.

As can be seen in FIG. 4, the protruding pattern 110 formed on the lower surface 100c of the light guide plate 100 has a rectangular cross-sectional structure. In more detail, the protruding pattern 110 has a portion of the lower surface 100c of the light guide plate 100 as the first side 110a and a second side extending from one end of the first side 110a. 110b), a third side 110c extending from the other end of the first side 110a, and a fourth side 110d connecting the second side 110b and the third side 110c. The second side 110b is a side close to the light source 200 and the third side 110c is a side far from the light source 200.

In this case, the second angle θ2 between the first side 110a and the third side 110c is smaller than the first angle θ1 between the first side 110a and the second side 110b. Set it. In particular, the second angle θ2 is larger than 0 ° and smaller than 10 °, preferably 1 ° or more and 5 ° or less. In addition, an angle θ3 between the third side 110c and the fourth side 110d is set to be larger than 180 ° and smaller than 270 °. When applying the protruding pattern 100 according to FIG. 4, since the light emitted from the light source 200 is reflected at various angles at the third side 110c and the fourth side 110d of the protruding pattern 110. More uniform light may be emitted toward the top surface 100d of the light guide plate 100.

FIG. 5 is a cross-sectional view of the light guide plate 100 according to another embodiment of the present invention, which is described above except that the angle θ3 between the third and fourth sides 110c and 110d is changed. Same as the light guide plate 100 according to FIG. 4. Therefore, only different configurations will be described below.

As can be seen in FIG. 5, the angle θ3 between the third side 110c and the fourth side 110d is set larger than 90 ° and smaller than 180 °. 5, the light emitted from the light source 200 is reflected at various angles from the third side 110c and the fourth side 110d of the protruding pattern 110, as in the case of FIG. More uniform light may be emitted in the direction of the top surface 100d of).

6 (a) illustrates a cross section of the light guide plate 100 according to another embodiment of the present invention, and FIG. 6 (b) illustrates a top surface 100 d of the light guide plate 100 according to another embodiment of the present invention. It is shown. FIG. 6 (a) corresponds to a cross section of the A-A line of FIG. 6 (b), and is particularly a cross section of an area where the protruding pattern 110 is not formed.

6 (a) and 6 (b) is the light guide plate 100 according to Figs. 3 (a) and 3 (b) described above except that the structure of the upper surface (100d) of the light guide plate 100 is changed. same. Therefore, only different configurations will be described below.

As shown in FIGS. 6A and 6B, a concave pattern 120 is formed on the upper surface 100d of the light guide plate 100.

The concave pattern 120 is formed in a straight line structure perpendicular to the first side surface 100a facing the light source 200, and a plurality of such straight line structures are arranged at predetermined intervals to form a stripe structure as a whole. Can be formed. As such, the concave pattern 120 is formed on the upper surface 100d of the light guide plate 100, thereby improving the spreadability of light emitted through the upper surface 100d of the light guide plate 100. The concave pattern 120 may have a triangular cross-sectional structure.

FIG. 7A is a cross-sectional view of the light guide plate 100 according to another embodiment of the present invention, and FIG. 7B is a top surface 100d of the light guide plate 100 according to another embodiment of the present invention. It is shown. FIG. 7A corresponds to a cross section of the A-A line of FIG. 7B, and is particularly a cross section of an area where the protruding pattern 110 is not formed.

7 (a) and 7 (b) are the above-described FIGS. 6 (a) and 6 (b) except that the structure of the region between the concave patterns 120 formed on the upper surface 100d of the light guide plate 100 is changed. It is the same as the light guide plate 100 according to. Therefore, only different configurations will be described below.

As shown in FIGS. 7A and 7B, a concave pattern 120 is formed on an upper surface 100d of the light guide plate 100, and a convex pattern 130 is formed in a region between the concave patterns 120. Formed. The convex pattern 130 is formed in a straight line structure perpendicular to the first side surface 100a of the light guide plate 100, and a plurality of such straight line structures are arranged at predetermined intervals to form a stripe structure as a whole. Can be. As a result, the concave pattern 120 and the convex pattern 130 may be alternately repeated. As such, the concave pattern 120 and the convex pattern 130 are alternately formed on the upper surface 100d of the light guide plate 100 to further improve the spreadability of light emitted through the upper surface 100d of the light guide plate 100. have. The convex pattern 130 may have a curved cross-sectional structure.

8 is a cross-sectional view of a light guide plate 100 according to another embodiment of the present invention, which is described in FIGS. 7A and 7B except that the structure of the convex pattern 130 is changed. Same as the light guide plate accordingly.

According to the aforementioned 7 (a) and 7 (b), although the plurality of convex patterns 130 are all formed in the same shape, according to FIG. 8, the plurality of convex patterns 130 are not all formed in the same shape. . That is, as shown in FIG. 8, the plurality of convex patterns 130 includes a first convex pattern 130a and a second convex pattern 130b different in height from each other. In other words, the height h1 of the first convex pattern 130a is higher than the height h2 of the second convex pattern 130b.

As such, when the first convex pattern 130a and the second convex pattern 130b having different heights are formed, the spreadability of light emitted through the upper surface 100d of the light guide plate 100 may be further improved.

9 illustrates a cross section of an optical sheet 300 according to an embodiment of the invention.

As can be seen in FIG. 9, the optical sheet 300 is formed of an inverted prism sheet, wherein the plurality of prisms includes a first prism pattern 310a and a second prism pattern 310b having different heights. That is, the height h1 of the first prism pattern 310a is higher than the height h2 of the second prism pattern 310b.

As such, when the first prism pattern 310a and the second prism pattern 310b having different heights are formed, more uniform light may be transmitted in the liquid crystal panel direction.

10 illustrates a bottom surface of the light guide plate 100 according to another embodiment of the present invention.

Referring to FIG. 3B, the plurality of protruding patterns 110 are spaced apart from each other at predetermined intervals in the horizontal and vertical directions on the lower surface 100c of the light guide plate 100. ) Consists of a rectangular planar structure as a whole.

In contrast, according to FIG. 10, the protruding pattern 110 has a trapezoidal planar structure as a whole. More specifically, the fifth side 110e close to the light source 200 and the sixth side 110f opposite to the light source 200 are parallel to each other and connect the fifth side 110e and the sixth side 110f. The seven sides 110g and the eighth sides 110h are not parallel to each other. In particular, the length of the sixth side 110f is longer than the length of the fifth side 110e.

When the protrusion pattern 110 having the above structure is used, the light emitted from the light source 200 is spread in a wide range within the light guide plate 100. In particular, when a point light source such as an LED is used as the light source 200, an area in which light emitted from the point light source is not transmitted into the light guide plate 100 may occur. In the case of applying the protrusion pattern 110 as illustrated in FIG. Since the light is spread in a wide range, it is possible to minimize the area in which the light is not transmitted in the light guide plate 100.

FIG. 11A illustrates a bottom surface of the light guide plate 100 according to another exemplary embodiment. FIG. 11B is a cross-sectional view taken along line AA of FIG. 11A, and FIG. It is sectional drawing of the BB line of FIG.

11A and 11C, the light guide plate according to FIGS. 11A to 11C is described above with the exception that the structure of the region between the protruding patterns 110 formed on the bottom surface 100c of the light guide plate 100 is changed. It is the same as the light guide plate according to 3 (b). Therefore, only different configurations will be described below.

11 (a) to 11 (c), the plurality of protruding patterns 110 are spaced apart from each other at predetermined intervals in the horizontal and vertical directions on the lower surface 100c of the light guide plate 100.

In addition, a protective pattern 140 is formed in an area between the plurality of protruding patterns 110. The protective pattern 140 serves to protect the protruding pattern 100.

As described above, since the light emitted from the light source 200 is reflected by the protrusion pattern 110, when the crack is applied to the protrusion pattern 110, the light efficiency is lowered. In general, when a liquid crystal display is used, pressure may be applied to the backlight unit by a user's hand or for various reasons, and in this case, damage such as a crack may occur on the protruding pattern 110.

Therefore, in the case of the embodiment according to FIGS. 11A to 11C, the protective pattern 140 is additionally formed in the area between the plurality of protruding patterns 110, so that the pressure is applied to the backlight unit. Even if the pressure is absorbed in the protective pattern 140 to prevent damage to the protruding pattern 110.

The protective pattern 140 having such a function is formed higher than the height of the protruding pattern 110. In addition, it is preferable that the protective pattern 140 is formed in a curved cross section. The reason is that when the cross section of the protective pattern 140 is formed in a curved shape, the protective plate 140 is formed on the bottom surface thereof. This is because the phenomenon of being pressed against (see reference numeral 400 in Fig. 2) can be reduced.

In addition, the protective pattern 140 may be formed in a straight line structure perpendicular to the first side surface 100a of the light guide plate 100, and a plurality of such straight line structures are arranged at predetermined intervals so that the overall stripe is formed. It may be formed into a structure, but is not necessarily limited thereto.

12 (a) to 12 (c) illustrate a method of designing a liquid crystal display device according to an exemplary embodiment of the present invention, and FIG. 12 (a) illustrates a liquid crystal panel according to an exemplary embodiment of the present invention. FIG. 12B is a schematic plan view of a light guide plate according to an embodiment of the present invention, and FIG. 12C illustrates a method of designing a protrusion pattern of a light guide plate according to an embodiment of the present invention.

In general, when two wavelengths having different pitches are combined, interference may occur, and a moire phenomenon may occur due to such interference. In the case of the liquid crystal display device, when light emitted from the light source is reflected from the protruding pattern formed on the lower surface of the light guide plate and proceeds upward, one wavelength having a pitch between the protruding patterns is formed, and the light transmitted to the liquid crystal panel has a matrix structure. The other wavelength having a pitch between the pixels is formed while passing through the plurality of pixels arranged as.

Therefore, the moiré phenomenon may occur by combining one wavelength having a pitch between the protrusion patterns and another wavelength having a pitch between the pixels.

12 (a) to 12 (c) illustrate a method of designing a liquid crystal display device capable of minimizing such moiré phenomenon.

As can be seen from FIG. 12A, in the liquid crystal panel 2, subpixels of red (R), subpixels of green (G), and subpixels of blue (B) are formed. One pixel is formed by the combination of the red (R) subpixel, the green (G) subpixel, and the blue (B) subpixel. The pixel may be defined by such a combination of three subpixels, but is not necessarily limited thereto, and may be defined by a combination of four subpixels in some cases.

The plurality of pixels is arranged in a first direction (e.g., vertical direction) and a second direction (e.g., horizontal direction). In this case, the size of the pixel is determined according to the use of the liquid crystal panel 2 or the like. When the size of the pixel is determined, a pitch between the plurality of pixels is determined.

In this specification, the pitch between the predetermined components means the distance between the central portions of each of the two components adjacent to each other in the first direction or the second direction. 12A, the pitch between the plurality of pixels in the vertical direction is P1a and the pitch between the plurality of pixels in the horizontal direction is P1b.

As shown in FIG. 12B, a protruding pattern 110 is formed on the lower surface 100c of the light guide plate 100.

The plurality of protruding patterns 110 are arranged in a first direction (eg, longitudinal direction) and a second direction (eg, horizontal direction). The plurality of protruding patterns 110 are arranged at a pitch of P2a in the vertical direction and at a pitch of P2b in the horizontal direction.

It is preferable to properly set the pitches P2a and P2b between the plurality of protrusion patterns in consideration of the pitches P1a and P1b between the plurality of pixels as described above to prevent the moire phenomenon. This will be described in detail below.

Hereinafter, the pattern pitch means a pitch between a plurality of protruding patterns, and the pixel pitch means a pitch between a plurality of pixels.

As can be seen in FIG. 12C, the plurality of pixels are arranged at the pixel pitch P1, and the plurality of protruding patterns are arranged at the pattern pitch P2. Although not shown in FIG. 12C about the directivity in the first direction or the second direction, when the pixel pitch P1 is the pitch in the vertical direction, the pattern pitch P2 also means the pitch in the same vertical direction. When the pixel pitch P1 is a pitch in the horizontal direction, the pattern pitch P2 also means a pitch in the same horizontal direction.

Here, when the pixel pitch P1 is repeated n (n is an integer of 1 or more) times, the pattern pitch P2 may be repeated (n + m) (n is an integer of 1 or more, m is an integer) times. Therefore, the distance corresponding to n times the pixel pitch P1 or (n + m) times the pattern pitch P2 is the moiré pitch Pm where the moiré is repeated.

Such a matter may be expressed as Equation 1 and Equation 2 below, and eventually, the moire pitch Pm may be defined as Equation 3 below.

Equation 1

Pm / P1 = n

Equation 2

Pm / P2 = n + m = Pm / P1 + m

Equation 3

(Where m is an integer)

In this case, when the moiré pitch Pm is minimized to be close to 0, the user may not recognize the moiré. More specifically, when the moiré pitch (Pm) is less than 500㎛ may not recognize the user moiré. This moiré pitch (Pm) range is more preferable when the liquid crystal panel 2 is HD + class.

In addition, when the moiré pitch Pm is maximized to be close to ∞, the user does not recognize the moiré. In particular, when the moiré pitch Pm is equal to or greater than the length of the liquid crystal panel 2, generation of moiré phenomenon is prevented. For example, when the moiré pitch Pm in the longitudinal direction is equal to or greater than the length in the longitudinal direction of the liquid crystal panel 2, the moiré phenomenon does not occur.

13 illustrates a bottom surface of a light guide plate according to another embodiment of the present invention.

As can be seen in FIG. 13, the light guide plate 100 includes a first side surface 100a facing the light source 200 and a second side surface 100b facing the first side surface 100a.

A plurality of protruding patterns 110 are formed on the bottom surface 100c of the light guide plate 100. For convenience, the protrusion pattern 110 of the row closest to the first side surface 100a is referred to as the first protrusion pattern 110-1, and the protrusion pattern 110 of the row closest to the second side surface 100b is projected to the second side. This is referred to as a pattern 110-2.

The protrusion patterns 110 are arranged in a plurality of rows from the first side surface 100a to the second side surface 100b, and a plurality of protrusion patterns 110 are spaced apart from each other in the plurality of columns. .

In this case, the first width W1 of the first protrusion pattern 110-1 and the first width W1 of the second protrusion pattern 110-2 are the same. Here, the first width W1 means the width of the side parallel to the first side surface 100a among the widths of the first and second protrusion patterns 110-1 and 110-2. In addition, all of the first widths W1 of the protruding patterns in all rows are the same.

In addition, the pattern pitch P2a-1 between the two rows of protruding patterns 110 close to the first side surface 100a and between the two rows of protruding patterns 110 close to the second side surface 100b are provided. The pattern pitches P2a-2 are the same. In addition, the pattern patches of all rows from the first side surface 100a to the second side surface 100b are identical to each other.

As a result, according to FIG. 13, all rows of protrusion patterns have the same shape and are arranged at the same separation distance.

FIG. 14 is a schematic view of a bottom surface of a light guide plate according to another exemplary embodiment of the present invention. Hereinafter, repeated description of the same configuration as that of FIG. 13 will be omitted.

As can be seen in FIG. 14, the first width W1 of the first protrusion pattern 110-1 and the first width W1 of the second protrusion pattern 110-2 are the same. In addition, all of the first widths W1 of the protruding patterns in all rows are the same.

However, the pattern pitch P2a-1 between the two rows of protruding patterns 110 close to the first side surface 100a may include two rows of the protruding patterns 110 far from the first side surface 100a. For example, the pattern pitch P2a-2 between two rows of protruding patterns 110 close to the second side surface 100b may be greater than the pattern pitch P2a-2. That is, the pattern pitch is set relatively large near the light source 200, and the pattern pitch is set relatively small near the light source 200, so that uniform light emission can be achieved in the entire light guide plate. In other words, since the amount of light reaching the far side from the light source 200 is relatively small, the pattern pitch is set small so as to increase the amount of light emitted toward the upper side.

Meanwhile, the pattern pitch may be gradually set to be smaller from the first side surface 100a to the second side surface 100b.

FIG. 15 is a schematic view of a bottom surface of a light guide plate according to still another embodiment of the present invention, hereinafter, repeated description of the same configuration as in FIG. 13 will be omitted.

As can be seen in FIG. 15, the pattern pitch P2a-1 between the two rows of protruding patterns 110 close to the first side surface 100a and the two rows of protruding patterns 110 close to the second side surface 100b. The pattern pitch (P2a-2) between them is the same. In addition, the pattern patches of all rows from the first side surface 100a to the second side surface 100b are identical to each other.

However, the first width W1 of the first protrusion pattern 110-1 is smaller than the first width W1 of the second protrusion pattern 110-2. That is, the first width of the protruding pattern is set relatively small on the side closer to the light source 200, and the first width of the protruding pattern is set relatively large on the side farther from the light source 200, thereby providing uniform light throughout the light guide plate. The release can be made. In other words, since the amount of light reaching the far side from the light source 200 is relatively small, the first width of the protruding pattern is set large so as to increase the amount of light emitted upward.

Meanwhile, the first width of the protruding pattern may be gradually increased from the first side surface 100a to the second side surface 100b.

Here, the end of the first protruding pattern 110-1 and the end of the second protruding pattern 100-2 are more specifically, the first side of the light guide plate 100 that does not face the light source 200. The end of the first protruding pattern 110-1 and the end of the second protruding pattern 100-2 are preferably arranged in a straight line with each other in terms of moiré prevention. That is, when the ends of the first protruding pattern 110-1 and the second protruding pattern 100-2 are arranged in a straight line with each other, an area where the protruding pattern is not formed on the entire lower surface of the light guide plate is formed on the first side surface ( 100a) is inclined to form a reference, it may be advantageous in terms of moiré prevention.

16 is a schematic diagram of a bottom surface of a light guide plate according to another embodiment of the present invention.

According to FIG. 16, the second width W2 of the protruding pattern 110 is greater than the width D of the spaced space between the plurality of protruding patterns 110. Here, the second width W2 of the protruding pattern 110 refers to the width of the side of the protruding pattern 110 that is perpendicular to the first side surface 100a.

That is, as in the above-described embodiment according to FIGS. 13 to 15, the second width W2 of the protruding pattern 110 may be smaller than the width D of the separation space between the plurality of protruding patterns 110. 16, the second width W2 of the protrusion pattern 110 may be set larger than the width D of the spaced space between the plurality of protrusion patterns 110.

Meanwhile, the specific arrangement of the protrusion pattern 110 illustrated in FIG. 16 may be variously changed as described with reference to FIGS. 13 to 15, and a repeated description thereof will be omitted.

1: backlight unit 2: liquid crystal panel
100: light guide plate 110: protrusion pattern
120: concave pattern 130: convex pattern
140: protection pattern 200: light source
300: optical sheet 400: reflector

Claims (13)

Light source; A light guide plate facing the light source; An optical sheet formed on the light guide plate; And a reflector formed under the light guide plate,
The light guide plate includes a first side surface facing the light source and serving as a light incident surface, a second side surface facing the first side surface, a bottom surface facing the reflecting plate, and an upper surface facing the bottom surface and functioning as a light emitting surface. Done,
A plurality of protruding patterns are formed on the lower surface of the light guide plate,
Each of the plurality of protruding patterns has a cross-sectional structure including a first side including a portion of the lower surface, a second side extending from one end of the first side, and a third side extending from the other end of the first side,
The second side is a side close to the light source, the third side is a side far from the light source, and between the first side and the third side compared to the first angle between the first side and the second side. The second angle of is small,
Each of the plurality of protruding patterns has a planar structure, and includes a fifth side close to the light source and a sixth side opposite thereto, a seventh side connecting one end of the fifth side and one end of the sixth side, and the other side of the fifth side. And an eighth side connecting a stage and the other end of the sixth side, wherein the fifth side and the sixth side are parallel to each other, and the seventh side and the eighth side are not parallel to each other and have a length of the fifth side. And a sixth side longer than the backlight unit. The method of claim 1,
And the second angle is greater than 0 ° and less than 10 °. The method of claim 1,
The cross-sectional structure of the protruding pattern further comprises a fourth side connecting the second side and the third side. The method of claim 1,
A concave pattern is further formed on an upper surface of the light guide plate, wherein the concave pattern has a straight structure perpendicular to the first side surface, and a plurality of concave patterns of the straight structure are arranged at predetermined intervals. Backlight unit. The method of claim 4, wherein
A convex pattern is further formed in a region between the concave patterns, and the convex pattern has a straight structure perpendicular to the first side surface, and a plurality of convex patterns of the straight structure are arranged at predetermined intervals. Backlight unit. The method of claim 5,
The convex pattern includes a first convex pattern and a second convex pattern, and the height of the first convex pattern is higher than the height of the second convex pattern. The method of claim 1,
The protruding pattern has a rectangular flat structure. The method of claim 1,
And a protection pattern is further formed between the plurality of protrusion patterns, and the height of the protection pattern is higher than the height of the protrusion pattern. The method of claim 8,
The protective pattern is a backlight unit, characterized in that consisting of a curved cross-sectional structure. The method of claim 1,
The optical sheet may include an inverted prism sheet having a prism structure facing an upper surface of the light guide plate, and the inverted prism sheet may include a first prism pattern and a second prism pattern, and the height of the first prism pattern may be increased. And a height higher than a height of the second prism pattern. It comprises a backlight unit and a liquid crystal panel formed on the backlight unit,
The backlight unit,
Light source; A light guide plate facing the light source; An optical sheet formed on the light guide plate; And a reflector formed under the light guide plate,
The light guide plate includes a first side surface facing the light source and functioning as a light incident surface, a second side surface facing the first side surface, a bottom surface facing the reflecting plate, and an upper surface facing the bottom surface and functioning as a light exit surface. Done,
A plurality of protruding patterns are formed on the lower surface of the light guide plate,
Each of the plurality of protruding patterns has a cross-sectional structure including a first side including a portion of the lower surface, a second side extending from one end of the first side, and a third side extending from the other end of the first side,
The second side is a side close to the light source, the third side is a side far from the light source, and between the first side and the third side compared to the first angle between the first side and the second side. The second angle of is small,
Each of the plurality of protruding patterns has a planar structure in which a fifth side close to the light source and a sixth side facing the light source, a seventh side connecting one end of the fifth side and one end of the sixth side, and the other side of the fifth side. And an eighth side connecting a stage and the other end of the sixth side, wherein the fifth side and the sixth side are parallel to each other, and the seventh side and the eighth side are not parallel to each other and have a length of the fifth side. And the sixth side is longer than the liquid crystal display. The method of claim 11,
A plurality of pixels are arranged in the liquid crystal panel with a predetermined pixel pitch P1 in the first direction.
The plurality of protruding patterns provided in the light guide plate are arranged with a predetermined pattern pitch P2 in the first direction.
Moiré pitch (Pm) defined by the following equation:

(Where m is an integer)
And the pixel pitch (P1) and the pattern pitch (P2) are set to be 500 탆 or less. The method of claim 11,
A plurality of pixels are arranged in the liquid crystal panel with a predetermined pixel pitch P1 in the first direction.
The plurality of protruding patterns provided in the light guide plate are arranged with a predetermined pattern pitch P2 in the first direction.
Moiré pitch (Pm) defined by the following equation:

(Where m is an integer)
And the pixel pitch (P1) and the pattern pitch (P2) are set such that is equal to or greater than the length of the liquid crystal panel in the first direction.

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