KR20170089177A - Optical film and lighting apparatus using the same - Google Patents

Optical film and lighting apparatus using the same Download PDF

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Publication number
KR20170089177A
KR20170089177A KR1020160009247A KR20160009247A KR20170089177A KR 20170089177 A KR20170089177 A KR 20170089177A KR 1020160009247 A KR1020160009247 A KR 1020160009247A KR 20160009247 A KR20160009247 A KR 20160009247A KR 20170089177 A KR20170089177 A KR 20170089177A
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KR
South Korea
Prior art keywords
light
waveguide
optical film
color
resin
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KR1020160009247A
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Korean (ko)
Inventor
김종만
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김종만
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Publication of KR20170089177A publication Critical patent/KR20170089177A/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
    • G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
    • G02B6/0031—Reflecting element, sheet or layer
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
    • F21K9/00—Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
    • F21K9/60—Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0066—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form characterised by the light source being coupled to the light guide
    • G02B6/0073—Light emitting diode [LED]

Abstract

The optical film of the present invention includes a transparent base film, a plurality of waveguides formed on the transparent base film, and a color composition filled in a space between the adjacent waveguide, wherein at least a part of the light incident from the rear of the transparent base film And a part of the light is totally reflected by the waveguide and transmitted forward.

Description

TECHNICAL FIELD The present invention relates to an optical film and a lighting apparatus using the same,

The present invention relates to an optical film and a lighting apparatus using the same, and more particularly, to an optical film having a color pattern for information display and having high light transmittance and a lighting apparatus using the same.

The optical film refers to a thin film having a property of transmitting, dispersing, or reflecting light, and is widely used in lighting devices, display devices, and the like.

Optical films have various configurations for transmitting, dispersing, or reflecting light depending on the application. The optical film that transmits light is important in light transmittance. When necessary, ink having a transparent property is applied so that a specific color can be realized. In an optical film used for dispersing light, a material capable of dispersing light is filled And transmits light while dispersing the light in various directions. In the optical film for reflection, a reflective layer is formed on the surface, or each layer constituting the multilayer film selectively transmits light, thereby enhancing light transmittance in one direction or selectively transmitting light in a specific wavelength range, thereby enhancing light utilization .

Various techniques are used to appropriately disperse, diffuse, or homogenize the light incident on the rear surface of the optical film. In particular, in the case of a display device or a lighting device, a film coated with a diffusing agent, a film having a micro lens array, a light shaping diffuser made by a holography method (US Pat. No. 5,324,386) A micro prismatic film (US Pat. No. 5,825,543), or a tapered waveguide (US Pat. No. 5,481,385) is used or combined to obtain a desired diffusion angle or uniformity. Such conventional optical films sometimes require a plurality of optical films in order to have required light transmission characteristics, which causes a manufacturing cost to increase.

A functional film used for a lighting device or a display device is mainly manufactured to serve as a light source of a liquid crystal display device and therefore information can not be displayed on the surface of a film or the like. In addition, except for the case of a tapered wave guide, A color resin or the like for information display is applied, the brightness is remarkably lowered. Also, other means must be provided to adjust the diffusing angle (spreading angle), which is the degree of diffusion of light as needed (Light shaping diffuser (US 5,5324,386), US 5,825,543).

Therefore, the first problem to be solved by the present invention is to provide a color composition layer for information display, which has both a front light reflection function and a rear light transmission function in one optical film, and has a light diffusion property, a diffusion direction, And to provide an optical film that can be widely used for a lighting device, a display device, and the like.

A second object of the present invention is to provide a lighting apparatus using the optical film.

In order to achieve the first object of the present invention, there is provided a transparent base film, comprising: a transparent base film; a plurality of waveguides formed on the transparent base film; and a color composition filled in a space between the adjacent waveguides, Most of the light incident from the rear side is totally reflected within the wave guide and is transmitted forward.

According to an embodiment of the present invention, a reflection layer may be formed between the waveguide and the color composition.

According to another embodiment of the present invention, the waveguide may be formed at an inclined angle so that the cross-sectional area of the waveguide decreases as the waveguide moves away from the base film, and a light transmitting surface through which the totalized light can be transmitted may be formed on the waveguide.

According to another embodiment of the present invention, irregularities may be formed so that light is diffused on the light transmitting surface.

According to another embodiment of the present invention, the vertical section of the waveguide may be trapezoidal.

According to another embodiment of the present invention, the inclination angle of the trapezoid is preferably adjusted in the range of 45 to 85 degrees.

According to another embodiment of the present invention, it is preferable that the ratio of the base to the height of the trapezoid is adjusted in the range of 0.5 to 2.

According to another embodiment of the present invention, it is preferable that the area of the light transmitting surface is adjusted to 0.1 to 50% of the bottom surface area of the wave guide.

According to another embodiment of the present invention, the color composition is formed on the light transmission surface, a reflection layer is formed between the side surface of the wave guide having the inclination angle and the color composition, and between the light transmission surface and the color composition, Is not formed.

According to another embodiment of the present invention, the color composition can transmit a part of light.

According to another embodiment of the present invention, the inclination angle of the waveguide, the ratio of the base to the height of the trapezoid, and the refractive index of the waveguide are set such that at least 50% And may be selected to pass through the light transmitting surface.

According to another embodiment of the present invention, the color composition may be filled in a part of the space between the plurality of guides so as to realize a predetermined shape, and the other part may be filled with the transparent composition.

According to another embodiment of the present invention, the color composition may be dispersed with a dye or pigment in a transparent resin.

According to another embodiment of the present invention, it is preferable that the refractive index of the color composition is smaller than the refractive index of the wave guide.

According to another embodiment of the present invention, a protective film may be attached to the upper part of the waveguide or the color composition, or a protective layer may be applied using a general hard coating resin.

In order to achieve the second object, the present invention provides a lighting apparatus including the optical film and a light source disposed behind the transparent base film of the optical film.

The optical film of the present invention has the following effects.

1. Since a color composition layer capable of information display is formed on the optical film, it is possible to realize a free display for transmitting information or transmitting sensibility.

2. Because it has excellent reflection characteristics at the front surface due to the difference in refractive index or the reflection layer, it can be used as a film for advertisement window and interior interiors because it has excellent information display or identification function by front incidence light.

3. The transmittance of the back light is improved by the wave guide, and the light transmittance, dispersion angle, dispersion direction, etc. can be freely adjusted by the geometric design of the waveguide, so that it can be variously used for lighting devices, interior films, Optical properties can be imparted.

4. By using the light reflection and transmission characteristics of the waveguide, the light transmittance and the light reflectivity in the front direction can be adjusted differently, so that the information display function and the mining function can be satisfied at the same time by applying to the large window of a building.

5. The asymmetrical design of the inclination angle of the waveguide can control the dispersion direction of the light, so that the luminance in the room can be differently implemented in the space.

6. Since the light incident from the front side of the optical film is reflected from the side of the wave guide, the reflection layer on the side of the wave guide can be realized by applying metal alone or by lamination using various metals.

Fig. 1 shows the structure of a conventional optical film for displaying information.
Figure 2 illustrates the structure of an optical film to which a layer of opaque color composition is applied in accordance with an embodiment of the present invention.
3 illustrates a structure of an optical film to which a translucent color composition layer is applied according to an embodiment of the present invention.
4 illustrates a structure of an optical film without a reflective layer according to an embodiment of the present invention.
FIG. 5 illustrates a method of manufacturing an optical film to which an opaque color composition layer is applied according to an embodiment of the present invention.
FIG. 6 illustrates a method of manufacturing an optical film to which a semi-transparent color composition layer is applied according to an embodiment of the present invention.
FIG. 7 shows an example of displaying information using an optical film to which an opaque color composition layer is applied.
FIG. 8 shows an example of displaying information using an optical film to which a translucent color composition layer is applied.
Fig. 9 shows the shapes of various wave guides that can be applied to the optical film of the present invention.
10 shows a method of arranging various waveguides applicable to the optical film of the present invention.
Fig. 11 is a view for explaining the change of the light transmission angle according to the height of the waveguide.
12 is a result of measuring the change in the angle of diffusion of light according to the angle of the bevel of the waveguide.
13 is an optical microscope photograph of an optical film to which a waveguide having a square bottom surface is applied.
Fig. 14 is an optical microscope photograph of an optical film to which a waveguide is applied, the bottom of which is a regular hexagon.
FIG. 15 is an optical microscope photograph of an optical film to which a waveguide with concave and convex portions formed on its upper surface is applied.
16 shows the distribution of transmitted light in an optical film to which a waveguide with concave and convex portions formed on its upper surface is applied.
FIG. 17A shows a waveguide in which the longitudinal and transverse lengths of the bottom surface are different, and FIG. 17B shows the waveguide in which the longitudinal length and the transverse length are different and the inclination angle is also asymmetric.
Fig. 18 is an optical microscope photograph of an optical film to which a wave guide having a different length in the longitudinal direction and the transverse direction is applied.
Fig. 19 shows the distribution of transmitted light in the lateral direction and the longitudinal direction in the waveguide-applied optical film in which the longitudinal direction and the transverse direction length are different from each other.
20 shows a distribution of transmitted light of an optical film to which a waveguide having an asymmetric inclination angle is applied.
21 shows the change in transmittance when the angle of incidence of the back light is changed after fixing the angle of inclination of the waveguide.
22 schematically shows a lighting apparatus to which the optical film of the present invention is applied.
23 shows the light transmission characteristics when the optical film of the present invention is attached to a window of a building.
24 shows the reflection characteristics of the optical film of the present invention by the front light.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

The optical film of the present invention comprises a transparent base film, a plurality of waveguides formed on the transparent base film, and a color composition filled in a space between the adjacent waveguides, wherein the majority of the light incident from the rear of the transparent base film Is totally reflected within the waveguide and is transmitted forward.

The optical film of the present invention is provided with a plurality of horn-shaped wave guides whose upper portions are cut, and the space between the wave guides is filled with a color composition. The side wall of the waveguide totally reflects the light incident from the rear side due to the refractive index difference or the reflection layer in the waveguide, and passes the light to the upper portion of the waveguide. The light passed over the waveguide can reflect information on the surrounding color composition.

The optical film of the present invention is characterized not only when the color composition layer for displaying information is translucent, but also when it is opaque. In addition, when the color composition is translucent, the incident light from the front side is reflected at the back of the color composition layer to improve the color implementation of the color composition.

In order to understand the structure and effects of the optical film of the present invention in detail, a conventional optical film for displaying information through the back light is first described.

Fig. 1 shows the structure of a conventional optical film for displaying information.

1 (a) shows a cross-section of an optical film having a layer of a certain thickness. The optical film 110 includes a color resin 112 and a transparent resin layer 112 on a base film 111 having light- The resin 113 is applied. The color resin 112 is a translucent resin having a specific color, and the light having passed through the color resin is colored by absorbing light of a specific wavelength band. The transparent resin 113 passes through all the wavelength bands of the visible light region while allowing the color of the back light to pass therethrough. By adjusting the application area of the color resin, it is possible to display information such as text, pictures, etc. on the front side.

1 (b) shows a cross section of an optical film to which a microlens and a translucent color resin are applied. In the optical film 120, a microlens 122 is provided on a base film 121, The translucent color resin 123 and the transparent resin 124 are separately applied on the area. The microlens 122 has a function of focusing light incident from the rear surface and passing the light through the front surface of the microlens 122. The color resin 123 has a semitransparent property to transmit a part of light and has a color resin 123 and a transparent resin 124, Transmits information while displaying the information.

1 (c) shows a cross section of an optical film to which a microlens and an opaque color resin are applied. In the optical film 130, a microlens 132 is provided on a base film 131, The opaque color resin 133 and the transparent resin 134 are separately applied on the area. Since the light incident from the rear surface does not pass through the opaque color resin 133, the opaque color resin implements the color by the front light.

Unlike the conventional optical film, the optical film of the present invention has a function of transmitting light even when opaque color resin is applied.

Figure 2 illustrates the structure of an optical film to which a layer of opaque color composition is applied in accordance with an embodiment of the present invention. 2 (a), the optical film 200 is provided with a plurality of waveguides 202 on a base film 201, and an opaque color resin 203 is provided in a space between the waveguides 202 It is packed. At this time, the waveguide is formed at an inclination angle so that the cross-sectional area becomes smaller as the waveguide moves away from the base film 201. A light transmitting surface is formed on the waveguide so that the light totally reflected by the inclined angle can be transmitted to the front surface. The waveguide may be in the form of a horn with the top cut out, in which the total reflection takes place on the inclined plane of the horn and the cut plane of the horn becomes the light transmitting plane. The opaque color resin 203 is filled in a space between the inclined angles of the waveguide 202 and is not coated on the light transmitting surface. Referring to FIG. 2 (B), a reflective layer 204 is formed in a space between the waveguide 202 and the opaque color resin 203. The reflective layer 204 may be a metal layer, and when the opaque color resin 203 is made of a metal or a material having high reflectivity, a part of the opaque color resin may form a reflective layer. The left arrow indicates a light path that is once reflected by the reflective layer 204 and passes through the light transmission surface among the light incident from the rear surface. The middle arrow indicates the light path passing through the reflective layer 204, And the right arrow shows a light path passing through the light transmitting surface after colliding with the reflective layer 204 twice in the light incident from the rear surface. Referring to (C) of FIG. 2, the light incident on the rear surface of the optical film can not pass through the area where the opaque color resin is formed due to the total reflection in the reflective layer, passes through the light transmitting surface of the wave guide, . The light thus emitted is reflected by the surrounding opaque color resin, thereby realizing the color more effectively. The conventional optical film coated with the opaque color resin only implements the color by reflection and absorption by the front light. However, even when the opaque color resin is applied, the optical film of the present invention can display information while passing the back light have. Also, the color composition may be a resin in which metal particles are dispersed, or in the case of a coated metal layer, a metal color that is displayed as if it emits light by itself may be displayed even when the entire surface is dark. In FIG. 2, opaque color resin is filled in the space between the wave guides. However, even when the space between the wave guides is filled with transparent or translucent resin, color implementation and information display are possible.

3 illustrates a structure of an optical film to which a translucent color composition layer is applied according to an embodiment of the present invention. 3A, the optical film 300 includes a plurality of waveguides 302 formed on a base film 301, and a space between the waveguides 302 and a light transmitting surface above the waveguide A translucent color resin 303 is formed. 3 (b), the light incident from the rear surface is reflected by the side surface of the waveguide, passes through the light transmitting surface, and the light passing through the light transmitting surface passes through the translucent color resin, And color is realized. Referring to (C) of FIG. 3, the light passing through the light transmitting surface passes through the translucent color resin and implements color on the surface.

The optical film of the present invention is characterized in that information is displayed with an opaque or semi-transparent color resin while transmitting the light to the front surface while minimizing the loss of light incident from the rear surface. In addition, since the diffusing angle of light can be controlled by the geometric design of the waveguide, different colors can be realized even in the case of the same color resin, and if the side angle of the waveguide is adjusted to the nonwoven layer, It is possible. Although the size of the waveguide is enlarged in FIGS. 2 and 3, the size of the waveguide is so small that it can not be recognized by the naked eye. The opaque or translucent colored resin may be a mixture of a dye and a pigment dispersed in a transparent resin, and a filler which diffuses or disperses light may be mixed together in some cases.

Although not shown in the figure, a protective layer may be formed on the entire surface of the optical film. The refractive index of the protective layer may be formed by joining a coating or a film, and the refractive index of the protective layer may be formed by a waveguide or a color resin so as to be able to extract the light coming through the waveguide or the color resin, It is preferable to use a material having a large refractive index or the like. The protective layer may have an ultraviolet shielding function to prevent deterioration of the lower layer.

4 illustrates a structure of an optical film without a reflective layer according to an embodiment of the present invention. 4, a reflection layer is not formed between the waveguides 202 and 302 and the color resins 203 and 303, unlike in FIGS. In this case, the total reflection must be induced by adjusting the refractive index of the waveguide and the refractive index of the color resin. The refractive index of the color resin is smaller than the refractive index of the waveguide. In addition, in the optical film having a structure in which the reflection layer is omitted, when the geometry of the waveguide is designed, it is preferable that the incidence angle of the light incident on the side of the waveguide is relatively reduced to cause total reflection.

The production process of the optical film of the present invention requires forming a waveguide having a protruding structure on the base film and not applying color resin to the light transmitting surface of the waveguide when the opaque color resin is applied need. A method of producing the optical film of the present invention will be described below with reference to the drawings.

FIG. 5 illustrates a method of manufacturing an optical film to which an opaque color composition layer is applied according to an embodiment of the present invention. Referring to FIG. 5 (a), first, a base film 201 is prepared. The material of the base film can be selected from various kinds of polymer resins having a transparent property.

Next, referring to FIG. 5 (B), a wave guide 202 is formed on the base film 201. The waveguide is made of a transparent material and can be formed by a method such as photolithography, embossing, ultraviolet molding, transfer, imprinting, or the like. At this time, the geometrical shape of the wave guide can be determined after simulation in consideration of the thickness and refractive index of the base film, the wave guide, the color resin, etc., and the reflectivity of the reflective layer.

Next, referring to FIG. 5 (C), the color resin 203 is applied to the space between the wave guides 202 and the upper part thereof. The color resin may be opaque or translucent color resin, and may be in the form of a transparent resin containing a pigment or a dye. The color resin can be applied as a composition in the form of an ink or a paint, and the composition can comprise a raw material of a transparent resin, a pigment or a dye, a dispersant, a photoinitiator or a scattering agent and exhibits a coating property, a hardenability, It may further include additives for improvement. At this time, the transparent resin forming the color resin preferably has a transmittance of 70% or more. Specifically, it is preferable to use urethane, propylene, ethylene, styrene or the like based on methyl methacrylate. , Carbonate, epoxy, and the like, and the refractive index is preferably selected to be smaller than that of the waveguide. The size of the pigment contained in the color resin is preferably 150 nm or less, more preferably 80 nm or less in the case of translucent color resin. In the case of the opaque color resin, the size of the pigment is preferably 150 nm or more, more preferably 300 nm or more, and the color such as black, white, red, blue, green, cyan, And the content thereof is preferably 0.001 to 10% by weight. The scattering agent preferably has a particle size of 50 nm to 2 μm, and may be air, metal oxide or polymer resin having a refractive index of 1 to 2.5, and the content is preferably in the range of 0.001 to 20 wt%. Color resin can be applied by screen printing, gravure printing, pattern roll, wiping, inkjet, etc.

5 (d), a part of the color resin applied on the upper part of the wave guide is removed so that the color resin remains only in the space between the side surfaces of the adjacent wave guide, and the color resin remains on the light- Do not. The reason for removing the color resin on the light transmission side of the wave guide is that when the color resin is opaque, the light on the back side is difficult to pass through to the front if the color resin remains on the light transmission side.

Next, referring to FIG. 5 (e), a protective film 205 is formed on the light transmitting surface of the waveguide and the color resin layer. The protective film may be bonded by a method of coating resin or a method of bonding a protective layer in the form of a film. Although not shown in the drawing, in the latter case, an adhesive layer may be provided under the protective film 205. It is preferable that the protective film is equal to or larger than the refractive index of the lower waveguide. Specifically, the protective film may be formed by using a monomer such as urethane, propylene, ethylene, styrene, carbonate, or epoxy based on methyl methacrylate And the composition may further comprise an initiator for heat or ultraviolet curing and an additive for improving coatability, hardenability, adhesion, planarization and the like. The protective film may include a particle or plastic resin for shielding ultraviolet rays incident on the front surface of the optical film, and a high weather-resistant transparent film may be provided with a mechanical structure of the underlying structure or coating layer and durability against ultraviolet rays or changes in external environment And the surface may be coated with an ultraviolet screening agent, considering that the ultraviolet ray is installed outdoors in a strong environment.

FIG. 6 illustrates a method of manufacturing an optical film to which a semi-transparent color composition layer is applied according to an embodiment of the present invention. Referring to FIGS. 6A and 6B, first, a base film 201 is prepared, and a wave guide 202 is formed on a base film 201.

6 (c), a sacrificial layer 206 is formed on the light transmitting surface above the waveguide 202. As shown in FIG. The reason for forming the sacrificial layer 206 is that when the reflective layer is applied to the light transmitting surface of the waveguide, the light incident from behind the optical film can not pass through the light transmitting surface, Together with the reflective layer applied thereon. The sacrificial layer may be made of a material soluble in a specific solvent after drying or curing. When the sacrificial layer is made of photoresist, the sacrificial layer can be removed by stripping, washing and drying with a weak solvent or weakly alkaline solution Do.

Next, referring to FIG. 6 (D), a reflective layer 204 is formed on a waveguide having a sacrificial layer formed on the light transmitting surface. The reflective layer may be formed by a physical vapor deposition method such as sputtering deposition, thermal deposition, electron beam deposition, gravure coating, bar coating, knife coating, slit coating, roll coating, ink jet, electroless plating and the like. The reflective layer may be formed of a multilayer or a multilayer using metals such as aluminum, gold, silver, titanium, nickel, chrome, and tin.

Next, referring to FIG. 6 (e), the reflective layer 204 and the sacrificial layer 206 are removed from the light transmitting surface of the waveguide. As a method of removing the sacrificial layer, a lift-off method can be used, and the sacrificial layer can be removed together with the upper reflective layer by removing the sacrificial layer with a solvent or an alkali solution that dissolves the sacrificial layer. A process of breaking the reflective layer by applying pressure to the light transmitting surface so that the solvent or alkali solution penetrates the reflective layer and contacts the sacrificial layer may be added.

6A to 6C, the color resin 203 is filled between the wave guides, the color resin 203 on the light transmitting surface is removed, and the protective film 205 is attached .

FIG. 7 shows an example of displaying information using an optical film to which a layer of opaque color composition is applied. 7A, a wave guide 202 is formed on the base film 201, and opaque red resin 203a and transparent (transparent) resin are provided in spaces between the wave guides of the left area, the center area and the right area, The resin 203b and the opaque blue resin 203c are applied. Referring to FIG. 7 (b), in the front surface of the optical film, areas coated with red resin, transparent resin, and blue resin are displayed in red, gray, and blue, respectively. Red and blue are colors imple- mented by opaque resin, and gray is the color embodied by the back-side background of the optical film.

FIG. 8 shows an example of displaying information using an optical film to which a translucent color composition layer is applied. 8A, a wave guide 302 is formed on a base film 301, and a translucent red resin 303a, a transparent resin 303B, A resin 303b and a translucent blue resin 303c are applied. Referring to FIG. 8 (B), in the front side of the optical film, red, white, and blue regions are coated with red resin, transparent resin, and blue resin, respectively. Red and blue are the colors realized by the backlight passing through the translucent resin, and white is the color realized by the backlight passing through the transparent resin.

9 shows wave guides of various shapes that can be applied to the optical film of the present invention. 9 (a), the waveguide has a tilt angle of 45 degrees, and the relative lengths of the bottom surface, the height, and the light transmitting surface are 13, 30 and 4, respectively. From the triangle, square, octagon, circle. The waveguide shown in (B) of FIG. 9 has an inclination angle of 60 degrees and a relative height of 22.5, and the waveguide shown in (C) has an inclination angle of 75 degrees, a relative height of 28, And the waveguide shown in (d) has an inclination angle of 75 degrees, a relative height of 40, and a relative length of the light transmitting surface of 8.6.

The wave guide can be designed in various shapes from triangle to circle on the underside. In the present invention, the size of the underside of the waveguide is not an important factor for determining the optical characteristics, but can be determined in consideration of the fabrication process parameters of the waveguide, the characteristics of the optical film after the fabrication, and the final thickness. In consideration of the characteristics of the waveguide manufacturing process and the color resin application process applied thereon, it is preferable that the length of one base is 5 m or more. Also, the angle of the inclined surface is preferably at least 45 degrees to minimize light retroreflected back to the rear surface, and preferably at least 89 degrees to reduce the area of the upper surface, and more preferably, 45 degrees To 85 < RTI ID = 0.0 > degrees. ≪ / RTI >

10 shows a method of arranging various waveguides applicable to the optical film of the present invention. Referring to FIG. 10, the waveguide includes an array structure in which the bottom faces of the triangles are connected to each other as shown in (a), an array structure in which the bottom faces of the square are in contact with each other as shown in (b) You can have a linked array structure.

In the optical film of the present invention, the ratio of the lower area to the upper area of the wave guide may be determined according to the length of the lower surface, the length of the upper surface, the height, and the inclination, which are factors that determine the geometric shape of the wave guide.

Table 1 below shows the case where the inclination angle is fixed at 45 degrees and the height is changed. As the height increases, the ratio of the upper area to the lower area decreases.

Since the optical film of the present invention has to serve as a transmitting body at the same time as displaying certain information, it is preferable to design the shape of the wave guide so that the upper surface area is less than 30%.

Height (μm) Upper side length (μm) Top area (μm 2 ) % Of the bottom area (%) 25 1.155 1.33 0.1 20 5.77 33.3 3.7 15 11.55 133 14.8 10 18.48 341 37.9

Table 2 below shows the case where the inclination angle is changed from 45 degrees to 75 degrees. It can be seen that the ratio of the upper surface area to the lower surface area is changed by various geometric shapes of the waveguide.

Angle (deg) Height (μm) Upper side length (μm) Top area (μm 2 ) % Of the bottom area (%) 45 13 4 16 1.8 60 22 4.6 21.3 2.4 75 40 8.6 73.5 8.1

The shape of the waveguide is determined according to the inclination angle and height of the waveguide. The case where the inclination angle is fixed and the height is changed and the case where the height is determined while changing the inclination angle can be considered.

When the height is changed after fixing the inclination angle, there is no significant change in the transmittance within a certain range, but the diffusion angle tends to increase as the height increases. This can be easily determined as shown in FIG.

Fig. 11 is a view for explaining the change of the light transmission angle according to the height of the waveguide. Referring to FIG. 11, when passing through the A side and passing through the B side, it increases in proportion to the angle of the oblique side when passing through the B side than when passing through the A side. That is, as the number of times of reflection on each oblique plane increases (the angle of 90-bevel plane), the diffuse angle increases. Therefore, it is preferable that the ratio of the length and height of the base line, that is, the aspect ratio is 2 or less. However, if the aspect ratio is too low, the area of the top plane becomes large.

When the angle of the hypotenuse is small, the diffusing angle is not only large but also the retroreflection increases toward the rear surface, so that the transmittance tends to decrease. However, in this case, if the diffuse reflection function is included on the surface of the light source located on the rear side, the light that is retroreflected can be recycled.

12 is a result of measuring the change in the angle of diffusion of light according to the angle of the bevel of the waveguide. 12 (a), 12 (b) and 12 (c) show the relative luminance according to the diffusing angle when the bottom surface of the waveguide is fixed at 51 μm and the inclination angles are 60 °, 55 ° and 50 °, respectively. Referring to FIG. 12, it can be seen that as the inclination angle decreases, a diffusion angle with a high diffusion angle is generated.

13 is an optical microscope photograph of an optical film to which a waveguide having a square bottom surface is applied. Referring to FIG. 13, the underside of the waveguide, the upper surface, and the side end surface of the waveguide with the bottom surface of the square having a side length of 25 .mu.m, the inclination angle of 65.degree., And the height of 30 .mu.m can be confirmed.

Fig. 14 is an optical microscope photograph of an optical film to which a waveguide is applied, the bottom of which is a regular hexagon. Referring to FIG. 14, the underside and upper surface of the wave guide having a bottom surface of a diameter of 25 mm and a bevel angle of 65 degrees and a height of about 25 mm can be identified.

The waveguide applied to the optical film of the present invention may have irregularities on the light transmitting surface or a curved surface on the light transmitting surface. If irregularities are formed on the light transmitting surface, the light scattering property can be improved. If the light transmitting surface is formed into a curved surface, it can have a function of dispersing or focusing light.

FIG. 15 is an optical microscope photograph of an optical film to which a waveguide having a concavo-convex top surface is applied, and FIG. 16 shows a transmission light distribution in an optical film to which a waveguide having concavo-convexes on the top surface is applied. 15 and 16, when the concave and convex portions are formed on the upper surface of the waveguide, the light distribution of the transmitted light is changed. The diffraction or scattering due to the irregularities causes the light scattering angle to become slightly larger, It becomes soft.

In the optical film of the present invention, if the side inclination angle of the waveguide is designed to be asymmetric, the direction of the light transmitted to the front side can be adjusted. In the case of a waveguide having a square bottom, the amount of transmitted light in the longitudinal direction and the transverse direction can be adjusted to be different from each other when the length and the length are different, and when the inclination angles of the two sides are different from each other in the trapezoidal cross section, . In the latter case, it functions to send more light to a darker space when applied to a window or a lighting device of a building.

FIG. 17A shows a waveguide in which the longitudinal length and the transverse length of the bottom surface are different, and FIG. 17B shows the waveguide in which the longitudinal length and the transverse length are different and the inclination angle is also asymmetric. If the waveguide is designed as shown in FIG. 17 (A), light divergence angles in the longitudinal direction and in the lateral direction are different, and if the waveguide is designed as shown in (B), light can be dispersed in different directions.

Fig. 18 is an optical microscope photograph of an optical film to which a wave guide having a different length in the longitudinal direction and the transverse direction is applied.

19 shows the distribution of transmitted light in the transverse direction and the longitudinal direction in the optical film applied with the waveguide in which the longitudinal direction and the transverse direction length are different as shown in Fig. 17A shows the light distribution in the lateral direction, and FIG. 17B shows the light distribution in the longitudinal direction. It can be seen that the light distribution in the longitudinal direction is relatively small in the divergence angle.

20 shows a distribution of transmitted light of an optical film to which a waveguide having an asymmetric inclination angle is applied. 20 (a), 20 (b), and 20 (c) show the case where the inclination angle of the left side surface is fixed and the right side surface inclination angle is sequentially decreased. Referring to FIG. 20, as the right-hand side inclination angle decreases, the magnitude of light emitted to the right side gradually increases.

21 shows the change in transmittance when the angle of incidence of the back light is changed after fixing the angle of inclination of the waveguide. Referring to FIG. 21, as the incident angle of incident light increases, the transmittance decreases because the amount of light that returns to the back surface increases. When the optical film according to the present invention is used for illumination, the light incident on the rear surface can be returned to the top surface by the diffuse reflection function provided on the top surface of the roughened surface to recycle the light.

The optical film of the present invention can be widely used as a lighting device, a display device, a building window coating material, and the like. When used as a lighting device, it has a structure in which an optical film is installed on the front side of a thin light source made of LED, so that it does not occupy a large volume like a conventional luminaire and has a flexible property. It is also possible. It is also possible to effectively display information on the inside and outside of a building while increasing the transmission of external light by coating it on a building's glass window. An application field of the optical film of the present invention will be described below with reference to FIGS. 22 to 24. FIG.

22 schematically shows a lighting apparatus to which the optical film of the present invention is applied. Referring to FIG. The lighting device is composed of the light source 500 and the optical film 400. The light source 500 may be an LED 502 mounted on the support plate 501, or may be a planar light source having a diffusion plate on the LED. The optical film 400 may have a structure in which a base film 401, a wave guide 402, a color resin 403, and a protective film 405 are sequentially laminated. The color resin 403 may be translucent, transparent, or opaque in different areas. In this case, light emitted to the front surface may display information with different colors.

23 shows the light transmission characteristics when the optical film of the present invention is attached to a window of a building. Referring to FIG. 23, when the optical film of the present invention is installed on a window of a building, light outside the building serves as a light source, and light is introduced into the room similarly to the lighting apparatus. At this time, information can be displayed on the optical film according to the arrangement of the color resin, and high transmittance to external light can be obtained.

24 shows the reflection characteristics of the optical film of the present invention by the front light. When the optical film of the present invention is attached to a window of a building, the intensity of light entering the inside of the building from outside can be minimized at night. At this time, the optical film of the present invention can display information effectively. Referring to FIG. 24, if there is no light on the back surface of the optical film of the present invention, the light on the front surface is reflected on the optical film to display information. At this time, when the translucent color resin is used, the effect of information display can be maximized by the reflective layer on the rear side.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, . Therefore, the embodiments described in the present invention are not intended to limit the scope of the present invention but to limit the scope of the present invention. The scope of protection of the present invention should be construed according to the claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

110: Optical film 111: Base film
112: Color Resin 113: Clear Resin
120: optical film 121: base film
122: Micro lens 123: Color resin
124: transparent resin 130: optical film
131: Base film 132: Micro lens
133: Color Resin 134: Transparent Resin
200: Optical film 201: Base film
202: Wave Guide 203: Opaque Color Resin
203a: Red resin 203b: Transparent resin
203c: blue resin 204: reflective layer
205: protective film 206: sacrificial layer
300: optical film 301: base film
302: Wave Guide 303: Translucent Color Resin
303a: translucent red resin 303b: transparent resin
303c: translucent blue resin 304: reflective layer
400: optical film 401: base film
402: Wave Guide 403: Color Resin
404: adhesive layer 405: protective film
500: light source 501:
502: LED

Claims (16)

Transparent base film;
A plurality of waveguides formed on the transparent base film; And
And a color composition filled in a space between the adjacent wave guides,
And at least a part of the light incident from behind the transparent base film is totally reflected by the waveguide and is transmitted forward. The method according to claim 1,
Wherein a reflective layer is formed between the waveguide and the color composition. The method according to claim 1,
Wherein an inclined angle is formed so that the cross-sectional area of the waveguide decreases as the waveguide moves away from the base film, and a light transmitting surface through which the totally-reflected light is transmitted is formed on the waveguide. The method of claim 3,
And an unevenness is formed so that light is diffused on the light transmitting surface. The method of claim 3,
Wherein the vertical cross section of the waveguide is trapezoidal. The method of claim 5,
Wherein the inclination angle of the trapezoid is adjusted in a range of 45 to 85 degrees. The method of claim 5,
Wherein the trapezoid is adjusted in a ratio of a base to a height in a range of from 0.5 to 2. The method of claim 5,
Wherein an area of the light transmitting surface is adjusted to 0.1 to 50% of a bottom surface area of the wave guide. The method of claim 3,
Wherein the color composition is formed on the light transmission surface, a reflective layer is formed between the side of the wave guide having the inclination angle and the color composition, and no reflective layer is formed between the light transmission surface and the color composition. The method of claim 9,
Wherein the color composition transmits a part of light. The method of claim 5,
The inclination angle of the waveguide, the ratio of the base to the height of the trapezoid, and the refractive index of the waveguide are selected such that at least 50% of light incident from behind the transparent base film passes through the light transmission surface through total internal reflection Lt; / RTI > The method according to claim 1,
Wherein the color composition is filled in a part of a space between the plurality of guides so as to realize a predetermined shape and the other part is filled with a transparent composition. The method according to claim 1,
Wherein the color composition is a dispersion of a dye or pigment in a transparent resin. The method according to claim 1,
Wherein the refractive index of the color composition is smaller than the refractive index of the waveguide. The method according to claim 1,
Characterized in that a protective film is attached on the top of the waveguide or above the collar composition. An optical film according to claim 1; And
And a light source provided behind the transparent base film of the optical film.
KR1020160009247A 2016-01-26 2016-01-26 Optical film and lighting apparatus using the same KR20170089177A (en)

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Publications (1)

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