Exposure device and exposure method for large-size holographic grating

Abstract

The invention discloses an exposure device and an exposure method of a large-size holographic grating, the exposure device comprises a matching pool, a light source assembly and a mother set grating, and the matching pool is provided with an accommodating groove capable of being filled with matching liquid; the light source assembly is arranged opposite to the matching pool and is used for emitting an exposure light beam towards the accommodating groove; the mother set grating is arranged in the accommodating groove; a holographic dry plate can be stacked above the mother set grating; the matching liquid is filled between the mother set grating and the holographic dry plate; and the mother set grating is used for diffracting the exposure light beam so as to form coherent light irradiating the holographic plate. The mother set grating and the holographic dry plate are stacked, and exposure is carried out only by a single beam of light, so that the exposure process is simplified, the exposure efficiency is improved, and cost reduction and batch production are facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of holographic grating exposure, and in particular to an exposure device and an exposure method for a large-size holographic grating. Background Art

[0002] Holographic waveguide is one of the important components for making augmented reality devices. Holographic waveguide is equipped with coupled-in holographic grating, folded holographic grating, coupled-out holographic grating, etc. With the continuous development of holographic waveguide technology, the demand for large-sized holographic waveguides has increased, and the production of corresponding large-sized holographic gratings has become increasingly important. Generally speaking, gratings are made by irradiating two beams of coherent light onto a holographic dry plate to form interference fringes. Due to the limitations of production technology and cost, the irradiation range of existing laser light sources is limited, and the exposure cannot be completed at one time when irradiating a holographic dry plate. Therefore, the production of large-sized holographic dry plates is generally carried out in a partitioned or scanning manner.

[0003] However, since the exposure device often needs to use two beams of coherent light for irradiation, the structure of the exposure device is complex, and the light path needs to be repeatedly adjusted during multiple exposures. The two beams of coherent light also need to be calibrated to expose the same position. The operation steps are numerous and the operation is difficult. The single exposure cycle is long and the work efficiency is low, which leads to increased production costs.

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide an exposure device and exposure method for a large-size holographic grating, aiming to solve the problem that the existing exposure device is complicated to operate, has low working efficiency and affects production costs when making large-size holographic gratings.

[0006] The technical solution of the present invention is as follows:

[0007] An exposure device for a large-size holographic grating comprises a matching pool, a light source assembly and a master grating, wherein the matching pool is provided with a receiving groove for filling a matching liquid; the light source assembly is arranged opposite to the matching pool and is used to emit an exposure beam toward the receiving groove; the master grating is arranged in the receiving groove; a holographic dry plate can be stacked above the master grating; the matching liquid is filled between the master grating and the holographic dry plate; the master grating is used to diffract the exposure beam to form coherent light for irradiating the holographic dry plate.

[0008] The exposure device for large-size holographic gratings, wherein the master grating includes a plurality of grating units, and a plurality of the grating unit arrays are arranged in the accommodating groove.

[0009] In the exposure device for large-size holographic grating, a plurality of the grating units are arranged in a straight line, and the diffraction efficiency of the grating units increases or decreases in sequence along the arrangement direction.

[0010] The exposure device for large-size holographic grating, wherein the accommodating groove comprises a first accommodating cavity and a second accommodating cavity which are connected, the first accommodating cavity is used to accommodate the holographic dry plate, and the second accommodating cavity is sunken and arranged below the first accommodating cavity to accommodate the master grating; the side wall of the accommodating groove is stepped and formed with a supporting step, and the supporting step is used to support the holographic dry plate.

[0011] The exposure device for large-size holographic grating, wherein the thickness of the master grating is less than or equal to the depth of the second accommodating cavity.

[0012] The exposure device for large-size holographic grating, wherein the holographic dry plate comprises a transparent substrate and a holographic material layer, the holographic material layer is coated on the transparent substrate; the transparent substrate and the master grating are made of the same material.

[0013] The exposure device for large-size holographic grating, wherein the transparent substrate is a glass plate or a transparent resin plate.

[0014] The exposure device for large-size holographic grating, wherein the light source assembly includes an emitter, a beam expander and a collimator, wherein the emitter is used to emit a source light beam; the beam expander and the collimator are arranged in sequence along the optical path of the source light beam; the beam expander is used to expand the diameter of the source light beam; and the collimator is used to collimate and guide the source light beam to the receiving groove.

[0015] The present application also discloses an exposure method for a large-size holographic grating, which is used in any of the exposure devices for large-size holographic gratings as described above, wherein the exposure method comprises:

[0016] Make a master raster;

[0017] Stacking the master grating and the holographic dry plate in a matching pool, filling a matching liquid into a containing tank of the matching pool to form a matching liquid layer between the master grating and the holographic dry plate;

[0018] The light source assembly is started to emit an exposure beam to the receiving groove to complete the exposure.

[0019] The exposure method of the large-size holographic grating, wherein the master grating includes a plurality of grating units; the steps of making the master grating specifically include:

[0020] Determining the exposure partition layout of the large-size holographic grating and the maximum diffraction efficiency of the holographic dry plate;

[0021] Based on the maximum diffraction efficiency of the holographic dry plate and the exposure partition layout, a plurality of grating units are linearly arranged in an increasing or decreasing order of diffraction efficiency to form a master grating.

[0022] Compared with the prior art, the embodiments of the present invention have the following advantages:

[0023] The exposure device disclosed in the present invention can manufacture a large-size holographic grating only by emitting a single beam of light from the light source assembly. Specifically, a master grating is first placed in a matching pool, and then a holographic dry plate is stacked, and then a matching liquid is poured into the receiving tank, and the matching liquid is filled into the gap between the master grating and the holographic dry plate, thereby forming a whole with a consistent refractive index. Finally, a single exposure beam is emitted through the light source assembly, and the beam directly irradiated onto the holographic dry plate is the first coherent light; the exposure beam passes through the holographic dry plate and irradiates the master grating, and after diffraction, it irradiates the holographic dry plate again to form a second coherent light, and the two coherent light beams interfere, thereby manufacturing a holographic grating.

[0024] It can be seen that by setting the master grating and the holographic dry plate to fit together, the exposure operation can be performed through a single beam of light during the exposure process, which simplifies the structure of the exposure device. When making large-size holographic gratings, whether it is scanning for multiple exposures or single exposure through a large-size light beam, it can improve the exposure efficiency and reduce the production cost, which is conducive to the mass production of large-size holographic gratings.

[0025] The exposure device of the present application has a simple structure, a compact size, greatly shortens the optical path, has a strong ability to resist vibration interference, and is conducive to improving production efficiency and product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a schematic structural diagram of an exposure device for a large-size holographic grating in the present invention;

[0028] Figure 2 It is a structural schematic diagram of a part of the structure of the exposure device of the large-size holographic grating in the present invention;

[0029] Figure 3 It is a schematic structural diagram of a part of the structure of an exposure device for a large-size holographic grating in another embodiment of the present invention;

[0030] Figure 4The figure is a flow chart of the exposure method of the large-size holographic grating in the present invention.

[0031] Among them, 10, matching pool; 11, receiving groove; 111, first receiving cavity; 112, second receiving cavity; 113, supporting step; 20, light source assembly; 21, emitter; 22, beam expander; 23, collimator; 30, master grating; 31, grating unit; 40, holographic dry plate. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] See also Figure 1 and Figure 2 In one embodiment of the present invention, an exposure device for a large-size holographic grating is disclosed, comprising a matching pool 10, a light source assembly 20 and a master grating 30. The matching pool 10 is provided with a receiving tank 11 for filling with a matching liquid; the light source assembly 20 is arranged opposite to the matching pool 10 and is used to emit an exposure beam toward the receiving tank 11; the master grating 30 is arranged in the receiving tank 11; a holographic dry plate 40 can be stacked above the master grating 30; the matching liquid is filled between the master grating 30 and the holographic dry plate 40; the master grating 30 is used to diffract the exposure beam to form coherent light for irradiating the holographic dry plate 40.

[0034] The exposure device disclosed in this embodiment is used in the production line of large-size holographic gratings. A large-size grating master is arranged in the matching pool 10 to diffract the exposure light, thereby replacing the scheme of using two light sources to emit coherent light. Only a single beam of light is needed from the light source assembly 20 to complete the exposure process, thereby simplifying the exposure device.

[0035] Specifically, according to the parameter requirements of the large-size holographic grating, a master grating 30 with a diffraction function can be manufactured in a targeted manner before processing. The size of the master grating 30 matches the size of the large-size holographic grating. If a single exposure cannot be made, the master grating 30 can be made by scanning exposure or partition exposure. The master grating 30 only needs to be manufactured once and can be reused multiple times. Compared with the solution that requires multiple adjustments to the exposure device for each large-size holographic grating, it still has the advantages of simple structure and convenient processing, which is conducive to mass production of large-size holographic gratings and reduces production costs.

[0036] During mass production, the master grating 30 is placed in the receiving groove 11 of the matching pool 10, and then the holographic dry plate 40 is stacked, and then the matching liquid pre-configured with the same refractive index as the holographic dry plate 40 and the master grating 30 is poured into the receiving groove 11. The matching liquid is filled into the tiny gap between the master grating 30 and the holographic dry plate 40, so that the master grating 30 and the holographic dry plate 40 form a whole with the same refractive index. Finally, the light source assembly 20 is started to emit a single exposure beam, and the exposure beam is directly irradiated onto the holographic dry plate 40 to form a first beam of coherent light; in addition, the exposure beam also passes through the holographic dry plate 40 and enters the master grating 30, and after diffraction occurs in the master grating 30, it is irradiated onto the holographic dry plate 40 again to form a second beam of coherent light; the two beams of coherent light interfere, thereby forming interference fringes on the holographic dry plate 40, and a large-size holographic grating is made.

[0037] It can be seen that in this embodiment, by arranging the master grating 30 and the holographic dry plate 40 to be bonded together, the exposure operation can be performed by a single beam of light during the exposure process, thereby simplifying the structure of the exposure device. When manufacturing a large-size holographic grating, whether it is a scanning type for multiple exposure operations or a single exposure operation after beam expansion by a large-size optical element, the exposure efficiency can be improved, the production cost can be reduced, and it is conducive to the mass production of large-size holographic gratings.

[0038] In addition, the exposure device of this embodiment has a simple structure and a compact size, greatly shortens the optical path, and has a strong ability to resist vibration interference, which is conducive to improving production efficiency and product quality.

[0039] Specifically, the matching pool 10 disclosed in this embodiment is used to contain the matching liquid, and to hold the master grating 30 and the holographic dry plate 40 . The light source assembly 20 is arranged opposite to the matching pool 10 .

[0040] Preferably, Figure 1 As shown, the receiving groove 11 opens upward, and the light source assembly 20 is arranged above the matching pool 10 to emit an exposure light beam from top to bottom so as to align the holographic dry plate 40 for exposure.

[0041] In addition, the present embodiment utilizes the diffraction performance of the master grating 30. The exposure light beam may be incident on the holographic dry plate 40 at an angle or vertically, and then forms a second coherent light beam through diffraction.

[0042] Preferably, Figure 1 and Figure 2 As shown, in order to facilitate the calculation of the diffraction angle, the exposure light beam can be set to vertically enter the holographic dry plate 40, and after diffraction, a second coherent light beam is formed that is obliquely emitted to the holographic dry plate 40, thereby forming a plurality of interference fringes on the holographic dry plate 40.

[0043] Specifically, the master grating 30 disclosed in this embodiment is aligned with the center of the holographic dry plate 40, and the projection area of ​​the master grating 30 on the holographic dry plate 40 covers the area to be processed on the holographic dry plate 40. During the exposure process, if the diameter of the exposure beam is large enough (for example, a large-sized lens is used to expand the exposure beam to increase the diameter of the exposure spot), the entire area to be processed can be covered at one time for exposure, and the exposure operation can be completed quickly; if the diameter of the exposure beam is not enough to cover the area to be processed, multiple exposures can be performed.

[0044] In particular, even if multiple exposures are performed, in this embodiment, it is only necessary to move the light source assembly 20 and adjust the optical path of a single exposure light beam. Compared with the traditional exposure process that requires simultaneous adjustment of two optical paths to achieve synchronous adjustment of two coherent light beams, the solution of this embodiment has the advantages of simple operation and convenience in improving exposure efficiency.

[0045] In addition, the master grating 30 disclosed in this embodiment can be a large-size holographic grating manufactured separately. The traditional manufacturing method can be used to form interference fringes on the master grating 30 for exposure so that it has diffraction ability, and then it can be used in the production line of the large-size holographic grating of this embodiment to achieve the purpose of mass production and improve production efficiency.

[0046] Specifically, the structure of the interference fringes on the large-size holographic grating in the present embodiment is determined by the diffraction performance of the master grating 30, so the large-size holographic grating finally exposed on the production line has the same structure as the master grating 30 and the same diffraction direction of the light. The optical performance of the final product is controlled by adjusting the structure of the master grating 30 during the processing. Compared with the traditional means of controlling the exposure time and exposure power of the coherent light, the scheme of the present embodiment is simpler and more accurate, which is conducive to improving the production yield of large-size holographic gratings.

[0047] Specifically, Figure 1 As shown, as another implementation of this embodiment, the accommodating groove 11 includes a first accommodating cavity 111 and a second accommodating cavity 112 that are connected. The first accommodating cavity 111 is used to accommodate the holographic dry plate 40, and the second accommodating cavity 112 is sunken below the first accommodating cavity 111 to accommodate the master grating 30. The side wall of the accommodating groove 11 is stepped and formed with a supporting step 113. The supporting step 113 is used to support the holographic dry plate 40.

[0048] In this embodiment, the cross-sectional area of ​​the holographic dry plate 40 can be set to be slightly larger than the cross-sectional area of ​​the master grating 30, so that when stacked, the edge of the holographic dry plate 40 protrudes laterally from the master grating 30 and overlaps with the matching pool 10. By setting the side wall of the accommodating groove 11 to be stepped, the holographic dry plate 40 is stably placed in the first accommodating cavity 111, and the master grating 30 in the second accommodating cavity 112 is completely covered. The master grating 30 and the holographic dry plate 40 are only in contact with each other without being squeezed against each other. The contact gap between the two is filled with matching liquid, and no air is left. Therefore, the structure is stable, there is no interference with the transmission of the light beam, and it is conducive to smooth exposure.

[0049] In addition, in this embodiment, the size of the first accommodating cavity 111 can be adapted to the size of the holographic dry plate 40, and the size of the second accommodating cavity 112 can be adapted to the size of the master grating 30, so as to facilitate positioning and assembly, reduce misalignment problems, and improve stability during exposure.

[0050] Specifically, Figure 2 and Figure 3 As shown, as another implementation of this embodiment, it is disclosed that the thickness of the master grating 30 is less than or equal to the depth of the second accommodating cavity 112. The master grating 30 disclosed in this embodiment is completely accommodated in the second accommodating cavity 112, and the holographic dry plate 40 is supported by the side wall of the accommodating groove 11, which reduces the squeezing of the master grating 30 and is conducive to the reuse of the grating unit 31.

[0051] Specifically, Figure 3 As shown, as another implementation of this embodiment, it is disclosed that the depth value of the first accommodating cavity 111 is less than the thickness value of the holographic dry plate 40. In this embodiment, the upper part of the holographic dry plate 40 protrudes out of the first accommodating cavity 111 to facilitate transportation. Before exposure, the side wall of the holographic dry plate 40 is clamped by a manipulator or a clamp to move the holographic dry plate 40 to the accommodating groove 11; after exposure, the holographic dry plate 40 can be quickly clamped and transferred. Only the side surface of the holographic dry plate 40 is contacted during the movement, which is conducive to reducing the contact with the top surface of the holographic dry plate 40 and improving the stability of transportation.

[0052] For example Figure 1 As shown, as another implementation of this embodiment, it is disclosed that the light source assembly 20 includes an emitter 21, a beam expander 22 and a collimator 23, wherein the emitter 21 is used to emit a source light beam; the beam expander 22 and the collimator 23 are arranged in sequence along the optical path of the source light beam; the beam expander 22 is used to expand the diameter of the source light beam; the collimator 23 is used to collimate and guide the source light beam to the receiving slot 11.

[0053] In this embodiment, the emitter 21 includes but is not limited to a laser, the beam expander 22 includes but is not limited to an objective lens, and the collimator 23 includes but is not limited to a convex lens. The source light beam emitted by the emitter 21 has a small spot area, so the beam expander 22 is arranged on the optical path to increase the irradiation area of ​​the light beam; and the collimator 23 is arranged to collimate the expanded light beam to form an exposure light beam parallel to the receiving groove 11. In this embodiment, only one emitter 21 is arranged, and only one optical path is controlled by the beam expander 22 and the collimator 23, so that the exposure processing of a large-size holographic grating can be realized, which has a simple structure, convenient operation, low cost, and easy maintenance.

[0054] Specifically, Figure 3 As shown, as an implementation of this embodiment, it is disclosed that the master grating 30 includes a plurality of grating units 31, and the plurality of grating units 31 are arranged in an array in the receiving groove 11. In this embodiment, a plurality of grating units 31 can be manufactured through a traditional exposure process, using an optical lens and an exposure device of a commonly used size, thereby reducing the production cost. Then, according to the manufacturing requirements, a suitable number of grating units 31 are arranged to form a master grating 30, and the arrangement can be linear, rectangular, arc, annular, etc., which can be flexibly selected according to actual processing needs. Compared with the directly molded integrated master grating, the operation is simpler, more flexible, and has good versatility, and it can be repeatedly used according to manufacturing needs, which is conducive to reducing the manufacturing cost of the master grating 30.

[0055] Specifically, the grating units 31 disclosed in this embodiment are bonded to each other and placed in the matching pool 10. When the matching liquid is poured into the receiving tank 11, the matching liquid can also fill the tiny gaps between adjacent grating units 31, thereby connecting the multiple grating units 31 into one to form a master grating 30, thereby improving the uniformity of diffraction.

[0056] In one implementation of this embodiment, it is disclosed that the diffraction efficiency of each grating unit 31 is the same. A plurality of grating units 31 are spliced ​​together in a manner similar to movable type printing, and are randomly combined in the receiving groove 11. During the exposure process, the diffraction efficiency of each position on the master grating 30 is uniform, which is conducive to forming regularly arranged interference fringes and improving the production yield.

[0057] Specifically, when a large-sized holographic grating is applied to an optical waveguide display, in order to ensure the uniformity of the brightness of the coupled-out image, the coupled-out grating is divided into regions, and different regions have different exposure amounts, and therefore have different diffraction efficiencies. Although the specific grating sizes are different, the structure of the partitioned grating has a certain degree of versatility and repeatability. Therefore, in the manufacturing process of the large-sized holographic grating, it can be planned in advance. In another implementation of the present embodiment, a plurality of the grating units 31 are arranged in a straight line, and the diffraction efficiency of the grating units 31 increases or decreases successively along the arrangement direction.

[0058] In this embodiment, the partitions on the large-scale holographic grating are determined by the propagation direction of the light path in the optical waveguide, so during the manufacturing process, it is necessary to divide multiple regions perpendicular to the light path direction, so a number of partitions are arranged in a linear manner. In order to make a large-scale holographic grating with multiple partitions with different diffraction efficiencies, multiple grating units 31 with different diffraction efficiencies can be arranged in sequence to form a master grating 30 with a clear partition effect.

[0059] For example, the size requirement of a large-size holographic grating is 400 millimeters (mm) in length and 200 mm in width, and it needs to be divided into 5 regions according to the image uniformity requirement. Then, the master grating 30 can be divided into 5 80 mm×200 mm strip grating units 31 according to the light guiding direction of the large-size holographic grating. In addition, the maximum diffraction efficiency of the grating unit 31 can be determined according to the material type of the grating unit 31, and then the diffraction efficiency of each region can be calculated according to the number of partitions. For example, if the maximum diffraction efficiency of the grating unit 31 is 80%, the diffraction efficiencies of the five grating units 31 are set to 19.0%, 23.5%, 30.7%, 44.4%, and 80% respectively.

[0060] The partition positions of different diffraction efficiencies on the large-size holographic grating manufactured in this embodiment are clear, and the exposure process is simple to operate. Compared with the traditional exposure process that needs to control the diffraction efficiency by adjusting parameters such as the exposure time and exposure power of the two coherent light beams, the method of directly adjusting the master grating 30 in this embodiment is more direct, simple to operate, and has less adjustment workload, which is conducive to flexible response to different production requirements.

[0061] Specifically, in another implementation of the present embodiment, it is disclosed that a plurality of grating units 31 can be reused. By adjusting the arrangement and combination of the grating units 31 on different production lines, the production cost can be further reduced and the production efficiency can be improved.

[0062] For example, the production line for producing large-size holographic gratings with a size of 400mm×200mm can share some grating units 31 with the production line for producing large-size holographic gratings with a size of 320mm×300mm. Specifically, a batch of grating units 31 with different diffraction efficiencies of 80mm×50mm can be pre-made, and in the production line for large-size holographic gratings with a size of 400mm×200mm, the grating units 31 with diffraction efficiencies of 19.0%, 23.5%, 30.7%, 44.4%, and 80% are arranged in a 5×4 matrix to form a master grating 30; in the production line for large-size holographic gratings with a size of 320mm×300mm, the grating units 31 with diffraction efficiencies of 23.5%, 30.7%, 44.4%, and 80% are arranged in a 4×6 matrix to form a master grating 30.

[0063] It can be seen that compared with the method of adjusting exposure parameters to produce holographic gratings with different diffraction efficiencies in the traditional exposure process, the grating unit disclosed in this embodiment has the advantages of high flexibility in use and can be reused for the production of holographic gratings of different sizes, which is conducive to further reducing the cost of the production line of large-size holographic gratings and improving production efficiency.

[0064] Specifically, as another implementation of this embodiment, it is disclosed that the holographic dry plate 40 includes a transparent substrate and a holographic material layer, and the holographic material layer is coated on the transparent substrate; the transparent substrate and the master grating 30 are made of the same material.

[0065] The matching liquid disclosed in this embodiment has the same refractive index as the transparent substrate, so that after filling with the matching liquid, the holographic dry plate 40 and the master grating 30 are connected as one, and the exposure light beam can be directly transmitted to the master grating 30 after entering the holographic dry plate 40 without refraction, so that the optical path of the second coherent light beam can be more accurately controlled to increase the control accuracy of the interference fringes on the holographic dry plate 40.

[0066] Specifically, in another implementation of this embodiment, the transparent substrate and the master grating 30 can be a glass plate or a transparent resin plate. The high light transmittance of glass or resin materials is beneficial to improve exposure efficiency.

[0067] like Figure 4 As shown, as another embodiment of the present application, an exposure method of a large-size holographic grating is disclosed, which is used in any of the exposure devices for large-size holographic gratings as described above, wherein the exposure method comprises:

[0068] S100, making a master grating 30;

[0069] S200, stacking the master grating 30 and the holographic dry plate 40 in a matching pool 10, filling a matching liquid into the containing tank 11 of the matching pool 10, and forming a matching liquid layer between the master grating 30 and the holographic dry plate 40;

[0070] S300, start the light source assembly 20 to emit an exposure beam to the receiving groove 11 to complete exposure.

[0071] In this embodiment, the master grating 30 is placed below the holographic dry plate 40, and then a single exposure light beam is injected from above, so that the exposure processing of the large-size holographic grating is realized, with fewer operation steps and high processing efficiency; and the holographic dry plate 40 is on the top and the master grating 30 is on the bottom. After the processing is completed, the holographic dry plate 40 can be taken out separately, leaving the master grating 30, and then the next holographic dry plate 40 to be processed is put in, so that the exposure of the next workpiece can be carried out quickly, which is convenient for the transportation of the workpiece and suitable for mass production.

[0072] Specifically, as an implementation of this embodiment, it is disclosed that the master grating 30 includes a plurality of grating units 31; the step S100 specifically includes:

[0073] S110, determining the exposure partition layout of the large-size holographic grating and the maximum diffraction efficiency of the holographic dry plate 40;

[0074] S120 , based on the maximum diffraction efficiency of the holographic dry plate 40 and the exposure partition layout, a plurality of the grating units 31 are linearly arranged in an increasing or decreasing order of diffraction efficiency to form a master grating 30 .

[0075] In this embodiment, the layout of the exposure partitions of the large-size holographic grating to be manufactured and the maximum diffraction efficiency of the holographic dry plate 40 (determined according to the material of the holographic dry plate 40) are determined in advance according to the coupling-out parameters of the optical waveguide. The structure of the large-size holographic grating can be reasonably designed, thereby inferring the structure of the master grating 30. Then, the corresponding grating units 31 are arranged according to the preset structure, so that the master grating 30 can be accurately and efficiently manufactured to facilitate mass production of products.

[0076] It should be understood that the various parts of the present application can be implemented in hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array, a field programmable gate array, etc.

[0077] In addition, each functional unit in each embodiment of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0078] In summary, the present application discloses an exposure device for a large-size holographic grating, which includes a matching pool 10, a light source assembly 20 and a master grating 30. The matching pool 10 is provided with a receiving groove 11 for filling a matching liquid. The light source assembly 20 is arranged opposite to the matching pool 10 and is used to emit an exposure beam toward the receiving groove 11. The master grating 30 is arranged in the receiving groove 11. A holographic dry plate 40 can be stacked above the master grating 30. The matching liquid is filled between the master grating 30 and the holographic dry plate 40. The master grating 30 is used to diffract the exposure beam to form coherent light for irradiating the holographic dry plate 40. The exposure device disclosed in this embodiment sets the master grating 30 and the holographic dry plate 40 in contact with each other, and the exposure operation can be performed by a single beam of light during the exposure process, thereby simplifying the structure of the exposure device. When making a large-sized holographic grating, whether it is a scanning method for multiple exposures or a single exposure through a large-sized light beam, the exposure efficiency can be improved, the production cost can be reduced, and it is conducive to the mass production of large-sized holographic gratings.

[0079] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0080] It should be noted that the present invention takes the exposure device and exposure method of a large-size holographic grating as an example to introduce the specific structure and working principle of the present invention, but the application of the present invention is not limited to the exposure device and exposure method of a large-size holographic grating, and can also be applied to the production and use of other similar workpieces.

[0081] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An exposure device for a large-size holographic grating, characterized in that: include: A matching pool, wherein the matching pool is provided with a receiving tank for filling the matching liquid; A light source assembly, arranged opposite to the matching pool, and configured to emit an exposure light beam toward the receiving slot; as well as A master grating is arranged in the containing groove; a holographic dry plate can be stacked on the master grating; the matching liquid is filled between the master grating and the holographic dry plate; The master grating is used to diffract the exposure light beam to form coherent light for illuminating the holographic dry plate.

2. The exposure device for large-size holographic grating according to claim 1, characterized in that: The master grating includes a plurality of grating units, and a plurality of the grating unit arrays are arranged in the containing groove.

3. The exposure device for large-size holographic grating according to claim 2, characterized in that: A plurality of the grating units are arranged in a straight line, and the diffraction efficiencies of the grating units increase or decrease in sequence along the arrangement direction.

4. The exposure device for large-size holographic grating according to claim 1, characterized in that: The receiving groove comprises a first receiving cavity and a second receiving cavity which are connected to each other, wherein the first receiving cavity is used to receive the holographic dry plate, and the second receiving cavity is sunken and arranged below the first receiving cavity to receive the master grating; Wherein, the side wall of the containing groove is in a stepped shape, forming a supporting step, and the supporting step is used to support the holographic dry plate.

5. The exposure device for large-size holographic grating according to claim 4, characterized in that: The thickness of the master grating is less than or equal to the depth of the second accommodating cavity.

6. The exposure device for a large-size holographic grating according to any one of claims 1 to 5, characterized in that: The holographic dry plate comprises a transparent substrate and a holographic material layer, wherein the holographic material layer is coated on the transparent substrate; the transparent substrate and the master grating are made of the same material.

7. The exposure device for large-size holographic grating according to claim 6, characterized in that: The transparent substrate is a glass plate or a transparent resin plate.

8. The exposure device for large-size holographic grating according to claim 1, characterized in that: The light source assembly comprises: an emitter, for emitting a source light beam; A beam expander and a collimator are sequentially arranged along the optical path of the source light beam; the beam expander is used to expand the diameter of the source light beam; and the collimator is used to collimate and guide the source light beam to the receiving groove.

9. An exposure method for a large-size holographic grating, used in an exposure device for a large-size holographic grating as claimed in any one of claims 1 to 8, characterized in that: The exposure method comprises: Make a master raster; Stacking the master grating and the holographic dry plate in a matching pool, filling a matching liquid into a containing tank of the matching pool to form a matching liquid layer between the master grating and the holographic dry plate; The light source assembly is started to emit an exposure beam to the receiving groove to complete the exposure.

10. The exposure method of a large-size holographic grating according to claim 9, characterized in that: The master grating includes a plurality of grating units; the steps of making the master grating specifically include: Determining the exposure partition layout of the large-size holographic grating and the maximum diffraction efficiency of the holographic dry plate; Based on the maximum diffraction efficiency of the holographic dry plate and the exposure partition layout, a plurality of grating units are linearly arranged in an increasing or decreasing order of diffraction efficiency to form a master grating.

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