WO2013012259A2

WO2013012259A2 - Optical film, method of producing the same, stereoscopic glasses and stereoscopic display having the same

Info

Publication number: WO2013012259A2
Application number: PCT/KR2012/005755
Authority: WO
Inventors: Cheol-Heung Ahn; Seung-Kyu Choi; Tae-Gyun Kim; Seok-Joon Kim
Original assignee: Cheol-Heung Ahn; Seung-Kyu Choi; Tae-Gyun Kim; Seok-Joon Kim
Priority date: 2011-07-20
Filing date: 2012-07-19
Publication date: 2013-01-24
Also published as: WO2013012259A3; KR101328109B1; KR20130011195A

Abstract

The present invention relates to an optical film, which allows a user to enjoy a stereoscopic image at various positions and angles by improving the viewing angle of stereoscopic glasses that is used to watch a stereoscopic image, a method of producing the optical film, and stereoscopic glasses and a stereoscopic display including the optical film. The optical film includes: a first base; a polarizing film stacked on the first base; a second base stacked on the polarizing film; and a hybrid liquid crystal layer formed on the second base; in which the hybrid liquid crystal layer includes: an alignment layer formed on the second base at an angle of 45° or -45° from a stretching direction of the polarizing film and rubbed in parallel with the surface of the second base; and horizontally-aligned liquid crystals and vertically-aligned liquid crystals that are aligned in parallel with and perpendicular to the rubbing direction on the alignment layer.

Description

OPTICAL FILM, METHOD OF PRODUCING THE SAME, STEREOSCOPIC GLASSES AND STEREOSCOPIC DISPLAY HAVING THE SAME

The present invention relates to an optical film, a method of producing the same, and stereoscopic glasses and a stereoscopic display having the same, particularly to an optical film, which allows a user to enjoy a stereoscopic image at various positions and angles by improving the viewing angle of stereoscopic glasses that is used to watch a stereoscopic image, a method of producing the optical film, and stereoscopic glasses and a stereoscopic display including the optical film.

As the demand for 3D stereoscopic images increases, the relating technologies have been greatly developed. In general, the principle of a visual difference between two eyes is used for 3D stereoscopic images. That is, when different images are input to two eyes, the brain recognizes the two images and a stereoscopic sense is given.

As the technology that is used to reproduce stereoscopic images, there are a glassless type of stereoscopic display, a glass type of stereoscopic display, a holographic type, and the like, and the types each have merits and demerits, so that various studies have been conducted to achieve more excellent stereoscopic images.

There are a lenticular type, a parallax barrier type, and the like in the glassless type of stereoscopic display and they have a merit that it is possible to see stereoscopic images even without wearing glasses, but there is a limit when a plurality of people watch stereoscopic images and the stereoscopic images are limited, depending on the position of the observer.

The holographic type has a merit that a plurality of observers can simultaneously watch stereoscopic images regardless of the positions, but has a demerit that the equipment is expensive and it is difficult to implement the technology.

Therefore, recently, the glass type of stereoscopic display that allows many people to watch together stereoscopic images and of which the technology is relatively easily implemented has been generally used. The glass type of stereoscopic display falls into a time division type and a space division type, in which the time division type and the time division type implement a stereoscopic image, using shutter glasses and polarized glasses, respectively.

The shutter glass type is expensive due to the complicated structure of the glasses and may cause dizziness due to blinking when being used in a room with a fluorescent lamp turned on. Further, the space division type using polarized glasses has a merit that many people can enjoy stereoscopic images because the glasses has a simple structure and is light and the price is relatively low, but the image quality may be deteriorated due to reduction of the number of pixels of the display unit and the left and right images may be partially mixed with each other in both lenses of the glasses without being completely separated. Accordingly, both the shutter glass type and the polarized glass type are developed in accordance with the manufacturers.

On the other hand, not only a polarizing film, but an optical film controlling the optical properties of the image transmitted from a display is included in the polarized glasses. The optical film generally includes a compensating layer that compensates for the phase of light and the compensating film is usually formed by attaching a base layer or coating a liquid crystal layer onto a stretching polymer film. The stretching polymer film is formed by stretching a polymer film in one direction and has a defect in that the thickness of the film increases in comparison to the liquid crystal layer-coating type. Further, the type of coating a liquid crystal layer has a problem in that a limit is caused in viewing angle in accordance with the alignment direction of the liquid crystals.

In particular, for the optical film used for stereoscopic glasses, the observer sees stereoscopic images at various angles in many cases. For example, when an observer watches a stereoscopic image in bed, the angle between the stereoscopic glasses and the stereoscopic image display may change and the observer can see the stereoscopic display through not the center portion, but the edge portion of the stereoscopic glasses. That is, when the observer does not see a stereoscopic image not at a predetermined angle, the viewing angle may be limited and the stretching polymer film or the liquid crystal coating type of optical film could not compensate for the viewing angle.

Therefore, it was necessary to develop an optical film that has a wide viewing angle without deteriorating the quality of a stereoscopic image.

Accordingly, it was necessary to develop an optical film that has a wide viewing angle without deteriorating the quality of a stereoscopic image.

The present invention has been made in an effort to provide an optical film, which allows a user to enjoy a stereoscopic image at various positions and angles by improving the viewing angle of stereoscopic glasses that is used to watch a stereoscopic image, a method of producing the optical film, and stereoscopic glasses and a stereoscopic display including the optical film.

The objects of the present invention are not limited to that described above and other objects not stated herein may be clearly understood by those skilled in the art from the following description.

An optical film according to an exemplary embodiment of the present invention includes: a first base; a polarizing film stacked on the first base; a second base stacked on the polarizing film; and a hybrid liquid crystal layer formed on the second base; in which the hybrid liquid crystal layer includes: an alignment layer formed on the second base at an angle of 45°or -45°from a stretching direction of the polarizing film and rubbed in parallel with the surface of the second base; and horizontally-aligned liquid crystals and vertically-aligned liquid crystals that are aligned in parallel with and perpendicular to the rubbing direction on the alignment layer.

An optical film according to another exemplary embodiment of the present invention includes: a first base; a polarizing film stacked on the first base; and a second base stacked on the polarizing film, in which the second base is made of triacetyl cellulose, polycarbonate, a cycloolefin polymer, and a cycloolefin copolymer and stretched at an angle of 45°or -45°from a stretching direction of the polarizing film

A method of producing an optical film according to another exemplary embodiment includes: stretching a polarizing film and attaching a first base and a second base to both sides of the polarizing film; forming a first alignment layer by applying and then rubbing an alignment layer composite on the second base or directly rubbing the second base, in parallel with the surface of the second base at an angle of 45°or -45°from a stretching direction of the polarizing film; coating a liquid crystal composite onto the first alignment layer; primarily hardening the liquid crystal composite by radiating ultraviolet rays onto the liquid crystal composite; vertically aligning some of liquid crystal molecules contained in the liquid crystal composite by forming electric fields above and under the liquid crystal composite; and forming a hybrid liquid crystal layer by performing secondary hardening, with the liquid crystal molecules vertically aligned.

Stereoscopic glasses according to another exemplary embodiment of the present invention includes a right-eye lens; and a left-eye lens, in which the right-eye lens and the left-eye lens each include: a first base; a polarizing film stacked on the first base; a second base stacked on the polarizing film; and a hybrid liquid crystal layer formed on the second base, the hybrid liquid crystal layers each include: an alignment layer formed on the second base at an angle of 45°or -45°from a stretching direction of the polarizing film and rubbed in parallel with the surface of the second base; and an optical film including horizontally-aligned liquid crystals and vertically-aligned liquid crystals that are aligned in parallel with and perpendicular to the rubbing direction on the alignment layer, and the phase difference between the hybrid liquid crystal layer of the right-eye lens and the hybrid liquid crystal layer of the left-eye lens is λ/2.

A stereoscopic display according to another exemplary embodiment of the present invention includes: a display panel displaying a right-eye image and a left-eye image; an optical filter including a first polarizing area that overlaps the display panel and controls the polarized state of the right-eye image and a second polarizing area that controls the polarized state of the left-eye image; and stereoscopic glasses including a right-eye lens that transmits the right-eye image and a left-eye lens that transmits the left-eye image, in which the right-eye lens and the left-eye lens each include: a first base; a polarizing film stacked on the first base; a second base stacked on the polarizing film; and a hybrid liquid crystal layer formed on the second base, the hybrid liquid crystal layers each include: an alignment layer formed on the second base at an angle of 45°or -45°from a stretching direction of the polarizing film and rubbed in parallel with the surface of the second base; and an optical film including horizontally-aligned liquid crystals and vertically-aligned liquid crystals that are aligned in parallel with and perpendicular to the rubbing direction on the alignment layer, and the phase difference between the hybrid liquid crystal layer of the right-eye lens and the hybrid liquid crystal layer of the left-eye lens is λ/2.

The optical film according to the present invention is thinner than compensating films of the related art, by using a hybrid liquid crystal layer, and makes it possible to achieve stereoscopic glasses having excellent optical performance.

In particular, it is possible to compensate for a limit in viewing angle according to observation positions, so that it is possible to observe a stereoscopic image at various positions.

FIG. 1 is a cross-sectional view of an optical film according to a first exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view of an optical film according to a second exemplary embodiment of the present invention.

FIG. 3 is a cross-sectional view of an optical film according to a third exemplary embodiment of the present invention.

FIG. 4 is a cross-sectional view of an optical film according to a fourth exemplary embodiment of the present invention.

FIGS. 5A and 5B are plan views of an optical film according to an exemplary embodiment of the present invention.

FIGS. 6A to 6E are cross-sectional views illustrating processes of producing an optical film according to an exemplary embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating a process of producing an optical film according to another exemplary embodiment of the present invention.

FIGS. 8A and 8B are cross-sectional views illustrating processes of producing an optical film according to another exemplary embodiment of the present invention.

FIG. 9 is a view illustrating an image display process of a stereoscopic display according to an exemplary embodiment of the present invention.

The advantages and features of the present invention, and methods of achieving them will be clear by referring to the exemplary embodiments that will be describe hereafter in detail with reference to the accompanying drawings. However, the present invention is not limited to the exemplary embodiments described hereafter and may be implemented in various ways, and the exemplary embodiments are provided to complete the description of the present invention and let those skilled in the art completely know the scope of the present invention and the present invention is defined only by claims. Like reference numerals indicate the same components throughout the specification.

In the description of disposing relationship of components, "on", "above", "beneath", and "under" a component will be described on the basis of the direction shown in the drawings and will be used to easily describe the spatial relative relationship of the components.

An optical film 100 according to a first exemplary embodiment of the present invention will be described hereafter in detail with reference to FIG. 1. FIG. 1 is a cross-sectional view of an optical film according to a first exemplary embodiment of the present invention.

The optical film 100 according to the first exemplary embodiment of the present invention is used for 3D stereoscopic glasses and can accurately separate a stereoscopic image displayed on a display 1 into a left-eye image and a right eye image and provide the left-eye image and the right-eye image to an observer. 3D stereoscopic glasses may be implemented by using only the optical film 100 or by adding individual functional film or functional layer on or under a first base 110, or on or under a second base 130, in the optical film 100. The functional film or functional layer in this configuration means all films and layers having optical properties for compensating for the function of 3D stereoscopic glasses, such as a phase difference compensation film or a phase difference compensation layer, a protective film or a protective layer, an antireflection film or an antireflection layer, a hard coat film or a hard coat layer, and a polymer film.

Describing the detailed structure of the optical film 100, the optical film 100 is implemented by sequentially stacking the first base 110, a polarizing film 120, the second base 130, an alignment layer 140, and a hybrid liquid crystal layer 150.

The first base 110 and the second base 130 are disposed with the polarizing film 120 therebetween and function as a structure supporting the optical film 100. The first base 110 and the second base 130 may be TAC (triacetyl cellulose) films. Further, the first base 110 and the second base 130 may be implemented by one of a polyethylene terephthalate polymer, a polyethylene naphthalate polymer, a polyester polymer, a polyethylene polymer, a polypropylene polymer, a polyvinylidene chloride polymer, a polyvinyl alcohol polymer, a polyethylene vinyl alcohol polymer, a polystyrene polymer, a polycarbonate polymer, a norbornene polymer, a poly methyl pentene polymer, a polyether ketone polymer, a polyether sulfone polymer, a polysulfone polymer, a polyether ketone imide polymer, a polyamide polymer, a polymethacrylate polymer, a polyacrylate polymer, a polyarylate polymer, and a fluoropolymer polymer.

The polarizing film 120 is stacked on the first base 110. The polarizing film 120 has a feature that transmits light perpendicular to an absorbing axis and is formed by stretching PVA (polyvinylalcohol) absorbing iodine, which is a polarizer.

The second base 130 is stacked on the polarizing film 120. That is, the polarizing film 120 has a structure where the first base 110 and the second base 130 are attached, on both sides, to support and protect the polarizing film 120. The first base 110 and the second base 130 may be formed to have a thickness of 10 ~ 1000㎛ in order to sufficiently support the polarizing film 120 and the polarizing film 120 may be formed to have a thickness of 5 ~ 100㎛. For example, when the polarizing film 120 is 30㎛ thick, films having a thickness of 00㎛ may be used for the first base 110 and the second base 130.

Meanwhile, the second base 130 may be made of triacetyl cellulose, polycarbonate, a cycloolefin polymer, and a cycloolefin copolymer and may be stretched at an angle of 45°or -45°from the stretching direction of the polarizing film 120. That is, the second base 130 may be made of a stretching polymer film to support the polarizing film 120 and function as a phase difference film. In this case, the hybrid liquid crystal layer 150 may not be included. The second base 130 may be formed to have a thickness of 1 ~ 1000㎛.

Meanwhile, the alignment layer 140 is formed by applying an aligning agent such as polyimide or polyvinyl alcohol onto the second base 130. The alignment layer 140 is rubbed in one direction such that liquid crystal molecules can be horizontally aligned.

The hybrid liquid crystal layer 150 is formed on the alignment layer 140. The hybrid liquid crystal layer 150 includes horizontally-aligned liquid crystals 151 and vertically-aligned liquid crystals 152 which are respectively aligned in parallel with and perpendicular to the surface of the second base 130 on the alignment layer 140 rubbed at 45° or -45°from the stretching direction of polyvinyl alcohol, which is the polarizing film 120. The alignment layer 140 may be formed by coating and rubbing an alignment layer composite on the second baser 130, but is not limited thereto, and may be formed by directly rubbing in one direction on the surface of the second base 130. That is, not only a layer made of a material different from the second base, but a structure formed by directly rubbing the surface of the second base 130 such that liquid crystals can be aligned may be the alignment layer 140.

The vertically-aligned liquid crystals 152 exist between the horizontally-aligned liquid crystals 151 in the hybrid liquid crystal layer 150 and function to compensate for the phase difference and the viewing angle of circularly-polarized light. The horizontally-aligned liquid crystals 151 that function to compensate for the phase difference are about 85 ~ 95% (for weight or volume) and the vertically-aligned liquid crystals 152 that function to compensate for the viewing angle are about 5 ~ 15% in the hybrid liquid crystal layer 150. That is, the main function of the hybrid liquid crystal layer 150 is to compensate for the phase difference and the horizontally-aligned liquid crystals 151 occupy most of the hybrid liquid crystal layer 150 to sufficiently achieve the function.

Meanwhile, the hybrid liquid layer 150 may include liquid crystals tilted at an angle of 0 ~ 90°(between horizontality and verticality), other than the horizontally-aligned liquid crystals 151 and the vertically-aligned liquid crystals 152. The liquid crystal molecules tilted at an angle of 0 ~ 90° as described above, can help compensate for the viewing angle, but it is preferable to control the ratio not to exceed 5 ~ 10% because the liquid crystal molecules may cause crosstalk when being used for 3D stereoscopic glasses, when the ratio in the hybrid liquid layer 150 is too large.

The hybrid liquid crystal layer 150 may be formed to have a thickness of 0.1 ~ 20㎛, in which the thickness is 1/10 or less, as compared with when a stretching polymer film is used.

The protective film 170 is attached on the hybrid liquid crystal layer 150 or the outermost side of the first base 110. The protective film 170 is attached to the outermost side to protect the optical film 100. The protective film 170 may be made of a polycarbonate film; a polyester-based film such as polyethylene terephthalate; a polyether sulfone-based film; a polyolefine-based film having a polyethylene, polypropylene, cyclo-based or norbornene structure; and a polyolefine-based film such as an ethylene propylene copolymer. The protective film may be removed when watching a stereoscopic film or in the process of producing the optical film, if necessary.

An optical film 100a according to a second exemplary embodiment of the present invention will be described hereafter in detail with reference to FIG. 2. FIG. 2 is a cross-sectional view of an optical film according to the second exemplary embodiment of the present invention.

The optical film 100a according to the second exemplary embodiment of the present invention has substantially the same components as those of the optical film 100 of the first exemplary embodiment described above, except for the hybrid liquid crystal layer 150. Therefore, the description of the other components, except for the hybrid liquid crystal layer 150, is not provided.

The hybrid liquid crystal layer 150 includes a first area A1 with only the horizontally-aligned liquid crystals 151 and a second area A2 with the horizontally-aligned liquid crystals 151 and the vertically-aligned liquid crystals 152. The first area A1 and the second area A2 are set by dividing the surface of the optical film 100a and the optical film 100a is composed of the first area A1 and the second area A2.

Describing the first area A1 and the second area A2 in detail, the first area A1 of the hybrid liquid crystal layer 150 is an area for compensating for a phase difference and the second area A2 is an area for compensating a viewing angle in addition to the phase difference.

When the optical filter 15 is used for 3D stereoscopic glasses, some area is less influenced by the viewing angle and some area has a portion where the viewing angle needs to be corrected. In this case, the area without a problem in viewing angle may be set as the first area A1 and the area where the viewing angle needs to be compensated may be set as the second area A2, in the optical filter 15. For example, the second area A2 may be positioned outside the first area A1 or may be formed at the edge of the optical filter 15. In detail, as shown in FIG. 5a, the firs area A1 and the second area concentrically disposed and the second area A2 may be positioned outside the first area A1. Further, as shown in FIG. 5b, the first area A1 and the second area A2 may be disposed in a stripe shape.

Meanwhile, the horizontally-aligned liquid crystals 151 may be 85 ~ 95% and the vertically-aligned liquid crystals 152 may be 5 ~ 15% in the second area A2. As described above, when the ratio of the horizontally-aligned liquid crystals 151 of the second area is 85% or less, the compensation effect of the phase difference is reduced, and when the horizontally-aligned liquid crystals 151 is above 95%, the compensation effect of the viewing angle is reduced.

An optical film 100b according to a third exemplary embodiment of the present invention will be described hereafter in detail with reference to FIG. 3. FIG. 3 is a cross-sectional view of an optical film according to the third exemplary embodiment of the present invention.

The optical film 100b according to the third exemplary embodiment of the present invention includes a hybrid liquid crystal layer including a first liquid crystal layer 150a and a second liquid crystal layer 160, and a hard coat layer 181 and a low-refractive index layer 182 are additionally stacked on the hybrid liquid crystal layer. That is, the first liquid crystal layer 150a and the second crystal layer 160 overlap each other, thereby forming the hybrid liquid crystal layer.

The structure in which the first base 110, the polarizing film 120, and the second base 130 are sequentially stacked is substantially the same as those in the exemplary embodiments described above. A first alignment layer 140 is applied on the second base 130 and rubbed in one direction. Further, an alignment layer may be formed by directly rubbing the second base 130 in one direction.

The first liquid crystal layer 150a including the horizontally-aligned liquid crystals 151 is formed on the first alignment layer 140. The first liquid crystal layer 150a is a liquid crystal layer for compensating for a phase difference and composed of only the horizontally-aligned liquid crystals 151. That is, the first alignment layer 140 is horizontally rubbed and the first liquid crystal layer 150a is horizontally aligned in the rubbing direction of the first alignment layer 140 without a specific processing. The first alignment layer 140 may not be provided in this configuration, the surface of the second base 130 may be rubbed in one direction, and the first liquid crystal layer 150a may be formed on the second base 130.

The second alignment layer 141 is formed on the first liquid crystal layer 150a and the second liquid crystal layer 160 including vertically-aligned liquid crystals 152 is formed on the second alignment layer 141. The second alignment layer 141 may not be provided in this configuration. That is, the second liquid crystal layer 160 may be formed by applying, vertically aligning, and hardening a liquid composite on the first liquid crystal layer 150a. The process of producing the hybrid liquid crystal layer including the first liquid crystal layer 150a and the second liquid crystal layer 160 is described in detail below.

Meanwhile, the ratio of the first liquid crystal layer 150a and the second liquid crystal layer 160 may be adjusted such that the horizontally-aligned liquid crystals 151 are 85 ~ 95% and the vertically-aligned liquid crystals 152 are 5 ~ 15% in the hybrid liquid crystal layer. That is, the hybrid liquid crystal layer is formed such that the first liquid crystal layer 150 is 85 ~ 95% and the second liquid crystal layer 160 is 5 ~ 15%, for thickness. For example, the first liquid crystal layer 150a may be formed to have a thickness of 0.1 to 20㎛ and the second liquid crystal layer 160 may be formed to have a thickness of 2㎛ or less.

The first liquid crystal layer 150a and the second liquid crystal layer 160 may be stacked on the second base 130 in the order of the first liquid crystal layer 150a and the second liquid crystal layer 160, but they are not limited thereto, and the second liquid crystal layer 160 may be stacked first on the second base 130 and then the first liquid crystal layer 150a may be formed on the second liquid crystal layer 160.

The hard coat layer 181 and the low-refractive index layer 182 that constitute an antireflective layer are sequentially stacked on the second liquid crystal layer 160. The hard coat layer 181 may contain ionizing radiation-curable resin and a conductive metal oxide of 5 ~ 15 wt%.

The ionizing radiation-curable resin may include at least one of a monomer, a pre-polymer, and a polymer having vinyl group, (meta) acryloyl group, epoxy group, oxetanyl group to be used. Further, the conductive metal oxide may be an antimony-tin oxide (ATO), an indium-tin oxide (ITO), a phosphorus-tin oxide (PTO), an oxidized zinc (ZnO), oxidized tin (SnO₂), antimonic acid zinc (ZnSb₂O₆), and 5-oxidized antimony (Sb₂O₅).

Further, the antireflective function may be improved by making the refractive index of the low-refractive index layer 182 smaller than the refractive index of the hard coat layer 181. The low-refractive index layer 182 may contain inorganic low-refractive index particles such as silica or fluoric magnesium having apertures therein, a binder, a solvent and the like. Further, a polymerizing initiator or various additives may be added, if necessary.

As the binder, for example, an organic binder made of ionizing radiation-curable resin composed of a monomer, a pre-polymer, and a polymer having vinyl group, (meta) acryloyl group, epoxy group, oxetanyl group, or an inorganic binder that is a thermosetting binder such as silica sol.

An optical film 100c according to a fourth exemplary embodiment of the present invention will be described hereafter in detail with reference to FIG. 4. FIG. 4 is a cross-sectional view of an optical film according to the fourth exemplary embodiment of the present invention.

Except that the second liquid crystal layer 160 is divided into the first area A1 including the horizontally-aligned liquid crystals 151 and the second area A2 including the vertically-aligned liquid crystals 152, the other components of the optical film 100c according to the fourth exemplary embodiment of the present invention are substantially the same as those of the optical film 100c of the third exemplary embodiment described above Therefore, the description of the other components, except for the second liquid crystal layer 160, is not provided.

The second liquid crystal layer 160 is disposed on the first liquid crystal layer 150a and divided into a first area A1 and a second area A2. The first area A1 is an area only with horizontally-aligned liquid crystals 151 and the second area A2 is an area only with vertically-aligned liquid crystals 152. However, only the vertically-aligned liquid crystals 152 may not necessarily exist in the second area A2. For example, it is preferable that the hybrid liquid crystal layer is formed such that the first liquid crystal layer 150a is 85 ~ 95% and the second liquid crystal layer 160 is 5 ~ 15%, for thickness, but when the second liquid crystal layer 160 is 10% or more of the hybrid liquid crystal layer, both the vertically-aligned liquid crystals 152 and the horizontally-aligned liquid crystals 151 may be distributed.

As described above, the first area A1 is a phase difference-compensating area and the second area A2 is an area that can compensate for a viewing angle in addition to the phase difference.

Referring to FIGS. 5A and 5B, the first area and the second area of the optical film according to an exemplary embodiment of the present invention may be disposed in various ways. FIGS. 5A and 5B are plan view of an optical film according to an exemplary embodiment of the present invention.

Referring to FIG. 5a first, the first area A1 and the second area A2 are concentrically disposed on the optical film 100a. When the optical film 100a is used for 3D stereoscopic glasses, the first area A1 may be formed at the center portion with a relatively small limit in viewing angle and the second area A2 may be formed outside the first area A1. It is only an example that the first area A1 is formed in a circle and the shape of the first area A1 is not necessarily a circle. That is, when the first area A1 is disposed at the center area of the optical film and the second area A2 is disposed at the edge, the first area A1 may be formed in a rectangle or any shape.

Referring to FIG. 5B, the first area A1 and the second area A2 are disposed in a stripe shape. The center portion may be formed as the first area A1 and the edge portion may be disposed as the second area A2 by dividing straight an optical film 100a'. Although FIG. 5B exemplifies an optical sheet that is horizontally divided, the present invention is not limited thereto, and the optical sheet may be vertically divided and the first area A1 may exist outside the second area A2. That is, the arrangement shapes shown in FIGS. 5A and 5B are only examples and may be changed in various shapes.

A method of producing an optical film according to an exemplary embodiment of the present invention is described hereafter in detail with reference to FIGS. 1, 6A, and 6B. FIGS. 6A to 6E are cross-sectional views illustrating processes of producing an optical film according to an exemplary embodiment of the present invention.

Referring to FIG. 6A first, a polarizing film 120 is stretched and a first base 110 and a second base 130 are attached to both sides of the polarizing film 120. The first base 110 and the second base 130 may be TAC (triacetyl cellulose) films and the polarizing film 120 is formed by stretching PVA (polyvinylalcohol) treated with iodine.

The polarizing film 120 is formed by stretching a PVA (polyvinylalcohol) film and then being impregnated in an iodine aqueous solution. When the iodine component is adsorbed to the surface in the stretching direction of the PVA film, the PVA film is colored into dark green, thereby completing the polarizing film 120. A support for the polarizing film 120 is formed by attaching the first base 110 and the second base 130 to both sides of the polarizing film 120. However, the producing process and the attaching method of the first base 110, the polarizing film 120, and the second base 130 may be implemented by various methods, in addition to the method described herein.

Next, referring to FIG. 6B, an alignment layer 140 is formed by applying and rubbing an alignment layer composite on the second base 130.

The alignment composite is coated onto the second base 130 to have a uniform thickness. The alignment layer composite may be coated by spin coating, gravure coating, deep coating, spray coating, or roll coating, and the solvent is removed by drying the alignment layer composite after the alignment layer composite is coated. The solvent can be completely hardened after pre-drying such that the alignment layer composite can be uniformly spread. When a photoinitiator is contained in the alignment layer composite, photo-hardening that uses ultraviolet rays may be used.

Meanwhile, the alignment layer 140 aligned in a predetermined direction is completed by rubbing the alignment layer 140, which has undergone hardening, with a rubbing fabric.

Next, referring to FIG. 6C, a liquid crystal composite is coated onto the alignment layer 140 and primary hardening is performed by radiating ultraviolet rays.

In detail, a liquid crystal composite is coated onto the alignment layer 140. The coating may be implemented by spin coating, gravure coating, deep coating, or spray coating, like the coating of the alignment layer. It is preferable to coat the liquid crystal composite to have a thickness of 0.1 ~20㎛ such that a phase difference can be appropriately compensated.

The solvent is removed by drying the liquid crystal composite after the liquid crystal composite is coated. The liquid crystal composite may be dried at a room temperature or may be heated and dried by an oven or a heating plate, or may be dried by ultraviolet rays.

Primary hardening is performed by polymerizing the horizontally-aligned liquid crystal layer after the liquid crystal composite is dried. The primary hardening is not a step that completely cures the liquid crystal composite, but a step that half cures the liquid crystal composite such that some liquid crystals contained in the liquid crystal composite can be moved by an external electric field.

As the liquid crystal composite is primarily hardened by ultraviolet rays, the direction of most of the horizontally-aligned liquid crystal molecules is fixed.

Next, referring to FIG. 6B, some liquid crystal molecules contained in the liquid crystal composite are vertically aligned by forming electric fields above and under the primarily-hardened liquid crystal composite.

Electrodes

191 and 192 are disposed above and under the liquid crystal layer 150, respectively, and electric fields are formed by applying power, so that the some of the horizontally-aligned liquid crystals are vertically rotated. The vertically-aligned liquid crystals 152 that are vertically rotated are made be uniformly generated throughout the liquid crystal layer 150. That is, the vertically-aligned liquid crystals 152 are uniformly generated throughout the liquid crystal layer 150, when the liquid crystal layer 150 is uniformly primarily hardened. It is possible to control the magnitude and time of the electric fields in consideration of the degree of the primary curing of the liquid crystal layer 150. As described above, it is possible to control the electric fields such that the horizontally-aligned liquid crystals 151 is about 85 ~ 95% and the vertically-aligned liquid crystals 152 is 5 ~ 15%.

Next, referring to FIG. 6E, the liquid crystal layer 150 is completely hardened by performing secondary hardening, with some liquid crystal molecules vertically aligned by applying the electric fields to the primarily cured liquid crystal layer 150.

The secondary curing may be performed by radiating ultraviolet rays, and after the secondary hardening is finished, the liquid crystal molecules in the liquid crystal layer 150 are completely fixed.

Next, referring to FIG. 1, the optical film 100 is completed by stacking a protective film 170 onto the liquid crystal layer 150.

A method of producing an optical film according to another exemplary embodiment of the present invention is described hereafter with reference to FIGS. 2 and 7. FIG. 7 is a cross-sectional view illustrating a process of producing an optical film according to another exemplary embodiment of the present invention.

The method of processing an optical film according to another exemplary embodiment of the present invention relates to a method of producing an optical film including a hybrid liquid crystal layer divided into a first area and a second area.

First, the processes shown in FIGS. 6A to 6C are the same as those of the exemplary embodiment described above, so that they are not described.

Referring to FIG. 7,

electrodes

191 and 192 are respectively disposed above and under the resultant of the process shown in FIG. 6C. In this process, the electrode 192 that overlaps only a second area A2 is disposed above a liquid crystal layer 150 such that an electric field is not formed in a first area A1.

As a result, only horizontally-aligned liquid crystals 151 exist in the first area A1, while the horizontally-aligned liquid crystals 151 and vertically-aligned liquid crystals 152 exist in the second area A2. The electrode overlapping only the second area A2 may be various electrodes such as a hollow electrode or a stripe electrode.

Next, when the liquid crystal layer 150 is secondarily hardened by radiating ultraviolet rays, a hybrid liquid crystal layer divided into the first area A1 and the second area A2 is completed, and the optical film 100 shown in FIG. 2 is completed by attaching a protective film 170 to the hybrid liquid crystal layer.

A process of producing an optical film according to another exemplary embodiment of the present invention is described hereafter in detail with reference to FIGS. 3, 8A, and 8B. FIGS. 8A and 8B are cross-sectional views illustrating processes of producing an optical film according to another exemplary embodiment of the present invention.

The method of processing an optical film according to another exemplary embodiment of the present invention relates to a method of producing an optical film including a first area and a second area.

Referring to FIG. 8A, a liquid crystal composite is coated onto the resultant of the process shown in FIG. 6B and primarily hardened by radiating ultraviolet rays. That is, the solvent is removed by drying the liquid crystal composite after the liquid crystal composite is coated. The liquid crystal composite may be dried at a room temperature or may be heated and dried by an oven or a heating plate, or may be dried by ultraviolet rays.

Primary curing is performed by polymerizing the horizontally-aligned liquid crystal layer after the liquid crystal composite is dried. However, the primary hardening means not half hardening in the exemplary embodiment described above, but complete hardening, and only horizontally-aligned liquid crystals 151 exist in a first liquid crystal layer 150 after primary hardening is finished.

Next, referring to FIG. 8B, a second liquid crystal layer 160 is formed by coating and vertically aligning a second alignment layer 140 on the first liquid crystal layer 150.

The second liquid crystal layer 160 is a liquid crystal layer containing only vertically-aligned liquid crystals 152 and may be vertically aligned by the vertically-aligned second alignment layer 140. Further, as in the exemplary embodiment described above, the liquid crystal molecules may be vertically aligned by forming an electric field.

Further, the optical film 100 shown in FIG. 3 is completed by forming a hard coat layer 181 and a low-refractive index layer 182 onto the second liquid crystal layer.

A stereoscopic display according to an exemplary embodiment of the present invention is described hereafter in detail with reference to FIG. 9. FIG. 9 is a view illustrating an image display process of a stereoscopic display according to an exemplary embodiment of the present invention.

A stereoscopic display 1 largely includes a display panel 10 that displays stereoscopic images and stereoscopic glasses that separates a stereoscopic image into a left-eye image and a right-eye image.

The display panel 10 is a device that creates and displays a left-eye image and a right-eye image such that an observer can feel a stereoscopic sense, and includes a backlight 11, a first polarizer12, a display element 13, a second polarizer14, and an optical filter 15.

The display panel 10 may use a liquid crystal display element, which displays images by moving liquid crystal molecules, as the display element 13. In detail, the liquid crystal display element is a passive light emitting element, so that the backlight 11 that provides light to the display element 13 is disposed at the rear portion and the display element 13 that is divided into left-eye pixels L and right-eye pixels R is disposed at the front portion.

The first polarizer 12 and the second polarizer 14 are disposed on both sides of the display element 13, respectively, and the first polarizer 12 and the second polarizer 14 are arranged such that the absorbing axes are perpendicular to each other. That is, when the absorbing axis of the first polarizer 12 is horizontally disposed, the absorbing axis of the second polarizer 14 is vertically disposed.

Meanwhile, an optical filter 15 is disposed on the front side of the second polarizer 14. The optical filter 15 functions to polarize the left-eye image and the right-eye image emitted from the display element 13, in different directions. That is, the optical filter 15 is patterned such that the areas overlapping the left-eye pixels L and the right-eye pixels R of the display element 13 have different polarizing properties. Therefore, the left-eye image emitted through the left-eye pixels L is, for example, circularly polarized counterclockwise and the right-eye filter emitted through the right-eye filters R is, for example, circularly polarized clockwise.

The left-eye image and the right-eye image emitted from the display panel 10 may be emitted by light that is circularly polarized in different directions.

Meanwhile, the observer sees the left-eye image and the right-eye image emitted from the display panel 10, through the stereoscopic glasses 20. The stereoscopic glasses 20, as described above, includes the optical film 100 including the polarizing film 120 and the hybrid liquid crystal layer 150.

The stereoscopic glasses 20 includes a left-eye lens and a right-eye lens and the optical films included in the left-eye lens and the right-eye lens make the phase difference of the hybrid liquid crystal layers 150, λ/2. That is, when the phase difference value of the hybrid liquid crystal layer 150 of the left-eye lens is λ/4, the phase difference value of the hybrid liquid crystal layer 150 of the right-eye lens may be 3λ/4.

Further, the hybrid liquid crystal layers 150 of the left-eye lens and the right-eye lens have a difference in alignment direction of 90° For example, when the alignment direction of the hybrid liquid crystal layer 150 of the left-eye lens is 135° the alignment direction of the hybrid liquid crystal layer 150 of the right-eye lens may be 45° The polarizing film 120 included in the stereoscopic glasses may have the same horizontal transmissive axes.

The process of operation of the stereoscopic display 1 is described.

The display panel 10 emits a left-eye image and a right-eye image, which have been circularly polarized in different directions. The left-eye image and the right-eye image are transmitted through the left-eye lens and the right-eye lens of the stereoscopic glasses 20. The left-eye image and the right-eye image transmitted through the left-eye lens are converted into linearly-polarized images by the hybrid liquid crystal layer 150 of the left-eye lens. The left-eye image is converted into linearly-polarized light that coincides with the transmissive axis of the polarizing film 120 and the right-eye image is converted into linearly-polarized light that is perpendicular to the transmissive axis of the polarizing film 120. Therefore, only the left-eye image of the images that are transmitted through the left-eye lens passes through the polarizing film 120.

On the contrary, the left-eye image and the right-eye image transmitted through the right-eye lens are converted into linearly-polarized images by the hybrid liquid crystal layer 150 of the right-eye lens. The left-eye image is converted into linearly-polarized light that is perpendicular to the transmissive axis of the polarizing film 120 and the right-eye image is converted into linearly-polarized light that coincides with the transmissive axis of the polarizing film 120. Therefore, only the right-eye image of the images that are transmitted through the right-eye lens passes through the polarizing film 120.

The observer sees the left-eye image and the right-eye image with the left eye and the right eye, respectively, through this process, and feels a stereoscopic sense.

The optical film according to the present invention is thinner than compensating films of the related art, by using a hybrid liquid crystal layer, and makes it possible to achieve stereoscopic glasses having excellent optical performance. In particular, it is possible to compensate for a limit in viewing angle according to observation positions, so that it is possible to observe a stereoscopic image at various positions.

Claims

An optical film comprising:

a first base;

a polarizing film stacked on the first base;

a second base stacked on the polarizing film; and

a hybrid liquid crystal layer formed on the second base;

wherein the hybrid liquid crystal layer includes:

an alignment layer formed on the second base at an angle of 45°or -45°from a stretching direction of the polarizing film and rubbed in parallel with the surface of the second base; and

horizontally-aligned liquid crystals and vertically-aligned liquid crystals that are aligned in parallel with and perpendicular to the rubbing direction on the alignment layer.
The optical film of claim 1, wherein the alignment layer is formed by directly rubbing the surface of the second base at an angle of 45°or -45°from the stretching direction of the polarizing film.
The optical film of claim 1, wherein the horizontally-aligned liquid crystals are 85 ~ 95% and the vertically-aligned liquid crystals are 5 ~ 15% in the hybrid liquid crystal layer.
The optical film of claim 1, wherein the hybrid liquid crystal layer includes a first area only with the horizontally-aligned liquid crystals and a second area with the horizontally-aligned liquid crystals and the vertically-aligned liquid crystals.
The optical film of claim 4, wherein the first area and the second area are concentrically disposed and the second area is positioned outside the first area.
The optical film of claim 4, wherein the first area and the second area are disposed in a stripe shape.
The optical film of claim 1, wherein the hybrid liquid crystal layer includes a first liquid crystal layer including the horizontally-aligned liquid crystals and a second liquid crystal layer overlapping the first liquid crystal layer and including the vertically-aligned liquid crystals.
The optical film of claim 1, wherein the hybrid liquid crystal layer includes a first liquid crystal layer including the horizontally-aligned liquid crystals and a second liquid crystal layer overlapping the first liquid crystal layer and including a first area only with the horizontally-aligned liquid crystals and a second area only with the vertically-aligned liquid crystals.
The optical film of any one of claims 7 and 8, the first liquid crystal layer is formed to have a thickness of 0.1 to 20㎛ and the second liquid crystal layer is formed to have a thickness of 2㎛ or less.
An optical film comprising:

a first base;

a polarizing film stacked on the first base; and

a second base stacked on the polarizing film,

wherein the second base is made of triacetyl cellulose, polycarbonate, a cycloolefin polymer, and a cycloolefin copolymer and stretched at an angle of 45°or -45°from a stretching direction of the polarizing film.
A method of producing an optical film, comprising:

stretching a polarizing film and attaching a first base and a second base to both sides of the polarizing film;

forming a first alignment layer by applying and then rubbing an alignment layer composite on the second base or directly rubbing the second base, in parallel with the surface of the second base at an angle of 45°or -45°from a stretching direction of the polarizing film;

coating a liquid crystal composite onto the first alignment layer;

primarily hardening the liquid crystal composite by radiating ultraviolet rays onto the liquid crystal composite;

vertically aligning some of liquid crystal molecules contained in the liquid crystal composite by forming electric fields above and under the liquid crystal composite; and

forming a hybrid liquid crystal layer by performing secondary hardening, with the liquid crystal molecules vertically aligned.
The method of claim 11, wherein the hybrid liquid crystal layer includes a first area only with horizontally-aligned liquid crystals and a second area with vertically-aligned liquid crystals, and

the vertically aligning of some of the liquid crystal molecules forms an electric field only in the second area.
The method of claim 11, wherein hybrid liquid crystal layer includes a first liquid crystal layer only with horizontally-aligned liquid crystals and a second liquid crystal layer overlapping the first liquid crystal layer and including vertically-aligned liquid crystals.
Stereoscopic glasses comprising:

a right-eye lens; and

a left-eye lens,

wherein the right-eye lens and the left-eye lens each include:

a first base;

a polarizing film stacked on the first base;

a second base stacked on the polarizing film; and

a hybrid liquid crystal layer formed on the second base,

the hybrid liquid crystal layers each include:

an alignment layer formed on the second base at an angle of 45° or -45°from a stretching direction of the polarizing film and rubbed in parallel with the surface of the second base; and

an optical film including horizontally-aligned liquid crystals and vertically-aligned liquid crystals that are aligned in parallel with and perpendicular to the rubbing direction on the alignment layer, and

the phase difference between the hybrid liquid crystal layer of the right-eye lens and the hybrid liquid crystal layer of the left-eye lens is λ/2.
The optical film of claim 14, wherein the horizontally-aligned liquid crystals are 85 ~ 95% and the vertically-aligned liquid crystal layers are 5 ~ 15% in the hybrid liquid crystal layer.
The method of claim 14, wherein hybrid liquid crystal layer includes a first liquid crystal layer only with horizontally-aligned liquid crystals and a second liquid crystal layer overlapping the first liquid crystal layer and including vertically-aligned liquid crystals.
A stereoscopic display comprising:

a display panel displaying a right-eye image and a left-eye image;

an optical filter including a first polarizing area that overlaps the display panel and controls the polarized state of the right-eye image and a second polarizing area that controls the polarized state of the left-eye image; and

stereoscopic glasses including a right-eye lens that transmits the right-eye image and a left-eye lens that transmits the left-eye image,

wherein the right-eye lens and the left-eye lens each include:

a first base;

a polarizing film stacked on the first base;

a second base stacked on the polarizing film; and

a hybrid liquid crystal layer formed on the second base,

the hybrid liquid crystal layers each include:

an alignment layer formed on the second base at an angle of 45°or -45°from a stretching direction of the polarizing film and rubbed in parallel with the surface of the second base; and

an optical film including horizontally-aligned liquid crystals and vertically-aligned liquid crystals that are aligned in parallel with and perpendicular to the rubbing direction on the alignment layer, and

the phase difference between the hybrid liquid crystal layer of the right-eye lens and the hybrid liquid crystal layer of the left-eye lens is λ/2.