KR20070071686A - Prism sheet and back light unit - Google Patents

Abstract

A prism sheet and a backlight unit using the same are provided to remove light in a side lobe region, thereby preventing light leakage, by forming reflection patterns below a light condensing film having a plurality of light condensing patterns oppositely to boundary portions between neighboring light condensing patterns. A light condensing film(501) condenses an incident light. A plurality of light condensing patterns(502) are formed on the light condensing film. A plurality of reflection patterns(503) are formed on the light condensing film, wherein the reflection patterns are positioned every n(n is natural number equal to or more than 2) boundary portions among respective boundary portions between neighboring light condensing patterns. Each of the reflection patterns is formed in a semi-cylindrical shape, a hemisphere shape, a triangular prism shape, or a triangular pyramid shape.

Description

Prism sheet and back light unit using it {PRISM SHEET AND BACK LIGHT UNIT}

1 shows a backlight unit according to the prior art;

FIG. 2 is a perspective view showing the prism sheet shown in FIG. 1

FIG. 3 is a view showing optical characteristics of the prism mountain shown in FIG.

4 is a view showing light transmission and angular distribution of the prism sheet shown in FIG.

5 is a view showing a prism sheet according to the first embodiment of the present invention.

6 is a cross-sectional view illustrating a traveling direction of light by cutting along the line I-I of FIG. 5.

7 illustrates a prism sheet according to a second embodiment of the present invention.

8 illustrates a prism sheet according to a third embodiment of the present invention.

9 is a view showing a prism sheet according to a fourth embodiment of the present invention.

10 is a view showing a prism sheet according to a fifth embodiment of the present invention

11 shows a prism sheet according to a sixth embodiment of the present invention.

12 illustrates a prism sheet according to a seventh embodiment of the present invention.

13 illustrates a backlight unit according to a first embodiment of the present invention.

14 illustrates a backlight unit according to a second embodiment of the present invention.

15 illustrates a backlight unit according to a third embodiment of the present invention.

* Explanation of symbols on the main parts of the drawings

500: prism sheet 501: light collecting film

502 condensing pattern 503 reflecting pattern

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight unit, and more particularly, to a prism sheet and a backlight unit using the same to improve light efficiency and viewing angle characteristics of a prism sheet.

Recently, various flat panel display devices that can reduce weight and volume, which are disadvantages of cathode ray tubes, have emerged. Such flat panel displays include a liquid crystal display, a field emission display, a plasma display panel, a light emitting display, and the like.

Among flat panel displays, a liquid crystal display includes a plurality of liquid crystal cells and a plurality of control switches for switching a video signal to be supplied to each of the liquid crystal cells. The amount of transmission is adjusted to display a desired image.

1 is a view showing a backlight unit according to the prior art.

As shown in FIG. 1, a lamp 10 generating light, a light guide plate 20 that receives light generated from the lamp 10 through an incident surface 22, and emits the light to a surface light source, and the light guide plate The lamp housing 12 is provided to surround the incident surface 22 and the lamp 10 of the 20, the reflecting plate 30 disposed on the lower surface of the light guide plate 20, and disposed on the light guide plate 20 And a diffusion sheet 40 for diffusing light via the light guide plate 20, and a prism sheet 50 for adjusting a traveling direction of light via the diffusion sheet 40.

Here, the lamp 10 mainly uses a cold cathode fluorescent lamp. The lamp 10 is turned on a lamp driving voltage from an inverter (not shown) to irradiate light onto the incident surface 22 present on the side of the light guide plate 20.

In addition, the lamp housing 12 is installed on the side of the light guide plate 20 so as to surround the incident surface 22 of the lamp 10 and the light guide plate 20. The lamp housing 12 has a reflecting surface on its inner surface to serve to reflect light from the lamp 10 toward the incident surface 22 of the light guide plate 20.

In addition, the light guide plate 20 allows the light incident from the lamp 10 to reach a distance far from the lamp 10 and guides the incident light toward the diffusion sheet 40. That is, a printed pattern formed on the lower surface of the light guide plate 20 is provided so that the light from the incident surface 22 is reflected at a predetermined inclination angle on the inclined back surface and uniformly proceeds toward the diffusion sheet 40.

In addition, the reflector 30 is disposed on the bottom surface of the light guide plate 20 to reduce light loss by reflecting light incident to itself through the back surface of the light guide plate 20 toward the light guide plate 20.

In addition, the diffusion sheet 40 diffuses the light passing through the light guide plate 20 to the entire area and irradiates the prism sheet 50.

In addition, the prism sheet 50 serves to condense the light passing through the diffusion sheet 40.

To this end, each of the prism sheet 50 is a light condensing film 52 made of polyester (Poly-ester, PET), as shown in Figure 2 and the prism mountains formed in a stripe shape on the upper surface of the light condensing film 52 ( 54).

Here, the prism mountain 54 has first and second inclined surfaces that are inclined at a predetermined angle from the vertex. At this time, each of the first and second inclined surfaces is formed to be inclined at about 45 from the upper surface of the light collecting film 52.

The prism sheet 50 has incident light incident on the prism sheet 50 having a refractive index of n1 at a predetermined angle θ1 by the Snell's law as shown in Equation 1 below. Is refracted at a predetermined angle θ2 and exits with an index of refraction n2.

The backlight unit according to the related art advances the light generated from the lamp 10 toward the diffusion sheet 40 disposed on the light guide plate 20 through the light guide plate 20 and passes through the light guide plate 20. After the light is diffused to the entire area by the diffusion sheet 40, the light is collected through the prism sheet 50 and emitted to the outside.

However, the light incident on the prism sheet 50 in the backlight unit according to the related art may be divided into three regions, that is, a total reflection region, a light collection region, and a side lobe region, as shown in FIG. 3.

Specifically, the light A of the total reflection region incident perpendicularly to the condensing film 52 is totally reflected by the first and second inclined surfaces of the prism acid 54 and then proceeds to the light guide plate 20 to be recycled. Condensed

In addition, the light B of the light collecting region incident on the light collecting film 52 at a predetermined angle is refracted and collected by the first and second inclined surfaces of the prism peak 54.

In addition, the light C of the side lobe region incident on the light condensing film 52 at a predetermined angle is totally reflected by the first and second inclined surfaces of the prism mountain 54 to reduce the efficiency of the light and the viewing angle characteristic. .

Therefore, the prism sheet 50 has bright areas on both sides of the symmetry point as shown in FIG. 4 by side lobes.

As a result, the backlight unit according to the related art has a problem in that the viewing angle asymmetry due to the brightness asymmetry and the light efficiency due to the side lobe are degraded due to the structure of the prism sheet 50.

The present invention has been made to solve the above problems, and an object thereof is to provide a prism sheet and a backlight unit using the same to improve the light efficiency and viewing angle characteristics of the prism sheet.

Prism sheet according to the present invention for achieving the above object, the light collecting film for condensing the incident light; A plurality of light collecting patterns formed on the light collecting film; And a plurality of reflective patterns formed on the light collecting film so as to be positioned at a multipleth boundary of n (n is a natural number of two or more) among the boundary parts between the light collecting patterns.

Here, each of the reflective patterns is formed on the light collecting film so as to be located at the 2m (m is a natural number) boundary.

Each of the reflective patterns may be formed on an upper surface, an inner lower surface, or an outer lower surface of the light collecting film.

Each condensing pattern may have a semi-cylindrical shape, a hemispherical shape, a triangular prism shape, or a triangular pyramid shape.

Each of the reflective patterns may be formed of any one of titanium oxide (TiO 2) or magnesium oxide (MgO).

In addition, the prism sheet according to the present invention for achieving the above object, a light condensing film for condensing the incident light, the first and second regions; A plurality of light collecting patterns formed on the light collecting film; A plurality of first reflection patterns formed on the light collecting film so as to be positioned at a multipleth boundary of n (n is a natural number of two or more) among the boundary parts between the light collecting patterns positioned in the first area; And a plurality of second reflection patterns positioned at respective boundary portions between the light collecting patterns positioned in the second area.

Here, each of the first reflection patterns positioned in the first region is formed on the light collecting film so as to be positioned at a 2 m (m is a natural number) th boundary.

Each of the first and second reflective patterns may be formed on an upper surface of the light collecting film, a lower surface of the inner surface, or a lower surface of the outer surface.

Each of the first and second condensing patterns may have a semi-cylindrical shape, a hemispherical shape, a triangular prism shape, or a triangular pyramid shape.

Each of the first and second reflective patterns may be formed of any one of titanium oxide (TiO 2) or magnesium oxide (MgO).

In addition, the backlight unit according to the present invention for achieving the above object, the light guide plate for changing the direction of the incident light; At least one light source provided on one side of the light guide plate; A lamp housing coupled to one side of the light guide plate to surround the light source; A backlight unit comprising a prism sheet for collecting light from the light guide plate, the prism sheet comprising: a light collecting film for collecting the incident light; A plurality of light collecting patterns formed on the light collecting film; And a plurality of reflective patterns formed on the light converging film so as to be positioned at a multipleth boundary of n (n is a natural number of two or more) among the boundary parts between the light converging patterns.

Here, each of the reflective patterns is formed on the light collecting film so as to be located at the 2m (m is a natural number) boundary.

Each of the reflective patterns may be formed on an upper surface, an inner lower surface, or an outer lower surface of the light collecting film.

Each condensing pattern may have a semi-cylindrical shape, a hemispherical shape, a triangular prism shape, or a triangular pyramid shape.

Each of the reflective patterns may be formed of any one of titanium oxide (TiO 2) or magnesium oxide (MgO).

A diffusion sheet disposed between the light guide plate and the prism sheet to diffuse light through the light guide plate; And a reflector disposed on a lower surface of the light guide plate.

At least one light source provided on the other side of the light guide plate; And a lamp housing coupled to the other side of the light guide plate to surround a light source provided on the other side of the light guide plate.

In addition, the backlight unit according to the present invention for achieving the above object, at least one light source for emitting light; A bottom cover for supporting and storing the light source; A diffusion sheet covering an upper surface of the bottom cover and diffusing light from the light source; A backlight unit comprising a prism sheet for condensing light from the diffusion sheet, the prism sheet comprising: a condensing film for condensing incident light; A plurality of light collecting patterns formed on the light collecting film; And a plurality of reflective patterns formed on the light converging film so as to be positioned at a multipleth boundary of n (n is a natural number of two or more) among the boundary parts between the light converging patterns.

Here, each of the reflective patterns is formed on the light collecting film so as to be located at the 2m (m is a natural number) boundary.

Each of the reflective patterns may be formed on an upper surface, an inner lower surface, or an outer lower surface of the light collecting film.

Each condensing pattern may have a semi-cylindrical shape, a hemispherical shape, a triangular prism shape, or a triangular pyramid shape.

Each of the reflective patterns may be formed of any one of titanium oxide (TiO 2) or magnesium oxide (MgO).

Hereinafter, a prism sheet according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

5 is a view showing a prism sheet according to a first embodiment of the present invention, Figure 6 is a cross-sectional view showing the traveling direction of the light cut along the line II 'shown in FIG.

As shown in FIGS. 5 and 6, the prism sheet 500 according to the first embodiment of the present invention is formed on the condensing film 501 for condensing incident light and on an upper surface of the condensing film 501. And a plurality of light collecting patterns 502 having a semi-cylindrical shape, and a bottom surface of the light collecting film 501 so as to be positioned at a multipleth boundary of n (n is a natural number of two or more) among the boundary portions of the light collecting patterns 502. A plurality of reflective patterns 503 are formed.

Here, each of the reflective patterns 503 has a rectangular pillar shape and is arranged in a stripe manner on the lower surface of the light collecting film 501.

Among the boundary portions of each of the light collecting patterns 502, n (n is a natural number of two or more) is formed at the multipleth boundary, and the light collecting pattern shown in FIG.

That is, as shown in FIGS. 5 and 6, the reflective pattern 503 is not formed at each boundary, but is formed at every multiple of the second boundary. Accordingly, the distance between the reflection patterns 503 adjacent to each other is constant.

Although not shown in the drawings, each of the reflective patterns 503 may be formed at every 2 m −1 (m is a natural number) th boundary portion, or may be formed at every 2 m th boundary portion.

In this case, each of the reflective patterns 503 is formed of a material such as titanium oxide (TiO 2) or magnesium oxide (MgO) including a reflective material in order to reflect incident light.

The position of each of the reflective patterns 503 may vary according to the refractive index of the condensing film 501 and the curvature and the refractive index of the condensing pattern 502. It is preferable to be formed to face the boundary of the reflective pattern 503.

On the other hand, the light collecting film 501 has a transparent material such as polyester (poly-ester, PET).

In addition, the width and thickness of each of the reflective patterns 503 may vary according to the thickness of the light collecting film 501, the curvature and refractive index of the light collecting pattern 502, and the angular distribution of the desired output light.

Looking at the movement path of the light passing through the prism sheet 500 according to the first embodiment of the present invention configured as described above are as follows.

That is, the light incident on the prism sheet 500 according to the first embodiment of the present invention is, as shown in FIG. 6, light A directed to four regions, that is, total reflection region, and light B directed to the condensing region. , Light C directed toward the diffusion region, and light D facing the side lobe region.

Specifically, the light A of the total reflection region incident perpendicularly to the condensing film 501 is totally reflected to the lower surface by the convex surface of the condensing pattern 502 and is condensed while being recycled.

In addition, the light B of the condensing region incident on the condensing film 501 at a predetermined angle or perpendicularly to the condensing film 501 to face the central portion of the condensing pattern 502 is formed in the condensing pattern 502. The light is refracted by the convex surface, condensed and emitted.

The light C in the diffusion region incident on the light condensing film 501 at a predetermined angle is refracted by the convex surface of the light condensing pattern 502 to be diffused and emitted.

In addition, the light D propagating to the side lobe area incident on the light collecting film 501 at a predetermined angle is totally reflected to the bottom surface by each reflection pattern 503, and then back to the light B of the light collecting area. It is concentrated and recycled.

Here, the light C directed to the diffusion region and the light D directed to the side lobe region are light having the same angle, and the light C is light that is not incident on the reflection pattern 503, and the light (D) is light reflected by the reflection pattern 503.

On the other hand, as the reflection pattern 503 is located at a multiple of the third or more boundary portion, as the distance d between the adjacent reflection patterns 503 is further increased, the diffusion area is increased to increase the amount of light diffused. However, since the number of reflective patterns 503 per unit area of the light collecting film 501 is reduced, the probability of recycling the light D toward the side lobe region is reduced. Therefore, it is preferable to vary the distance d between the reflective patterns 503 according to the area of the light collecting film 501.

As described above, the prism sheet 500 according to the first embodiment of the present invention has a reflection pattern 503 on the light collecting film 501 through which light C, which proceeds to the side lobe region, that is, light that generates light leakage is transmitted. By forming the light emitting device, the light C in the side lobe region may be removed to prevent light leakage, and the light collecting efficiency and luminance symmetry of the light may be improved to improve the viewing angle.

In addition, the prism sheet 500 according to the first embodiment of the present invention may increase the amount of light diffused because portions of the condensing film 501 located between the adjacent reflective patterns 503 face at least one boundary portion. .

Next, the prism sheet according to the second embodiment of the present invention will be described.

7 is a view showing a prism sheet according to a second embodiment of the present invention.

As shown in FIG. 7, the prism sheet 700 according to the second embodiment of the present invention includes a light collecting film 701 for condensing incident light, and a semi-cylindrical column formed on an upper surface of the light collecting film 701. A plurality of condensing patterns 702 having a shape and a plurality of condensing patterns formed on the bottom surface of the condensing film 701 so as to be located at a multipleth boundary of n (n is a natural number of two or more) among the boundary portions of each condensing pattern 702 It includes a reflective pattern 703 of.

That is, the prism sheet 700 according to the second embodiment of the present invention has the same structure as the prism sheet 500 according to the first embodiment of the present invention shown in FIG. ) Has a structure formed on the upper surface of the light collecting film 701.

Next, a prism sheet according to a third embodiment of the present invention will be described.

8 is a view showing a prism sheet according to a third embodiment of the present invention.

As shown in FIG. 8, the prism sheet 800 according to the third embodiment of the present invention includes a light collecting film 801 for condensing incident light, and a semi-circular column formed on an upper surface of the light collecting film 801. A plurality of condensing patterns 802, and a plurality of condensing patterns formed on the bottom surface of the condensing film 801 to be located at a multipleth boundary of n (n is a natural number of two or more) among the concave portions of the condensing patterns 802. The reflective pattern 803 is included.

That is, the prism sheet 800 according to the third embodiment of the present invention has the same structure as that of the prism sheet 500 according to the first embodiment of the present invention shown in FIG. ) Has a structure formed on the lower surface of the light collecting film 801.

Next, a prism sheet according to a fourth embodiment of the present invention will be described.

9 is a view showing a prism sheet according to a fourth embodiment of the present invention.

As shown in FIG. 9, the prism sheet 900 according to the fourth embodiment of the present invention collects incident light and has a first region and a second region. A plurality of light collecting patterns 902 formed on an upper surface of the 901 and forming a semi-cylindrical shape, and formed on the lower surface of the light collecting film 901 so as to be located at respective boundary portions between the light collecting patterns 901 located in the first region. The condensing film 901 of the condensing film 901 may be positioned at a multipleth boundary of n (n is a natural number of two or more) among the boundary portions between the plurality of first reflection patterns 903a and the condensing pattern 901 located in the second region. It includes a plurality of second reflection pattern 903b formed on the bottom surface.

In this case, each of the first reflective patterns 903a positioned in the first region is formed at each boundary positioned in the first region, and each of the second reflective patterns 903b positioned in the second region is positioned in the second region. It is formed for every multiple of 2 of the boundaries.

Although not shown in the drawings, the second reflection pattern 903b may be formed at every 2 m-1 (m is a natural number) th boundary portion, or may be formed at every 2 m th boundary portion.

Therefore, the distance d2 between each second reflection pattern 903b located in the second area and the distance d1 between each first reflection pattern 903a located in the first area are different from each other. Accordingly, more light diffuses in the second region than in the first region. On the other hand, more light is collected in the first region than in the second region.

Meanwhile, the first and second reflective patterns 903a and 903b of the prism sheet 900 according to the fourth embodiment of the present invention are the prism sheets according to the second embodiment of the present invention shown in FIG. 7. Like the reflective pattern 703 provided in 700. It may be formed on the upper surface of the light collecting film 901.

In addition, the first and second reflective patterns 903a and 903b of the prism sheet 900 according to the fourth embodiment of the present invention may be formed by the prism sheet according to the third embodiment of the present invention shown in FIG. 8. Like the reflective pattern 803 provided at 800, the light collecting film 901 may be formed on a lower surface of the light collecting film 901.

Next, a prism sheet according to a fifth embodiment of the present invention will be described.

10 is a view showing a prism sheet 100 according to the fifth embodiment of the present invention.

Prism sheet 100 according to the fifth embodiment of the present invention, as shown in Figure 10, the light collecting film 101 for condensing the incident light, and is formed on the upper surface of the light collecting film 101, hemispherical A plurality of condensing patterns 102 forming a plurality of condensing patterns 102 and a plurality of condensing patterns formed on a lower surface of the condensing film 101 so as to be positioned at a multipleth boundary of n (n is a natural number of two or more) among boundaries of the condensing patterns 102. The reflection pattern 103 is included.

Here, the light collecting patterns 102 are arranged in a matrix manner on the light collecting film 101, and each of the reflective patterns 103 has a rectangular pillar shape and has a stripe on the lower surface of the light collecting film 101. Arranged in a manner.

Here, each of the reflective patterns 103 has a rectangular pillar shape and is arranged in a stripe manner on the lower surface of the light collecting film 111.

Each of the reflective patterns 103 is formed at a multipleth boundary of n (n is two or more natural numbers) among the boundary portions of each condensing pattern 102, and FIG. 10 is a reflection pattern 103 formed at the multipleth boundary of two. It is shown as an example.

That is, as shown in FIG. 10, the reflective pattern 103 is not formed at each boundary, but is formed at every multiple of the boundary.

Although not shown in the drawings, each of the reflective patterns 103 may be formed at every 2 m-1 (m is a natural number) th boundary portion, or may be formed at every 2 m th boundary portion.

On the other hand, the reflective pattern 103 provided in the prism sheet 100 according to the fifth embodiment of the present invention, the reflective pattern provided in the prism sheet 700 according to the second embodiment of the present invention shown in FIG. Like 703. It may be formed on the upper surface inside the light collecting film 101.

In addition, the reflective pattern 103 provided in the prism sheet 100 according to the fifth embodiment of the present invention is the reflective pattern provided in the prism sheet 800 according to the third embodiment of the present invention illustrated in FIG. 8. Like (803). It may be formed on the lower surface of the light collecting film 101 inside.

In addition, the reflection pattern 103 provided in the prism sheet 100 according to the fifth embodiment of the present invention is a reflection pattern provided in the prism sheet 900 according to the fourth embodiment of the present invention shown in FIG. 9. Like (903a, 903b). It may be formed irregularly.

Next, a prism sheet according to a sixth embodiment of the present invention will be described.

11 is a view showing a prism sheet according to a sixth embodiment of the present invention.

As shown in FIG. 11, the prism sheet 110 according to the sixth embodiment of the present invention includes a light collecting film 111 for condensing incident light and a triangular surface formed on an upper surface of the light collecting film 111. A plurality of condensing patterns 112 having a columnar shape, and formed on the bottom surface of the condensing film 111 so as to be located at a multipleth boundary of n (n is a natural number of two or more) among the boundary portions of each condensing pattern 112. It includes a plurality of reflective patterns 113.

Here, each of the reflective patterns 113 has a rectangular pillar shape and is arranged in a stripe manner on the lower surface of the light collecting film 111.

Each of the reflective patterns 113 is formed at a multipleth boundary of n (n is a natural number of two or more) among the boundary portions of each condensing pattern 112. FIG. 11 illustrates the reflective pattern 113 formed at the multipleth boundary of two. It is shown as an example.

That is, as shown in FIG. 11, the reflective pattern 113 is not formed at each boundary, but is formed at every multiple of the second boundary.

Although not shown in the drawings, each of the reflective patterns 503 may be formed at every 2 m −1 (m is a natural number) th boundary portion, or may be formed at every 2 m th boundary portion.

On the other hand, the reflective pattern 113 provided in the prism sheet 110 according to the sixth embodiment of the present invention, the reflective pattern provided in the prism sheet 700 according to the second embodiment of the present invention shown in FIG. Like 703. It may be formed on the upper surface inside the light collecting film 111.

In addition, the reflection pattern 113 included in the prism sheet 110 according to the sixth embodiment of the present invention is the reflection pattern provided in the prism sheet 800 according to the third embodiment of the present invention illustrated in FIG. 8. Like (803). It may be formed on the lower surface of the light collecting film 111 inside.

In addition, the reflection pattern 113 included in the prism sheet 110 according to the sixth embodiment of the present invention is the reflection pattern provided in the prism sheet 900 according to the fourth embodiment of the present invention illustrated in FIG. 9. Like 903a and 903b, they may be formed irregularly.

Next, a prism sheet according to a seventh embodiment of the present invention will be described.

12 is a view showing a prism sheet according to the seventh embodiment of the present invention.

As shown in FIG. 12, the prism sheet 120 according to the seventh exemplary embodiment of the present invention includes a light collecting film 121 for condensing incident light and a triangular pyramid shape formed on an upper surface of the light collecting film 121. A plurality of condensing patterns 122 forming a plurality of condensing patterns 122, and a plurality of condensing patterns 122 formed on a lower surface of the condensing film 121 so as to be positioned at a multipleth boundary of n (n is a natural number of two or more) among boundaries of the condensing patterns 122. The reflection pattern 123 is included.

Here, the light collecting patterns 122 are arranged in a matrix form on the light collecting film 121, and each of the reflective patterns 123 has a rectangular pillar shape and has a stripe on the lower surface of the light collecting film 121. Arranged in a manner.

Each of the reflective patterns 123 is formed at a multipleth boundary of n (n is a natural number of two or more) among the boundary portions of each condensing pattern 122. FIG. 12 shows the reflective pattern 113 formed at the multipleth boundary of two. It is shown as an example.

That is, as shown in FIG. 12, the reflective pattern 123 is not formed at each boundary, but is formed at every multiple of the second boundary.

Although not shown in the drawings, each of the reflective patterns 123 may be formed at every 2 m-1 (m is a natural number) th boundary portion, or may be formed at every 2 m th boundary portion.

Meanwhile, the reflective pattern 123 provided in the prism sheet 123 according to the seventh embodiment of the present invention is the reflective pattern provided in the prism sheet 700 according to the second embodiment of the present invention illustrated in FIG. 7. Like 703. It may be formed on the upper surface of the light collecting film 121 inside.

In addition, the reflective pattern 123 provided in the prism sheet 120 according to the seventh exemplary embodiment of the present invention is the reflective pattern provided in the prism sheet 800 according to the third exemplary embodiment of the present invention illustrated in FIG. 8. Like (803). It may be formed on the lower surface inside the light collecting film 121.

In addition, the reflection pattern 123 provided in the prism sheet 120 according to the seventh embodiment of the present invention is the reflection pattern provided in the prism sheet 900 according to the fourth embodiment of the present invention illustrated in FIG. 9. Like (903a, 903b). It may be formed irregularly.

Next, the backlight unit having the prism sheet according to the embodiment of the present invention as described above will be described.

13 is a diagram illustrating a backlight unit according to a first embodiment of the present invention.

As shown in FIG. 13, the backlight unit 130 according to the first exemplary embodiment of the present invention guides the lamp 131 which generates light and the light incident from the lamp 131 through the incident surface. A light guide plate 132, a lamp housing 133 installed to surround the incident surface of the light guide plate 132 and the lamp 131, a reflective plate 136 disposed on a bottom surface of the light guide plate 132, and the light guide plate A diffusion sheet 134 disposed on the light guide plate 132 to diffuse light through the light guide plate 132 and a prism sheet 135 for collecting light through the diffusion sheet 134.

Here, the lamp 131 mainly uses a cold cathode fluorescent lamp 131. The lamp 131 is turned on by the driving voltage of the lamp 131 from an inverter (not shown) and irradiates light onto the incident surface existing on the side of the light guide plate 132.

In addition, the lamp housing 133 is installed on one side of the light guide plate 132 to surround the incident surface of the lamp 131 and the light guide plate 132. The lamp housing 133 has a reflective surface on the inner surface thereof to reflect light from the lamp 131 toward the incident surface of the light guide plate 132.

In addition, the light guide plate 132 allows the light incident from the lamp 131 to reach a distance far from the lamp 131 and guides the incident light toward the diffusion sheet 134.

That is, the printed pattern formed on the lower surface of the light guide plate 132 is provided so that the light from the incident surface is reflected at a predetermined inclination angle from the inclined back surface and proceeds uniformly toward the diffusion sheet 134.

In addition, the reflective plate 136 is disposed on the lower surface of the light guide plate 132 and serves to reduce light loss by reflecting light incident to itself through the rear surface of the light guide plate 132 toward the light guide plate 132.

In addition, the diffusion sheet 134 diffuses the light passing through the light guide plate 132 to the entire region and irradiates the prism sheet 135.

In addition, the prism sheet 135 may use any one of the prism sheets 500, 700, 800, 900, 100, 110, and 120 according to the first to seventh embodiments of the present invention. The description thereof is replaced with the description of the prism sheets 500, 700, 800, 900, 100, 110, and 120 according to the first to seventh embodiments of the present invention.

In the backlight unit 130 according to the first embodiment of the present invention, the light collecting and diffusing efficiency of the light is increased by the prism sheet 135 having the structure as described above, and the light is emitted to the side lobe region. You can prevent it.

Next, a backlight unit according to a second embodiment of the present invention will be described.

14 is a diagram illustrating a backlight unit according to a second embodiment of the present invention.

As shown in FIG. 14, the backlight unit 140 according to the second exemplary embodiment of the present invention is disposed so as to face the light guide plate 142 having a flat plate shape and the incidence surface of each of both side surfaces of the light guide plate 142. Lamp housings 143a and 143b respectively installed on both sides of the light guide plate 142 so as to surround at least one lamp 141a and 141b, an incident surface of the light guide plate 142, and each lamp 141a and 141b; A reflecting plate 146 disposed on a lower surface of the light guide plate 142, a diffusion sheet 144 disposed on the light guide plate 142 to diffuse light through the light guide plate 142, and the diffusion sheet 144. A prism sheet 145 for collecting light passing therethrough is provided.

The backlight unit 140 according to the second embodiment of the present invention has the same structure as the backlight unit 140 according to the first embodiment described above, and only the lamp 141b is provided on the other side of the light guide plate 142. ) And the lamp housing 143b is further provided.

Here, the prism sheet 145 may use any one of the prism sheets 500, 700, 800, 900, 100, 110, and 120 according to the first to seventh embodiments of the present invention. The description thereof is replaced with the description of the prism sheets 500, 700, 800, 900, 100, 110, and 120 according to the first to seventh embodiments of the present invention.

In the backlight unit 140 according to the second embodiment of the present invention, the light collecting and diffusing efficiency of the light is increased by the prism sheet 145 having the above structure, and the light is emitted to the side lobe region. You can prevent it.

Next, a backlight unit according to a third embodiment of the present invention will be described.

15 is a diagram illustrating a backlight unit according to a third embodiment of the present invention.

As shown in FIG. 15, the backlight unit 150 according to the third embodiment of the present invention includes a plurality of lamps 151 for generating light and a bottom cover 152 for accommodating the lamps 151. A diffusion plate 153 covering the upper surface of the bottom cover 152 and diffusing the light incident from the lamp 151 to the entire area; and a diffusion plate 153 disposed on the diffusion plate 153. ), A prism sheet 154 for collecting light from the light source.

Here, each of the lamps 151 mainly uses a cold cathode fluorescent lamp 151. The lamp 151 is turned on at the driving voltage of the lamp 151 from an inverter (not shown) to irradiate light to the rear surface of the diffusion plate 153.

In addition, the bottom cover 152 supports and stores a plurality of lamps 151. The inner wall of the bottom cover 152 is attached with a reflection sheet (not shown) for reflecting light incident from the plurality of lamps 151 toward the diffusion plate 153.

The diffusion plate 153 is disposed to cover the top surface of the bottom cover 152 and diffuses the light incident from the reflective sheets of the plurality of lamps 151 and the bottom cover 152 to the entire region to the prism sheet 154. Investigate.

Here, the prism sheet 154 may use any one of the prism sheets 500, 700, 800, 900, 100, 110, and 120 according to the first to seventh embodiments of the present invention. The description thereof is replaced with the description of the prism sheets 500, 700, 800, 900, 100, 110, and 120 according to the first to seventh embodiments of the present invention.

In the backlight unit 150 according to the third embodiment of the present invention, the light collecting and diffusing efficiency of the light is increased by the prism sheet 154 having the structure as described above, and the light is emitted to the side lobe region. You can prevent it.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is common in the art that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

The prism sheet and the backlight unit using the same according to the present invention as described above have the following effects.

The prism sheet and the backlight unit using the same according to the present invention remove light from the side lobe region by forming a reflective pattern on the lower portion of the light collecting film on which the plurality of light collecting patterns are formed to face each boundary of the light collecting pattern. In addition, the viewing angle may be improved by improving light condensing efficiency and luminance symmetry.

In addition, the prism sheet and the backlight unit using the same according to the present invention may increase the diffusion efficiency of light by irregularly forming the reflection pattern.

Claims (22)

A light condensing film for condensing incident light; A plurality of light collecting patterns formed on the light collecting film; And, And a plurality of reflective patterns formed on the light converging film so as to be positioned at a multipleth boundary of n (n is a natural number of two or more) among the boundary parts between the light converging patterns. The method of claim 1, And each reflective pattern is formed on the light collecting film so as to be positioned at a 2 m (m is natural number) th boundary portion. The method of claim 1, Each reflective pattern is formed on an upper surface, an inner lower surface, or an outer lower surface of the light collecting film. The method of claim 1, Each of the condensing patterns may have a semi-cylindrical shape, a hemispherical shape, a triangular prism shape, or a triangular pyramid shape. The method of claim 1, Each reflective pattern is formed of any one of titanium oxide (TiO 2) or magnesium oxide (MgO). A light condensing film condensing incident light and having first and second regions; A plurality of light collecting patterns formed on the light collecting film; A plurality of first reflection patterns formed on the light collecting film so as to be positioned at a multipleth boundary of n (n is a natural number of two or more) among the boundary parts between the light collecting patterns positioned in the first area; And, And a plurality of second reflection patterns positioned at respective boundary portions between the light collecting patterns positioned in the second area. The method of claim 6, The first prism sheet, wherein each of the first reflection patterns positioned in the first region is formed in the light collecting film so as to be positioned at a 2 m (m is a natural number) th boundary portion. The method of claim 6, Each of the first and second reflective patterns is formed on an upper surface, an inner lower surface, or an outer lower surface of the light collecting film. The method of claim 6, Each of the first and second light collecting patterns has a semi-cylindrical shape, a hemispherical shape, a triangular prism shape, or a triangular pyramid shape. The method of claim 6, Each of the first and second reflective patterns is formed of any one of titanium oxide (TiO 2) or magnesium oxide (MgO). A light guide plate for changing a direction of incident light; At least one light source provided on one side of the light guide plate; A lamp housing coupled to one side of the light guide plate to surround the light source; In the backlight unit comprising a prism sheet for collecting light from the light guide plate, The prism sheet, A light condensing film for condensing incident light; A plurality of light collecting patterns formed on the light collecting film; And, And a plurality of reflective patterns formed on the light converging film so as to be positioned at a multipleth boundary of n (n is a natural number of two or more) among the boundary parts between the light converging patterns. The method of claim 11, And each of the reflective patterns is formed on the light converging film so as to be positioned at a 2 m (m is natural number) th boundary portion. The method of claim 11, Each of the reflective patterns is formed on an upper surface, an inner lower surface, or an outer lower surface of the light collecting film. The method of claim 11, Each condensing pattern has a semi-cylindrical shape, a hemispherical shape, a triangular prism shape, or a triangular pyramid shape. The method of claim 11, Each reflective pattern is formed of any one of titanium oxide (TiO 2) or magnesium oxide (MgO). The method of claim 11, A diffusion sheet disposed between the light guide plate and the prism sheet to diffuse light through the light guide plate; And, And a reflector disposed on a lower surface of the light guide plate. The method of claim 11, At least one light source provided on the other side of the light guide plate; And, And a lamp housing coupled to the other side of the light guide plate to surround a light source provided at the other side of the light guide plate. At least one light source for emitting light; A bottom cover for supporting and storing the light source; A diffusion sheet covering an upper surface of the bottom cover and diffusing light from the light source; A backlight unit comprising a prism sheet for collecting light from the diffusion sheet, The prism sheet, A light condensing film for condensing incident light; A plurality of light collecting patterns formed on the light collecting film; And, And a plurality of reflective patterns formed on the light converging film so as to be positioned at a multipleth boundary of n (n is a natural number of two or more) among the boundary parts between the light converging patterns. The method of claim 18, And each of the reflective patterns is formed on the light converging film so as to be positioned at a 2 m (m is natural number) th boundary portion. The method of claim 18, Each of the reflective patterns is formed on an upper surface, an inner lower surface, or an outer lower surface of the light collecting film. The method of claim 18, Each condensing pattern has a semi-cylindrical shape, a hemispherical shape, a triangular prism shape, or a triangular pyramid shape. The method of claim 18, Each reflective pattern is formed of any one of titanium oxide (TiO 2) or magnesium oxide (MgO).

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