Preparation method for liquid-crystal photonic device, and exposure system and liquid-crystal photonic device

Abstract

A preparation method for a super-resolution liquid-crystal photonic device. The method comprises: using an exposure system to prepare an alignment layer, coating same with a liquid-crystal polymer layer, and performing curing, so as to obtain a liquid-crystal photonic device. The exposure system comprises a laser device (121), an optical path system, an operating platform (11) and a control system. A method for preparing an alignment layer comprises: S1, providing a substrate (20), and coating the substrate (20) with an azo dye; S2, providing an optical path system, which comprises a spatial light modulator for loading a pattern of an aperture (122), and a laser device (121) emitting linearly polarized light that passes through the spatial light modulator and is exposed in a field-of-view region (101) of the azo dye to form an alignment pattern (102); S3, controlling an operating platform (11) to move by a set distance, the spatial light modulator loading the pattern of the aperture (122), changing the angle of the linearly polarized light, and performing exposure to form another alignment pattern (102), wherein the previously formed alignment pattern (102) and the newly formed alignment pattern (102) have first regions (1021) that overlap each other and second regions (1022) that do not overlap each other; and S4, repeating steps S3-S4 until an alignment layer is prepared. The present invention further relates to a liquid-crystal photonic device.

Description

Method for manufacturing liquid crystal photon device, exposure system and liquid crystal photon device TECHNICAL FIELD

[0001] The present application relates to the technical field of liquid crystal device manufacturing, in particular to a method for manufacturing a super-resolution liquid crystal photon device, an exposure system and the liquid crystal photon device. BACKGROUND

[0002] Liquid crystals have a wide range of applications in information display, optics and photonics devices. Many of these applications require liquid crystals to be arranged according to the designed orientation to achieve amplitude, phase and polarization modulation of light, so the orientation arrangement control method of liquid crystals has become a research hotspot in academia and industrial production. In recent years, with the development of photosensitive materials, the concept of photo-controlled orientation has been proposed. It uses photosensitive materials to produce molecular orientation perpendicular to the direction of linearly polarized light under the irradiation of ultraviolet polarized light. This directional orientation of molecules produces an anchoring force similar to that of a groove, thereby inducing the directional arrangement of liquid crystal molecules and manufacturing liquid crystal optical elements. Existing liquid crystal optical alignment technologies mainly include photo-crosslinking type, photo-degradation type and photo-isomerization type. TECHNICAL PROBLEM

[0003] If these technologies are directly used to manufacture liquid crystal optical devices, the resolution will be affected by parameters such as the wavelength of the light source and the aperture of the lithography objective, and it is impossible to break through the diffraction limit to achieve super-resolution, thereby limiting the performance of the manufactured liquid crystal optical devices. TECHNICAL SOLUTION

[0004] Therefore, the present application provides a method for manufacturing a super-resolution liquid crystal photon device, which can break through the diffraction limit and achieve super-resolution to manufacture a liquid crystal photon device.

[0005] A method for manufacturing a super-resolution liquid crystal photon device, comprising:

[0006] An exposure system is used to prepare an alignment layer, coat a liquid crystal polymer layer, and solidify to obtain a liquid crystal photon device;

[0007] The exposure system comprises a laser, an optical system, a work platform, and a control system for controlling the cooperation of the laser, the optical system, and the work platform;

[0008] The method for preparing the alignment layer comprises:

[0009] S1: providing a substrate, and coating an azo dye with repeatable brushwriting properties on the surface of the substrate;

[0010] S2: the optical system comprises a spatial light modulator for uploading an aperture pattern, and the linearly polarized light emitted by the laser passes through the spatial light modulator to perform exposure on a field of view area of the azo dye to form an alignment pattern;

[0011] S3: controlling the displacement of the working platform by a set distance, loading the aperture pattern on the spatial light modulator, changing the angle of the linearly polarized light, exposing to form another alignment pattern, the previously formed alignment pattern and the newly formed alignment pattern having a first area of mutual overlap and a second area of non-mutual overlap;

[0012] S4: repeating steps S3-S4 until the alignment layer is prepared.

[0013] In an embodiment of the present application, the optical path system further comprises an objective lens arranged on the optical path between the spatial light modulator and the substrate, for scaling the aperture pattern.

[0014] In an embodiment of the present application, the optical path system further comprises a 1 / 2 wave plate arranged on the optical path between the laser and the spatial light modulator, the angle of the linearly polarized light being doubled after the linearly polarized light passes through the 1 / 2 wave plate.

[0015] In an embodiment of the present application, the method for changing the polarization direction of the polarized light in step S3 comprises:

[0016] rotating the 1 / 2 wave plate to change the angle of the polarized light.

[0017] In an embodiment of the present application, the step of controlling the displacement of the working platform by a set distance in step S3 specifically comprises:

[0018] placing the substrate on the working platform, controlling the displacement of the working platform by the set distance after each exposure, the set distance being less than the optical resolution of the exposure system.

[0019] In an embodiment of the present application, the azo dye with repeatable writing properties is SD1 or BY.

[0020] In an embodiment of the present application, in step S3, the first area is re-written by the newly formed alignment pattern, the width of the second area is equal to the set distance, and the long axis arrangement orientations of the molecules in the first area and the second area are different.

[0021] In an embodiment of the present application, the arrangement of the liquid crystal molecules of the liquid crystal polymer layer is the same as the long axis arrangement of the azo dye in the alignment layer.

[0022] In an embodiment of the present application, the smaller the line width of the liquid crystal photonic device, the smaller the thickness of the liquid crystal polymer layer.

[0023] The application also relates to an exposure system using the preparation method of the super-resolution liquid crystal photon device, which comprises a laser, an optical path system, a work platform and a control system for controlling cooperation of the laser, the optical path system and the work platform.

[0024] In the embodiment of the application, the optical path system further comprises an objective lens arranged on the optical path between the spatial light modulator and the substrate, which is used for scaling the aperture pattern.

[0025] In the embodiment of the application, the optical path system further comprises a 1 / 2 wave plate arranged on the optical path between the laser and the spatial light modulator, and the angle of the linearly polarized light is doubled after the linearly polarized light passes through the 1 / 2 wave plate.

[0026] The application further relates to a liquid crystal photon device prepared by using the preparation method of the super-resolution liquid crystal photon device. Advantages

[0027] The preparation method of the super-resolution liquid crystal photon device of the application uses the repeatable brush writing characteristic of the azo dye, so that the first area of the alignment pattern formed in the last time is re-brushed, and the second area is not re-brushed. By controlling the displacement accuracy of the work platform, the width of the second area can be equal to the displacement distance (set distance) of the work platform, the diffraction limit can be broken, that is, the set distance is smaller than the minimum resolution of the exposure system, the super-resolution liquid crystal photon device can be prepared, and the performance of the liquid crystal photon device can be improved. The preparation method of the super-resolution liquid crystal photon device of the application is not limited by the wavelength and power of the laser emitted by the laser, and is related to the displacement accuracy of the work platform. The higher the displacement accuracy of the work platform, the better the effect of realizing super-resolution. Therefore, the steps of the preparation method of the super-resolution liquid crystal photon device of the application are very convenient, the production efficiency can be improved, and a large-aperture super-resolution liquid crystal photon device can be prepared. BRIEF DESCRIPTION OF DRAWINGS

[0028] Fig. 1 is a schematic view of the preparation of the liquid crystal photon device by using the preparation method of the super-resolution liquid crystal photon device of the application.

[0029] Figs. 2 to 4 are flowcharts of the translation exposure of the substrate of the application.

[0030] Fig. 5 to Fig. 8 are flow diagrams of the method for preparing the super-resolution liquid crystal photonic device of the present application. Embodiments of the present application

[0031] The following describes embodiments of the present application by specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the disclosure.

[0032] In the following description, reference is made to the accompanying drawings, which show several embodiments of the present application. It is understood that other embodiments can be used and that mechanical, structural, electrical, and operational changes can be made without departing from the spirit and scope of the present application. The following detailed description is not intended to be taken in a limiting sense, and the terms used herein are for the purpose of description, not limitation.

[0033] Although in some examples the terms first, second, etc. are used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another.

[0034] Furthermore, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises", "comprising", "includes" and / or "including" used herein, specify the presence of stated features, steps, operations, elements, components, items, and / or groups but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, items, and / or groups thereof. As used herein, the terms "or" and "and / or" are to be interpreted as inclusive, i.e., as meaning one or more of the stated items is present. Therefore, "A, B, or C" or "A, B, and / or C" means any of the following: A; B; C; A and B; A and C; B and C; A, B, and C. An exception to this definition will occur only when a combination of elements, functions, steps or acts are in some way inherently mutually exclusive.

[0035] Fig. 1 is a schematic diagram of the method for preparing the super-resolution liquid crystal photonic device of the present application, and Fig. 2 to Fig. 4 are flow diagrams of the method for performing translational exposure of the substrate of the present application. Referring to Fig. 1 to Fig. 4, the method for preparing the super-resolution liquid crystal photonic device comprises:

[0036] The exposure system is used to prepare the alignment layer, coat the liquid crystal polymer layer, and solidify to obtain the liquid crystal photonic device.

[0037] The exposure system comprises a laser 121, an optical system, a work platform 11, and a control system for controlling the cooperation of the laser 121, the optical system, and the work platform 11.

[0038] The method for preparing the alignment layer comprises:

[0039] S1: providing a substrate 20, coating an azo dye with repeatable brush writing on the surface of the substrate 20;

[0040] S2: the light path system includes a spatial light modulator for uploading the aperture 122 pattern, the linearly polarized light emitted by the laser 121 passes through the spatial light modulator to form a first orientation pattern 102 in a field of view area 101 of the azo dye;

[0041] S3: controlling the displacement of the working platform 11 by a set distance (the control system controls the displacement of the working platform 11 by a set distance), the spatial light modulator uploads the aperture 122 pattern, changes the angle of the linearly polarized light, and forms another orientation pattern 102 by exposure, the orientation pattern 102 formed in the last time and the newly formed orientation pattern 102 have a first area 1021 of mutual overlap and a second area 1022 of non-mutual overlap;

[0042] S4: repeating steps S3-S4 until the preparation of the orientation layer is completed. In this embodiment, the control system can control the laser 121 to emit laser, and can control the emission power of the laser 121; the control system can control the light path system to output pattern light; the control system can also control the displacement of the working platform 11.

[0043] The preparation method of the super-resolution liquid crystal photonic device of the present application utilizes the repeatable brush writing characteristics of the azo dye, so that the first area 1021 of the orientation pattern 102 formed in the last time is re-written, and the second area 1022 is not re-written. By controlling the displacement accuracy of the working platform 11, the width of the second area 1022 can be equal to the displacement distance (set distance) of the working platform 11, which can break through the diffraction limit, i.e. the set distance is less than the minimum resolution of the exposure system, and the super-resolution liquid crystal photonic device can be realized, which is beneficial to improve the performance of the liquid crystal photonic device. The preparation method of the super-resolution liquid crystal photonic device of the present application for liquid crystal orientation is not limited by the wavelength and power of the laser emitted by the laser 121, but is related to the displacement accuracy of the working platform 11. The higher the displacement accuracy of the working platform 11, the better the effect of super-resolution. Therefore, the preparation method of the super-resolution liquid crystal photonic device of the present application is very convenient, which can improve the production efficiency and also can manufacture large-aperture super-resolution liquid crystal photonic devices.

[0044] Optionally, the set distance is less than the minimum resolution of the exposure system, for example, the set distance is 200nm, and the minimum resolution of the exposure system is 350nm, or the set distance is 300nm, and the minimum resolution of the exposure system is 444nm, but not limited thereto.

[0045] Optionally, as shown in FIG. 1, the optical path system comprises an objective lens 123 arranged on the optical path between the spatial light modulator and the substrate 20, for scaling the aperture 122 pattern. In the embodiment, the objective lens 123 is, for example, a 50x lens or a 100x lens, but is not limited thereto.

[0046] Optionally, the optical path system further comprises a 1 / 2 wave plate arranged on the optical path between the laser 121 and the spatial light modulator, and the angle of the linearly polarized light is doubled after the linearly polarized light passes through the 1 / 2 wave plate.

[0047] Optionally, the method for changing the polarization direction of the polarized light in step S3 comprises:

[0048] rotating the 1 / 2 wave plate to change the angle of the polarized light. In the embodiment, rotating the 1 / 2 wave plate can change the polarization direction of the polarized light.

[0049] Optionally, the method for controlling the displacement of the working platform 11 by a set distance in step S3 comprises:

[0050] placing the substrate 20 on the working platform 11, and controlling the displacement of the working platform 11 by a set distance after each exposure, wherein the set distance is less than the optical resolution of the exposure system.

[0051] Optionally, the azo dye with repeatable writing property is SD1 or BY. It is worth mentioning that the azo dye has the repeatable writing property, and when the linearly polarized light is irradiated at a specific angle, the long axis of the molecule will be arranged at a right angle to the angle of the linearly polarized light after reaching the material threshold; when the linearly polarized light angle is changed to repeat the above steps, the long axis arrangement angle of the molecule will change accordingly, so that the dye has the repeatable writing property.

[0052] Optionally, in step S3, the first area 1021 is rewritten by the newly formed alignment pattern 102, the width of the second area 1022 is equal to the set distance, and the long axis arrangement orientations of the molecules in the first area 1021 and the second area 1022 are different.

[0053] Optionally, the arrangement of the liquid crystal molecules in the liquid crystal polymer layer is the same as the long axis arrangement of the azo dye molecules in the alignment layer.

[0054] Optionally, the smaller the width of the liquid crystal photonic device, the smaller the thickness of the liquid crystal polymer layer.

[0055] Optionally, Figures 5 to 8 are flow diagrams of a method for preparing a super-resolution liquid crystal photonic device according to the present application. Referring to Figures 5 to 8, when a liquid crystal grating with three gray scales is to be prepared, an SD1 azo dye is coated on the surface of a substrate 20; a 355 nm linearly polarized laser 121 is used for photoalignment; the field area 101 is 1 pm; the objective lens 123 is a 50x lens; and the minimum resolution of the exposure system is calculated to be 444 nm (i.e. λ / NA = 0.355 pm / 0.8 = 444 nm, where λ is the wavelength of the linearly polarized laser, NA is the numerical aperture, and the objective lens is a 50x lens with an NA of 0.8). If a photoresist is used for etching, the minimum width is 444 nm. The displacement accuracy of the working platform 11 is set to 300 nm. During the displacement of the working platform 11, the polarization direction of the polarized light is changed every time the working platform 11 is displaced by 300 nm. The arrangement angle of the liquid crystal molecules is 0°, 60°, and 120°. According to the geometric phase principle, the polarization angle of the linearly polarized light is 0°, 30°, and 60°, respectively. The specific implementation steps are as follows:

[0056] Step one: when the polarization angle of the polarized light is 0°, the field area 101 (the area enclosed by the interrupted line) on the surface of the azo dye is exposed to light, thereby forming a first formed alignment pattern 102 of a first gray scale, as shown in Figure 5.

[0057] Step two: the working platform 11 is controlled to translate by 300 nm, and a 1 / 2 wave plate is rotated so that the polarization angle of the polarized light is 30°. The second field area 101 (the area enclosed by the interrupted line) on the surface of the azo dye is exposed to light, thereby forming a second formed alignment pattern 102 of a second gray scale, as shown in Figure 6. The first formed alignment pattern 102 and the second formed alignment pattern 102 have a first area 1021 that overlaps and a second area 1022 that does not overlap. The first area 1021 is re-written in the alignment direction of the second formed alignment pattern 102, and the width of the second area 1022 is 300 nm.

[0058] Step three: the working platform 11 is controlled to translate again by 300 nm, and the 1 / 2 wave plate is rotated so that the polarization angle of the polarized light is 60°. The third field area 101 (the area enclosed by the interrupted line) on the surface of the azo dye is exposed to light, thereby forming a third formed alignment pattern 102 of a third gray scale, as shown in Figure 7. The second formed alignment pattern 102 and the third formed alignment pattern 102 have a first area 1021 that overlaps and a second area 1022 that does not overlap. The first area 1021 is re-written in the alignment direction of the third formed alignment pattern 102, and the width of the second area 1022 is 300 nm.

[0059] Step four, the working platform 11 is controlled to translate again with the precision of 300 nm, and the 1 / 2 wave plate is rotated to expose the azo dye surface to form the fourth formed alignment pattern 102 with the first gray scale when the polarization angle of the polarized light is 0°, as shown in FIG. 8, that is, steps one to three are a cycle, and the subsequent steps are all repeated above-mentioned steps. The polarization angle of the linear polarized light is periodically changed according to the above angle, so that a three-gray-scale liquid crystal grating with a period of 900 nm and a width of 300 nm can be made, which realizes super-resolution compared with the minimum resolution 444 nm of the exposure system.

[0060] The application also relates to an exposure system using the preparation method of the super-resolution liquid crystal photon device, the exposure system comprising a laser 121, an optical path system, a working platform 11, and a control system for controlling the cooperation of the laser 121, the optical path system, and the working platform 11, the optical path system comprising a spatial light modulator for uploading an aperture pattern, the linear polarized light emitted by the laser 121 irradiating the substrate 20 through the spatial light modulator, the surface of the substrate 20 being coated with a repeatable brush-writable azo dye, and a field of view region of the azo dye being exposed to form an alignment pattern.

[0061] Optionally, the optical path system comprises an objective lens 123 arranged on the light path between the spatial light modulator and the substrate 20, and used for scaling the aperture 122 pattern. In the embodiment, the objective lens 123 is, for example, a 50 times lens or a 100 times lens, but is not limited thereto.

[0062] Optionally, the optical path system further comprises a 1 / 2 wave plate arranged on the light path between the laser 121 and the spatial light modulator, and the angle of the linear polarized light is doubled after the linear polarized light passes through the 1 / 2 wave plate.

[0063] The application also relates to a liquid crystal photon device formed by using the preparation method of the super-resolution liquid crystal photon device.

[0064] The above-mentioned embodiments only exemplarily illustrate the principles and effects of the application, and are not used to limit the application. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and category of the application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought of the application should be covered by the claims of the application. Industrial applicability

[0065] The preparation method of the super-resolution liquid crystal photonic device of the application utilizes the repeatable brush writing characteristics of azo dyes, so that the first area of the alignment pattern formed last time is re-brushed, and the second area is not re-brushed. By controlling the displacement accuracy of the working platform, the width of the second area can be equal to the displacement distance (set distance) of the working platform, the diffraction limit can be broken, that is, the set distance is smaller than the minimum resolution of the exposure system, the super-resolution liquid crystal photonic device can be prepared, and the performance of the liquid crystal photonic device can be improved.

Claims

1. A method for preparing a super-resolution liquid crystal photonic device, characterized in that, an alignment layer is prepared by using an exposure system, a liquid crystal polymer layer is coated and cured to obtain a liquid crystal photonic device; the exposure system comprises a laser, an optical system, a work platform and a control system for controlling the cooperation of the laser, the optical system and the work platform; the method for preparing the alignment layer comprises: S1: providing a substrate, and coating an azo dye with repeatable brush writing on the surface of the substrate; S2: the optical system comprises a spatial light modulator for uploading an aperture pattern, linearly polarized light emitted by the laser passes through the spatial light modulator to form an alignment pattern in a field of view of the azo dye; S3: controlling the work platform to displace a set distance, the spatial light modulator uploads the aperture pattern, changes the angle of the linearly polarized light, and performs exposure to form another alignment pattern, the alignment pattern formed in the previous step and the new alignment pattern have a first region of mutual overlap and a second region of non-mutual overlap; S4: repeating steps S3-S4 until the preparation of the alignment layer is completed.

2. The method of claim 1, wherein the super-resolution liquid crystal photonic device is prepared by the steps of: The optical system further comprises an objective lens arranged on the optical path between the spatial light modulator and the substrate for scaling the aperture pattern.

3. The method of claim 1, wherein the super-resolution liquid crystal photonic device is prepared by the steps of: The optical system further comprises a 1 / 2 wave plate arranged on the optical path between the laser and the spatial light modulator, after the linearly polarized light passes through the 1 / 2 wave plate, the angle of the linearly polarized light is doubled.

4. The method of producing a super-resolution liquid crystal photonic device according to claim 3, wherein The method for changing the polarization direction of the polarized light in step S3 comprises: rotating the 1 / 2 wave plate to change the angle of the polarized light.

5. The method of making a super-resolution liquid crystal photonic device of claim 1, wherein, In step S3, the work platform is controlled to displace a set distance, specifically comprising: placing the substrate on the work platform, and controlling the work platform to displace the set distance for each exposure, the set distance being less than the optical resolution of the exposure system.

6. The method of making a super-resolution liquid crystal photonic device of claim 1, wherein, The repeatable brush writing azo dye is SD1 or BY.

7. The method of making a super-resolution liquid crystal photonic device of claim 1, wherein, In step S3, the first region is re-written by the new alignment pattern, the width of the second region is equal to the set distance, and the long axis arrangement of the molecules in the first region and the second region is different.

8. The method of making a super-resolution liquid crystal photonic device of claim 1, wherein, The arrangement of liquid crystal molecules in the liquid crystal polymer layer is the same as the long axis arrangement of the azo dye molecules in the alignment layer.

9. The method of making a super-resolution liquid crystal photonic device of claim 1, wherein, The smaller the line width of the liquid crystal photonic device, the smaller the thickness of the liquid crystal polymer layer.

10. An exposure system using the method for manufacturing a super-resolution liquid crystal photonic device according to any one of claims 1 to 9, characterized by, The exposure system comprises a laser, an optical system, a work platform and a control system for controlling the cooperation of the laser, the optical system and the work platform, the optical system comprises a spatial light modulator for uploading an aperture pattern, linearly polarized light emitted by the laser passes through the spatial light modulator to irradiate on a substrate, the surface of the substrate is coated with an azo dye with repeatable brush writing, and an alignment pattern is formed in a field of view of the azo dye.

11. The exposure system of claim 10, wherein, The optical path system further comprises an objective lens arranged on the optical path between the spatial light modulator and the substrate, for scaling the aperture pattern.

12. The exposure system of claim 1, wherein, The optical path system further comprises a 1 / 2 wave plate arranged on the optical path between the laser and the spatial light modulator, after passing through the 1 / 2 wave plate, the angle of the linearly polarized light is doubled.

13. A liquid crystal photonic device, characterized in that, The liquid crystal photonic device is prepared by the preparation method of the super-resolution liquid crystal photonic device according to any one of claims 1 to 9.

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