KR20080002006A - Prism sheet, back light unit and liquid crystal display device using the same - Google Patents

Abstract

A prism sheet, and a backlight unit and an LCD device using the same are provided to dispose alternately plural equilateral prism mountains to be bisymmetrical, thereby improving the brightness and visual recognition properties of a car display at right and left viewing angles. A prism sheet(150) comprises a base film(152) and plural unequilateral prism mountains(154). The plural unequilateral prism mountains have unequilateral triangle sections in the upper side of the base film and are formed in parallel to be bisymmetrical. Each of the plural unequilateral prism mountains comprises a first incline, a second incline, and a summit. The first incline is inclined at a first angle from the base film. The second incline is inclined at a second angle from the base film. The summit is formed by the first and second inclines.

Description

Prism sheet, back light unit and liquid crystal display using the same {PRISM SHEET, BACK LIGHT UNIT AND LIQUID CRYSTAL DISPLAY DEVICE USING THE SAME}

1 is a view schematically showing a conventional backlight unit.

2 is a view showing a viewing angle characteristic of a conventional backlight unit.

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

FIG. 4 is a cross-sectional view showing an isosceles prism acid shown in FIG. 3. FIG.

5 to 12 are views showing the viewing angle characteristics according to the inclination angle of one anisotropic prism mountain.

13 and 14 are views showing viewing angle characteristics of a prism sheet according to the first embodiment of the present invention.

15 is a schematic view of a prism sheet according to a second embodiment of the present invention.

FIG. 16 is a cross-sectional view of an isosceles prism acid shown in FIG. 15. FIG.

17 is a view schematically showing a backlight unit according to a first embodiment of the present invention.

18 is a view schematically showing a backlight unit according to a second embodiment of the present invention.

19 is a schematic view of a liquid crystal display according to a first embodiment of the present invention.

20 is a schematic view of a liquid crystal display according to a second embodiment of the present invention.

<Explanation of Signs of Major Parts of Drawings>

110 lamp 120 light guide plate

130: reflector 140: diffusion sheet

150: prism sheet 152: base film

154: elongated prism acid 170: liquid crystal panel

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a prism sheet capable of improving brightness characteristics at left and right viewing angles of a vehicle display, a backlight unit, and a liquid crystal display device using the same.

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 light beam irradiated from a back light unit by a liquid crystal panel including 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 transmission amount of is adjusted to display a desired image.

1 is a view schematically showing a conventional backlight unit.

Referring to FIG. 1, a conventional backlight unit includes a lamp 10 for generating light, a light guide plate 20 for emitting light incident from the lamp 10 through an incident surface 22, and a light guide plate. A lamp housing 12 surrounding the incident surface 22 and the lamp 10 of the 20, a reflecting plate 30 disposed on the lower surface of the light guide plate 20 to reflect light, and disposed on the light guide plate 20. The diffusion sheet 40 which diffuses the light via the light guide plate 20, and the 1st and 2nd prism sheets 50 and 60 which collect the light via the diffusion sheet 40 are comprised.

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

The lamp housing 12 is installed at the side of the light guide plate 20 to surround the incident surface 22 of the lamp 10 and the light guide plate 20. The lamp housing 12 has a reflective surface on the inner surface thereof to reflect light from the lamp 10 to be incident on the incident surface 22 of the light guide plate 20.

The light guide plate 20 guides the traveling direction of the light incident from the lamp 10 through the incident surface 22 toward the diffusion sheet 40. To this end, the lower surface of the light guide plate 20 is formed to have a predetermined slope, and includes a scattering pattern for scattering the light incident from the lamp 10.

The reflector 30 is disposed on the lower surface of the light guide plate 20 to reduce light loss by reflecting light incident from the light guide plate 20 back toward the light guide plate 20.

The diffusion sheet 40 diffuses the light passing through the light guide plate 20 to irradiate the entire region of the first prism sheet 50.

The first prism sheet 50 collects light via the diffusion sheet 40 and irradiates the second prism sheet 60. To this end, the first prism sheet 50 includes a first base film 52 and a plurality of first prism mountains 54 formed side by side in a first direction on an upper surface of the first base film 52. do.

The first base film 52 has a material of polyester (PET) and light diffused by the diffusion sheet 40 is irradiated with a predetermined slope.

The plurality of first prism mountains 54 is formed in a triangular cross-sectional shape on the first base film 52, and is formed in a stripe shape to have a first direction parallel to the lamp 10. Here, the plurality of first prism mountains 54 has first and second inclined surfaces that are inclined at a predetermined angle from the vertices. In this case, each of the first and second inclined surfaces is formed to be inclined at about 45 ° from the upper surface of the first base film 52. The plurality of first prism mountains 54 condense the light irradiated from the diffusion sheet 40 in the first direction and irradiate the second prism sheet 60.

The second prism sheet 60 collects light passing through the first prism sheet 50 and emits the light to the outside. To this end, the second prism sheet 60 includes a second base film 62 and a plurality of second prism mountains 64 formed side by side in a second direction on an upper surface of the second base film 62. do.

The second base film 62 has a material of polyester, and the light collected by the first prism sheet 50 is irradiated.

The plurality of second prism mountains 64 is formed in a triangular cross-sectional shape on the second base film 62, and is formed in a stripe shape to have a second direction perpendicular to the plurality of first prism mountains 54. . Here, the plurality of second prism mountains 64 have first and second inclined surfaces that are inclined at a predetermined angle from the vertices. 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 second base film 62. The plurality of second prism mountains 64 are condensed by the first prism sheet 50 to re-condense the incident light and emit the light to the outside.

The conventional backlight unit collects light through the intersecting first and second prism sheets 50 so that peak values are formed at the center portion as shown in FIG. 2 to improve front luminance.

However, the backlight unit including the conventional prism sheet has a problem that it is not suitable for use in a vehicle display in which the luminance at the left and right viewing angles of about 30 ° is more important than the front luminance.

Accordingly, an object of the present invention is to provide a prism sheet, a backlight unit, and a liquid crystal display using the same, which can improve brightness characteristics at the left and right viewing angles of a vehicle display.

Prism sheet according to an embodiment of the present invention for achieving the above object comprises a base film, and a plurality of anisotropic prism acid formed side by side to be symmetrical with an equilateral triangular cross section on the upper surface of the base film It is characterized by.

The prism sheet according to another embodiment of the present invention has a plurality of non-equivalent sides formed side by side such that the base film and the inclined plane adjacent to the top surface of the base film have the same angle and length, and the pitch of the base side is different from each other. It is characterized by including a prism acid.

According to an embodiment of the present invention, a backlight unit includes a lamp for generating light; A light guide plate for emitting light incident from the lamp through an incident surface to a surface light source; A reflection plate disposed on a bottom surface of the light guide plate to reflect light; A diffusion sheet for diffusing light through the light guide plate; And a first prism sheet for condensing light through the diffusion sheet by using a plurality of anisotropic prism acids formed side by side to have an equilateral triangular cross section on the top surface of the base film and to be symmetrical to each other.

According to another embodiment of the present invention, a backlight unit includes: a lamp generating light; A light guide plate for emitting light incident from the lamp through an incident surface to a surface light source; A reflection plate disposed on a bottom surface of the light guide plate to reflect light; A diffusion sheet for diffusing light through the light guide plate; An agent for condensing light through the diffusion sheet using a plurality of anisotropic prism acids formed side by side to have an equilateral triangular cross-section having the same angle and length of the inclined surface adjacent to the upper surface of the base film and having different pitches of the base. It is characterized by including one prism sheet.

According to an embodiment of the present invention, a liquid crystal display device includes: a liquid crystal panel configured to display an image by adjusting light transmittance; A backlight unit for irradiating light to the liquid crystal panel, the backlight unit comprising: a backlight unit; A lamp for generating light; A light guide plate for emitting light incident from the lamp through an incident surface to a surface light source; A reflection plate disposed on a bottom surface of the light guide plate to reflect light; A diffusion sheet for diffusing light through the light guide plate; And a first prism sheet for condensing light through the diffusion sheet by using a plurality of anisotropic prism acids formed side by side to have an equilateral triangular cross section on the top surface of the base film and to be symmetrical to each other.

According to another exemplary embodiment of the present invention, a liquid crystal display device includes: a liquid crystal panel configured to display an image by adjusting light transmittance; A backlight unit for irradiating light to the liquid crystal panel, the backlight unit comprising: a backlight unit; A lamp for generating light; A light guide plate for emitting light incident from the lamp through an incident surface to a surface light source; A reflection plate disposed on a bottom surface of the light guide plate to reflect light; A diffusion sheet for diffusing light through the light guide plate; An agent for condensing light through the diffusion sheet using a plurality of anisotropic prism acids formed side by side to have an equilateral triangular cross-section having the same angle and length of the inclined surface adjacent to the upper surface of the base film and having different pitches of the base. It is characterized by including one prism sheet.

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

3 is a cross-sectional view schematically showing a prism sheet according to the first embodiment of the present invention.

Referring to FIG. 3, the prism sheet 150 according to the first embodiment of the present invention has a base film 152 and a plurality of sidewalls formed in parallel to have left and right symmetry with an isosceles triangular cross section on the top surface of the base film 152. An equilateral prismatic mountain 154.

The base film 152 has a material of polyester (Poly-ester, PET).

The plurality of equilateral prismatic mountains 154 have the same material as the base film 152, and have a stripe shape of an equilateral triangular cross section on the base film 52 and are formed side by side to be symmetric.

Specifically, each of the anisotropic prism mountains 154 of any of the equilateral prism mountains 154 that are symmetrical is defined by the vertex 155 and the vertex 155 of the base film 152 from the vertex 155. And first and second inclined surfaces 156 and 157 formed to have different lengths and inclinations from the upper surface. The internal angles θP, θL, and θR of each of the plurality of anisotropic prism peaks 154 are set at an acute angle.

An angle θL of the first inclined surface 156 is formed to have an inclination in a range of 50 ° to 74 ° between the vertex 155 from the base film 152.

An angle θR of the second inclined surface 157 is formed to have an inclination in the range of 30 ° to 40 ° between the vertex 155 and the base film 152. At this time, the length of the second inclined surface 157 is longer than the first inclined surface 156. Accordingly, each of the plurality of boiling sides prism peaks 154 has an equilateral triangle cross section because the length of the second slopes 157 is longer than that of the first slopes 156. The angle θR of the second inclined surface 157 and the angle θL of the first inclined surface 156 are different from each other.

The angle θP of the vertex 155 is less than 90 °, and is formed to have an inclination in the range of 74 ° to 89 ° by the inclination of each of the first and second inclined surfaces 156.

5 to 12 are waveform diagrams showing characteristics according to an inclination angle of one elongated prism mountain 154. In FIGS. 5 to 12, the horizontal axis represents a viewing angle and the vertical axis represents luminance.

First, it is assumed that the angle θL of the first inclined surface 156 is a first inclination angle θL and the angle θR of the second inclined surface 157 is assumed to be a second inclination angle θR.

The viewing angle characteristic of the prism mountain 154 formed to have a first inclination angle θL of 64 ° and a second inclination angle θR of 28 ° is shown in FIG. 5. Compared to the viewing angle characteristic of 154, the front side is moved from 25 ° to 30 ° in the right direction from 90 °.

The viewing angle characteristic of the prism mountain 154 formed to have a first inclination angle θL of 62 ° and a second inclination angle θR of 30 ° is shown in FIG. 6. Compared to the viewing angle characteristic of 154, the front side is moved from 25 ° to 30 ° in the right direction from 90 °.

The viewing angle characteristic of the prism mountain 154 formed to have a first inclination angle θL of 60 ° and a second inclination angle θR of 32 ° is shown in FIG. 7. Compared to the viewing angle characteristic of 154, the front side is moved from 25 ° to 30 ° in the right direction from 90 °.

The viewing angle characteristic of the prism mountain 154 formed to have a first inclination angle θL of 58 ° and a second inclination angle θR of 34 ° is shown in FIG. 8. Compared to the viewing angle characteristic of 154, the front side is moved from 25 ° to 30 ° in the right direction from 90 °.

The viewing angle characteristic of the prism mountain 154 formed to have a first inclination angle θL of 56 ° and a second inclination angle θR of 36 ° is shown in FIG. 9. Compared to the viewing angle characteristic of 154, the front side is moved from 25 ° to 30 ° in the right direction from 90 °.

The viewing angle characteristic of the prism mountain 154 formed to have a first inclination angle θL of 54 ° and a second inclination angle θR of 38 ° is shown in FIG. 10. Compared to the viewing angle characteristic of 154, the front side is moved from 25 ° to 30 ° in the right direction from 90 °.

The viewing angle characteristic of the prism mountain 154 formed to have a first inclination angle θL of 52 ° and a second inclination angle θR of 40 ° is shown in FIG. 11. Compared with the viewing angle characteristic of 154, the front face has a range of 90 ° to 30 °.

The viewing angle characteristic of the prism mountain 154 formed to have a first inclination angle θL of 50 ° and a second inclination angle θR of 42 ° is a conventional prism mountain having a vertex angle of 90 ° as shown in FIG. 12. It becomes the same as the viewing angle characteristic of 154.

On the other hand, the prism mountain 154 disposed on the left side of the symmetrical prism mountain 154 has the viewing angle characteristics shown in FIGS. 5 to 11 described above, and the viewing angle characteristic of the prism mountain 154 disposed on the right side is located on the left side. As it is opposed to the prism mountain 154 disposed, it moves 25 ° to 30 ° from the front 90 ° to the left direction.

Accordingly, the prism sheet 150 according to the first embodiment of the present invention alternately displaces the equilateral prism peaks 154 so as to be symmetrical with each other so that the front prism sheet 150 is 90 ° to 30 ° as shown in FIGS. 13 and 14. You will have a right and left viewing angle.

Therefore, the prism sheet 150 according to the first embodiment of the present invention is suitable for use in a vehicle display in which luminance at a left and right viewing angle of about 30 ° is important rather than front luminance, and the brightness characteristics at the left and right viewing angles of the vehicle display are shown. Can be improved.

15 is a schematic view of a prism sheet according to a second embodiment of the present invention.

Referring to FIG. 15, the prism sheet 250 according to the second embodiment of the present invention has the same angle and length of the base film 252 and the inclined surface adjacent to the upper surface of the base film 252, and the pitch of the bottom side thereof is different from each other. It comprises a plurality of anisotropic prismatic mountains 254 formed side by side to have different equilateral triangular cross sections.

The base film 252 has a material of polyester.

The plurality of boiling sides prism acid 254 has the same material as the base film 252.

Each of the plurality of isosceles prismatic mountains 254 is formed with a vertex 255 and a first length and a slope formed from the vertex 255 to have different lengths and inclinations from the top surface of the base film 252. It comprises two inclined surfaces 256 and 257. The internal angles θP, θL, and θR of each of the plurality of anisotropic prism mountains 254 are set at an acute angle.

The angle θL of the first inclined surface 256 is formed to have an inclination in the range of 50 ° to 74 ° between the vertex 255 from the base film 252.

The angle θR of the second inclined surface 257 is formed to have an inclination in the range of 30 ° to 40 ° between the vertex 255 from the base film 252. At this time, the length of the second inclined surface 257 is longer than the first inclined surface 256. Accordingly, each of the plurality of anisotropic prism peaks 254 has an isosceles triangular cross section because the length of the second inclined surface 257 is longer than the first inclined surface 256. The angle θR of the second inclined surface 257 and the angle θL of the first inclined surface 256 are different from each other.

An angle θP of the vertex 155 is less than 90 °, and is formed to have an inclination in the range of 74 ° to 89 ° by the inclination of each of the first and second inclined surfaces 256.

On the other hand, each of the plurality of anisotropic prism peaks 254 has different viewing angle characteristics according to the bottom pitch P and the height H. As a result, the luminance of the light passing through the prism sheet 250 decreases from the center portion toward the edge.

In order to prevent the luminance unevenness, the bottom pitches P1 to P6 of each of the plurality of anisotropic prism mountains 254 decrease toward the edge from the center C of the base film 252, and It is symmetric about the center (C). At this time, since the ratio of the base pitches P1 to P6 and the height H of each of the plurality of boiling sides prism peaks 254 is set in the range of about 1.53 to 1.91, the vertices 155 of each of the boiling sides prism peaks 254 The angle θP has a range of about 74 ° to 89 °.

As such, the prism sheet 250 according to the second embodiment of the present invention reduces the pitches P1 to P6 of the isosceles prism acid 254 toward the edges from the center C of the base film 252. In addition, the amount of light emitted is increased by alternately arranging the angles and lengths of the inclined planes of the adjacent boiling side prism mountains 254 to be the same.

Accordingly, the prism sheet 250 according to the second embodiment of the present invention has left and right viewing angles of about 90 ° to 30 ° in front as shown in FIGS. 13 and 14, and increases the amount of emitted light to increase luminance. Can be improved.

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

Referring to FIG. 17, the backlight unit according to the first embodiment of the present invention emits light incident from the lamp 110 through the incidence surface 122 and the lamp 110 generating light as a surface light source. A light guide plate 120, a lamp housing 112 surrounding the incident surface 122 and the lamp 110 of the light guide plate 120, a reflector 130 disposed on the bottom surface of the light guide plate 120 to reflect light, and a light guide plate Diffusion using a diffusion sheet 140 disposed on the 120 to diffuse the light via the light guide plate 120, and a plurality of anisotropic prism acid 154 having an equilateral triangular cross section and formed side by side to be symmetrical. And a first prism sheet 150 for condensing light via the sheet 140 and a second prism sheet 160 for condensing light via the first prism sheet 150.

The lamp 110 is turned on by a lamp driving voltage from an inverter (not shown) to irradiate light onto the incident surface 122 existing on the side of the light guide plate 120.

The lamp housing 112 is installed on the side of the light guide plate 120 to surround the incident surface 122 of the lamp 110 and the light guide plate 120. The lamp housing 112 has a reflective surface on the inner surface thereof to reflect light from the lamp 110 to be incident on the incident surface 122 of the light guide plate 120.

The light guide plate 120 guides the traveling direction of the light incident from the lamp 110 through the incident surface 122 toward the prism sheet 150. To this end, the lower surface of the light guide plate 120 has a wedge shape having a predetermined slope so that the light incident from the lamp 110 can reach a distance far from the lamp 110, and the light incident from the lamp 110 is provided. It includes a scattering pattern for scattering.

The light guide plate 120 irradiates the diffusion sheet 140 with light radiated from the lamp 110 at an angle of approximately 50 ° to 90 ° as shown in FIG. 5.

The reflector 130 is disposed on the lower surface of the light guide plate 120 to reduce light loss by reflecting light incident from the light guide plate 120 back toward the light guide plate 120.

The diffusion sheet 140 diffuses the light irradiated from the light guide plate 120 to the entire area and irradiates the first prism sheet 150.

The first prism sheet 150 has the same configuration as the prism sheet of the first embodiment of the present invention shown in FIGS. 3 and 4. Therefore, the detailed description of the first prism sheet 150 will be replaced with the above description.

The second prism sheet 160 collects light passing through the first prism sheet 150 and emits the light to the outside. To this end, the second prism sheet 160 is parallel to the top surface of the second base film 162 so as to be orthogonal to the elongated prism peak 154 of the first prism sheet 150. And a plurality of elongated prismatic mountains 164 formed.

The second base film 162 has a material of polyester.

The plurality of equilateral prism peaks 164 have first and second inclined surfaces that are inclined at an angle from the vertex. At this time, the angles of the vertices of each of the a plurality of elongated prism peaks 164 are formed at about 90 degrees. The plurality of anisotropic prism mountains 164 are condensed by the first prism sheet 150 and re-condens the incident light to be emitted to the outside.

As described above, the backlight unit according to the first embodiment of the present invention includes prism sheets 150 alternately arranged such that the anisotropic prism peak 154 is symmetrically, so that the backlight unit has a left and right viewing angle of about 30 ° rather than front luminance. It is suitable for use in a vehicle display where luminance is important, and can improve brightness characteristics at the left and right viewing angles of the vehicle display.

18 is a cross-sectional view schematically illustrating a backlight unit according to a second embodiment of the present invention.

Referring to FIG. 18, the backlight unit according to the second embodiment of the present invention emits light incident from the lamp 110 through the incidence surface 122 and the lamp 110 generating light as a surface light source. A light guide plate 120, a lamp housing 112 surrounding the incident surface 122 and the lamp 110 of the light guide plate 120, a reflector 130 disposed on the bottom surface of the light guide plate 120 to reflect light, and a light guide plate The diffusion sheet 140 disposed on the light guide plate 120 to diffuse the light via the light guide plate 120 and the sidewalls of the diffusion sheet 140 having the same angle and length of the adjacent inclined planes and having an equilateral triangular cross section with different pitches at the base. A second prism sheet for condensing light via the first prism sheet 250 and the first prism sheet 250 using a plurality of anisotropic prism mountains 254 to condense light via the diffusion sheet 140. And 160.

This backlight unit according to the second embodiment of the present invention has the same configuration as the backlight unit of the first embodiment of the present invention shown in FIG. 17 except for the first prism sheet 250. Accordingly, in the second embodiment of the present invention, descriptions of other configurations except for the first prism sheet 250 will be replaced with the description of the first embodiment of the present invention.

The first prism sheet 250 has the same configuration as the prism sheet of the second embodiment of the present invention shown in FIGS. 15 and 16. Therefore, the detailed description of the first prism sheet 250 will be replaced with the above description.

As described above, the backlight unit according to the second embodiment of the present invention has a prism sheet having a plurality of anisotropic prism peaks 254 whose angles and lengths of adjacent inclined surfaces are the same and the pitch of the base is reduced from the center to the edge. 250) is suitable for use in a vehicle display in which the luminance at the left and right viewing angles of about 30 ° is more important than the front luminance, and the brightness characteristics at the left and right viewing angles of the vehicle display can be improved.

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

Referring to FIG. 19, the liquid crystal display according to the first exemplary embodiment of the present invention includes a liquid crystal panel 170 and a backlight unit 100 for irradiating light to the liquid crystal panel 170.

The liquid crystal panel 170 includes a liquid crystal layer formed between the upper substrate 172 and the lower substrate 174, and includes a spacer for maintaining a constant gap between the upper substrate 172 and the lower substrate 174. do.

The upper substrate 172 of the liquid crystal panel 170 is formed with a color filter, a common electrode, a black matrix, and the like, not shown. The common electrode may be formed on the lower substrate 174 according to the liquid crystal mode of the liquid crystal panel 170.

The lower substrate 174 of the liquid crystal panel 170 is provided with signal lines, such as a data line and a gate line, not shown, and is connected to a thin film transistor and a thin film transistor at an intersection of the data line and the gate line. A pixel electrode is formed.

The thin film transistor switches the image signal to be transmitted from the data line toward the liquid crystal cell in response to the scan signal (gate pulse) from the gate line to the pixel electrode.

In the liquid crystal panel 170, data and gate pad regions connected to the data lines and the gate lines are formed.

Meanwhile, an upper polarizer not shown is attached to the front surface of the upper substrate 172, and a lower polarizer is attached to the rear surface of the lower substrate 174.

Since the backlight unit 100 has the same configuration as the backlight unit according to the first embodiment of the present invention illustrated in FIG. 17, a description thereof will be replaced with the above description.

The backlight unit 100 irradiates the liquid crystal panel 170 with light from the lamp 110 using the prism sheets 150 alternately arranged so that the boiling side prism acid 154 is symmetrically symmetrical.

As described above, the liquid crystal display according to the first exemplary embodiment of the present invention adjusts the transmittance of light emitted from the backlight unit 100 according to the image signal applied to the liquid crystal panel 170 to display the desired image. Will be displayed.

Accordingly, the liquid crystal display according to the first exemplary embodiment of the present invention is suitable for use in a vehicle display because the backlight unit 100 has a left and right viewing angle of about 30 ° rather than front luminance.

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

Referring to FIG. 20, the liquid crystal display according to the second exemplary embodiment of the present invention includes a liquid crystal panel 170 and a backlight unit 200 for irradiating light to the liquid crystal panel 170.

Since the liquid crystal panel 170 has the same configuration as the liquid crystal display according to the first embodiment of the present invention illustrated in FIG. 19, the description thereof will be replaced with the above description.

Since the backlight unit 200 has the same configuration as the backlight unit according to the second embodiment of the present invention illustrated in FIG. 18, a description thereof will be replaced with the above description.

Such a backlight unit 200 uses a prism sheet 250 having a plurality of anisotropic prism peaks 254 whose angles and lengths of adjacent inclined surfaces are the same and the pitch of the lower side decreases from the center to the edge. Light from 110 is irradiated to the liquid crystal panel 170.

As described above, the liquid crystal display according to the second exemplary embodiment of the present invention adjusts the transmittance of light emitted from the backlight unit 200 according to the image signal applied to the liquid crystal panel 170 to display the desired image. Will be displayed.

On the other hand, the present invention described above is not limited to the above-described embodiment and the accompanying drawings, it is possible that various substitutions, modifications and changes within the scope without departing from the technical spirit of the present invention It will be apparent to those skilled in the art.

The prism sheet, the backlight unit, and the liquid crystal display using the same according to the embodiment of the present invention improve the brightness and visibility at the left and right viewing angles of the vehicle display by alternately arranging a plurality of anisotropic prism mountains to be symmetrical. Can be.

In addition, the present invention reduces the pitch of the isosceles prism acid from the center to the edge of the base film, and alternately arranged so that the angles and lengths of the inclined surfaces of the adjacent isosceles prism mountains are the same, so that the luminance at the left and right viewing angles of the vehicle display And visibility can be improved.

Claims (32)

With base film, A prism sheet, comprising: a plurality of anisotropic prism acids formed side by side to have lateral symmetry with an equilateral triangular cross section on an upper surface of the base film. With base film, A prism sheet comprising a plurality of anisotropic prism mountains formed side by side such that the angle and length of the inclined surface adjacent to the upper surface of the base film have the same anisotropic triangular cross-section with the same pitch and the bottom pitch. The method according to claim 1 or 2, And an inner angle of each of the plurality of equilateral triangular prism mountains is an acute angle. The method of claim 3, wherein Each of the anisotropic prism acids of any one of the symmetrical anisotropic prism acids, A first inclined surface inclined at a first angle from the base film, A second inclined surface inclined at a second angle from the base film, And a vertex formed by the first and second inclined surfaces. The method of claim 4, wherein The first angle is a prism sheet, characterized in that 50 ° ~ 75 °. The method of claim 4, wherein The second angle is a prism sheet, characterized in that 30 ° ~ 40 °. The method of claim 4, wherein Prism sheet, characterized in that the angle of the vertex is 74 ° ~ 89 °. The method of claim 2, The base pitch of the plurality of boiling sides prism acid is reduced from the center to the edge of the base film. The method of claim 8, The ratio of the base pitch and the height of each of the plurality of anisotropic prism peaks is 1.53 to 1.91. The method of claim 8, The plurality of anisotropic prism acid is symmetrical with respect to the center of the base film, characterized in that the prism sheet. A lamp for generating light; A light guide plate for emitting light incident from the lamp through an incident surface to a surface light source; A reflection plate disposed on a bottom surface of the light guide plate to reflect light; A diffusion sheet for diffusing light through the light guide plate; And a first prism sheet configured to condense light passing through the diffusion sheet using a plurality of anisotropic prism acids formed side by side to have an equilateral triangular cross section on the upper surface of the base film and to be symmetrical. Light unit. A lamp for generating light; A light guide plate for emitting light incident from the lamp through an incident surface to a surface light source; A reflection plate disposed on a bottom surface of the light guide plate to reflect light; A diffusion sheet for diffusing light through the light guide plate; A material for condensing light through the diffusion sheet using a plurality of anisotropic prism acids formed side by side such that the angles and lengths of the inclined surfaces adjacent to the upper surface of the base film have the same anisotropic triangular cross-section with the same angle and length of the base; A back light unit comprising one prism sheet. The method according to claim 11 or 12, And a cabinet of each of the plurality of equilateral triangle prismatic mountains is an acute angle. The method of claim 13, Each of the anisotropic prism acids of any one of the symmetrical anisotropic prism acids, A first inclined surface inclined at a first angle from the base film, A second inclined surface inclined at a second angle from the base film, And a vertex formed by the first and second inclined surfaces. The method of claim 14, The first angle is a backlight unit, characterized in that 50 ° ~ 75 °. The method of claim 14, The second angle is a backlight unit, characterized in that 30 ° ~ 40 °. The method of claim 14, The angle of the vertex is a backlight unit, characterized in that 74 ° ~ 89 °. The method of claim 12, The bottom pitch of the plurality of boiling sides prism acid is reduced from the center of the base film toward the edge. The method of claim 18, The ratio of the pitch of the base to the base of each of the plurality of elongated prism peaks is 1.53 to 1.91. The method of claim 18, The plurality of anisotropic prism acid is symmetrical with respect to the center of the base film, characterized in that the backlight unit. The method according to claim 11 or 12, And a second prism sheet for condensing light via the first prism sheet using a plurality of prism mountains that intersect the plurality of elongated prism mountains. A liquid crystal panel which displays an image by adjusting light transmittance; It has a backlight unit for irradiating light to the liquid crystal panel, The backlight unit is; A lamp for generating light; A light guide plate for emitting light incident from the lamp through an incident surface to a surface light source; A reflection plate disposed on a bottom surface of the light guide plate to reflect light; A diffusion sheet for diffusing light through the light guide plate; And a first prism sheet configured to condense the light passing through the diffusion sheet by using a plurality of anisotropic prism acids formed side by side to have an equilateral triangular cross section on the upper surface of the base film so as to be symmetrical to each other. Display. A liquid crystal panel which displays an image by adjusting light transmittance; It has a backlight unit for irradiating light to the liquid crystal panel, The backlight unit is; A lamp for generating light; A light guide plate for emitting light incident from the lamp through an incident surface to a surface light source; A reflection plate disposed on a bottom surface of the light guide plate to reflect light; A diffusion sheet for diffusing light through the light guide plate; An agent for condensing light through the diffusion sheet using a plurality of anisotropic prism acids formed side by side to have an equilateral triangular cross-section having the same angle and length of the inclined surface adjacent to the upper surface of the base film and having different pitches of the base. A liquid crystal display device comprising one prism sheet. The method of claim 22 or 23, And an inner angle of each of the plurality of equilateral triangle prism acids is an acute angle. The method of claim 24, Each of the anisotropic prism acids of any one of the symmetrical anisotropic prism acids, A first inclined surface inclined at a first angle from the base film, A second inclined surface inclined at a second angle from the base film, And a vertex formed by the first and second inclined surfaces. The method of claim 25, And the first angle is 50 ° to 75 °. The method of claim 25, And the second angle is 30 ° to 40 °. The method of claim 25, The angle of the vertex is a liquid crystal display, characterized in that 74 ° ~ 89 °. The method of claim 23, And a bottom pitch of the plurality of boiling sides of the prism acid decreases from the center to the edge of the base film. The method of claim 29, And a ratio of the pitch and the height of the base of each of the plurality of boiling sides of the prism mountains is 1.53 to 1.91. The method of claim 29, And the plurality of anisotropic prism acids are symmetrical with respect to the center of the base film. The method of claim 22 or 23, The backlight unit may further include a second prism sheet configured to condense light passing through the first prism sheet using a plurality of prism acids that intersect the plurality of equilateral sides of the prism mountains. .

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