Volume holographic exposure equipment

Abstract

The utility model discloses volume holographic exposure equipment. The volume holographic exposure equipment comprises an optical system, a glue uniformizing system and an exposure platform, the glue uniformizing system is located in the first box body, the exposure platform is located in the second box body, a communication part is arranged between the first box body and the second box body, the first box body and the second box body are both inert gas boxes, one of the first box body and the second box body is provided with an inert gas inlet used for being connected with inert gas inlet equipment, and the other one of the first box body and the second box body is provided with an inert gas outlet used for being connected with inert gas outlet equipment. The other one is provided with an inert gas outlet; the glue uniformizing system is used for coating a material to be exposed on the surface of the waveguide substrate to form a glue uniformizing waveguide substrate and conveying the glue uniformizing waveguide substrate to the exposure platform through the communicating part; and the optical system is used for emitting an exposure light beam to the exposure platform so as to expose the spin-coating waveguide substrate to form an exposed waveguide substrate. According to the volume holographic exposure equipment, a volume holographic waveguide sheet formed in an inert gas environment is light and thin, and the contrast ratio and the resolution ratio are improved in the imaging effect.

Description

Technical Field

[0001] The utility model relates to the technical field of optical waveguides, in particular to a volume holographic exposure device. Background Art

[0002] Augmented Reality (AR) is an innovation in visual experience and human-computer interaction. It is a new technology that "seamlessly" integrates real-world information and virtual-world information.

[0003] In order to obtain a more realistic system that combines virtual and reality, so that the convenience of practical application is continuously improved and the use of colors is rich, the optical display system of AR devices is particularly important. The optical display system of AR devices is usually composed of a micro display screen and optical components. The display system used by AR glasses on the market is a combination of various micro display screens and optical components such as prisms, free-form surfaces, BirdBath, and optical waveguides. Among them, the current mainstream solution is the optical waveguide solution, which includes a surface relief grating waveguide solution and a volume holographic grating waveguide solution. The volume holographic grating waveguide uses a volume holographic grating instead of a surface relief grating. However, the problem is that the preparation of volume holographic waveguide sheets is relatively complicated and the cost is very high. Utility Model Content

[0004] The utility model provides a volume holographic exposure device to solve the problem in the related art that a single-piece volume holographic waveguide is prepared in a water-oxygen environment and that the volume holographic material is easily deteriorated when exposed in the water-oxygen environment, thereby improving the preparation yield of the volume holographic waveguide.

[0005] To achieve the above-mentioned purpose, the embodiment of the utility model provides a volume holographic exposure device, including: an optical system, a coating system and an exposure platform;

[0006] The coating system is located in a first box, and the exposure platform is located in a second box. A connecting portion is provided between the first box and the second box. Both the first box and the second box are inert gas boxes, wherein one of the first box and the second box is provided with an inert gas inlet for connecting to an inert gas inlet device, and the other is provided with an inert gas outlet;

[0007] The coating system is used to coat the surface of the waveguide substrate with the material to be exposed to form a coated waveguide substrate, and transmit the coated waveguide substrate to the exposure platform through the connecting part; the optical system is used to emit an exposure light beam to the exposure platform to expose the coated waveguide substrate to form an exposed waveguide substrate.

[0008] Optionally, one of the first box body and the second box body is provided with a dust removal air outlet to connect a dust removal device.

[0009] Optionally, the optical system comprises:

[0010] A laser, for emitting a laser beam;

[0011] A first beam expander, an aperture, a second beam expander and a reflective element are sequentially arranged in the transmission direction of the laser beam to guide the laser beam to form the exposure beam.

[0012] Optionally, the laser beam is a polarized beam, and the optical system further includes a half-wave plate, and the half-wave plate is located between the aperture and the second beam expanding element.

[0013] Optionally, the glue-spinning system comprises: a cleaning device, a glue-spinning device and a conveying device;

[0014] The cleaning device is located upstream of the glue-spreading device and is used to clean the waveguide substrate. The glue-spreading device is used to glue the cleaned waveguide substrate. The conveying device is located downstream of the glue-spreading device and is used to convey the glue-spread waveguide substrate to the exposure platform through the connecting part.

[0015] Optionally, a first glove operation port is provided on a side wall of the first box body, and the side wall where the first glove operation port is provided corresponds to the space between the cleaning device and the glue spreading device.

[0016] Optionally, the exposure platform includes a baffle, a mask, and an angle rotation device which are sequentially arranged along the direction of transmission of the exposure beam; and are all located in a plane displacement device; the plane displacement device is equipped with a workpiece table, a first through hole is arranged on the workpiece table, and the mask is embedded in the first through hole to form the bottom of the second box;

[0017] The first through hole is further provided with the angle rotating device, a waveguide fixing frame is provided on the angle rotating device, and the baffle is located at a side of the mask away from the waveguide fixing frame;

[0018] The plane displacement device is capable of translating the workpiece stage, the rotation axis of the angle rotation device is colinear with the central axis of the first through hole, and the baffle is provided with a second through hole for exposure by the exposure beam.

[0019] Optionally, the waveguide fixing frame includes at least two brackets, each bracket includes a support rod and a limiter, one end of the support rod is fixed to the angle rotation device, and the other end is fixedly connected to the limiter, and the limiter is used to limit the position of the glue-bonded waveguide substrate on the exposure platform.

[0020] Optionally, the inner walls of the second box are coated with light absorbing material.

[0021] Optionally, a second glove operation port is provided on a side wall of the second box body, and the side wall where the second glove operation port is provided corresponds to the exposure platform.

[0022] Optionally, the volume holographic exposure device further comprises: a curing light source and a curing platform, the curing platform is located in the second box, and the curing light source is used to cure the exposure waveguide substrate.

[0023] The volume holographic exposure device proposed in the embodiment of the utility model includes: an optical system, a coating system and an exposure platform; the coating system is located in a first box, the exposure platform is located in a second box, a connecting portion is provided between the first box and the second box, and the first box and the second box are both inert gas boxes, wherein one of the first box and the second box is provided with an inert gas inlet for connecting to an inert gas inlet device, and the other is provided with an inert gas outlet; the coating system is used to coat the surface of the waveguide substrate with a material to be exposed to form a coating waveguide substrate, and the coating waveguide substrate is transferred to the exposure platform through the connecting portion; the optical system is used to emit an exposure beam to the exposure platform to expose the coating waveguide substrate to form an exposure waveguide substrate. The volume holographic waveguide sheet formed by the volume holographic exposure device in an inert gas environment is thin and light, and the contrast and resolution are improved in the imaging effect.

[0024] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present utility model, nor are they intended to limit the scope of the present utility model. Other features of the present utility model will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 It is a structural schematic diagram of a volume holographic exposure device proposed in an embodiment of the utility model;

[0027] Figure 2 It is a structural schematic diagram of a volume holographic exposure device proposed in one embodiment of the utility model;

[0028] Figure 3 is a structural schematic diagram of a volume holographic exposure device proposed in another embodiment of the utility model;

[0029] Figure 4is a structural schematic diagram of a volume holographic exposure device proposed in yet another embodiment of the utility model;

[0030] Figure 5 It is a schematic structural diagram of an exposure platform of a volume holographic exposure device proposed in one embodiment of the utility model;

[0031] Figure 6 It is a schematic diagram of a two-dimensional pupil expansion waveguide in the related art;

[0032] Figure 7 It is a schematic structural diagram of an exposure platform of a volume holographic exposure device proposed in another embodiment of the utility model;

[0033] Figure 8 It is a structural schematic diagram of an exposure platform of a volume holographic exposure device proposed in another embodiment of the utility model;

[0034] Fig. 9 It is a structural schematic diagram of an exposure platform of a volume holographic exposure device proposed in yet another embodiment of the utility model.

[0035] Reference numerals: 100, volume holographic exposure equipment; 200, optical system; 300, coating system; 400, exposure platform; 500, coating waveguide substrate; 600, curing light source; 601, curing platform;

[0036] 101, first box; 102, second box; 103, connecting part; 104, inert gas inlet 105, inert gas outlet; A, inert gas inlet device; 106, dust removal air outlet; 107, first glove operation port; 108, second glove operation port;

[0037] 201, laser; 202, first beam expanding element; 203, aperture; 204, second beam expanding element; 205, reflecting element; 206, half-wave plate;

[0038] 301, cleaning equipment, 302, glue spreading equipment; 303, conveying equipment;

[0039] 401, baffle; 402, mask; 403, plane displacement device; 404, angle rotation device; 405, workpiece stage; 406, workpiece stage base; 407, waveguide fixing frame; 4071, first bracket; 4072, second bracket; 408, first through hole; 409, second through hole; 410, X-axis displacement axis; 411, Y-axis displacement axis;

[0040] 071, support rod; 072, limiter; 501, coupling-in zone baffle; 502, turning zone baffle; 503, coupling-out zone baffle; 701, coupling-in zone; 702, turning zone; 703, coupling-out zone. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0042] It should be noted that the terms "first", "second", etc. in the specification and claims of the present utility model and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the utility model described herein can be implemented in an order other than those illustrated or described herein.

[0043] Figure 1 It is a schematic diagram of the structure of the volume holographic exposure device proposed in the embodiment of the utility model. Figure 2 FIG. 1 is a schematic diagram of the structure of a volume holographic exposure device according to an embodiment of the present invention. Figure 1 and Figure 2 As shown, the volume holographic exposure device 100 includes: an optical system 200, a coating system 300 and an exposure platform 400;

[0044] The coating system 300 is located in the first box 101, and the exposure platform 400 is located in the second box 102. A connecting portion 103 is provided between the first box 101 and the second box 102. Both the first box 101 and the second box 102 are inert gas boxes, wherein one of the first box 101 and the second box 102 is provided with an inert gas inlet 104 for connecting to an inert gas inlet device A, and the other is provided with an inert gas outlet 105;

[0045] The coating system 300 is used to coat the surface of the waveguide substrate with the material to be exposed to form a coated waveguide substrate, and transmit the coated waveguide substrate to the exposure platform 400 through the connecting part 103; the optical system 200 is used to emit an exposure light beam to the exposure platform 400 to expose the coated waveguide substrate 500 to form an exposed waveguide substrate.

[0046] It should be noted that the above-mentioned material to be exposed can be a HPDLC (Holographic Polymer Dispersed Liquid Crystal) material. Nitrogen or rare gas (helium) can be introduced into the inert gas box, and the utility model does not impose specific restrictions on this. The inert gas intake device is used to introduce inert gas into the first box body 101 and the second box body 102 through the inert gas inlet 104. The inert gas can be discharged from the inert gas outlet 105 after circulating in the first box body 101 and the second box body 102. The waveguide substrate is placed in an inert gas environment during the coating process and the exposure process, thereby avoiding chemical reactions of the volume holographic material in the water-oxygen environment during the coating process of the coating system and the exposure process of the exposure platform, thereby reducing the imaging effect of the volume holographic waveguide sheet.

[0047] It is understandable that the above-mentioned connecting portion 103, in Figure 1 The size of the opening in the x-direction shown can be less than or equal to the size of the opening in the x-direction of the first box 101 or the second box 102. In one embodiment, the first box 101 and the second box 102 can be integrally formed and combined into an inert gas box to reduce the complexity of the preparation process. It should be noted that the first box 101 and the second box 102 can be integrally formed into a straight line shape or an L-shape, which is not limited here. In practice, the corresponding design can be made according to the specific structure of the coating system 300 and the exposure platform 400.

[0048] Therefore, when the coating system 300 coats the waveguide substrate with the material to be exposed, it is in an inert gas environment that isolates water and oxygen, so that the material to be exposed is easier to maintain stability and is not easy to deteriorate. After the coating system 300 coats the waveguide substrate, the coated waveguide substrate 500 is transmitted to the exposure platform 400 through the connecting portion 103. When the exposure platform 400 exposes the coated waveguide substrate, the material to be exposed coated on the waveguide substrate is still in an inert gas environment that isolates water and oxygen, so that water and oxygen are isolated during the coating and exposure process of the waveguide substrate, the stability of the material to be exposed is maintained, the quality of the final volume holographic waveguide sheet is improved, and then, the imaging effect of the volume holographic waveguide sheet is improved.

[0049] Optionally, refer to Figure 2 As shown, one of the first box body 101 and the second box body 102 is provided with a dust removal air outlet 106 for connecting a dust removal device.

[0050] It is understandable that the dust removal device can perform dust removal operations on the first box 101 and the second box 102 through the dust removal vents 106, so that the first box 101 and the second box 102 are both in a dust-free environment, further improving the glue quality of the glue system 300 during the glue process and the exposure quality of the exposure platform 400 during the exposure process.

[0051] Optionally, refer to Figure 2 As shown, the optical system 200 includes:

[0052] Laser 201, used for emitting a laser beam;

[0053] The first beam expanding element 202, the aperture 203, the second beam expanding element 204 and the reflecting element 205 are sequentially arranged in the transmission direction of the laser beam to guide the laser beam to form an exposure beam.

[0054] It is understandable that the laser 201 can use a 532nm laser, and the first beam expander 202 can use a 10x beam expander. The aperture 203 can be used as a switch for the exposure process (for example, the aperture 203 can be kept closed before the exposure process begins, and the laser 201 is opened first, so that the light source is stabilized first. At the beginning of the exposure process, the aperture 203 is then opened to output a stable light source). The second beam expander 204 can use a Keplerian beam expansion method or a Galilean beam expansion method. When the Keplerian beam expansion method is used, that is, two lenses with positive focal lengths are composed to obtain a 4x beam expansion. The reflective element 205 can be a reflector, which is used to reflect the light spot to the exposure platform 400 and play a role in adjusting the exposure angle. In other embodiments, the reflective element 205 can also be one of a scanning galvanometer, a rotating prism, or a reflecting prism. The present invention does not make specific restrictions on this.

[0055] Optionally, Figure 3 FIG. 1 is a schematic diagram of the structure of a volume holographic exposure device according to another embodiment of the present invention. Figure 3 As shown, the laser beam is a polarized beam, and the optical system 200 further includes a half-wave plate 206 , which is located between the aperture 203 and the second beam expanding element 204 .

[0056] It should be noted that a mask is required during the exposure process of the rear exposure platform 400. Since the mask has a grating structure, different grating structures have different diffraction efficiencies for different polarized lights. Furthermore, during the exposure process of the photosensitive waveguide substrate 500, if different grating structure areas are formed, the half-wave plate 206 can be adjusted to change the polarization direction of the exposure beam so that the direction of the polarized light matches the corresponding grating structure, and the diffraction efficiency can reach the target value.

[0057] Optionally, refer to Figure 2 and Figure 3 As shown, the glue-spinning system 300 includes: a cleaning device 301, a glue-spinning device 302 and a conveying device 303;

[0058] The cleaning device 301 is located upstream of the glue-spreading device 302 and is used to clean the waveguide substrate. The glue-spreading device 302 is used to spread glue on the cleaned waveguide substrate. The conveying device 303 is located downstream of the glue-spreading device 302 and is used to convey the waveguide substrate after spread glue to the exposure platform 400 through the connecting part.

[0059] Among them, the cleaning device 301 is used to clean the waveguide substrate to remove small particles on the surface of the waveguide substrate to avoid uneven glue spreading in the subsequent glue spreading device 302. The glue spreading device 302 can be a glue spreading machine, which is used to coat the HPDLC material on the surface of the waveguide substrate. After the pre-treatment of the waveguide substrate is completed, the conveying device 303 can be a conveyor belt to convey the glued waveguide substrate 500 to the exposure platform 400.

[0060] Optionally, refer to Figure 2 and Figure 3 As shown, a first glove operation port 107 is provided on the side wall of the first box body 101 , and the side wall where the first glove operation port 107 is provided corresponds to the space between the cleaning device 301 and the glue-spinning device 303 .

[0061] Among them, since the glue-spreading system 300 is in a closed space, a first glove operation port 107 can be set on the side wall of the first box body 101 corresponding to the space between the cleaning device 301 and the glue-spreading device 303 to facilitate manual turning over or shifting of the waveguide substrate.

[0062] Optionally, Figure 5 Schematic diagram of the structure of the exposure platform of the volume holographic exposure device proposed in one embodiment of the utility model. Figure 2 , Figure 3 and Figure 5 As shown, the exposure platform 400 includes a baffle 401 , a mask plate 402 , and an angle rotation device 404 which are sequentially arranged along the transmission direction of the exposure beam and are all located in the plane displacement device 403 .

[0063] The plane displacement device 403 is equipped with a workpiece stage 405, and a first through hole 408 is provided on the workpiece stage 405. The mask 402 is embedded in the first through hole 408 to form the bottom of the second box 102;

[0064] The first through hole 408 is further provided with an angle rotating device 404, on which a waveguide fixing frame 407 is provided, and the baffle 401 is located on a side of the mask 402 away from the waveguide fixing frame 407;

[0065] The plane displacement device 403 can translate the workpiece stage 405 , the rotation axis of the angle rotation device 404 is colinear with the central axis of the first through hole 408 , and the baffle 401 is provided with a second through hole 409 for exposure by an exposure beam.

[0066] The workpiece stage 405 is located on a workpiece stage base 406, and the workpiece stage base 406 is adapted to the plane displacement device 403. The plane displacement device 403 can drive the workpiece stage base 406 to move along the x direction or the y direction, so as to drive the workpiece stage 405 to move in the x / y plane.

[0067] It is understandable that the workpiece platform 405 is provided with a first through hole 408, which can be Figure 5 The circular hollow shown in the figure, the light spot can be transmitted along the z direction through the circular hollow. The side wall of the second box body 102 can be set at the edge of the workpiece stage 405, and the shape is a cover covering the workpiece stage 405. The circular hollow part of the workpiece stage 405 is sealed by the mask 402, so as to form a closed environment. The workpiece stage 405 is equipped with two electrically controlled displacement axes and an electrically controlled angle rotation device 404, which are the X-axis displacement axis 410, the Y-axis displacement axis 411, and the θ-angle rotation axis. Among them, the accuracy of the electrically controlled displacement axis is 0.01mm, and the accuracy of the electrically controlled angle rotation device 404 is 0.01°. The X-axis displacement axis 410 and the Y-axis displacement axis 411 are used to adjust the center point of the exposure area to align with the center of the light spot. The angle rotation device 404 is a circular rotatable frame with a scale, which can be rotated arbitrarily by an angle of θ to move the glue-bonded waveguide substrate 500, and expose gratings with different angles and different grating inclinations. The baffle 401 is used for shielding light. Its outer contour can be a circle that is consistent with the angle rotating device 404. Its inner contour (i.e., the second through hole 409) is the pattern shape of the required exposure grating. The entire baffle 401 is made of an opaque material. The contour of the mask 402 is consistent with the circular contour of the angle rotating device 404. In one embodiment, the mask 402 can also be fixed on the bottom ring frame of the angle rotating device 404, and the bottom ring frame will not rotate the angle of the mask 402. The entire surface of the mask 402 is a grating structure, which can cause diffraction to form interference. The outer contour of the mask 402 is the single maximum exposure area.

[0068] Therefore, combined with Figure 3 and Figure 5 The exposure beam first reaches the baffle 401, passes through the second through hole 409 (the shape is generally the outer contour of the exposure grating) in the baffle 401, irradiates the mask 402, and irradiates the smeared waveguide substrate 500 on the mask 403 through the mask 403, thereby completing the exposure of the smeared waveguide substrate 500. If grating areas of different shapes are exposed on the same waveguide substrate, the corresponding baffle 401 can be replaced.

[0069] In this embodiment, since the workpiece table base 406 drives the workpiece table 405 to move, and the side wall of the second box body 102 is located at the edge of the workpiece table 405, the connecting part 103 between the first box body 101 and the second box body 102 can be set as a retractable connecting part, such as a corrugated type or spring type connecting part.

[0070] Optionally, continue to refer to Figure 5 The waveguide fixing frame 407 includes at least two brackets (4071 / 4072), the bracket includes a support rod 071 and a limiter 072, one end of the support rod 071 is fixed to the angle rotation device 404, and the other end is fixedly connected to the limiter 072, and the limiter 072 is used to limit the position of the glue-bonded waveguide substrate 500 on the exposure platform 400.

[0071] It should be noted that when there are two waveguide fixing frames 407, they include a first bracket 4071 and a second bracket 4072, wherein the first bracket 4071 and the second bracket 4072 are located on the same diameter of the first through hole 408 to better fix the glue-spreading waveguide substrate 500. When there are three waveguide fixing frames 407, the central angle between the three brackets can be 120°. By analogy, when the waveguide fixing frame 407 has multiple brackets, the multiple brackets can be distributed on the angle rotating device 404 at intervals of the same central angle. In one embodiment, the material of the waveguide fixing frame 407 can be a glass block.

[0072] Optionally, the inner wall of the second box 102 is coated with light absorbing material. Thus, the light absorbing wall made of light absorbing material is used to absorb the laser diffracted during exposure, so as to prevent the laser from hitting the second box 102 and reflecting back to the waveguide substrate, and the stray light formed will affect the exposure.

[0073] Alternatively, if Figure 2 and Figure 3 As shown, a second glove operation port 108 is provided on the side wall of the second box body 102, and the side wall where the second glove operation port 108 is provided corresponds to the exposure platform 400. This facilitates manual turning over or shifting of the waveguide substrate.

[0074] Alternatively, if Figure 2 and Figure 3 As shown, the volume holographic exposure device 100 further includes: a curing light source 600 and a curing platform ( Figure 2 and Figure 3 The curing platform is located in the second box 102, and the curing light source 600 is used to cure the exposed waveguide substrate.

[0075] In one embodiment, Figure 4 As shown, the curing platform 601 can be placed between the exposure platform 400 and the conveying device 303, or as shown in FIG. Figure 2 and Figure 3 As shown, it is placed downstream of the exposure platform 400 and is made of glass. The conveying device 303 (i.e., the conveyor belt) contacts the bottom of the first box 101 at one end of the first box 101, and the first box 101 provides it with support. The conveyor belt is in a free state at one end of the second box 102, and will not cause obstruction to the second box 102 when the exposure platform 400 is displaced. Among them, the curing light source 600 is located below the curing platform 601. The curing platform 601 can be located in the second box 102, near the second glove operation port 108, so that after the exposure is completed, the exposure waveguide substrate can be manually transferred to the curing platform 601, and the curing light source 600 located below the curing platform 601 is turned on to cure the exposure waveguide substrate.

[0076] When the curing platform 601 is placed between the exposure platform 400 and the conveying device 303, the coated waveguide substrate 500 can be conveyed to the curing platform 601 after the coating is applied, and then the coated waveguide substrate 500 can be placed on the exposure platform 400 from the curing platform 601. When the curing platform 601 is located downstream of the exposure platform 400, the coated waveguide substrate 500 can be conveyed to the exposure platform 400 by the conveying device 303, and then, after the exposure platform 400 is exposed to form an exposed waveguide substrate, the exposed waveguide substrate is taken out and placed on the curing platform 601. The curing platform 601 can be integrated with the bottom of the second box 102 (the curing platform is made of transparent glass) or set independently from the second box 102, and the part of the second box 102 where the curing platform 601 is set can be hollowed out and inlaid with the curing platform 601.

[0077] The curing light source 600 may be an incandescent light source, which is in a plane shape and is located next to the exposure platform 400 and below the curing platform 601 in the second box 102, and plays a role in post-curing the waveguide substrate after the exposure. Therefore, the steps of cleaning, coating, conveying, exposure and curing of the waveguide substrate are all located in the inert gas box, which isolates water and oxygen, and improves the preparation quality of the waveguide substrate.

[0078] Based on the above-mentioned volume holographic exposure equipment, a specific implementation method is as follows: the waveguide substrate and the HPDLC material are placed in the interior of the inert gas box in advance, and dust removal is performed, and then the inert gas box is filled with nitrogen. After the nitrogen is filled, the wind speed is reduced, and only a weak nitrogen circulation is left. Then, the waveguide substrate is placed in a cleaning machine for cleaning, and can be taken out of the cleaning machine through the first glove operation port 107 and placed in the air outlet for drying. Then, the waveguide substrate can be placed in a glue-splitting machine through the first glove operation port 107, and the material is dripped on the glass for glue-splitting, so as to form a uniform layer of HPDLC material on the glass. Then, the glue-splitting waveguide substrate is placed on the conveyor belt, and the glue-splitting waveguide substrate 500 is moved to the exposure platform 400. Then, the refractive index matching liquid is dripped on the mask 401, and the glue-splitting waveguide substrate 500 is covered on the mask 401 to remove the small bubbles in the middle. Then, the laser 201 is turned on in advance, and the aperture 203 is in a closed state. Open the aperture 203 to start exposure, and close the aperture immediately after the exposure is completed. Then, after the exposure is completed, the exposed waveguide substrate can be taken down through the second glove operation port 108, and the refractive index matching liquid underneath can be wiped off. The exposed waveguide substrate is moved above the incandescent lamp board, and the incandescent lamp is turned on to post-cure the exposed waveguide substrate. After the post-curing is completed, the cured waveguide substrate can be taken out from the nitrogen environment.

[0079] The following introduces a specific embodiment of an exposure platform for exposing a waveguide. Figure 6 It is a schematic diagram of a two-dimensional pupil expansion waveguide plate in the related art. The waveguide plate includes three grating areas, and the three grating areas are all one-dimensional gratings with the same period. In the coupling-in area 701, the angle between the grating and the vertical direction (i.e., the y-axis direction) is 60°, in the turning area 702, the angle between the grating and the vertical direction is -60°, and in the coupling-out area 703, the angle between the grating and the vertical direction is 0°. After the pre-exposure treatment of the waveguide substrate (the glue-leveling process is completed), the waveguide substrate is bonded to the mask 401. Adjust to the initial state: the waveguide substrate is located at the center of the mask 401, and the angle is returned to 0°.

[0080] Figure 7 It is a structural schematic diagram of an exposure platform of a volume holographic exposure device proposed in another embodiment of the utility model. Figure 8 It is a structural schematic diagram of an exposure platform of a volume holographic exposure device proposed in yet another embodiment of the utility model. Fig. 9 FIG. 1 is a schematic diagram of the structure of an exposure platform of a volume holographic exposure device according to another embodiment of the present invention. Figures 7 to 9As shown, firstly, the coupling region 701 is exposed, and the coupling region baffle 501 is used to control the θ angle rotation axis, and the waveguide substrate is rotated 30 degrees. In order to ensure the best exposure effect, the X / Y displacement axis is controlled, and the workpiece stage 405 moves 14.6 mm to the right and 49.4 mm downward, and the center point of the grating area is moved to the center of the light spot. Then, the turning region 702 is exposed, and the turning region baffle 502 is replaced, and the θ angle rotation axis is controlled to rotate the waveguide substrate -60 degrees. In order to ensure the best exposure effect, the X / Y displacement axis is controlled, and the workpiece stage 405 moves 34.2 mm to the left and 22.1 mm upward, and the center point of the grating area is moved to the center of the light spot. Finally, the out-coupling area 703 is exposed, and the out-coupling area baffle 503 is replaced. The θ angle rotation axis is controlled to rotate the waveguide substrate -60 degrees. In order to ensure the best exposure effect, the X / Y displacement axis is controlled, and the workpiece stage 405 moves 31.4 mm to the right and 32.9 mm downward to move the center point of the grating area to the center of the light spot. (Where positive represents clockwise, negative represents counterclockwise, and the basis of rotation is Figure 6 The waveguide in the horizontal right direction, that is, the direction where the θ angle rotation axis is 0 degrees).

[0081] In summary, the volume holographic exposure device proposed in the embodiment of the utility model includes: an optical system, a coating system and an exposure platform; the coating system is located in a first box, the exposure platform is located in a second box, a connecting portion is provided between the first box and the second box, and the first box and the second box are both inert gas boxes, wherein one of the first box and the second box is provided with an inert gas inlet for connecting to an inert gas inlet device, and the other is provided with an inert gas outlet; the coating system is used to coat the surface of the waveguide substrate with a material to be exposed to form a coating waveguide substrate, and the coating waveguide substrate is transferred to the exposure platform through the connecting portion; the optical system is used to emit an exposure beam to the exposure platform to expose the coating waveguide substrate to form an exposed waveguide substrate. The volume holographic waveguide sheet formed by the volume holographic exposure device in an inert gas environment is thin and light, and the contrast and resolution are improved in the imaging effect.

[0082] The above specific implementations do not constitute a limitation on the protection scope of the present utility model. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. A volume holographic exposure device (100), characterized in that: include: An optical system (200), a coating system (300) and an exposure platform (400); The coating system (300) is located in a first box (101), and the exposure platform (400) is located in a second box (102). A connecting portion (103) is provided between the first box (101) and the second box (102). Both the first box (101) and the second box (102) are inert gas boxes, wherein one of the first box (101) and the second box (102) is provided with an inert gas inlet (104) for connecting to an inert gas inlet device (A), and the other is provided with an inert gas outlet (105); The coating system (300) is used to coat the surface of the waveguide substrate with a material to be exposed to form a coated waveguide substrate (500), and to transfer the coated waveguide substrate (500) to the exposure platform (400) through the connecting portion (103); the optical system (200) is used to emit an exposure light beam to the exposure platform (400) to expose the coated waveguide substrate (500) to form an exposed waveguide substrate.

2. The volume holographic exposure device according to claim 1, characterized in that: One of the first box body (101) and the second box body (102) is provided with a dust removal air outlet (106) for connecting to dust removal equipment.

3. The volume holographic exposure device according to claim 1, characterized in that: The optical system (200) comprises: A laser (201) for emitting a laser beam; A first beam expanding element (202), an aperture (203), a second beam expanding element (204) and a reflecting element (205) are sequentially arranged in the transmission direction of the laser beam to guide the laser beam to form the exposure beam.

4. The volume holographic exposure device according to claim 3, characterized in that: The laser beam is a polarized beam, and the optical system (200) further comprises a half-wave plate (206), wherein the half-wave plate (206) is located between the aperture (203) and the second beam expansion element (204).

5. The volume holographic exposure device according to claim 1, characterized in that: The glue-splitting system (300) comprises: a cleaning device (301), a glue-splitting device (302) and a conveying device (303); The cleaning device (301) is located upstream of the glue-sizing device (302) and is used to clean the waveguide substrate. The glue-sizing device (302) is used to glue the cleaned waveguide substrate. The conveying device (303) is located downstream of the glue-sizing device (302) and is used to convey the glue-sizing waveguide substrate to the exposure platform (400) through the connecting portion (103).

6. The volume holographic exposure device according to claim 5, characterized in that: A first glove operation port (107) is provided on the side wall of the first box body (101), and the side wall of the first glove operation port (107) is arranged to correspond to the space between the cleaning device (301) and the glue spreading device (302).

7. The volume holographic exposure device according to claim 1, characterized in that: The exposure platform (400) comprises a baffle (401), a mask plate (402), and an angle rotation device (404) which are sequentially arranged along the transmission direction of the exposure light beam and are all located in the plane displacement device (403); The plane displacement device (403) is provided with a workpiece table (405), the workpiece table (405) is provided with a first through hole (408), the mask (402) is embedded in the first through hole (408), and forms the bottom of the second box (102); The first through hole (408) is further provided with the angle rotating device (404), a waveguide fixing frame (407) is provided on the angle rotating device (404), and the baffle (401) is located on a side of the mask (402) away from the waveguide fixing frame (407); The plane displacement device (403) is capable of translating the workpiece stage (405), the rotation axis of the angle rotation device (404) is colinear with the central axis of the first through hole (408), and the baffle (401) is provided with a second through hole (409) for exposure by the exposure light beam.

8. The volume holographic exposure device according to claim 7, characterized in that: The waveguide fixing frame (407) comprises at least two brackets, wherein the bracket comprises a support rod (071) and a stopper (072), one end of the support rod (071) is fixed to the angle rotating device (404), and the other end is fixedly connected to the stopper (072), and the stopper (072) is used to limit the position of the coated waveguide substrate (500) on the exposure platform (400).

9. The volume holographic exposure device according to claim 8, characterized in that: The inner wall of the second box (102) is coated with light absorbing material.

10. The volume holographic exposure device according to claim 8, characterized in that: A second glove operation port (108) is provided on the side wall of the second box body (102), and the side wall on which the second glove operation port (108) is provided corresponds to the exposure platform (400).

11. The volume holographic exposure device according to claim 1, characterized in that: Also includes: A curing light source (600) and a curing platform (601), wherein the curing platform (601) is located in the second housing (102), and the curing light source (600) is used to cure the exposure waveguide substrate.

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