Apparatus and method for duplicating photo alignment layer of a large area Pancharatnam-Berry Lens using direct duplication

Abstract

The present invention relates to an apparatus and method for replicating a photoalignment film of a large-area PB lens using a direct replication method, comprising: a light source unit for irradiating light; a master PB lens having an orientation pattern of a shape to be replicated recorded on a photoalignment film for replication, positioned on an optical path between the light source unit and the photoalignment film to form a divergent light of circularly polarized light that rotates in the opposite direction by transmitting a portion of the circularly polarized light irradiated from the light source unit; and a liquid crystal layer positioned on an optical path between the light source unit and the photoalignment film to form a parallel light of circularly polarized light that rotates in the same direction by transmitting the remainder of the circularly polarized light irradiated from the light source unit; wherein the master PB lens, the liquid crystal layer, and the photoalignment film are spaced apart by a predetermined distance so that the divergent light of circularly polarized light and the parallel light interfere to replicate the orientation pattern on the photoalignment film.

Description

Technology Field

[0001] The present invention relates to an apparatus and method for replicating a photoalignment film of a large-area PB lens on a photoalignment film through a direct replication method using a master PB lens having an orientation pattern of a shape to be replicated recorded thereon and a nematically aligned liquid crystal layer. Background Technology

[0003] Due to the rapid advancement of small, high-resolution display panels, portable devices for implementing Virtual Reality (VR) or Augmented Reality (AR) are becoming commonplace. In particular, AR / VR devices provide stereopsis, which is the perception of depth derived from the difference between the images formed on the retinas of the user's two eyes. However, when different images are presented to each eye, dizziness or motion sickness may occur due to the difference between stereopsis and the eyes' focal lengths.

[0004] Recently, Pancharatnam-Berry lenses (PB lenses) are used to narrow the distance between focal points, form appropriate images at different distances, and maintain high resolution. The Pancharatnam-Berry Optical Element (PBOE) that constitutes the PB lens is a patterned half-wavelength plate with a spatially varying crystal axis direction. These PB lenses are installed in devices such as Head-Up Displays (HUDs) and Head Mounted Displays (HMDs) to provide better stereoscopic vision and enable virtual or augmented reality.

[0005] However, due to the characteristics of this device, it is necessary to install a large-diameter lens to ensure a wide field of view when the user wears the device.

[0006] Meanwhile, the photoalignment film in which liquid crystals are arranged in a PB lens can be manufactured through a photolithography process. In particular, in the case of a PB lens, the liquid crystal pattern must become shorter as it goes from the center of the lens to the end of the lens; therefore, in order to form such a pattern, the photoalignment film must be manufactured using linear polarization formed through a collimated parallel light and diverging light having a predetermined focal length.

[0007] Methods for manufacturing photo-alignment films include a method of recording an alignment pattern by separating two lights and interfering them with each other, and a method of recording an alignment pattern by passing a single light through a phase mask containing a PBP pattern. In the former case, since two lights must be irradiated along a single axis, it is sensitive to changes in the light's travel path and wavelength. Furthermore, because the number of components in the recording device (beam splitter, mirror, lens, QWP, etc.) is large, it is difficult to record the alignment pattern as desired due to problems occurring in each piece of equipment. In contrast, the latter method is very advantageous in terms of error and manufacturing speed because it is faster at recording the pattern and can reduce the number of components in the recording device.

[0008] However, even in the case of the direct replication method, which records the orientation pattern by passing it through a phase mask, the overall size of the optical component is small, making it difficult to manufacture large-area PB lenses with a diameter of 2 inches or more. The problem to be solved

[0010] The technical problem to be solved by the present invention is to replicate a photoalignment film of a large-area PB lens onto a photoalignment film through a direct replication method using a master PB lens having an orientation pattern of the shape to be replicated recorded thereon and a nematically aligned liquid crystal layer.

[0011] However, the problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned problems will be clearly understood by those skilled in the art from the description below. means of solving the problem

[0013] A device for replicating a photo-alignment film of a large-area PB lens using a direct replication method according to one embodiment of the present invention comprises: a light source unit for irradiating light; a master PB lens, which is a lens having an orientation pattern of a shape to be replicated recorded on a photo-alignment film for replication, positioned on the optical path between the light source unit and the photo-alignment film to form a divergent light of circularly polarized light that rotates in the opposite direction by transmitting a portion of the circularly polarized light irradiated from the light source unit; and a liquid crystal layer positioned on the optical path between the light source unit and the photo-alignment film to form a parallel light of circularly polarized light that rotates in the same direction by transmitting the remainder of the circularly polarized light irradiated from the light source unit; and may be characterized by separating the master PB lens and the liquid crystal layer from the photo-alignment film by a predetermined distance so that the divergent light of circularly polarized light and the parallel light interfere to replicate the orientation pattern on the photo-alignment film.

[0014] A photoalignment film replication device for a large-area PB lens using a direct replication method, further comprising a conversion unit that converts light into circularly polarized light on the optical path between a light source, a master PB lens, and a liquid crystal layer.

[0015] According to one embodiment of the present invention, the thickness of the master PB lens may be characterized as being the same as the thickness of the liquid crystal layer.

[0016] According to one embodiment of the present invention, the liquid crystal layer may be characterized as being a nematic liquid crystal layer.

[0017] According to one embodiment of the present invention, the master PB lens and the liquid crystal layer may be characterized as being formed on the same plane.

[0018] According to one embodiment of the present invention, the master PB lens and the liquid crystal layer may be formed coaxially, and the master PB lens may be formed on the inside and the liquid crystal layer on the outside.

[0019] According to one embodiment of the present invention, the polarization efficiency of the master PB lens may be characterized as 50%.

[0020] According to one embodiment of the present invention, a predetermined interval may be characterized as being equal to the focal length of the master PB lens.

[0021] A method for replicating a photoalignment film of a large-area PB lens using a direct replication method according to one embodiment of the present invention may include: a step of irradiating light from a light source; a step of positioning a master PB lens, having an alignment pattern of a shape to be formed on the photoalignment film, on an optical path between the light source and the photoalignment film so that a portion of the circularly polarized light irradiated from the light source is transmitted to form divergent light of circularly polarized light rotating in the opposite direction; a step of positioning a liquid crystal layer on an optical path between the light source and the photoalignment film so that the remaining portion of the circularly polarized light irradiated from the light source is transmitted to form parallel light of circularly polarized light rotating in the same direction; and a step of separating the master PB lens, the liquid crystal layer, and the photoalignment film by a predetermined distance so that the divergent light of circularly polarized light and the parallel light interfere to form an alignment pattern on the photoalignment film.

[0022] According to one embodiment of the present invention, the method further includes the step of manufacturing a photo-alignment film of a master PB lens through a Mach-Zehnder interferometer, and is characterized by focusing the parallel light and divergent light separated in the Mach-Zehnder interferometer into a single axis, and then transmitting the interference light propagating along the axis through a Quarter Wave Plate (QWP) to polarize it into left-circular polarization and right-circular polarization to form an alignment pattern on the photo-alignment film of the master PB lens.

[0023] According to one embodiment of the present invention, the thickness of the master PB lens may be characterized as being the same as the thickness of the QWP used when manufacturing the photoalignment film of the master PB lens.

[0024] According to one embodiment of the present invention, a large-area PB lens manufactured with a photoalignment film replicated by a photoalignment film replication method may include a large-area PB lens having a diameter that is magnified by the value according to Equation 1 compared to the diameter of a master PB lens.

[0025] [Mathematical Formula 1]

[0026]

[0027] D represents the magnification of the large-area PB lens manufactured relative to the diameter of the master PB lens, L represents a predetermined interval, and f represents the focal length of the master PB lens. Effects of the invention

[0029] According to one embodiment of the present invention, a photo-alignment film of a large-area PB lens can be manufactured.

[0030] In addition, according to one embodiment of the present invention, the diameter and focal length of the master PB lens can be arbitrarily adjusted.

[0031] In addition, according to one embodiment of the present invention, the mass production efficiency of the photoalignment film can be improved by being insensitive to changes in the light travel path and wavelength.

[0032] In addition, according to one embodiment of the present invention, the number of parts can be reduced compared to a Mach-Zehnder interferometer, thereby reducing costs.

[0033] The effects obtainable from the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present invention belongs from the description below. Brief explanation of the drawing

[0035] FIG. 1 is a side view illustrating a photo-alignment film replication device for a large-area PB lens according to one embodiment of the present invention. FIG. 2 is a plan view illustrating a master PB lens and a liquid crystal layer of a photoalignment film replication device for a large-area PB lens according to one embodiment of the present invention. FIG. 3 is a block diagram of a method for replicating a photoalignment film of a large-area PB lens according to one embodiment of the present invention. FIG. 4 is a plan view illustrating a method for manufacturing a master PB lens according to one embodiment of the present invention. FIG. 5 is a drawing relating to a b / w crossed polarizer image of a large-area PB lens manufactured with a photoalignment film replicated by a photoalignment film replication device of a large-area PB lens according to the present invention. Figure 6 is a diagram relating to a b / w crossed polarizer image of a PB lens manufactured with a photoalignment film replicated by a photoalignment film replication device according to Comparative Example 1. Figure 7 is a diagram showing a b / w crossed polarizer image of a PB lens manufactured with a photoalignment film produced using a conventional Mach-Zehnder interferometer. Specific details for implementing the invention

[0036] The present invention will become clear from the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Meanwhile, the terms used in this specification are for describing the embodiments and are not intended to limit the present invention.

[0037] Throughout this specification, the singular form includes the plural form unless specifically stated otherwise in the text.

[0038] Throughout this specification, the terms “comprises” and / or “comprising” as used mean that the mentioned components, steps, actions and / or elements do not exclude the presence or addition of one or more other components, steps, actions and / or elements, and that, unless specifically stated otherwise, they do not exclude other components but may include additional components.

[0039] Throughout this specification, "photoalignment film" refers to a film that controls the alignment state of liquid crystals, and generally refers to a film made of a resin such as polyimide.

[0040] Throughout this specification, "Direct Duplication" may mean a method of manufacturing a liquid crystal optical element and then using the element itself as a phase mask to duplicate (record) an orientation pattern shape on the element to be duplicated.

[0041] Throughout this specification, "recording an orientation pattern" may mean imparting photoanisotropic properties to the orientation set on the photo-alignment film by irradiated light.

[0042] Throughout this specification, "large area" may mean that the diameter is larger than that of the master PB lens to be replicated.

[0043] The present invention will be described in more detail below.

[0045] Referring to FIG. 1, a photo-alignment film replication device for a large-area PB lens according to one embodiment of the present invention may include a light source unit (10), a master PB lens (20), and a liquid crystal layer (30).

[0046] The light source unit (10) is configured to irradiate light in a photo-aligned film manufacturing device through exposure interference, and can use a high-power laser such as a UV laser.

[0047] The Master PB lens (20) (Master Pancharatnam-Berry lens) is a lens in which an orientation pattern of the shape to be replicated is recorded on a replication photoalignment layer (PAL). More specifically, in order to manufacture the photoalignment layer (PAL) of the PB lens through an exposure interference process, it is necessary to interfere left-handed circularly polarized light (LCP) that rotates to the left relative to the direction of light propagation and right-handed circularly polarized light (RCP) that rotates to the right through one axis so that they are incident on the photoalignment layer (PAL) as a single linear polarized light.

[0048] In addition, since the liquid crystal pattern of a PB lens becomes shorter from the center to the ends, one parallel light and one divergent light must be irradiated during the manufacturing of the photoalignment layer (PAL) of the PB lens.

[0049] First, to form circularly polarized light incident on the PB lens, a conversion unit (40) may be further included in the light path of the light source unit (10), the PB lens, and the liquid crystal layer (30). This configuration for converting linearly polarized light generally irradiated into circularly polarized light may be a QWP (Quarter Wave Plate).

[0050] In the case of the present invention, the direct replication method, that is, the device records an orientation pattern by passing a single light through a phase mask containing a PBP pattern and causing the resulting light to interfere with each other. Here, the phase mask is a master PB lens (20) positioned in the optical path between the light source unit (10) and the optical alignment film (PAL), so that a portion of the circularly polarized light irradiated from the light source unit (10) is transmitted to form divergent circularly polarized light that rotates in the opposite direction. That is, when left-circularly polarized light is incident on the master PB lens (20), right-circularly polarized light is formed, and when right-circularly polarized light is incident, left-circularly polarized light is formed.

[0051] In addition, since the phase mask is a (master) PB lens, divergent light is formed when parallel light is incident due to the pattern characteristics of the lens.

[0052] Meanwhile, a single parallel light required for manufacturing the photoalignment layer (PAL) of the PB lens can be formed through the liquid crystal layer (30). The liquid crystal layer (30) is positioned on the optical path between the light source unit (10) and the photoalignment layer (PAL) so that the remaining portion of the circularly polarized light irradiated from the light source unit (10) that does not pass through the master PB lens (20) passes through to form a parallel light of circularly polarized light that rotates in the same direction. That is, when left-circularly polarized light is incident on the liquid crystal layer (30), left-circularly polarized light is formed, and when right-circularly polarized light is incident, right-circularly polarized light is formed.

[0053] Ultimately, when a single circularly polarized light is transmitted through the master PB lens (20) and the liquid crystal layer (30), the circularly polarized light rotating in one direction formed in the liquid crystal layer (30) and the circularly polarized light rotating in the opposite direction formed in the master PB lens (20) interfere with each other to form a single linearly polarized light, which can be replicated in the photoalignment layer (PAL). Additionally, since the light formed in the master PB lens (20) forms divergent light due to the pattern characteristics of the PB lens, the photoalignment layer (PAL) of the PB lens can be replicated through interference with the parallel light formed in the liquid crystal layer (30).

[0054] In addition, this configuration allows for the manufacture of a photo-alignment film (PAL) for a PB lens with a diameter equal to that of the master PB lens (20), as well as a photo-alignment film (PAL) for a large-area PB lens that is larger than the diameter of the master PB lens (20). This is possible by separating the distance between the master PB lens (20) and the photo-alignment film (PAL) for replication at a predetermined interval. More specifically, regarding the divergent light formed from the master PB lens (20), the area of ​​the divergent light reaching the photo-alignment film (PAL) for replication increases as the distance between the master PB lens (20) and the photo-alignment film (PAL) for replication increases. Therefore, when parallel light is irradiated, a photo-alignment film (PAL) for a PB lens with a corresponding area can be manufactured according to the area where linear polarization caused by interference between the divergent light and the parallel light reaches the photo-alignment film (PAL) for replication.

[0055] However, when light irradiated from a light source passes through the master PB lens (20) and the liquid crystal layer (30), the phase retardation value is particularly important. More specifically, in order to replicate the alignment pattern of the master PB lens (20) on the replication photoalignment layer (PAL), it is necessary to appropriately adjust the polarization efficiency of each circularly polarized light rotating in different directions.

[0056] This polarization efficiency is the difference in refractive index between air and the device ( ), thickness of the element (d) and wavelength of light ( It varies depending on ) etc. In a typical replication device, the difference in refractive index between air and the element ( ) and wavelength of light( Since the value of ) is constant, the thickness (d) of the device is an essential factor in increasing polarization efficiency.

[0057] Ultimately, polarization efficiency can be achieved by forming the thickness of the master PB lens (20) to be the same as the thickness of the liquid crystal layer (30). That is, the phase of circularly polarized light incident on the master PB lens (20) can be changed to circularly polarized light rotating in the opposite direction, and the circularly polarized light incident on the liquid crystal layer (30) can be transmitted in the same direction.

[0058] Additionally, referring to FIGS. 1 and 2, the master PB lens (20) and the liquid crystal layer (30) can be formed on the same plane. By being located on the same plane, the phase difference that may occur depending on the position of each element can be eliminated.

[0059] Additionally, referring to FIG. 2, the master PB lens (20) and the liquid crystal layer (30) may be formed coaxially, and the master PB lens (20) may be formed on the inside and the liquid crystal layer (30) on the outside. By positioning the master PB lens (20) on the inside of the liquid crystal layer (30), the diverging light transmitted through the master PB lens can effectively cause interference with the parallel light transmitted through the liquid crystal layer (30).

[0060] Meanwhile, the liquid crystal layer (30) may be formed as a nematic liquid crystal layer (30). Nematic liquid crystals are liquid crystal orientations in which rod-shaped molecules are arranged parallel to each other, and have the characteristic of exhibiting anisotropy with respect to electro-optical properties such as refractive index, permittivity, and magnetic susceptibility due to the directionality between the molecules. Depending on this electrical anisotropy, the polarization of light passing through the liquid crystal can be changed.

[0061] On the other hand, in the optical alignment layer (PAL) replication device of a large-area PB lens according to one embodiment of the present invention, the phase of the light passing through the liquid crystal layer (30) can be controlled so as not to change. More specifically, while the light passing through the master PB lens (20) changes its phase to circularly polarized light with a different rotation direction, the light passing through the liquid crystal layer (30) must be controlled to form the same incident circularly polarized light. In particular, when the master PB lens (20) and the liquid crystal layer (30) are formed with a predetermined distance from the optical alignment layer (PAL) for replication of the large-area PB lens, there is a problem that the phase of the light passing through the liquid crystal layer (30) may change.

[0062] Ultimately, even if the master PB lens (20) and the liquid crystal layer (30) are separated from the replication optical alignment layer (PAL) by a predetermined distance (L), the liquid crystal layer (30) can be adjusted by inserting a layer formed of nematic liquid crystal into the optical path to form parallel light of the same phase.

[0063] In addition, the polarization efficiency of the master PB lens (20) can be formed to 50% and replicated. More specifically, when the polarization efficiency of the master PB lens (20) is formed to 50% and the polarization efficiency of the liquid crystal layer (30) is formed to 50%, the alignment pattern formed on the master PB lens (20) can be appropriately recorded on the replication photoalignment layer (PAL).

[0064] This is, as explained earlier, the difference in refractive index between air and the element ( ) and wavelength of light( The value can be adjusted according to the thickness (d) of the element in a certain device. The thickness of each element for 50% polarization efficiency of the master PB lens (20) and the liquid crystal layer (30) can be achieved by forming it to be the same as the thickness of the QWP (Quarter Wave Plate) used when manufacturing the photoalignment layer (PAL) of the master PB lens (20), which will be explained below in the step of the method for manufacturing the master PB lens (20).

[0065] In a photoalignment film replication device for a large-area PB lens according to one embodiment of the present invention, a predetermined gap between the master PB lens (20), the liquid crystal layer (30), and the photoalignment film (PAL) for replication can be formed with a gap equal to the focal length of the master PB lens (20). In particular, as shown in FIGS. 1 and 2, when the master PB lens (20) and the liquid crystal layer (30) are formed at the same position on the optical path and the focal length of the master PB lens (20) and the predetermined gap (L) between the master PB lens (20) and the photoalignment film (PAL) for replication are spaced equally, a PB lens equipped with a photoalignment film (PAL) produced through this device can be manufactured as a lens having a focal length and a diameter of the PB lens that are each double. This will be determined in more detail through the following embodiments and comparative examples.

[0067] Referring to FIG. 3, a method (S1) for replicating a photo-alignment film of a large-area PB lens according to an embodiment of the present invention comprises: a step (S10) of irradiating light from a light source unit (10); a step (S20) in which a master PB lens (20), having an orientation pattern of a shape to be formed on a photo-alignment film (PAL), is positioned on an optical path between the light source unit (10) and the photo-alignment film (PAL) so that a portion of the circularly polarized light irradiated from the light source unit (10) is transmitted to form divergent light of circularly polarized light rotating in the opposite direction; a step (S30) in which a liquid crystal layer (30) is positioned on an optical path between the light source unit (10) and the photo-alignment film (PAL) so that the remaining portion of the circularly polarized light irradiated from the light source unit (10) is transmitted to form parallel light of circularly polarized light rotating in the same direction; and a step of separating the master PB lens (20), the liquid crystal layer (30), and the photo-alignment film (PAL) by a predetermined distance. The method may include a step (S40) in which divergent light of circular polarization and parallel light interfere to form an orientation pattern on the photo-alignment film (PAL). Ultimately, a photo-alignment film (PAL) mounted on a PB lens with a diameter larger than the diameter of the master PB lens (20) can be recorded according to a predetermined interval.

[0068] In particular, the method may further include a step (S50) of manufacturing a photo-alignment film (PAL) of a master PB lens (20) through a Mach-Zehnder interferometer. Referring to FIG. 4, light irradiated from a light source unit (100) in a Mach-Zehnder interferometer is separated by a beam splitter or a polarizing beam splitter (200), and each separated light is reflected by a mirror (300) and focused into one axis through a beam splitter (400), etc. Then, the interference light traveling along the axis is transmitted through a QWP (500) (Quarter Wave Plate) to polarize it into left-circular polarization and right-circular polarization, thereby forming an alignment pattern on the photo-alignment film (PAL) of the master PB lens (20).

[0069] A Mach-Zehnder interferometer is an interferometer that can form an orientation pattern through the interference fringes generated after creating two optical paths using a beam splitter and combining and interfering them. As previously explained, since it requires two lights to be projected along a single axis, it is sensitive to changes in the light's path and wavelength. Furthermore, because there are many components of the recording device (beam splitter, mirror, lens, QWP, etc.), it is difficult to record the orientation pattern as desired due to problems occurring in each piece of equipment.

[0070] On the other hand, when a master PB lens (20) is manufactured using a Mach-Zehnder interferometer and then the optical alignment film manufacturing method according to one embodiment of the present invention is used, there is an advantage in that an alignment pattern identical to that of the master PB lens (20) or an alignment pattern of a large-area PB lens can be formed.

[0071] Here, the QWP required for manufacturing the master PB lens (20) is a delayer that delays the phase of the incident light by 1 / 4 wavelength, and the polarization efficiency, which is the phase delay value, varies depending on the thickness of the QWP. Consequently, when the thickness of the QWP in the apparatus for manufacturing the optical alignment layer (PAL) of the master PB lens (20) and the thickness of the master PB lens (20) are formed to be the same, the polarization efficiency of the light transmitted through the master liquid crystal PB lens in the method for replicating the optical alignment layer of a large-area PB lens according to one embodiment of the present invention can be formed to be 50%.

[0072] Each of the above steps and configurations may include all of the configurations and technical features of the optical alignment film replication device of a large-area PB lens according to one embodiment of the present invention mentioned above.

[0074] The present invention may further include a large-area PB lens manufactured from a photoalignment film (PAL) replicated by a large-area photoalignment film replication method according to one embodiment of the present invention. In particular, the large-area PB lens may have a diameter that is magnified by the value according to Equation 1 compared to the diameter of the master PB lens (20).

[0075] [Mathematical Formula 1]

[0076]

[0077] D represents the magnification of the large-area PB lens manufactured relative to the diameter of the master PB lens (20), L represents a predetermined interval, and f represents the focal length of the master PB lens (20).

[0078] For example, referring to FIGS. 1 and 2, if the focal length of the master PB lens (20) is set to 1, the distance between the master PB lens (20), the liquid crystal layer (30), and the photoalignment layer (PAL) for replication is formed to 0.5, then the photoalignment layer (PAL) of the PB lens having a diameter and focal length 1.5 times that of the master lens can be replicated. Alternatively, if the distance between the master PB lens (20), the liquid crystal layer (30), and the photoalignment layer (PAL) for replication is formed to 1, then the photoalignment layer (PAL) of the PB lens having a diameter and focal length 2 times that of the master lens can be replicated.

[0079] This allows the focal length and a predetermined interval (L) of the master PB lens (20) to be adjusted according to the properties of the PB lens to be replicated.

[0080] This can be determined through the following examples and comparison examples.

[0081] Examples and Comparative Examples

[0082] Referring to FIGS. 5 to 7, an example of a photoalignment layer (PAL) replication device for a large-area PB lens according to the present invention and a comparative example show a b / w crossed polarizer image of a PB lens manufactured with a replicated photoalignment layer (PAL).

[0083] Example 1 is composed of a light source unit (10) that irradiates light, a master PB lens (20) having an orientation pattern of a shape to be replicated recorded on a replication photo-alignment film (PAL), and a nematic liquid crystal layer (30) formed coaxially on the same plane as the master PB lens (20), and the master PB lens (20) and the liquid crystal layer (30) are spaced apart from the photo-alignment film (PAL) by a distance of 80 mm.

[0084] The focal length of the master PB lens (20) is 80mm and the diameter is 24mm.

[0085] The light irradiated from the light source (10) is circularly polarized light having a wavelength of 355 nm, and the light irradiated on the QWP required for manufacturing the master PB lens (20) is also produced by irradiating light having a wavelength of 355 nm.

[0086] Comparative Example 2 differs from Example 1 only in that the master PB lens (20), the liquid crystal layer (30), and the photoalignment layer (PAL) are not separated, and the nematic liquid crystal layer (30) is not installed, but the type of light, wavelength, master PB lens (20), etc. are all set to be the same.

[0087] Comparative Example 3 is manufactured by using a PB lens fabricated using a conventional Mach-Zehnder interferometer, by irradiating the light separated by a beam splitter and the light focused by the beam splitter onto a photo-aligning film (PAL).

[0089] Referring to FIG. 5, this is a drawing relating to a b / w crossed polarizer image of a large-area PB lens manufactured with a photoalignment layer (PAL) replicated by a photoalignment layer (PAL) replication device of a large-area PB lens according to the present invention. The replicated PB lens has a focal length of 160 mm, a diameter of 48 mm, and a lens thickness of 1.8 μm. This is a result according to Equation 1, as the master PB lens (20) and the liquid crystal layer (30) are spaced apart from the photoalignment layer (PAL) by a distance of 80 mm, and it can be seen that the focal length and diameter are doubled compared to the existing master PB lens (20).

[0090] On the other hand, referring to FIG. 6, this is a drawing of a b / w crossed polarizer image of a PB lens manufactured with a photoalignment layer (PAL) replicated by a photoalignment layer (PAL) replication device according to Comparative Example 1. The manufactured PB lens has a focal length of 80 mm, a diameter of 25 mm, and a lens thickness of 0.4 μm. This is the same focal length as the master PB lens (20). However, the change in lens diameter is due to the fact that the distance between the master PB lens (20) and the replicated photoalignment layer (PAL) must be separated by the thickness of the master PB lens (20), so it has increased by about 1 mm due to the diverging light of the master PB lens (20). Ultimately, as the PB lens is formed with the same focal length and a similar diameter as the master PB lens (20), it can be seen that the PB lens replication device according to Comparative Example 1 has limitations in manufacturing large-area PB lenses.

[0091] Also, referring to FIG. 7, this is a drawing of a b / w crossed polarizer image of a PB lens manufactured using a photoalignment layer (PAL) produced using a conventional Mach-Zehnder interferometer. The replicated PB lens has a focal length of 80 mm, a diameter of 24 mm, and a thickness of 0.4 mm. This is also a PB lens formed with the same focal length and diameter as the master PB lens (20), and it can be seen that the PB lens replication device according to Comparative Example 2 has limitations in producing large-area PB lenses.

[0093] Although the present invention has been described above by limited embodiments, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs. Explanation of the symbols

[0095] 10: Light source 20: Master PB Lens (Master Pancharatnam-Berry Lens) 30: Liquid crystal layer PAL: Photoorientation membrane 40: Transition section

Claims

Claim 1 A PB lens photoalignment film replication device using a direct replication method, comprising: a light source unit for irradiating light; a master PB lens, which is a lens having an orientation pattern of a shape to be replicated recorded on a photoalignment film for replication, positioned on the optical path between the light source unit and the photoalignment film to form a divergent light of circularly polarized light that rotates in the opposite direction by transmitting a portion of the circularly polarized light irradiated from the light source unit; and a liquid crystal layer positioned on the optical path between the light source unit and the photoalignment film to form a parallel light of circularly polarized light that rotates in the same direction by transmitting the remainder of the circularly polarized light irradiated from the light source unit; wherein the master PB lens is arranged to surround the liquid crystal layer, and the master PB lens, the liquid crystal layer, and the photoalignment film are spaced apart by a predetermined distance so that the divergent light of circularly polarized light and the parallel light interfere to replicate the orientation pattern on the photoalignment film. Claim 2 A photoalignment film replication device of a PB lens using a direct replication method, wherein, in claim 1, the device further comprises a conversion unit that converts the light into circularly polarized light on the light path between the light source unit, the master PB lens, and the liquid crystal layer. Claim 3 A photo-alignment film replication device for a PB lens using a direct replication method, characterized in that, in claim 1, the thickness of the master PB lens is the same as the thickness of the liquid crystal layer. Claim 4 A photo-alignment film replication device for a PB lens using a direct replication method, wherein, in claim 1, the liquid crystal layer is a nematic liquid crystal layer. Claim 5 A photo-alignment film replication device for a PB lens using a direct replication method, characterized in that, in claim 1, the master PB lens and the liquid crystal layer are formed on the same plane. Claim 6 A photo-alignment film replication device for a PB lens using a direct replication method, characterized in that, in claim 1, the master PB lens and the liquid crystal layer are formed coaxially, and the master PB lens is formed on the inside and the liquid crystal layer is formed on the outside. Claim 7 A photoalignment film replication device for a PB lens using a direct replication method, characterized in that, in claim 1, the polarization efficiency of the master PB lens is 50%. Claim 8 A photo-alignment film replication device for a PB lens using a direct replication method, characterized in that, in claim 1, the predetermined interval is the same interval as the focal length of the master PB lens. Claim 9 A method for replicating a photoalignment film of a PB lens using a direct replication method, comprising: a step of irradiating light from a light source; a step of positioning a master PB lens, having an orientation pattern of a shape to be formed on the photoalignment film, on an optical path between the light source and the photoalignment film so that a portion of the circularly polarized light irradiated from the light source is transmitted to form divergent light of circularly polarized light rotating in the opposite direction; a step of positioning a liquid crystal layer on an optical path between the light source and the photoalignment film so that the remaining portion of the circularly polarized light irradiated from the light source is transmitted to form parallel light of circularly polarized light rotating in the same direction; and a step of separating the master PB lens, the liquid crystal layer, and the photoalignment film by a predetermined distance so that the divergent light of circularly polarized light and the parallel light interfere to form an orientation pattern on the photoalignment film; wherein the master PB lens is arranged to surround the liquid crystal layer. Claim 10 A method for replicating the photoalignment film of a PB lens using a direct replication method, wherein, in claim 9, the method further comprises the step of manufacturing the photoalignment film of the master PB lens through a Mach-Zehnder interferometer, and after focusing the parallel light and divergent light separated in the Mach-Zehnder interferometer into a single axis, the interference light propagating along the axis is transmitted through a Quarter Wave Plate (QWP) to polarize it into left-circular polarization and right-circular polarization to form an alignment pattern on the photoalignment film of the master PB lens. Claim 11 A method for replicating the photoalignment film of a PB lens using a direct replication method, characterized in that, in claim 10, the thickness of the master PB lens is the same as the thickness of the QWP used when manufacturing the photoalignment film of the master PB lens. Claim 12 A PB lens manufactured from a photoalignment film replicated by the photoalignment film replication method of any one of claims 9 to 11, wherein the PB lens has a diameter that is magnified by a value according to Equation 1 compared to the diameter of the master PB lens. [Equation 1] D represents the magnification of the manufactured PB lens relative to the diameter of the master PB lens, L represents the predetermined interval, and f represents the focal length of the master PB lens.

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