KR20120066514A - Apparatus of manufacturing patterned retarder for stereoscopic 3d display and method of fabricating patterned retarder - Google Patents

Abstract

PURPOSE: A pattern manufacturing device for a three-dimensional image display device and a manufacturing method thereof are provided to form an alignment layer having respectively different alignment directions. CONSTITUTION: A refractive layer(260) is included of an anisotropic material. A mask(250) is located on the birefringence layer. The transmission unit of the mask is crossed with a blocking unit. A plurality of strips is formed in the mask. The light is divided according to a polarizing state of incident light. An alignment layer is aligned to respectively difference alignment directions.

Description

Manufacturing apparatus and method for manufacturing pattern retarder for stereoscopic image display device {APPARATUS OF MANUFACTURING PATTERNED RETARDER FOR STEREOSCOPIC 3D DISPLAY AND METHOD OF FABRICATING PATTERNED RETARDER}

The present invention relates to a manufacturing apparatus and a manufacturing method of a pattern retarder for a stereoscopic image display apparatus, and more particularly, to an apparatus for manufacturing a pattern retarder for a stereoscopic image display apparatus for orienting an alignment layer of a pattern retarder using optical alignment; It is a manufacturing method.

3D display is simply defined as "the whole system of artificially reproducing 3D screens."

Here, the system includes both software technology that can be viewed in 3D and hardware that actually implements the content created by the software technology in 3D. The reason for including the software domain is that the 3D display hardware requires a separate software content for each stereoscopic implementation.

In addition, the virtual 3D display allows a user to literally feel a three-dimensional effect on a flat display hardware by using a binocular disparity, which appears when the human eye is about 65 mm apart in a horizontal direction, among other factors. The totality of the system. In other words, even though our eyes look at the same thing because of binocular parallax, each one sees a slightly different image (exactly, it shares some of the left and right spatial information), and when these two images are passed through the retina to the brain, the brain sees them. By fusion of each other precisely, we can feel a three-dimensional feeling, and it is a virtual 3D display that creates a virtual three-dimensional effect through a design that displays two left and right images simultaneously and sends them to each eye using a 2D display device.

In order to display two-channel images on one screen in such a virtual 3D display hardware device, for example, one channel is output one by one by changing a line in one direction of a horizontal or vertical direction. At the same time, when two channels of images are output from one display device, in the case of the autostereoscopic method, the right image enters the right eye and the left image only enters the left eye. In addition, in the case of wearing glasses, the right image is hidden from the left eye and the left image is hidden from the right eye through special glasses for each type.

Even if we print it out one by one like this, the thickness and spacing of the lines are very fine, about 0.1mm ~ 0.5mm, so our eyes don't notice the gap and the two images of each channel are displayed one by one. However, since the amount of information that enters the eye is divided into half for each channel, the resolution and the sensory brightness are reduced by about half compared to the 2D screen.

The display method of such a stereoscopic image includes a method of wearing glasses and a glasses-free method of not wearing glasses.

The method of wearing the glasses periodically repeats an anaglyph method using blue and red sunglasses on left and right, and a polarization method using polarized glasses with different left and right polarization directions and a time-divided screen. There is a liquid crystal shutter method using glasses equipped with a liquid crystal shutter to match the polarization method and the liquid crystal shutter method is mainly used. For reference, the polarization method and the liquid crystal shutter method have a difference in a method of separating left and right images, and the left and right images are separated through spatial division and time division, respectively.

In this case, the liquid crystal shutter system allows the left eye image and the right eye image displayed on the screen to be alternately transmitted to each eye by the shutter glasses. The viewer recognizes the left eye image and the right eye image alternately appearing on the screen in this way by using shutter glasses, respectively, and senses a three-dimensional effect by synthesizing two different images in the brain. However, the liquid crystal shutter type stereoscopic display device not only increases costs due to the use of shutter glasses, but also directly exposes to electromagnetic waves generated when driving the shutter glasses.

In the polarization method, a patterned retarder is attached to the image panel so that a left eye image and a right eye image having different polarization characteristics are projected through polarized glasses to feel a three-dimensional effect. Polarization method has the disadvantage of wearing glasses, but generally has the advantage of less viewing angle constraints, and easier to manufacture than other methods.

As the optical film used in the polarization type stereoscopic image display device, a pattern retarder is a tri-acetatecellulose (TAC) film and an iodine-stretched polyvinyl alcohol, as disclosed in US Pat. No. 5,327,285. PVA) is produced by coating a photoresist on a laminated film laminated with a film, exposing a predetermined portion, and then treating with a potassium hydroxide solution to lose a phase difference retardation function of a predetermined portion.

However, the manufacturing method of US Pat. No. 5,327,285 has a problem of complicated manufacturing steps according to chemical etching, and thus high manufacturing cost and low productivity.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an apparatus and a manufacturing method of a pattern retarder for a stereoscopic image display apparatus, in which an alignment film having different alignment directions is formed for each region in one optical alignment process. have.

Other objects and features of the present invention will be described in the configuration and claims of the invention described below.

In order to achieve the above object, the apparatus for manufacturing a pattern retarder for a stereoscopic image display device of the present invention comprises a birefringent layer made of an anisotropic material; And a mask positioned on the birefringence layer, the transmissive part and the blocking part alternately forming each other, and forming a plurality of strips, wherein the alignment layer is differently aligned for each region by one exposure by separating light according to the polarization state of the incident light. Orientation to have a direction.

In this case, the anisotropic material is characterized in that the refractive index is different depending on the polarization direction.

The anisotropic material is characterized in that it comprises a liquid crystal or reactive mesogen (RM).

Method of manufacturing a pattern retarder for a three-dimensional image display device of the present invention comprises the steps of forming an alignment film on the entire substrate; Placing a birefringent layer made of an anisotropic material on the alignment layer; Positioning a mask on the birefringent layer, the permeable and the shield alternate with each other to form a plurality of strips; Injecting parallel light traveling at a constant angle [theta] 0 into the birefringent layer on which the mask is located; Irradiating the entire surface of the alignment layer with light whose polarization direction is controlled for each region through the birefringence layer; And coating a photocrosslinkable liquid crystal on the alignment layer.

In this case, the birefringence layer is formed to have a thickness d by using anisotropic materials such as liquid crystal and RM.

The birefringence layer is characterized in that the alignment layer is aligned to have different alignment directions for each region by one exposure by separating the light according to the polarization state of the incident light.

The parallel light incident on the birefringence layer is characterized in that the birefringence layer is separated into S wave and P wave having a refractive angle of θ 1 and θ 2.

In this case, when the relative angle between the mask and the substrate is 0 °, the pattern period X = d * (tanθ2) (tanθ1) is obtained, wherein θ1 = asin (sin (θ0) / n1) and θ2 = asin (sin (? 0) / n2), wherein n1 represents the refractive index of the S wave and n2 (n1> n2) represents the refractive index of the P wave.

At this time, when the relative angle between the mask and the substrate is 0 ° it is characterized in that it is obtained by the pattern period Y = X * cos (θ0) / cos (θ2-θs).

In this case, the pattern period (X, Y) means the interval between the S wave and P wave separated by the birefringence layer, the interval between the first region and the second region of the alignment layer is determined by this interval. It is done.

It characterized in that it further comprises the step of photocrosslinking by irradiating the liquid crystal with light such as ultraviolet rays.

In this case, the optical cross-linked liquid crystal is characterized in that arranged in the direction having a different optical axis in each region having the different orientation direction.

As described above, the apparatus and method for manufacturing a pattern retarder for a stereoscopic image display device according to the present invention provide an effect of simplifying the manufacturing process of the pattern retarder and improving process yield and productivity.

In addition, the apparatus and method for manufacturing a pattern retarder for a stereoscopic image display device according to the present invention reduce the tack time and manufacturing cost by orienting the alignment layer of the pattern retarder in one optical alignment process. It provides an effect that the accuracy of the region-specific orientation orthogonality is improved.

In addition, the apparatus and method for manufacturing a pattern retarder for a stereoscopic image display device according to the present invention provide an effect of improving light intensity by not using a polarizer for an exposure light source.

1 is an exemplary view for explaining the structure of a three-dimensional image display device of the polarization method.
2A and 2B are perspective views sequentially illustrating a method of manufacturing a pattern retarder for a stereoscopic image display device according to a first embodiment of the present invention.
3 is a perspective view illustrating a manufacturing apparatus and a manufacturing method of a pattern retarder for a stereoscopic image display device according to a second embodiment of the present invention.
4 is a plan view schematically illustrating a pattern retarder manufactured by the manufacturing method illustrated in FIG. 3.
FIG. 5 is a cross-sectional view schematically illustrating a pattern retarder manufactured by the manufacturing method illustrated in FIG. 3.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the apparatus and method for manufacturing a pattern retarder for a stereoscopic image display device according to the present invention.

1 is an exemplary view for explaining a structure of a polarization type stereoscopic image display device.

Referring to FIG. 1, a polarization method uses a polarization phenomenon to spatially separate left and right images by arranging a patterned retarder 120 on the front surface of the image panel 100.

The pattern retarder 120 of the polarization type stereoscopic image display device refers to a film in which a predetermined pattern is formed according to a position so that left and right images can implement a polarization state having a direction perpendicular to each other.

For example, the pattern retarder 120 includes a substrate made of glass, on which alignment layers and birefringence layers are formed. The alignment layer and the birefringence layer have a regular pattern of the first region 121 and a regular pattern of the second region 122. The first region 121 and the second region 122 are formed of strips that alternate with each other in correspondence to the image line of the image panel 100, and each region 121 and 122 has the same orientation. Has a direction. In this case, the first region 121 and the second region 122 may have different alignment directions, for example, may have about 45 ° and 135 °, respectively.

The image panel 100 may include a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), an electroluminescent display (Electroluminescent Display); EL). When the image panel 100 is configured as a liquid crystal display, a polarizing film 101 having, for example, a horizontal light absorption axis is disposed between the image panel 100 and the pattern retarder 120. .

Currently widely used is a method of disposing the left and right images by line. That is, as shown, the left image L is disposed on the odd lines in the vertical direction and the right image R is disposed on the even lines. When the left and right images (L, R) are displayed on the image panel 100, the viewer can enjoy 3D images by separating the left and right images (L, R) by wearing the glasses 130 for viewing 3D images. .

That is, when a viewer views the polarization type stereoscopic image display device, a quarter wave plate (not shown) of the left eye lens 135L and the right eye lens 135R of the glasses 130 for viewing the stereoscopic image are provided. The quarter wave plate (not shown) of the X) is formed of, for example, a +1/4 wave plate and a -1/4 wave plate, respectively, through the pattern retarder 120 and finally in different directions. Polarized left and right images, for example, left-handed circularly polarized images and right-handed circularly polarized images are transmitted separately.

In this case, the circular polarization method is shown as the polarization method, for example, but the present invention is not limited thereto, and the linear polarization method may be used as the polarization method.

Hereinafter, the pattern retarder of the polarization type stereoscopic image display device will be described in detail with reference to the accompanying drawings.

2A and 2B are perspective views sequentially illustrating a method of manufacturing a pattern retarder for a stereoscopic image display device according to a first embodiment of the present invention.

As shown in FIG. 2A, after the alignment layer 123 is formed on the entire surface of a predetermined substrate 110, the entire surface of the alignment layer 123 is primarily formed by using a light source 140 such as ultraviolet (UV) light. Orientation treatment.

In this case, for example, as the ultraviolet rays polarized through the first polarization filter 141 are irradiated onto the entire surface of the alignment layer 123, the alignment layer 123 has a first alignment direction ①.

As described above, in the first alignment step, all the regions of the alignment layer 123 are photo-aligned in the same first alignment direction ① by irradiating polarized ultraviolet rays without using a photo mask. The entire alignment layer 123 has a single alignment pattern.

In this case, the present invention is characterized by using an optical alignment film that is surface-oriented treated by the reversible reaction instead of using the optical alignment film that is subjected to the orientation irreversible reaction by light. Here, reversible means that the orientation direction formed in the first photoalignment can be changed in another direction through the subsequent photoalignment.

In general, a photoalignment film that is reversibly reacted by light and is oriented is limited to a limited photoreactive material. Such reversible reactions are found in materials such as photoreactive polymers having characteristic groups that cause cis-trans isomerization reactions, or materials such as photoreactive polymers having characteristic groups that fries rearrangement by light. can see. There are many examples of such characteristic groups in addition to those described above, and in the case of irreversible characteristic groups such as those causing photo dimerization reactions, the characteristic groups are combined with the reversibly reactive characteristic groups to form a photoreactive material. Sometimes they are reversible.

In the case of photo-alignment, the orientation direction is generally determined by the polarization direction of the irradiated light. Therefore, if the light having different polarization axes is repeatedly irradiated to the same point of the photo-alignment film having reversible characteristics, the orientation direction can be changed at least twice. .

After the entire surface exposure, as shown in FIG. 2B, the mask 150 having the transmissive part 151 and the blocking part 152 is positioned on the first alignment-oriented alignment layer 123, and the blocking part ( The second region 122 of the alignment layer 123 which is not masked by 152 is secondarily aligned.

In this case, for example, as the ultraviolet rays polarized through the second polarization filter 142 are irradiated only to the exposed second region 122 of the alignment layer 123, the second region 122 of the alignment layer 123 may be formed. It has two orientation directions (②).

The secondary alignment requires a larger exposure energy than the previous primary alignment in order to orient the molecules having the first alignment direction (①) back to the second alignment direction (②), which is another alignment direction.

As described above, in the second alignment step, the mask 150 may change light in which the polarization axis is changed in order to change the alignment direction formed in the first alignment step with respect to a predetermined area, for example, the second area 122, to another. ) To investigate again.

Through this process, the alignment direction of the second region 122 through which the light passing through the mask 150 reaches is changed, and the first region 121 where the light does not reach maintains the original alignment direction. Therefore, the alignment layer 123 forms an alignment layer in which the first region 121 and the second region 122 having different alignment directions are mixed.

Subsequently, after the photocrosslinkable liquid crystal is coated on the alignment layers having two different alignment directions, and then crosslinked by irradiating the liquid crystal with light such as ultraviolet rays, the liquid crystals may have different optical axes in respective regions having different alignment directions. A pattern retarder arranged in the direction having the different optical phase modulation characteristics for each region is manufactured.

In this case, any one or more of the liquid crystals having nematic properties, discotic properties, cholesteric properties, and the like may be used. The liquid crystal may be diluted in a solvent and used for coating, and the solvent is evaporated through a drying process.

Meanwhile, in the method of manufacturing the pattern retarder according to the first embodiment of the present invention, the tack time increases as two exposure processes are performed to change the alignment direction, and the orthogonality of the alignment direction is misaligned when the light source is misaligned. This has the disadvantage of deteriorating.

Therefore, by using an anisotropic material that feels the refractive index differently according to the polarization direction by separating the light according to the polarization, it is possible to orient the alignment layer of the pattern retarder to have a different orientation direction for each region in one exposure. The second embodiment of the invention will be described in detail.

3 is a perspective view illustrating a manufacturing apparatus and a manufacturing method of a pattern retarder for a stereoscopic image display device according to a second embodiment of the present invention.

As shown in FIG. 3, the apparatus for manufacturing a pattern retarder for a stereoscopic image display device according to a second exemplary embodiment of the present invention includes a birefringent layer 260 made of an anisotropic material having different refractive indices according to a polarization direction, and a birefringence layer 260. The transmissive part 251 and the blocking part 252 are formed of a mask 250 that alternates with each other to form a plurality of strips.

In this case, the birefringence layer 260 serves to separate light according to the polarization direction by using a characteristic having a refractive angle different according to the polarization direction, which is an intrinsic property of the anisotropic material.

The proposed birefringent medium can be formed by using anisotropic materials, and can be made by using commercially available liquid crystal or reactive mesogen (RM). The birefringence medium may be implemented by attaching chromium (Cr) or a shadow mask, which is a general mask material.

For reference, birefringence is the optical property of a crystal that causes one incident light to split into two rays of light in different directions, one of which is called an extraordinary ray. Refract even if light enters vertically.

However, if light enters parallel to the axis of symmetry of the crystal known as the crystal axis, the light does not split. This direction is called the optical axis and is represented by an imaginary line throughout the crystal parallel to the crystal axis.

All transparent crystals except the equiaxed system show birefringence and the refractive index is constant regardless of the direction in which the light is ordinary ray among the two lights in birefringence. This changes.

In the method of the second embodiment of the present invention, for example, when the parallel light traveling at a constant angle θ0 is incident on the birefringent layer 260 in which the mask 250 is patterned, the polarization directions (S wave and P wave) As the refractive index is felt differently, the advancing directions of the S wave and the P wave can be spatially separated.

In this case, when the S wave and the P wave are incident on the birefringent layer 260, the S wave and the P wave are refracted to θ 1 and θ 2, respectively, and proceed in different directions.

By irradiating the separated S-waves and P-waves to the entire surface of the substrate 210, different alignment directions may be formed for the regions 221 and 222 in the alignment layer 223 of the pattern retarder with a single exposure.

As a result, for example, the first region 221 of the alignment layer 223 has a first alignment direction while the second region 222 of the alignment layer 223 has a second alignment direction.

In this case, the substrate 210 may be any substrate as the substrate for the polymer alignment layer 223, but is not limited thereto. For example, triacetyl cellulose, polyethylene terephthalate, polymethyl methacrylate, polycarbonate, and polyethylene And cycloolefin polymers such as norbornene derivatives, polyvinyl alcohol, diacetyl cellulose substrates or glass substrates.

In addition, the alignment layer 223 may be any resin generally used in forming a polymer alignment layer as a polymer resin to which alignment is imparted by light irradiation. Although not limited thereto, for example, it may be formed of at least one polymer resin selected from the group consisting of polyamide, polyimide, polyvinyl alcohol, polyamic acid, poly cinnamate.

At this time, when the relative angle between the mask 250 and the substrate 210 is 0 degrees, the pattern period X has a relationship as shown in Equation 1 below.

Equation 1 X = d * (tanθ2) (tanθ1)

Here, θ1 = asin (sin (θ0) / n1), θ2 = asin (sin (θ0) / n2), and d represents the thickness of the birefringence layer 260.

In addition, n1 represents the refractive index of the S wave, and n2 (n1> n2) represents the refractive index of the P wave.

The pattern period X denotes an interval between S and P waves separated by the birefringent layer 260, and the first and second regions 221 and 222 of the alignment layer 223 are separated by the intervals. The interval between them is determined.

The pattern period X may be changed by adjusting a relative angle between the mask 250 and the substrate 210. When the angle is θ s, the pattern period Y is given by Equation 2 below.

Equation 2 Y = X * cos (θ0) / cos (θ2-θs)

As a result of the optical alignment as described above, the alignment layer 223 forms an alignment layer in which the first region 221 and the second region 222 having different alignment directions are mixed.

Thereafter, a photocrosslinkable liquid crystal is coated on the alignment layers having two different alignment directions, and then irradiated with light such as ultraviolet rays to the liquid crystal to photocrosslink the liquid crystal in each of the regions 221 and 222 having different alignment directions. Pattern retarders arranged in directions having different optical axes and exhibiting different optical phase modulation characteristics for each region 221 and 222 are manufactured.

In this case, any one or more of the liquid crystals having nematic properties, discotic properties, cholesteric properties, or the like may be used, or RMs may be used. The liquid crystal may be diluted in a solvent and used for coating, and the solvent is evaporated through a drying process.

The photocrosslinked liquid crystal is coated in an isotropic material state on the alignment layer, and then is phase-transformed into the liquid crystal by a polymerization reaction in a process such as drying and curing, and the alignment direction is fixed in a specific direction.

According to the second embodiment of the present invention, by aligning the alignment layer of the pattern retarder in one optical alignment process, the tack time and manufacturing cost are reduced, and the accuracy of the alignment orthogonality for each region is improved.

In addition, the light intensity is improved by not using a polarizer for the exposure light source.

4 is a plan view schematically illustrating the pattern retarder manufactured by the manufacturing method illustrated in FIG. 3, and FIG. 5 is a cross-sectional view schematically illustrating the pattern retarder manufactured by the manufacturing method illustrated in FIG. 3.

As shown in the figure, the pattern retarder 220 includes a substrate 210 made of glass, on which an alignment layer 215 and a birefringence layer 216 are formed. The alignment layer 215 and the birefringence layer 216 have a regular pattern of the first region 221 and a regular pattern of the second region 222. The first region 221 and the second region 222 are formed of alternating strips, and each region 221, 222 has the same alignment direction. In this case, the first region 221 and the second region 222 may have different orientation directions, and may have, for example, about 45 ° and 135 °, respectively.

Many details are set forth in the foregoing description but should be construed as illustrative of preferred embodiments rather than to limit the scope of the invention. Therefore, the invention should not be defined by the described embodiments, but should be defined by the claims and their equivalents.

100: image panel 120,220: pattern retarder
121,221: first area 122,222: second area
123,223 alignment film 250 mask
260: birefringence layer

Claims (12)

A birefringent layer made of an anisotropic material; And
A mask disposed on the birefringence layer, the transmissive part and the blocking part alternate with each other to form a plurality of strips, wherein the alignment layer is different from one region to another by one exposure by separating light according to the polarization state of the incident light; Apparatus for manufacturing a pattern retarder for a stereoscopic image display device, characterized in that the orientation to have. The apparatus of claim 1, wherein the anisotropic material feels a refractive index differently according to a polarization direction. The apparatus of claim 1, wherein the anisotropic material comprises liquid crystal or reactive mesogen (RM). Forming an alignment layer on the entire surface of the substrate;
Placing a birefringent layer made of an anisotropic material on the alignment layer;
Positioning a mask on the birefringent layer, the permeable and the shield alternate with each other to form a plurality of strips;
Injecting parallel light traveling at a constant angle [theta] 0 into the birefringent layer on which the mask is located;
Irradiating the entire surface of the alignment layer with light whose polarization direction is controlled for each region through the birefringence layer; And
A method of manufacturing a pattern retarder for a stereoscopic image display device comprising coating a photocrosslinkable liquid crystal on the alignment layer. The method of claim 4, wherein the birefringence layer is formed to have a thickness d by using anisotropic materials such as liquid crystal and RM. 5. The pattern retarder of claim 4, wherein the birefringence layer orientates the alignment layer to have different alignment directions for each region by one exposure by separating the light according to the polarization state of the incident light. Manufacturing method. 6. The method of claim 5, wherein the parallel light incident on the birefringent layer is separated into S and P waves having refractive angles of θ1 and θ2 by the birefringent layer. The method of claim 7, wherein the relative period between the mask and the substrate is 0 ° to obtain a pattern period X = d * (tanθ 2) (tanθ 1), wherein θ 1 = asin (sin (θ 0) / n 1) and θ 2. = asin (sin (θ0) / n2), wherein n1 represents the refractive index of S-wave and n2 (n1> n2) represents the refractive index of P-wave. . 9. The patterned rita for a stereoscopic image display device according to claim 8, wherein a pattern period Y = X * cos (θ0) / cos (θ2-θs) is obtained when the relative angle between the mask and the substrate is 0 °. More manufacturing methods. The method of claim 9, wherein the pattern period (X, Y) means the interval between the S wave and P wave separated by the birefringence layer, the interval between the first region and the second region of the alignment layer A method for manufacturing a pattern retarder for a stereoscopic image display device, characterized in that determined. 5. The method of claim 4, further comprising irradiating the liquid crystal with light such as ultraviolet light to crosslink the liquid crystal. 12. The method of claim 11, wherein the optically crosslinked liquid crystals are arranged in directions having different optical axes in the respective regions having different alignment directions.

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