WO2005012990A1

WO2005012990A1 - Patterned optical retarder and method for manufacturing the same

Info

Publication number: WO2005012990A1
Application number: PCT/KR2004/001907
Authority: WO
Inventors: Taemin Kim
Original assignee: Advue Co., Ltd.
Priority date: 2003-08-02
Filing date: 2004-07-29
Publication date: 2005-02-10

Abstract

Provided is a method for manufacturing a patterned optical retarder including a) forming an alignment layer on a substrate, b) surface aligning an overall surface of the alignment layer (the first aligning step), c) surface aligning only a portion that is not masked by placing an optical mask having a predetermined pattern on the first aligning alignment layer, to form a predetermined alignment pattern on the alignment layer (the second aligning step), d) coating liquid crystal on the second aligned alignment layer where a predetermined alignment pattern is formed, and e) forming a polymer liquid crystal film where a predetermined optical axis pattern is formed by irradiating light to the coated liquid crystal to be photocrosslinked. Thus, a mask process including an photomask process to form a pattern is reduced by half so that materials and process costs can be reduced and further productivity of the optical retarder can be remarkably increased. Also, an area between the patterns (pattern boundary areas) can be divided more accurately.

Description

Description PATTERNED OPTICAL RETARDER AND METHOD FOR MANUFACTURING THE SAME Technical Field

[1] The present invention relates to a patterned optical retarder performing an optical phase modulation function and a method for manufacturing the same, and more particularly, to a patterned optical retarder including a patterned polymer liquid crystal film and a method for manufacturing the same. Background Art

[2] In general, a 3D imaging technique can be classified into a stereoscopic technique and an autostereoscopic technique. The stereoscopic technique uses parallax displays of the left and right eyes showing a great 3D effect and be classified into glasses type and non-glasses type.

[3] In the 3D imaging technique, an optical retarder using liquid crystal is widely used. A typical optical retarder using liquid crystal includes a substrate, an alignment layer coated on the substrate and making the surface aligned, and liquid crystal coated on the alignment layer and then aligned. The liquid crystal that is photosensitive is surface- aligned on the alignment layer, crosslinked to be solidified by irradiation of light such as an ultraviolet ray into polymerized liquid crystal film. An optical axis formed along the aligned direction of the liquid crystal based on the direction of the surface alignment of the layer has an optical phase modulation function.

[4] In an alignment technique, the alignment layer is rubbed with a soft textile roll to have an alignment direction according to a rubbing direction on the surface, or the surface alignment direction is made by irradiating polarized an ultraviolet ray to the alignment layer.

[5] According to a conventional method for manufacturing a patterned optical retarder with an alignment layer formed using the above technique, a substrate is prepared (Step p-a); an alignment layer is formed on the substrate (Step p-b); a pattern is formed on the alignment layer in a photolithography method and the alignment layer is aligned by rubbing (Step p-c); photoresist is removed by etching, a pattern is formed again in a photolithography method, and non-aligned portion in Step p-c is aligned by rubbing (Step p-d); liquid crystal is coated on the alignment layer where the pattern is formed (Step p-e); and the coated liquid crystal is photocrosslinked by irradiating light thereon to make a polymerized liquid crystal film (Step p-f). [6] The above manufacturing method adopting the rubbing technique is very complicated since photolithography is used in order to make the patterns. Also, since costs of materials and a defect ratio are high so that productivity of the patterned optical retarder is deteriorated.

[7] To overcome the above drawbacks of the rubbing alignment technique, a photo- alignment technique that is non-contact alignment technique has been developed. Referring to FIG. 1, a method for manufacturing an optical retarder including the step of forming an alignment layer according to the conventional photo- alignment technique is described below.

[8] According to a conventional method for manufacturing an optical retarder using the photo- alignment method, a substrate is prepared (Step p-g); an alignment layer is formed on the substrate (Step p-h); light is irradiated to a photomask 1 having a predetermined pattern placed on the alignment layer and only the portion where the light passes through the photomask 1 is aligned (Step p-i); light is irradiated to a photomask 2 having a predetermined pattern placed on the alignment layer that is partially surface-aligned in Step p-I and only a portion where the light passes through the photomask 2 is surface- aligned (Step p-j); liquid crystal is coated on the surface alignment processed alignment layer (Step p-k); and the coated liquid crystal is photocrosslinked by radiating light thereon to make a polymerized liquid crystal film (Step P-D.

[9] This technique is a 2-mask process (a process in which mask is used two times) which is characterized in that the photomask 1 is placed on the substrate where the alignment layer is formed and the first optical alignment is formed on the substrate, and the photomask 2 is placed thereon and the second optical alignment is formed thereon.

[10] This method of the optical alignment technique that is a non-contact alignment technique is advantageous in that dust inlet is fundamentally prevented and the productivity is much higher in comparison with the rubbing-alignment method.

[11] However, the above method requires two different photomasks to form the respective patterns. If the dimensional accuracy of the aligned photomask is low when the photomask is aligned to form each pattern, an area in which alignment is not well defined is generated between the patterns so that quality of an optical retarder may be deteriorated. When the alignment positions of the masks is inappropriate, the alignment in a boundary region between the photomasks may be not harmonized. FIG. 2 shows a state in which non-aligned portion 63c where photo alignment is not made at all in the first and second alignments and a portion 60d where the first and second optical alignments overlap each other when the alignment of the positions of the masks is inappropriate.

[12] Also, since the alignment of the photomasks must be aligned at a high dimensional accuracy, tact time is prolonged in the alignment process but also an expensive equipment such as a mask aligner is needed. Disclosure of Invention Technical Problem

[13] To solve the above andor other problems, the present invention provides a patterned optical retarder in which use of a mask is minimized, and a method for manufacturing the same.

[14] The present invention provides a patterned optical retarder which can minimize eye fatigue by improving a 3D sensitivity and clarity by changing a polarization method for a 3D image liquid crystal display device and a method for manufacturing the same. The above changed polarization method is obtained by effectively depositing at least one polymerized liquid crystal film on the optical retarder.

[15] The present invention provides a 3D image display device and an optical retarder parallax barrier including the optical retarder. Technical Solution

[16] According to the aspect of the present invention, a method for manufacturing a patterned optical retarder comprises a) forming an alignment layer on a substrate, b) surface aligning an overall surface of the alignment layer (the first aligning step), c) surface aligning only a portion that is not masked by placing an photomask having predetermined patterns on the first aligned layer, to form predetermined alignment patterns on the alignment layer (the second aligning step), d) coating liquid crystal on the second aligned layer where the predetermined alignment patterns is formed, and e) forming a polymerized liquid crystal film where a predetermined optical axis pattern is formed by irradiating light to the coated liquid crystal to be photocrosslinked.

[17] The first aligning step adopts at least one method selected from the group consisting of a method for irradiating a polarized ultraviolet ray to the aligned layer, a method of irradiating an ion beam or plasma beam at a predetermined angle, and a rubbing method. The second aligning step adopts at least one method selected from the group consisting of a method of irradiating a polarized ultraviolet ray to the alignment layer and a method for radiating an ion beam or plasma beam at a predetermined angle.

[18] The polymerized liquid crystal film has a phase modulation feature that λ/(n+l), where n is an integer. An optical axis of the polymerized liquid crystal film is different by an optical axis pattern. The optical axis patterns have at least two different optical axes.

[19] The liquid crystal coated in the step d) is at least one of liquid crystal selected from a group consisting of nematic liquid crystal, discotic liquid crystal, and cholesteric liquid crystal.

[20] The method for manufacturing the optical retarder further comprises b') surface aligning an entire surface of the polymerize liquid crystal film having a predetermined optical axis patterns (a third aligning step), c') placing a mask having a predetermined pattern on the alignment layer after the third aligning step and surface aligning an unmasked portion only to form a predetermined alignment pattern on the alignment layer (a fourth aligning step), d') coating liquid crystal on the fourth aligned layer where a predetermined alignment pattern is formed, and e') irradiating light to the coated liquid crystal for photocros slinking so that a polymerized liquid crystal film with a predetermined optical axis pattern is formed. The method may further comprises performing the steps of b'), c'), d'), and e') to the polymerized liquid crystal film at least one more time.

[21] The above alignment layer is preferably made of a reversible optical alignment material.

[22] The first aligning step uses a polarized ultraviolet ray, and the second aligning step is performed by a method of irradiating an ion beam or plasma beam at a predetermined angle.

[23] According to another aspect of the present invention, an optical retarder is manufactured by a method defined in any of claims 1 through 12.

[24] According to yet another aspect of the present invention, a 3D image display device to be attached to a display device comprises the optical retarder and a polarization film. An optical retarder parallax barrier comprises a liquid crystal display device having the optical retarder in a liquid crystal cell, and a linear polarization plate. Advantageous Effects

[25] According to the manufacturing method of a patterned optical retarder according to the present invention, the mask processes including the photomask processes to form patterns are reduced by half compared with the conventional technology so that materials and process costs can be reduced and further productivity of the optical retarder can be remarkably increased. Also, since an area between the patterns (the boundary area between patterns) can be divided more accurately compared with the conventional technology, the overlap of aligned portion or the unaligned portion can be prevented. Description of Drawings

[26] FIG. 1 is a view showing a state of aligning an alignment layer in the conventional optical alignment method;

[27] FIG. 2 is a view to show a problem when the alignment layer is aligned in the conventional optical alignment method, in which a portion of the alignment layer where the problem occurs is shown in an enlarged circle;

[28] FIG. 3 is a view showing a state of aligning the overall alignment layer in an optical alignment method according to an embodiment of the present invention; and

[29] FIG. 4 is a view showing a state of forming an alignment layer having a predetermined alignment pattern in the optical alignment method according to an embodiment of the present invention. Best Mode

[30] An optical retarder according to an embodiment of the present invention is manufactured by a) forming an alignment layer 60 on a substrate 100; b) surface aligning an overall surface of the alignment layer 60 (a first aligning step); c) surface alignment processing only a portion that is not masked by placing an optical mask 50 having a predetermined pattern on the first aligned layer 60, to form a predetermined alignment pattern on the alignment layer 60 (a second aligning step); d) coating liquid crystal on the second aligned layer 60 where a predetermined alignment pattern is formed; and e) forming a polymerized liquid crystal film where a predetermined optical axis pattern is formed by irradiating light to the coated liquid crystal to be photocrosslinked.

[31] As the first alignment method to surface alignment process the overall surface of the alignment layer 60, one or more method selected from the group consisting of a method for irradiating a polarized ultraviolet ray to the alignment layer 60, a method for irradiating an ion beam or plasma beam at a predetermined angle, and a rubbing method can be adopted.

[32] An optical aligning method which is characterized in that a polarized ultraviolet ray is irradiated to the alignment layer 60 is firstly described. The polarized ultraviolet ray is made by passing through a polarization unit 4Q

[33] In the conventional optical alignment layer, the surface of the alignment layer 60 is permanently surface processed by only one optical aligning step so that the direction of alignment of liquid crystal coated on the optical alignment layer 60 is determined. The determination is made as the surface alignment is processed in a manner that organic materials (such as photosensitive polymers) constituting the optical alignment layer 60 perform irreversible reactions by light, such as photo-dimerization and photo- dissociation.

[34] The present invention is characterized in that an optical alignment layer that is surface aligned by reversible reaction instead of using an optical alignment layer that is aligned by irreversible reaction. Here, being reversible means that the direction of alignment formed from the initial optical alignment can be changed to a different direction by optical alignment, irradiation of an ion beam or plasma beam, or rubbing at the later stage.

[35] The optical alignment layer that is generally aligned by reversible reaction by light can be obtained from only restrictive photosensitive materials. The reversible reaction can be seen from a material such as photosensitive polymer having a characteristic group generating cis-trans isomerization by light or photosensitive polymer having a characteristic group performing a fries -rearrangement. There are numerous examples of a characteristic group in addition to the above characteristic groups. An irreversible characteristic group generating a photo-dimerization reaction may have a reversible characteristic group when being combined with the characteristic groups that can reversibly react and constituting a photosensitive material.

[36] The determination of the alignment direction during optical alignment is typically determined according to the direction (axis) of polarization of light being irradiated. Accordingly, the alignment direction can be changed at least two times by repeating the irradiation of light having different polarization axes at the same position on the optical alignment layer 60 having a property of being reversible. Thus, when optical alignment is performed in the first and second aligning steps of the present invention, polarized light is used each time. Preferably, a polarized ultraviolet ray is used as the light.

[37] Since in most cases the reversible optical alignment layer has an inferior liquid crystal alignment force compared to the irreversible optical aligned layer, there is a limit in selecting a material forming the reversible optical alignment layer that can be actually used. However, the reversible optical alignment layer 60 can be manufactured with a greatly reduced number of steps, compared to the conventional method, under the following manufacturing process.

[38] The optical alignment layer 60 of the present invention can be manufactured through the following steps.

[39] Firstly, in the first aligning step, it is characteristic that, by irradiating a polarized ultraviolet ray without using the optical mask 50, the whole area is optically aligned in the same alignment direction. Thus, the entire alignment layer has a uniform alignment pattern 60e.

[40] Next, in the second aligning step, it is characteristic that the photomask 50 having a predetermined pattern is used to change the alignment direction formed in the first aligning step to a different alignment direction with respect to a predetermined area. To form a predetermined area having a changed alignment direction, the photomask 50 is placed and light having a changed polarization axis direction is irradiated again. After this step, the alignment direction of a portion (an unmasked portion), at which the light passing through the photomask 50 arrives, changes while the alignment direction of a portion (a masked portion), at which the light does not arrive, remains unchanged, that is, the original alignment direction is maintained. That is, the portion of the aligned layer where light arrives has a changed alignment 60f and the portion of the aligned layer where light does not arrive maintains the original alignment 60e. Thus, areas having different alignment directions are present in the alignment layer 60 so that the alignment layer 60 of the present invention has a predetermined alignment pattern. FIG. 4 shows the alignment layer 60 in which two types of alignment patterns 60e and 60f are alternately formed.

[41] As a result, according to the above steps, with only one step using the photomask 50, the alignment layer 60 having two different aligning directions, that is, two different alignment patterns, can be formed.

[42] When liquid crystal is coated on the alignment layer 60 having two different aligning directions, that is, two different alignment patterns, the liquid crystal is arranged in directions having different optical axes on the areas having different aligning directions. Thus, an optical retarder exhibiting a different optical phase modulation property for each area can be obtained.

[43] When the alignment layer 60 is aligned, instead of the optical alignment, a rubbing alignment method with the optical alignment can be used. It is well known that, when a layer formed of an organic or inorganic material is rubbed at an appropriate frictional strength and liquid crystal is coated thereon, the liquid crystal tends to be aligned in the rubbing direction. Also, to optimize a liquid crystal alignment force, an organic material, such as polymide, designed to a particular chemical structure is widely used as an alignment layer for rubbing. In addition, an alignment layer formed of a general polymer can have a surface state in which liquid crystal can be aligned as a polymer chain is physically deformed by a force (stress) applied to the polymer during rubbing. [44] The polymer alignment layer can be optical alignment processed by being photo- dissociated by light of a strong intensity. Also, it is possible to give a property of being optically aligned reversibly or irreversibly to the materials that can be used as the alignment layer by adopting a photosensitive side chain. Thus, the alignment layer 60 where two different aligned areas are formed can be formed by coating the alignment layer 60 on the substrate 100 and rubbing-alignment processing the same in one direction, and then, optical aligning only a portion where the photomask 50 is placed. By coating liquid crystal on the alignment layer 60, a polymer liquid crystal film layer having a different optical axis for each area can be formed. In this case, since only one time of the photomask process is needed, the manufacturing process is effective.

[45] Aligning methods by an ion beam or plasma beam can be used together or separately.

[46] The ion beam or plasma beam tends to proceed straight when being emitted in a vacuous state and collides with the substrate 100 to modify the outermost surface of the substrate 10Q When the ion beam or plasma beam is irradiated at an angle with respect to a normal to the substrate 100, it has a liquid crystal aligning force. Also, the ion beam or plasma beam is known to be capable of aligning the substrate 100 formed of an organic material or an inorganic material.

[47] An ion beam or plasma beam equipment used in the present invention includes an ion or plasma source part, a discharge part discharging an ion or plasma beam, and a beam collimating part collimating the beam irradiated to a target. The source may be one of a group consisting of Ar, He, Ne, He, Xe, kr, N , O , Co, and SF . 2 2 ₃

[48] When the ion beam or plasma beam is irradiated to the alignment layer 60 formed of an organic material, in particular, an organic material formed of polymer, various chemical changes are caused to a polymer chain or a branch molecular structure so that the surface is modified. This modification is characteristically different from the physical deformation by photosensitiveness or rubbing of the optical alignment.

[49] Thus, it is possible to change the aligning direction of the surface processed by the optical alignment or rubbing alignment in the first aligning step by the ion beam or plasma beam alignment process. Also, when the surface is aligned using the ion beam or plasma beam in the first aligning step, the alignment direction can be changed by irradiating an ion beam or plasma beam of higher intensity than that in the first aligning step, at an angle in a different direction. Furthermore, the aligned surface by the ion beam or plasma beam in the first aligning can be aligned again using an optical alignment method in the second aligning step. This means that photosensitive radicals remaining on the surface after the ion beam or plasma beam irradiation can be optically realigned by an additional light irradiation.

[50] In the above second aligning step, a mask having a predetermined pattern is used to change the alignment direction formed in the first aligning step to a different alignment direction. To form a predetermined area in which the alignment direction is changed, a predetermined mask is provided in place and an ion beam or plasma beam is irradiated again. After this step, the alignment direction of a portion (an unmasked portion) at which the beam passing through the mask arrives changes, while a portion (a masked portion) at which the beam passing through the mask does not arrive maintains the original alignment direction. Thus, areas having different alignment directions are mixed in the alignment layer 60 so that the alignment layer 60 has a predetermined alignment pattern.

[51] However, when the first alignment is performed by irradiating the ion beam or plasma beam to a surface formed of an inorganic material, it is not possible to change the alignment direction using the optical alignment method during the second alignment. Also, it is not preferable to perform a non-contact type alignment process such as optical alignment for the first alignment and then a contact type alignment process such as rubbing for the second alignment because such a process combination can not be considered to be improved.

[52] The above-described alignment methods that can be combined are listed below. [53] [Table 1] [54]

[55] That is, the first alignment can be performed by using at least one selected from a group consisting of the optical alignment method, the rubbing method, and the ion beam or plasma beam alignment method. The second alignment can be performed by using at least one selected from a group consisting of the optical alignment method and the ion beam or plasma beam alignment method. Preferably, the first alignment is performed by the optical alignment method and the second alignment is performed by the ion beam or plasma beam alignment method.

[56] Photocrosslinked liquid crystal can be coated on the surface of the aligned substrate 100 to have the alignment layer 60 having a predetermined alignment pattern. As the liquid crystal, at least one of liquid crystals having a nematic feature, a discotic feature, or a cholesteric feature may be used. The liquid crystal may be used for coating by being diluted by a solution. The solution is vaporized through a drying process. As a coating method, a spin coating, a cole coating, dispensing coating, or gravure coating may be used. The selection of the coating method is usually determined by the type of the solution and a dilution ratio.

[57] When light such as an ultraviolet ray irradiated to the photocrosslinking liquid crystal arranged on the surface of the aligned substrate to photocros slink the liquid crystal, a liquid crystal polymer film having a predetermined optical axis and an optical phase modulation property is obtained. The above polymer film becomes a liquid crystal film having a different optical axis according to each area, that is, a predetermined optical axis pattern.

[58] The optical phase modulation property varies according to the thickness of the coated liquid crystal or the index of refraction anisotropy of the liquid crystal. A liquid crystal layer formed as above may have a thickness not more than several micrometers.

[59] When there is a need to modify the surface of the polymer liquid crystal film, the polymer liquid crystal film is located in a vacuum room and the beam is irradiated. The intensity of the beam may be different from the beam irradiated to the substrate. Next, the photocrosslinking liquid crystal is coated again on the surface modified polymer liquid crystal film and an ultraviolet ray is irradiated thereon to photocros slink the liquid crystal so that a polymerized liquid crystal film can be formed.

[60] When the step of forming the polymerized liquid crystal film is partially or entirely repeated, an optical retarder formed into a dual layer and having two or more polymer liquid crystal film layers can be manufactured.

[61] The dual layered optical retarder is manufactured by adding the following steps to the above-described method for manufacturing an optical retarder. The added steps are b') surface aligning an entire surface of the polymer liquid crystal film having a predetermined optical axis pattern (the third aligning step); c') placing a mask having a predetermined pattern on the third aligned layer and surface alignment processing an unmasked portion only to form a predetermined alignment pattern on the alignment layer (the fourth aligning step); d') coating liquid crystal on the fourth aligning layer where a predetermined alignment pattern is formed; and e') irradiating light to the coated liquid crystal so as to be photocrosslinked so that a polymer liquid crystal film where a predetermined optical axis pattern is formed.

[62] By performing the steps b'), c'), d'), and e') at least one time with respect to the polymer liquid crystal film where a predetermined optical axis pattern, a multilayered optical retarder having three or more polymer liquid crystal film layers can be manufactured.

[63] In general, a patterned optical retarder having a predetermined optical axis pattern is a useful part for making a 3D display which can realize a 3D image with a flat panel display (in particular, an LCD). When a multilayered optical retarder is adopted in making the above display (when the optical retarder is formed in a multilayer), it has the following advantages compared to the optical retarder of a single layer.

[64] In diffraction of polarized light by a phase delay, when a retarder having a 1/2 wavelength feature is formed of a single layer, uniform diffraction of red (R), green (G), and blue (B) three colors is difficult compared to a case in which the retarder is formed of a multiple of layers. Thus, when the retarder is applied to a flat panel display, a minute variation in color is caused so that quality is deteriorated. This is quite important when a glasses type 3D image is displayed by dividing pixels or pixel groups of a display by polarization of 90 ° . When the 1/2 wavelength retarder is formed of a single layer, compared to the multilayered 1/4 wavelength retarder, a sensitivity of the depth of a 3D image is lowered due to mixing phenomenon of a left and right image so that a sensitivity of reality is remarkably deteriorated.

[65] Thus, according to an object that the optical retarder tends to achieve, the polymer liquid crystal film having a predetermined phase modulation feature (λ/(n+l), where n is an integer) is formed of multiple layers so as to maximize a function thereof. An optical retarder having a polymer liquid crystal film formed of multiple layers can be used in various applied fields.

[66] It is advantageous that, when being applied to an LCD, the polymer liquid crystal film can be selectively formed on either an outer surface or an inner surface of a liquid crystal cell as necessary. Also, when photocrosslinking discotic liquid crystal is arrange or a polymer liquid crystal film having a predetermined linear inclination angle is configured as a single layer or multilayers, the polymer liquid crystal film can be used as a wide- view angle compensation film of an LCD using a horizontal alignment mode. When a polymer liquid crystal film on which photocrosslinking discotic cholesteric liquid crystal is arranged is configured as a single layer or multilayer, the polymer liquid crystal film can be used as a functional optical film for color com- pensation or brightness improvement.

[67] As another applied example of the present invention, there is a patterned retarder for 3D image display. For a glasses type 3D image display device, a use can feel a real 3D sense by making the left and right eyes separately recognize images, each being cross-polarized by 90 ° , through a polarized glasses having two polarized lenses (or polarization plates) which are cross-polarized by 90 ° .

[68] Typically, since light emitted from an LCD is a polarized light, the polarized light is divided into area A and B. The area A forms an optical axis of the optical retarder to maintain an output polarized light direction while the area B forms the optical axis of the optical retarder to diffract the output polarized light by 90 ° , so that images that are cross-polarized by 90 ° can be emitted.

[69] Here, in order to maintain the output polarized light direction, the optical axis of the optical retarder is made identical to the polarization direction. To diffract the output polarized light by 90 ° (clockwise), an optical retarder having 45 ° (clockwise) with respect to the output polarized light for a λ/2 optical retarder, and 22.5 ° and 67.5 ⁰ (clockwise) with respect to the output polarized light for a λ/4 optical retarder, is configured as multilayer. Besides, a variety of configurations with various angles and various multilayer for the polarization diffraction and maintenance are available.

[70] For a PDP, EL, or FED in which the output light is not a polarized light, a glasses type 3D image display can be configured by attaching a combination of the optical retarder and a polarization film. When the output light is not a polarized light, since the light becomes a polarized light by passing through the polarization film, when the polarization film is combined to the optical retarder, the same effect as an optical retarder used in the LCD can be obtained.

[71] As a yet another example of the present invention, there is a patterned optical retarder for a non-glasses type 3D image display. For the non-glasses type 3D image display using an optical retarder, an optical retarder parallax barrier having an optical retarder and an additional linear polarization plate or cell can be used. A polarized output light of an LCD passes through a polymer liquid crystal film, in which an optical axis divided into area A and B, and then a linear polarizer, so that a non-glasses type 3D image LCD is possible by an effect of a parallax barrier of the two areas. Here, the same effect can be obtained by forming the polarized output light and the optical axis identical for the area A and, for the area B, forming the optical axis by 45 ° clockwise for a retarder having a λ/2 phase modulation feature, for example, and appropriately adjusting the optical axis by making the polymer liquid crystal film into multilayer for λ/2, with respect to the polarized output light. Also, by combining the optical retarder and the polarized film, a 3D image display such as a PDP, EL, and FED in which the output light is not a polarized light.

[72] When one layer λ/2 is used in polarization diffraction by an optical retarder, since red, green, and blue color lights emitted from a display are difficult to diffract uniformly, image mixing phenomenon or moir? phenomenon can occur. However, by using a multilayer retarder having a λ/(n+2) feature, where n is an integer, like a two- layer λ/4 optical retarder, the above drawback can be overcome.

[73] The above-described optical retarder for a 3D image display can perform a function by being attached to a front surface of a conventional display. Also, for an L CD, a patterned optical retarder for a 3D image can be selectively applied to an inner surface or an outer surface of a liquid crystal cell. Since an output polarization plate needs to be installed on the inner surface of the cell when the patterned optical retarder is applied to the inner surface, an in-cell polarization plate needs to be added. Mode for Invention

[74] Industrial Applicability

[75] As described above, the present invention can be used in a field of manufacturing an optical retarder used to realize a 3D image. In addition, the present invention may be applied to all of the technical fields needed optical patterning. Sequence List Text

[76]

Claims

[1] A method for manufacturing a patterned optical retarder comprising: a) forming an alignment layer on a substrate; b) surface aligning an overall surface of the alignment layer (the first aligning step); c) surface aligning only a portion that is not masked by placing a photomask having a predetermined pattern on the first aligned layer, to form a predetermined alignment pattern on the alignment layer (the second aligning step); d) coating liquid crystal on the second aligned alignment layer where a predetermined alignment pattern is formed; and e) forming a polymer liquid crystal film where a predetermined optical axis pattern is formed by irradiating light to the coated liquid crystal to be photocrosslinked.

[2] The method of claim 1, wherein the first aligning step adopts at least one method selected from a group consisting of a method of irradiating a polarized ultraviolet ray to the alignment layer, a method of irradiating an ion beam or plasma beam at a predetermined angle, and a method of rubbing.

[3] The method of claim 1, wherein the second aligning step adopts at least one method selected from a group consisting of a method of irradiating a polarized ultraviolet ray to the alignment layer and a method of irradiating an ion beam or plasma beam at a predetermined angle.

[4] The method of claim 1, wherein the polymer liquid crystal film has a phase modulation feature that λ/(n+l), where n is an integer.

[5] The method of claim 1, wherein an optical axis of the polymer liquid crystal film is different by an optical axis pattern.

[6] The method of claim 1, wherein the optical axis pattern has at least two different optical axes.

[7] The method of claim 1, wherein the liquid crystal coated in step d) is photocrosslinking liquid crystal.

[8] The method of claim 1, wherein the liquid crystal coated in step d) is at least one of liquid crystal selected from a group consisting of nematic liquid crystal, discotic liquid crystal, and cholesteric liquid crystal.

[9] The method of claim 1, further comprising: b') surface aligning an entire surface of the polymer liquid crystal film having a predetermined optical axis pattern (the third aligning step); c') placing a mask having a predetermined pattern on the third aligned alignment layer and surface aligning an unmasked portion only to form a predetermined alignment pattern on the alignment layer (the fourth aligning step); d') coating liquid crystal on the fourth aligned alignment layer where a predetermined alignment pattern is formed; and e') irradiating light to the coated liquid crystal so as to be photocrosslinked so that a polymer liquid crystal film with a predetermined optical axis pattern is formed. [10] The method of claim 9, further comprising performing the steps b'), c'), d'), and e') at least one more time with respect to the polymer liquid crystal film. [11] The method of claim 1, wherein the alignment layer is formed of a reversible optical alignment material. [12] The method of claim 1, wherein the first aligning step uses a polarized ultraviolet ray and the second aligning step is performed by a method of irradiating an ion beam or plasma beam at a predetermined angle. [13] An optical retarder manufactured by a method defined by any of claims 1 through 12. [14] A 3D image display device comprising the optical retarder of claim 13 and a polarization film. [15] An optical retarder parallax barrier comprising: a liquid crystal display device having the optical retarder of claim 13 in a liquid crystal cell; and a linear polarization plate or cell.