WO2006046791A1

WO2006046791A1 - Optical film and back-light unit with the same

Info

Publication number: WO2006046791A1
Application number: PCT/KR2004/003280
Authority: WO
Inventors: Yong-Shig Shim; Sung-Min Cho; Young-Il Kim; Eun-Mi Lee
Original assignee: Lgs Corporation Ltd.
Priority date: 2004-10-29
Filing date: 2004-12-14
Publication date: 2006-05-04
Also published as: KR100512193B1

Abstract

The present invention relates to an optical film and a back-light unit with the same. The optical film comprises a plurality of first patterns formed on one Surface of the film; and a plurality of second patterns and a plurality of third patterns formed on the other surface of the film, wherein the first patterns have optical sections for scattering incident light, the second patterns have optical sections for emitting the incident light in all directions, and the third patterns are formed along pattern surfaces of the second patterns and have optical sections for emitting the incident light in a substantially vertical direction. According to the present invention, there are provided an optical film and a back-light unit with the same, which can enhance productivity and workability and reduce manufacturing costs and a fraction defective. Further, there are provided an optical film and a back-light unit with the same, which can minimize optical defects such as moire or mottles. Moreover, there are provided an optical film and a backlight unit with the same, which can represent a wide viewing angle and high luminance.

Description

OPTICAL FILM AND BACK-LIGHT UNIT WITH THE SAME

TECHNICAL FIELD The present invention relates to an optical film and a back-light unit with the same, and more particularly, to an optical film with an improved structure being capable of solving optical defects and a back-light unit with the same.

BACKGROUND ART In a display device for use in displaying an image, a variety of optical films are used for enhancing the image display performance of the device.

As an example, as shown in Fig. 21, a back-light unit 101 of a display device comprises optical films such as a reflective film 130, a diffusion film 140, a prism film 150 and a protective film 160, which are sequentially disposed between a light guide panel 110 and a panel 120, so that light traveling from the light guide panel 110 to the panel 120 is optically controlled, thereby improving image display performance such as a viewing angle, luminance and sharpness of an image displayed on the panel 120.

In a case where a combination of a variety of optical films such the diffusion film 140 and the prism film 150 is used, however, there are problems in that the size of a device increases, and productivity is lowered and manufacturing costs increase according to an increase in the number of production processes.

Further, when the optical films are optically coupled to one another, foreign substances are frequently introduced or a scratch resulting from contact is produced due to minor carelessness. Thus, there is a problem in that workability is lowered and a fraction defective increases.

In addition, since a wide range of optical contact is formed between the optical films, there are problems in that moire patterns are created due to a wet-out phenomenon and mottle patterns are formed due to introduction of dust particles and the like. DISCLOSURE OF INVENTION

TECHNICAL PROBLEM

Accordingly, an object of the present invention is to provide an optical film and a back-light unit with the same, which can enhance productivity and workability and reduce manufacturing costs and a fraction defective.

Another object of the present invention is to provide an optical film and a back¬ light unit with the same, which can minimize optical defects such as moire or mottles.

A further another object of the present invention is to provide an optical film and a back-light unit with the same, which can represent a wide viewing angle and high luminance.

TECHNICAL SOLUTION

The objects are achieved by an optical film according to an aspect of the present invention. The optical film comprises a plurality of first patterns formed on one surface of the film; and a plurality of second patterns and a plurality of third patterns formed on the other surface of the film, wherein the first patterns have optical sections for scattering incident light, the second patterns have optical sections for emitting the incident light in all directions, and the third patterns are formed along pattern surfaces of the second patterns and have optical sections for emitting the incident light in a substantially vertical direction.

The optical section of each of the first patterns may have a partially arcuate shape, the optical section of each of the second patterns may have a partially arcuate shape, and the optical section of each of the third patterns may have a triangular shape. Preferably, the second patterns are distributed in the form of embossments when viewed in a plan view thereof, and the third patterns are linearly arranged at a predetermined interval when viewed in a plan view thereof.

At this time, more preferably, the second patterns have any one of a circular shape, an elliptical shape or a polygonal shape when viewed in the plan view thereof. Alternatively, the second patterns may be linearly arranged at a predetermined interval when viewed in a plan view thereof, and the third patterns may be linearly arranged at a predetermined interval parallel with the second patterns when viewed in a plan view thereof.

Alternatively, the second patterns may be linearly arranged at a predetermined interval when viewed in a plan view thereof, and the third patterns may be linearly arranged at a predetermined interval in a direction in which the third patterns intersect the second patterns when viewed in a plan view thereof.

At this time, the optical section of each of the first patterns preferably has a size smaller than that of the optical section of each of the second patterns.

Preferably, the optical section of each of at least one of the second patterns and the first patterns has a concave shape depressed into the film or a convex shape protruding outwardly from the film, and the optical section of each of the other of the second patterns and the first patterns has a concave shape depressed into the film or a convex shape protruding outwardly from the film.

At this time, the optical sections of at least one of the second patterns, the third patterns and the first patterns may be formed at a constant interval or at irregular intervals.

Preferably, the first patterns are distributed in the form of embossments when viewed in a plan view thereof.

Alternatively, the first patterns may have any one of a circular shape, an elliptical shape or a polygonal shape when viewed in a plan view thereof. Alternatively, the first patterns may be linearly arranged at a predetermined interval when viewed in a plane view thereof.

Meanwhile, the film, the second patterns, the third patterns and the first patterns are preferably formed integrally with one another using any one of polycarbonate, PVC, PP, PE, PET, acrylic-based polymers. Alternatively, the film, the second patterns, the third patterns and the first patterns may be made of at least one of polycarbonate, PVC, PP, PE, PET, acrylic-based polymers, respectively, and then laminated one above another.

At this time, light-diffusing particles are preferably contained in at least one of the film, the second patterns, the third patterns and the first patterns. At this time, the light-diffusing particles are preferably transparent particles that are any one of acryl particles, styrene particles, silicone particles, synthetic silica, glass beads and diamond, or white particles that are any one of titanium oxide, zinc oxide, barium sulfate, calcium carbonate, magnesium carbonate, aluminum hydroxide and clay.

The objects are achieved by a back-light unit according to another aspect of the present invention. The back-light unit includes a light guide panel as a light source, an optical film disposed above the light guide panel, and a panel disposed above the optical film to display an image, wherein the optical film is an optical film according to any one of claims 1 to 17 and is disposed such that the third patterns face the panel and the first patterns face the light guide panel.

The objects are achieved by a back-light unit according to a further aspect of the present invention. The back-light unit includes a light guide panel as a light source, an optical film disposed above the light guide panel, and a panel disposed above the optical film to display an image, wherein the optical film is an optical film according to any one of claims 1 to 17 and is disposed such that the third patterns face the light guide panel and the first patterns face the panel.

ADVANTAGEOUS EFFECTS

According to the present invention, there are provided an optical film and a back¬ light unit with the same, which can enhance productivity and workability and reduce manufacturing costs and a fraction defective. Further, there are provided an optical film and a back-light unit with the same, which can minimize optical defects such as moire or mottles.

Moreover, there are provided an optical film and a back-light unit with the same, which can represent a wide viewing angle and high luminance.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a perspective view of an optical film according to a first embodiment of the present invention.

Figs. 2 and 3 are sectional views of the optical film of Fig. 1 in normal and inverted states, respectively. Fig. 4 is a bottom view of the optical film of Fig. 1.

Figs. 5 to 18 are views showing optical films according to other embodiments of the present invention.

Figs. 19 and 20 are views schematically showing the configurations of an optical film and back-light units with the same according to the present invention.

Fig. 21 is a view schematically showing the configurations of a conventional optical film and a back-light unit with the same.

BESTMODEFORCARRYINGOUTTHEINVENTION

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Fig. 1 is a perspective view of an optical film according to a first embodiment of the present invention, Figs. 2 and 3 are sectional views of the optical film of Fig. 1 in normal and inverted states, respectively, and Fig. 4 is a bottom view of the optical film of Fig. 1.

As shown in these figures, the optical film 1 of this embodiment has a structure in which second patterns 11 for diffusing and refracting incident light and third patterns 13 for collecting and refracting the incident light along pattern surfaces of the second patterns 11 are formed on one surface of the film, and first patterns 15 for scattering the incident light are formed on a back surface of the film.

The film is made of any one of polycarbonate, PVC, PP, PE, PET, acrylic-based polymers that are light-transmitting materials through which light falling within a visible range can be smoothly transmitted. This film may be formed integrally with at least one of the second patterns 11, the third patterns 13 and the first patterns 15, or these components may be laminated one above another after being separately formed. At this time, the film, the second patterns 11, the third patterns 13 and the first patterns 15 may be formed of any one of the aforementioned materials, or they may be formed of different respective ones of the aforementioned materials.

Each of the second patterns 11 takes the shape of a partial sphere that has a partially arcuate optical section when viewed in a sectional view thereof and is in the form of a circle when viewed in a plan view thereof. In a plan view of the film, the plurality of second patterns 11 are distributed at a predetermined interval in the form of embossments. Here, as described above, the second patterns 11 may be formed integrally with one surface of the film, or may be separately formed of a material identical to or different from a material used for forming the film among the aforementioned materials and then laminated on one surface of the film. Alternatively, the second patterns 11 may be formed to protrude outwardly from the film as shown in Figs. 1, 2 and 3, or to be depressed into the film as shown in Figs. 7 to 9. Otherwise, although not shown in the drawings, the second patterns 11 may be formed to have a concavo-convex structure in which protrusion sections and depression sections are formed alternately. At this time, it will be apparent that the second patterns 11 may be distributed at a constant interval as shown in the drawings or at irregular intervals to adjust optical properties of the optical film 1.

Each of the third patterns 13 is formed to have a triangular optical section when viewed in a sectional view thereof. In the plan view of the film, the plurality of third patterns 13 are linearly arranged parallel to one another at a predetermined interval. The third patterns 13 collect incident light on pattern surfaces thereof and then refract and emit the light in directions substantially perpendicular to the respective pattern surfaces. At this time, since the third patterns 13 are formed along the pattern surfaces of the second patterns 11, light refracted in the directions perpendicular to the respective pattern surfaces is emitted radially as shown in Figs. 2 and 3. Therefore, the emitted light is diffused in a wide range of viewing angle while maintaining high luminance.

As described above, the third patterns 13 may also be formed integrally with one surface of the film along the pattern surfaces of the second patterns 11, or may be separately formed of a material identical to or different from a material used for forming the film among the aforementioned materials and then laminated on the pattern surfaces of the second patterns 11 at one surface of the film.

Here, it will be apparent that the third patterns 13 may be distributed at a constant interval as shown in Figs. 1, 2 and 3 or at irregular intervals to adjust optical properties of the optical film 1.

Meanwhile, like the second patterns 11, each of the first patterns 15 takes the shape of a partial sphere that has a partially arcuate optical section when viewed in a sectional view thereof and is in the form of a circle when viewed in a plan view thereof. In the plan view of the film, the plurality of first patterns 15 are distributed at a predetermined interval in the form of embossments, as seen from Figs. 1 to 4.

The size of the optical section of each of the first patterns 15 is smaller than that of each of the second patterns 11. This is to collect and scatter incident light, thereby representing high luminance and simultaneously lowering a possibility that a viewer will visually perceive a scratch or foreign substances contained in the optical film 1 due to scattering of the light.

Here, as described above, the first patterns 15 may be formed integrally with the back surface of the film, or may be separately formed of a material identical to or different from a material used for forming the film among the aforementioned materials and then laminated on one surface of the film.

Alternatively, the first patterns 15 may be formed to be depressed in the back surface of as shown in Figs. 1, 2 and 3, or to protrude outwardly from the film as shown in Figs. 5 and 6. Otherwise, although not shown in the drawings, the first patterns 15 may be formed to have a concavo-convex structure in which protrusion sections and depression sections are formed alternately. This includes a case where the second patterns 11 have a protruding structure and the first patterns 15 are formed to have a protruding structure, a depressed structure or a concavo-convex structure; and a case where the second patterns 11 has a depressed structure and the first patterns 15 are formed to have a protruding structure, a depressed structure or a concavo-convex structure.

At this time, it will be apparent that the first patterns 15 may also be distributed at a constant interval as shown in Figs. 1 to 6 or at irregular intervals to adjust optical properties of the optical film 1.

Meanwhile, in the optical film 1 according to the present invention, the structures of the second patterns 11, the third patterns 13 and the first patterns 15 can be variously modified to adjust optical properties thereof.

When the structure of the second patterns 11 is observed in the plan view of the film, for example, each of the second patterns 11 is formed to have any one of a circular shape shown in Figs. 1 and 7, an elliptical shape shown in Figs. 10 and 11, and a polygonal shape shown in Figs. 12 and 13, and the third patterns 13 are linearly arranged along the pattern surfaces of the second patterns 11. Further, as shown in Figs. 14 and 15, when the structure of the second patterns 11 is observed in the plan view of the film, the second patterns 11 may be linearly arranged at a predetermined interval and the third patterns 13 may be linearly arranged parallel to the second patterns 11 at a predetermined interval along the pattern surfaces of the second patterns 11.

Alternatively, as shown in Figs. 16 and 17, when the structure of the second patterns 11 is observed in the plan view of the film, the second patterns 11 may be linearly arranged at a predetermined interval and the third patterns 13 may be linearly arranged at a predetermined interval along the pattern surfaces of the second pattern 11 in a direction in which the third patterns intersect the second patterns.

When the structure of the first patterns 15 is observed in the plan view of the film, the first patterns may be formed to have any one of a circular shape, an elliptical shape and a polygonal shape, and constructed to have partially arcuate sections linearly arranged at a predetermined interval. In the optical film 1 of the present invention constructed as above, once light is incident on a side of the optical film 1 in which the first patterns 15 are formed, the incident light is collected by the first patterns 15 and scattered toward the second patterns 11, as shown in Fig. 2. The scattering of the light prevents a scratch, foreign substances such as dust, or mottles, which may be included in the optical film 1, from being visually perceived by a viewer.

The light, which has passed through the first patterns 15 and travels toward the second patterns 11, is collected by diffusion patterns and then travels toward the third patterns 13.

The light that is incident on the third patterns 13 is collected by the pattern surfaces of the third patterns 13 and then refracted and emitted in directions that are substantially perpendicular to the pattern surfaces. At this time, since the third patterns 13 are formed along the pattern surfaces of the second patterns 11, the light refracted in the directions substantially perpendicular to the respective pattern surfaces is emitted radially as shown in Fig. Accordingly, the emitted light is diffused in a wide range of viewing angle while maintaining high luminance. Meanwhile, in the optical film 1 of the present invention, light may be incident on a side of the optical film 1 in which the third patterns 13 are formed and then emitted toward the first patterns 15 as shown in Fig. 3.

The light that has been incident on the third patterns 13 is collected by the pattern surfaces of the third patterns 13 and then refracted in directions substantially perpendicular to the pattern surfaces and travels toward the first patterns 15 through the second patterns 11. ^'

At this time, since the third patterns 13 are formed along the pattern surfaces of the second patterns 11, the light refracted in the directions substantially perpendicular to the respective pattern surfaces is diffused radially and travels toward the first patterns 15 as described above. The diffusion of the light also prevents a scratch, foreign substances such as dust, or mottles, which may be included in the optical film 1, from being visually perceived by a viewer.

Since the light that has been incident on the first patterns 15 is collected by the first patterns 15 and then diffused and scattered on the pattern surfaces in all directions, the emitted light is diffused in a wide range of viewing angle while maintaining high luminance.

Meanwhile, as shown in Fig. 18, the optical film 1 of the present invention may include light-diffusing particles 17 for diffusing light. It is preferred that any one of acryl particles, styrene particles, silicone particles, synthetic silica, glass beads and diamond, which are transparent particles, be used as the light-diffusing particles 17, or any one of titanium oxide, zinc oxide, barium sulfate, calcium carbonate, magnesium carbonate, aluminum hydroxide and clay, which are white particles, be used as the light-diffusing particles. When the optical film 1 is formed, the light-diffusing particles 17 may be distributed evenly in the interior of at least one of the film, the second patterns 11, the third patterns 13 and the first patterns 15 as shown in. Fig. or in the entire area of the interior of the optical film 1 as shown in Fig. If the optical film 1 includes the light- diffusing particles 17 in such a manner, incident light is diffused within the film without loss, so that high luminance is achieved at a side from which the light is emitted, and at the same time, a scratch, foreign substances such as dust, or mottles which may be included in the film is prevented from being perceived by a viewer.

Meanwhile, Figs. 19 and 20 schematically show the configurations of back-light units to which the optical film of the present invention is applied. As shown in these figures, the optical film 1 of the present invention is disposed between a light guide panel 110 and a panel 120 of a back-light unit 101 to emit light incident from the light guide panel 110 toward the panel 120.

At this time, the optical film 1 may be arranged such that the second patterns 11 and the thirds pattern 13 face the panel 120 and the first patterns 15 face the light guide panel 110 as shown in Fig. 19. Alternatively, as shown in Fig. 20, the optical film may be arranged such that the second patterns 11 and the third patterns 13 face the light guide panel 110 and the first patterns 15 face the panel 120. The optical film 1 arranged as such widely diffuses the light, which passes through the optical film 1, with high luminance toward an emitting side by means of collection, diffusion and scattering described above. As described above, by forming the second patterns and the third patterns with optical sections, which emit incident light in all directions, on one surface of the optical film and by forming the first patterns for scattering the incident light on the back surface of the optical film, the optical film and the back-light unit with the same according to the present invention can diffuse the incident light in a wide range while maintaining high luminance when the incident light is emitted.

Further, even though optical defects such as a scratch, foreign substances including dust, or mottles are produced in the optical film due to minor carelessness during manufacturing processes of the optical film and the back-light unit with the same, a viewer cannot visually perceive such defects due to the diffusion and scattering of light. Therefore, workability can be improved and a fraction defective can be reduced during the manufacturing processes of the optical film and the back-light unit with the same.

Moreover, since the third patterns are formed along the pattern surfaces of the second patterns to establish a structure with relative high peaks and relative low valleys and the first patterns also have an optical sectional structure with undulations, when the film is optically coupled to an adjacent other optical component (for example, the protective film or the light guide panel shown in Fig., the range of contact can be reduced to a minimum range in which observation cannot be made by the naked eye. Accordingly, the occurrence of a wet-out phenomenon is minimized so that the formation of moire patterns is minimized.

In comparison with a conventional optical film in which a variety of films such as a diffusion film and a prism film are combined, the optical film of the present invention has the collection, diffusion and scattering functions of light, which are incorporated into a single optical film, thereby enabling manufacture of a multi-functional compact optical film and reduction in the size of a device such as a back-light unit. Since manufacturing processes and costs can be reduced, productivity is improved.

INDUSTRIAL APPLICABILITY

As described above, according to the present invention, there are provided an optical film and a back-light unit with the same, which can enhance productivity and workability and reduce manufacturing costs and a fraction defective. Further, there are provided an optical film and a back-light unit with the same, which can minimize optical defects such as moire or mottles.

Claims

1. An optical film, comprising: a plurality of first patterns formed on one surface of the film; and a plurality of second patterns and a plurality of third patterns formed on the other surface of the film, wherein the first patterns have optical sections for scattering incident light, the second patterns have optical sections for emitting the incident light in all directions, and the third patterns are formed along pattern surfaces of the second patterns and have optical sections for emitting the incident light in a substantially vertical direction.

2. The optical film as claimed in claim 1, wherein the optical section of each of the first patterns has a partially arcuate shape, the optical section of each of the second patterns has a partially arcuate shape, and the optical section of each of the third patterns has a triangular shape.

3. The optical film as claimed in claim 2, wherein the second patterns are distributed in the form of embossments when viewed in a plan view thereof, and the third patterns are linearly arranged at a predetermined interval when viewed in a plan view thereof.

4. The optical film as claimed in claim 3, wherein the second patterns have any one of a circular shape, an elliptical shape or a polygonal shape when viewed in the plan view thereof.

5. The optical film as claimed in claim 2, wherein the second patterns are linearly arranged at a predetermined interval when viewed in a plan view thereof, and the third patterns are linearly arranged at a predetermined interval parallel with the second patterns when viewed in a plan view thereof.

6. The optical film as claimed in claim 2, wherein the second patterns are linearly arranged at a predetermined interval when viewed in a plan view thereof, and the third patterns are linearly arranged at a predetermined interval in a direction in which the third patterns intersect the second patterns when viewed in a plan view thereof.

7. The optical film as claimed in any one of claims 2 to 6, wherein the optical section of each of the first patterns has a size smaller than that of the optical section of each of the second patterns.

8. The optical film as claimed in claim 7, wherein the optical section of each of at least one of the second patterns and the first patterns has a concave shape depressed into the film or a convex shape protruding outwardly from the film, and the optical section of each of the other of the second patterns and the first patterns has a concave shape depressed into the film or a convex shape protruding outwardly from the film.

9. The optical film as claimed in claim 8, wherein the optical sections of at least one of the second patterns, the third patterns and the first patterns are formed at a constant interval.

10. The optical film as claimed in claim 8, wherein the optical sections of at least one of the s ieeccoonndd p paatttteerrnnss, the third patterns and the first patterns are formed at irregular intervals.

11. The optical film as claimed in claims 8 to 10, wherein the first patterns are distributed in the form of embossments when viewed in a plan view thereof.

12. The optical film as claimed in claims 8 to 10, wherein the first patterns have any one of a circular shape, an elliptical shape or a polygonal shape when viewed in a plan view thereof.

13. The optical film as claimed in claims 8 to 10, wherein the first patterns are linearly arranged at a predetermined interval when viewed in a plane view thereof.

14. The optical film as claimed in claim 1, wherein the film, the second patterns, the third patterns and the first patterns are formed integrally with one another using any one of polycarbonate, PVC, PP, PE, PET, acrylic-based polymers.

15. The optical film as claimed in claim 1, wherein the film, the second patterns, the third patterns and the first patterns are made of at least one of polycarbonate, PVC, PP, PE, PET, acrylic-based polymers, respectively, and then laminated one above another.

16. The optical film as claimed in claim 1, wherein light-diffusing particles are contained in at least one of the film, the second patterns, the third patterns and the first patterns.

17. The optical film as claimed in claim 16, wherein the light-diffusing particles are transparent particles that are any one of acryl particles, styrene particles, silicone particles, synthetic silica, glass beads and diamond, or white particles that are any one of titanium oxide, zinc oxide, barium sulfate, calcium carbonate, magnesium carbonate, aluminum hydroxide and clay.

18. A back-light unit including a light guide panel as a light source, an optical film disposed above the light guide panel, and a panel disposed above the optical film to display an image, comprising: the optical film being an optical film according to any one of claims 1 to 17, wherein the optical film is disposed such that the third patterns face the panel and the first patterns face the light guide panel.

19. A back-light unit including a light guide panel as a light source, an optical film disposed above the light guide panel, and a panel disposed above the optical film to display an image, comprising: the optical film being an optical film according to any one of claims 1 to 17, wherein the optical film is disposed such that the third patterns face the light guide panel and the first patterns face the panel.