KR20120029576A - Prism sheet and back light assembly having the same - Google Patents

Abstract

PURPOSE: A prism sheet and a back light assembly having the same are provided to uniformly maintain brightness according to a viewing angle without reducing the brightness by forming a complex pattern in which a triangle prism, a lenticula prism, and a curved surface triangle prism, are mixed. CONSTITUTION: A prism pattern mixes two or more prisms of different form on a base film. The prism pattern arranges a plurality of prisms. An optical source section(110) is composed of a lamp(111) and a mp reflector(112). A light guide plate(120) guides light delivered from the optical source section to an LCD panel(P). A reflective sheet(150) is arranged in the lower side of the light guide plate. The surface of the light guide plate is formed into an uneven shape or a dot shape in order to easily reflect and diffuse the light and transfer to a direction of the LCD panel.

Description

Prism sheet and backlight assembly having the same {PRISM SHEET AND BACK LIGHT ASSEMBLY HAVING THE SAME}

The present invention relates to a prism sheet and a backlight assembly having the same, and more particularly, to prevent luminance deterioration at the front viewing angle and at the same time obtain brightness uniformity for each viewing angle, and in particular, to prevent damage to adjacent sheets. A seat and a backlight assembly having the same.

Recently, the liquid crystal display (Liquid Crystal Display) is one of the flat panel display device that displays the image by using the liquid crystal (Liquid Crystal), thinner and lighter than other display devices, low driving voltage and low power consumption There is an advantage in that it is widely used throughout the industry.

The liquid crystal display device is a liquid crystal made of a thin film transistor substrate, a color filter substrate facing the thin film transistor substrate, and a liquid crystal interposed between the two substrates, and a liquid crystal changing the transmittance of light as an electric signal is applied. And a liquid crystal display panel. In addition, the liquid crystal display device further includes a backlight assembly for supplying separate light since the liquid crystal display panel does not emit light by itself.

The backlight assembly includes a lamp for generating light, a light guide plate for guiding a path of light generated from the lamp in the direction of the liquid crystal display panel, a reflective sheet disposed below the light guide plate to reflect leakage light, and a liquid crystal display panel disposed above the light guide plate. A diffusion sheet for increasing the uniformity of the light incident to the light, a prism sheet for improving the brightness characteristics of the light emitted from the diffusion sheet and a storage container for storing them. Here, the backlight assembly may be further provided with a protective sheet for protecting the prism sheet as necessary.

1 is a perspective view for explaining a conventional prism sheet.

The prism pattern 31 is formed on the upper surface of the prism sheet 30 to refract or reflect the light introduced from the bottom surface of the prism sheet 30 to collect the overall direction of the light in the direction of the user's view. ) Is formed in the form of a triangular prism consisting of a triangular cross-section continuously on the upper surface where the light is emitted as shown in (a) of Figure 1, or the light is emitted as shown in (b) of FIG. A lenticular prism having a semicircular cross section may be formed on the upper surface to be continuously arranged.

At this time, when a triangular prism having a triangular cross section is continuously arranged as a prism pattern 31 on the upper surface of the prism sheet 30, the effect of condensing toward the front becomes large, so that the triangular prism is sharply formed. The luminance in the normal region (front viewing angle) is increased, but the luminance is sharply lowered in the inclined region or the valley region, thereby degrading the luminance uniformity for each viewing angle. Especially in the off axis (eg 45 degrees or less), the brightness may be drastically deteriorated, which may deviate from the TCO specification.

Furthermore, such triangular prismatic patterns can cause scratches on the top sheet due to the sharp shape of the mountain area, which can cause scratches on the top sheet or damage it by itself, resulting in lower brightness and uneven optical properties. .

In addition, when the lenticular prism having a semicircular cross section is continuously arranged as the prism pattern 31 on the upper surface of the prism sheet 30, unlike the above-described triangular prism, the scratch problem with respect to the upper sheet or the luminance at the off axis Although the degradation problem can be solved to some extent, there is a problem in that the luminance in the normal region is relatively reduced.

The problem to be solved by the present invention is to provide a prism sheet that can maintain the uniform brightness for each viewing angle without a decrease in the brightness in the front viewing angle, and can solve the problem of bending of adjacent sheets.

Prism sheet according to an embodiment of the present invention for solving the above problems, the base film; A prism pattern in which a plurality of prisms are formed by combining at least two of a triangular prism, a lenticular prism, and a curved triangular prism on the base film; It is made, including.

In this case, the heights of the triangular prism, the lenticular prism, and the curved triangular prism may be formed to have different pitches or different pitches.

In addition, it is preferable that the height of the lenticular prism or the curved triangular prism is higher than the height of the triangular prism, and it is preferable to disperse and arrange the prism having the highest height among the lenticular prism or the curved triangular prism.

In addition, the plurality of prisms may be formed to have various heights or may have various pitches, and the plurality of prisms may be arranged such that the prism cross-section gradually increases from one edge to the other edge.

Preferably, the plurality of prisms are formed such that the prism pitch of the edge portion is relatively wider than the prism pitch of the center portion, and the pitch interval is formed such that the luminance of the edge portion has a luminance of 2% or more greater than that of the center portion. desirable.

In addition, a prism sheet according to another embodiment of the present invention for solving the above problems, the base film; A prism pattern formed by arranging at least one of a triangular prism, a lenticular prism, and a curved triangular prism on the base film by a plurality of prisms; Preferably, the plurality of prisms are formed such that the prism pitch of the edge portion is relatively wider than the prism pitch of the center portion, and the pitch interval is such that the luminance of the edge portion is at least 2% greater than the luminance of the center portion. It is preferably formed.

On the other hand, the backlight assembly according to an embodiment of the present invention for solving the above problems, the light source for generating light; A light guide plate for emitting light incident from the light source unit upward; And a prism disposed on the light guide plate, wherein a prism in which a plurality of prisms are arranged by combining at least two or more of a triangular prism, a lenticular prism, and a curved triangular prism on the base film to which light emitted from the light guide plate is incident; A prism sheet forming a pattern; It is made, including.

The prism sheet according to the present invention forms a complex pattern in which a triangular prism and a lenticular prism or a curved triangular prism are mixed, so that the luminance can be maintained uniform for each viewing angle without deteriorating the luminance at the front viewing angle.

In addition, it is possible to accurately express the intended luminance for each viewing angle through individual adjustments to the height, pitch, or upper peak curved angle of each prism in a combination of prism combinations.

In addition, scratch problems that occur in adjacent sheets due to relatively high lenticular prisms or curved triangular prisms having a curved surface contact the adjacent sheets, or the number of contact prisms is reduced by different height prism patterns. Can be solved.

In addition, the overall luminance uniformity can be improved by changing the prism pitch intervals of the center portion and the edge portion.

1 is a perspective view for explaining a conventional prism sheet.
2 is an exploded perspective view of a backlight assembly according to an embodiment of the present invention.
3 to 7 are cross-sectional views of the prism sheet according to an embodiment of the present invention.
8 is a cross-sectional view of a prism sheet according to another embodiment of the present invention.
9 illustrates another example of a spherical triangular prism in the prism sheet of FIG. 8.
10 is a cross-sectional view of a prism sheet 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.

Advantages and features of the present invention, and methods for achieving them will be apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various other forms, and it should be understood that the present embodiment is intended to be illustrative only and is not intended to be exhaustive or to limit the invention to the precise form disclosed, To fully disclose the scope of the invention to a person skilled in the art, and the invention is only defined by the scope of the claims. Thus, in some embodiments, well known structures or techniques have not been described in detail in order to avoid obscuring the present invention. Like reference numerals refer to like elements throughout.

The spatially relative terms above, above, above, below, below, or the like (below, beneath, lower) facilitate the correlation of one component with another, as shown in the figure. Can be used to describe. The components can be oriented in other directions as well, so that spatially relative terms can be interpreted according to the orientation.

In addition, the accompanying drawings have been shown in a simplified manner in order to facilitate describing the invention, and thus, they may be used only within the understanding of the invention, and the actual specific shapes may be different.

2 is an exploded perspective view of a backlight assembly according to an exemplary embodiment of the present invention.

Referring to FIG. 2, the backlight assembly for supplying light from the liquid crystal display device to the liquid crystal display panel P includes the light source unit 110, the light guide plate 120, the diffusion sheet 125, the prism sheet 130, and the reflective sheet 150. ).

The light source unit 110 includes a lamp 111 and a lamp reflector 112, so that light emitted from the lamp 111 toward the light guide plate 120 is directly transmitted to the light guide plate 120, and is opposite to the light guide plate 120. Light emitted by the light is reflected by the lamp reflector 112 and transmitted to the light guide plate 120.

The light guide plate 120 serves to guide the light transmitted from the light source unit 110 to the upper liquid crystal display panel P. To this end, the light guide plate 120 is surface-treated in a concave-convex or dot form such that light is more easily refracted and scattered and transmitted in the direction of the liquid crystal display panel P.

The reflective sheet 150 is disposed under the light guide plate 120 to reflect the light emitted downward from the light guide plate 120 to change the path of the light upward. The reflective sheet 150 is coated with a reflective member having a high reflectance on a base material.

The diffusion sheet 125 is disposed on the light guide plate 120, and diffuses the light emitted from the light guide plate 120 to increase the uniformity of the light incident on the liquid crystal display panel P. FIG.

The prism sheet 130 is positioned above the light guide plate 120 to refract and focus light emitted from the light guide plate 120 to increase the luminance. In this case, a liquid crystal display panel P is disposed on the prism sheet 130, and a separate polarizing film may be provided between the liquid crystal display panel P and the prism sheet 130.

In FIG. 2 and the above description, the light source is an example of an edge type backlight assembly positioned on a side of the light guide plate, but the present invention is not limited thereto. Of course it is possible to apply the prism sheet.

The prism sheet 130 includes a base film and a prism pattern 131 formed on an upper surface of the base film.

3 is a cross-sectional view of the prism sheet 130 according to an embodiment of the present invention.

The prism sheet 130 is a kind of optical sheet, which is installed on the upper surface of the light guide plate 120 of the backlight assembly in order to improve the brightness in the front direction, and is capable of providing transparency, heat resistance, and strength to the sheet. The prism pattern 131 is formed on the base film of the (PET) material.

Here, the base film on which the prism pattern 131 is formed is manufactured in the form of a flat plate having a constant refractive index. Material is a transparent material that can transmit light, for example, polycarbonate-based, poly sulfone-based, poly acrylate-based, polystyrene-based, polyvinyl chloride ( It can be made of poly vinyl chloride series, poly vinyl alcohol series, poly norbornene series, polyester series. Preferably it may be made of polyethylene terephtalate (polyethylene terephtalate) or polyethylene naphthalate (polyethylene naphthalate).

The thickness of the base film is not limited, and those skilled in the art will be able to select an appropriate range of values in consideration of the environment in which the prism sheet 130 is used. In general, however, the thickness of the base film is between 20 and 400.

In the prism sheet of the present invention, the prism pattern 131 is a combination of at least two or more of the triangular prism 131a, the lenticular prism 131b, or the curved triangular prism 131c, and the luminance at the front viewing angle, which is an object of the present invention. The luminance may be variously adjusted within a range in which luminance may be uniformly maintained for each viewing angle without deterioration.

The prism pattern 131 may be a polymer resin including a thermosetting or photocurable acrylic resin. For example, the prism pattern 131 may use unsaturated fatty acid esters, aromatic vinyl compounds, unsaturated fatty acids and derivatives thereof, vinyl cyanide compounds such as methacrylonitrile, and the like. Crylic acrylate resins and the like can be used.

The prism pattern 131 may be formed of a material having a higher refractive index than that of the base film. When the refractive index of the base film is higher, a part of the light incident to the rear surface of the base film may be totally reflected at the surface of the prism pattern and thus may not be incident to the prism structure. Because it can.

Each prism formed as described above collects light incident through the base film and emits the light upwardly. From the viewpoint of luminance, the prism is preferably a triangular prism 131a having a sharp angle as described above. From the viewpoint of the viewing angle, a lenticular prism 131b having a peak angle having a curved surface is preferable.

That is, in the present invention, when the high luminance is important, it is preferable to increase the ratio of the triangular prism 131a, and to increase the viewing angle, increase the ratio of the lenticular prism 131b or the curved triangular prism 131c. It is preferable to configure the composite prism pattern 131.

The triangular prism 131a of the prism pattern 131 has a triangular shape in a uniaxial direction, and each triangular prism is arranged in one direction while forming a valley region and a valley region through connection with neighboring prisms. The peak angle of the acid region in the triangular prism 131a is preferably 60 ° to 130 °.

Here, the cross-sectional length from the base film to the peak of the triangular prism 131a is called the prism height H, and the length between one valley and another adjacent valley is called the pitch L.

In addition, the lenticular prism 131b of the prism pattern 131 has a semi-circular (round) cross section in a uniaxial direction, and each of the lenticular prisms forms valleys and valleys between adjacent prisms.

Here, the cross-sectional length from the base film of the lenticular prism 131b to the upper half circle of the lenticular prism is referred to as the prism height (H), and the degree of warpage of the upper half circle is called the curved angle (A) and is adjacent to one valley. The length between the other valleys is called pitch (L).

In addition, the curved triangular prism 131c of the prism pattern 131 has a triangular shape in which a cross section in the short axis direction has a curved shape, and each curved triangular prism forms adjacent valleys and valleys.

The cross-sectional length from the base film of the curved triangular prism 131c to the peak of the curved surface formed on the peak is called the prism height (H), and the degree of warpage of the upper curved surface is called the curved angle (A), and the other adjacent to one valley is The length between the valleys is called the pitch (L).

Various forms of the prism pattern 131 formed on the prism sheet 130 will be described in more detail with reference to FIG. 3. The prism pattern 131 formed in FIG. 3 is formed by combining at least two or more of the above-described triangular prism 131a, the lenticular prism 131b, and the curved triangular prism 131c, and the ratio or combination of each prism Height or pitch may be set in various ways.

Referring to FIG. 3A, the prism pattern 131 formed on the prism sheet 130 has triangular prisms 131a distributed at its center and curved triangular prisms 131c distributed at the edge thereof.

In this case, the curved triangular prisms 131c of the edge portion compensate for the luminance rapidly lowered at the edges of the triangles in the triangular prisms 131a of the center, thereby obtaining the overall luminance uniformity.

Next, referring to FIG. 3B, the prism pattern 131 formed on the prism sheet 130 has the curved triangular prisms 131c distributed at the center thereof and the triangular prisms 131a distributed at the edge portion thereof. .

In particular, in this case, since the prism height H of the curved triangular prisms 131c distributed in the center is higher than the triangular prism 131a of the edge portion, the number of contact prisms on the upper adjacent sheet can be reduced, as well as the curved triangular prism ( Since the peak of 131c is a curved phenomenon, the scratch causing phenomenon for the upper adjacent sheet is almost disappeared. In addition, by combining the triangular prism 131a of the edge portion and the curved triangular prism 131c of the central portion, luminance uniformity can be obtained for each viewing angle.

Next, FIG. 3C shows the prism pattern 131 in which the triangular prism 131a and the curved triangular prism 131c are adjacently combined, and FIG. 3D shows the triangular prism 131a and lenti. FIG. 3E illustrates a plurality of triangular prisms 131a, a plurality of lenticular prisms 131b, and a curved triangular prism 131c. ) Shows a prism pattern 131 which is adjacently combined.

3 and the above description are just examples, and the present invention is not limited thereto.

As described above, when at least two or more of the triangular prism 131a, the lenticular prism 131b, or the curved triangular prism 131c are combined to form the prism pattern 131 of the prism sheet 130, the lenticular prism 131b Or the curved triangular prism 131c prevents scratches, etc. from being brought into contact with an adjacent sheet (such as a polarizing film or a liquid crystal display panel), and at the same time, a triangular prism 131a, a lenticular prism 131b, or a curved surface. Through the various aspects in which the triangular prism 131c is disposed, luminance uniformity can be adjusted for each viewing angle, thereby preventing the luminance from being lowered.

Next, FIG. 4 is variously formed by adjusting the height H, pitch L, or peak curved angle A for each type of prism in the composite prism sheet 130 according to an embodiment of the present invention. It is a symbolic illustration of an example.

Accordingly, in the composite prism pattern 131 formed on the prism sheet 130, the prism height H, the pitch L, or the peak curved angle A with respect to each prism can be adjusted and variously formed. .

That is, the prism pattern 131 formed on the upper portion of the prism sheet 130 is configured by combining at least two or more of the triangular prism 131a, the lenticular prism 131b, or the curved triangular prism 131c, respectively. By configuring the height (H) or pitch (L) or upper peak curved angle (A) of the prism differently, the number of contact prisms for the upper adjacent sheet can be reduced, and the type of contact prism for the upper adjacent sheet Since the pitch angle of the contact prism with respect to the upper adjacent sheet can be adjusted, the degree of scratch induction with respect to the upper adjacent sheet can be precisely adjusted at the time of manufacture.

Furthermore, individual adjustments to the height (H) or pitch (L) of the respective prism or the upper peak curved angle (A) allow accurate display of the intended luminance for each viewing angle.

5 and 6 are cross-sectional views of the prism sheet 130 according to an embodiment of the present invention.

According to this, the prism pattern 131 formed on the prism sheet 130 may be configured by different pitch intervals of the prism at the central portion and the opposite edge portions.

The luminance depends not only on the shape of the prism but also on the pitch of the prism. In general, the larger the pitch of the prism, the higher the luminance, but in proportion to this, there is a problem in that the moire pattern becomes clear. Therefore, it is very important from the standpoint of display quality to set a value in a range where moiré does not occur while maintaining high brightness. This configuration can be applied to a single pattern as in FIG.

That is, as shown in FIG. 5, the edge portion E lowered by arranging the pitch intervals of the prisms formed at both edge portions E in comparison with the prisms formed at the upper center portion C of the prism sheet 130. It is possible to increase the luminance of) and to obtain the uniformity of the overall luminance. Of course, the prism height may also be configured to be higher than those of the prisms formed in the center portion C.

At this time, it is preferable to adjust the pitch so that the luminance of the edge portion has a luminance of 2% or more higher than that of the central portion.

Also, as shown in FIGS. 6A and 6B, a single prism of the lenticular prism 131b or the triangular prism 131a may be arranged in a gradation manner on the prism sheet 130. have.

That is, compared to prisms formed at the upper center portion C of the prism sheet 130, the luminance of the lowered edge portion E may be increased by arranging the pitch intervals of the prisms formed at both edge portions E in a wider manner. And uniformity of overall luminance can be obtained. Of course, the prism height may also be configured to be higher than those of the prisms formed in the center portion C.

Preferably, in the gradation prism arrangement method, the prism pattern 131 is configured by combining at least two or more of the triangular prism 131a, the lenticular prism 131b, or the curved triangular prism 131c, and the edge portion E It is characterized in that the pitch of to be arranged wider than the pitch of the center (C), through which the brightness of the edge portion (E) can be more than 2% of the brightness of the center.

7 shows another example of such a gradation type prism arrangement.

Referring to FIG. 7, the pitch intervals of the prisms formed at both edge portions E of the prism sheet 130 are wider than those of the prisms formed at the central portion C, and the prism formed at the edge portion E. This feature is characterized in that the pitch interval gradually widens toward the edge side. Of course, the prism height may also be configured to be higher than those of the prisms formed in the center portion C.

According to the arrangement of the gradation method of FIG. 7, in addition to the above-described brightness rise and brightness uniformity, a sharp pattern height change in the relationship between the prisms formed in the center portion C and the prisms formed in the edge portion E is obtained. It is possible to minimize the occurrence of bright lines caused by.

8 is a cross-sectional view of the prism sheet 130 according to another embodiment of the present invention.

In this embodiment, the prism pattern 131 formed on the prism sheet 130 is formed by combining a plurality of triangular prisms 131a and a plurality of spherical triangular prisms 131d.

Here, the spherical triangular prism 131d has a triangular shape as a whole like the curved triangular prism 131c described above, but the peak portion is formed in the shape of a hemispherical surface in the cross section of the short axis direction.

The upper peak of the spherical triangular prism 131d has a larger radius of curvature than the upper peak of the curved triangular prism 131c.

Accordingly, although the spherical triangular prism 131d has lower luminance than the triangular prism 131a and the curved triangular prism 131c having a more sharp peak angle, the spherical triangular prism 131d collects the light incident through the base film, 131a and the curved triangular prism 131c can be spread more widely.

In this case, the spherical triangular prism 131d may include a plurality of diffusion beads 131d-1.

The configuration of the diffusion beads to diffuse the light collected by scattering may be configured such that the spherical triangular prism 131d contains a plurality of diffusion beads 131d-1 as shown in FIG. 8. The diffusion beads 131d-1 may be arranged in a regular matrix form within the spherical triangular prism 131d, or may be irregularly arranged.

The diffusion beads 131d-1 may have a spherical shape or an oval shape. In addition, the diffusion beads 131d-1 may have various shapes such as non-spherical shape, triangular pyramid, cube, polygon, and amorphous shape.

The diffusion beads 131d-1 may include, for example, at least one of organic beads and inorganic beads. Examples of the organic beads include homopolymers or copolymers obtained by using monomers such as acrylic, styrene, melamine formaldehyde, propylene, ethylene, silicone, urethane, methyl (meth) acrylate, polycarbonate, and the like. Examples of the inorganic beads include silica, zirconia, calcium carbonate, barium sulfate, titanium oxide, and the like.

Here, the prism combination of the prism pattern has a form in which a plurality of triangular prisms 131a are configured adjacent to each other and a spherical triangular prism 131d is inserted therebetween.

At this time, the cross-sectional length from the base film of the spherical triangular prism 131d to the peak of the spherical surface formed on the peak is called the prism height H, and the degree of deflection of the upper spherical surface is called spherical angle R. The length between the valleys is called the pitch (L).

In this embodiment, the height of the prism of the spherical triangular prism 131d is larger than the height of the prism of the triangular prism 131a which is combined together. Therefore, since the prism height of the spherical triangular prisms 131d is higher than the prism heights of the surrounding triangular prisms 131a, the number of contact prisms on the upper adjacent sheet can be reduced, and the peak portion of the spherical triangular prism 131d can be reduced. Because of its spherical shape, the scratch causing phenomenon for the upper adjacent sheet is almost disappeared. In addition, by mixing a plurality of triangular prism (131a) and the spherical triangular prism (131d) in the surroundings it is possible to obtain the luminance uniformity for each viewing angle.

For example, FIG. 8 illustrates a combination in which one spherical triangular prism 131d is inserted between groups of ten neighboring triangular prisms 131a. However, the present invention is not limited thereto, and as described above, the prism combination of the prism pattern is provided as an example if a plurality of triangular prisms 131a are configured adjacently and a spherical triangular prism 131d is inserted therebetween. In addition, various modifications are possible, of course.

Meanwhile, in the exemplary embodiment described with reference to FIG. 8, even if the spherical triangular prism 131d is simply replaced by the curved triangular prism 131c, the same effect may be obtained.

9 illustrates another example of the spherical triangular prism 131d in the prism sheet of FIG. 8 described above.

Unlike the embodiment of FIG. 8 in which the spherical triangle prism 131d contains a plurality of diffusion beads 131d-1, in the embodiment shown in FIG. 9, the plurality of diffusion beads 131d-1 are spherical triangle prisms 131d. Protruding from the outer surface of the) may be formed.

That is, the diffusion beads 131d-1 may have an embossed pattern partially protruding from the spherical triangular prism 131d.

In this case, since the diffusion beads 131d-1, not the spherical triangular prism 131d, are in contact with the upper optical film, scratches may be minimized by minimizing friction with the upper optical film. In order to achieve this purpose, the diffusion beads 131d-1 may be concentrated at a peak portion on the outer surface of the spherical triangular prism 131d.

The diffusion beads 131d-1 may be arranged in a regular matrix form on the outer surface of the spherical triangular prism 131d, or may be arranged irregularly.

As described above, the diffusion beads 131d-1 include at least one of organic beads and inorganic beads, and the diffusion beads 131d-1 exposed to the outside in an embossed pattern are supported on the prism by a support coating film. Can be. A support coating film is formed on the top surface of the prism, at least partially surrounding the diffusion beads 131d-1. Such a support coating film may be, for example, a thermosetting resin such as an acrylic resin, a urethane resin or a polyester resin, or an epoxy acrylate resin, a urethane acrylate resin, a silicone acrylate resin, an acrylic acrylate or an ester acrylate, or the like. It can be made by including the same ultraviolet curable resin.

Here, the diffusion beads 131d-1 described with reference to FIGS. 8 and 9 diffuse the light toward the front surface by scattering while passing the collected light. Therefore, it is possible to prevent the light from being partially concentrated, to make the luminance uniform, and to improve the viewing angle.

The diffusion beads 131d-1 are formed of a material having a refractive index different from that of the spherical triangular prism 131 d, so that the light emitted from the lower portion passes through the upper prism sheet 130, and the diffusion beads 131d-1 are formed. It allows to be refracted in different directions or diffusely reflected in various directions.

That is, as described above, organic beads or inorganic beads are used as the diffusion beads 131d-1. When light transmission is prioritized, many organic beads similar to the refractive index of the prism material should be used, and light blocking effects, etc. should be considered. In this case, you will use weapon beads. Here, the organic beads have a refractive index of about 1.4 to 1.5, and the inorganic beads have a high refractive index of about 1.7 to 1.8 (for a prism, the refractive index of about 1.4 to 1.7). Therefore, when the bead is applied to the prism, high luminance and low haze should be considered. Therefore, many organic beads having a small difference in refractive index from the prism material are used.

The diffusion beads 131d-1 may have various different sizes and may be formed in different shapes.

In total, when the diffusion beads 131d-1 are contained in the prism, the diffusion beads 131d-1 are preferably filled to less than 50% of the prism volume.

As described with reference to FIGS. 8 and 9, the plurality of diffusion beads 131d-1 may be included in the prism of the prism sheet 130, or the plurality of diffusion beads 131d-1 may protrude in an embossed pattern on the outer surface of the prism. 8 and 9 are not limited to those applied to the shape of the spherical triangular prism 131d, and the triangular prism 131a, the lenticular prism 131b, the curved triangular prism 131c, and the like. Of course, it is possible to apply to the spherical triangular prism (131d).

10 is a cross-sectional view of the prism sheet 130 according to another embodiment of the present invention.

In this embodiment, the prism pattern 131 formed on the prism sheet 130 has a first prism group composed of a plurality of neighboring first prisms LP having the same prism height H, and a first space between the prism groups. Various combinations are shown in which a second prism HP having a prism height H higher than the prism is inserted.

Here, the first prism LP is preferably composed of a triangular prism 131a having a sharp peak angle. It is also possible to configure as one.

Also, if the prism height H is higher than that of the first prism LP, the second prism HP has a triangular prism 131a, a lenticular prism 131b, a curved triangular prism 131c, and a spherical triangular prism ( 131d) and trapezoidal prism 131e are possible.

In FIG. 10, (a) shows that the second prism HP is a triangular prism 131a, and (b) shows that the second prism HP is a lenticular prism 131b, and (c) ) Shows that the second prism HP is a curved triangular prism 131c, (d) shows that the second prism HP is a spherical triangular prism 131d, and (e) shows a second prism HP. It is shown that prism HP is a trapezoidal prism 131e.

Here, the trapezoidal prism 131e has a lower cross section of the prism larger than the upper cross section and the upper peak portion has a planar shape to have a trapezoidal shape.

That is, in the present embodiment, a small number of second prisms HP having a higher prism height H are inserted between groups of prisms composed of first prisms LP having a lower prism height H. Only the second prisms HP can be in contact with the upper adjacent sheet, thereby reducing the scratch causing phenomenon. And by adjusting the number and type of contact prism for the upper adjacent sheet it is possible to accurately express the intended brightness and viewing angle for each viewing angle. Here, the second prism HP preferably has a larger pitch L than the first prism LP for stability of the configuration, adjustment of brightness and viewing angle.

In this case, in FIG. 10, a combination ratio of a plurality of neighboring first prisms LP having the same prism height H and a second prism HP having a prism height H higher than the corresponding first prism LP is shown. Although illustrated as being 10: 1, the present invention is not limited thereto, and various combinations, such as 30: 1, 50: 1, are possible, and preferably, various ratios can be configured between 2: 1 and 100: 1. Do.

The best embodiments have been disclosed in the drawings and specification above. The specific terminology used herein is for the purpose of describing the present invention only and is not used to limit the scope of the invention as defined in the meaning or claims. Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible from this. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

Claims (1)

Base film;
A prism pattern formed by combining two or more prisms of different shapes on the base film and arranging a plurality of prisms; Prismatic sheet comprising a.

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