Volume holographic optical waveguide vacuum lamination device

Abstract

The utility model relates to the field of vacuum lamination, more particularly to a kind of body holographic optical waveguide vacuum lamination device, including upper cover plate, lower cover plate and vacuum generating device, upper cover plate includes top plate and first side plate, and first vacuum passage is provided on top plate;Lower cover plate includes bottom plate and second side plate, and second vacuum passage is provided on bottom plate;Upper cover plate can be with lower cover plate and die to form airtight chamber;First vacuum passage and second vacuum passage are connected with vacuum generating device by first vacuum pipeline and second vacuum pipeline;First vacuum pipeline and second vacuum pipeline are respectively provided with first vacuum valve and second vacuum valve;Intercommunicating pipeline is arranged between first vacuum pipeline and second vacuum pipeline, and intercommunicating valve is arranged on intercommunicating pipeline.First vacuum passage adsorbs upper glass on upper cover plate, second vacuum passage extracts airtight chamber to high vacuum degree, and intercommunicating pipeline balances the pressure of upper glass upper and lower sides, so that upper glass falls under the action of gravity, and is laminated with lower glass.

Description

Technical Field

[0001] This utility model relates to the field of vacuum bonding, and more specifically, to a vacuum bonding device for a volume holographic waveguide. Background Technology

[0002] Augmented reality (AR) technology, especially AR glasses based on volume holographic waveguides, is increasingly becoming a core device for next-generation human-computer interaction. As the optical core of AR glasses, the performance of the volume holographic waveguide directly determines the user's visual experience. These waveguides are typically composed of multiple layers of precision optical glass or wafers, with optical coupling achieved between layers through a bonding process. During this process, any micron-level bubbles, impurities, or misalignment can lead to a decrease in the diffraction efficiency of the waveguide and a deterioration in image quality (such as ghosting and stray light), thereby significantly reducing product yield.

[0003] Currently, the mainstream vacuum bonding process involves first aligning and bonding the upper and lower glass layers in a non-vacuum environment. Then, the cavity is evacuated, and external pressure is applied using airbags or mechanical pressure heads to expel air between the two glass layers, achieving final bonding. However, this method has two inherent drawbacks: First, in a non-vacuum environment, air inevitably becomes trapped between the two glass layers during initial bonding. Subsequent vacuuming and external pressure application cannot completely remove this dispersed air, easily leaving behind tiny air bubbles. Second, the uneven external pressure applied to remove air (such as airbag pressure) can cause deformation of the optical glass during bonding, damaging the fragile grating structure and generating residual stress in the glass, affecting long-term reliability. Furthermore, when air bubbles exist within the bonded glass assembly, the industry commonly uses a pressure degassing machine for post-processing. However, this method of eliminating bubbles by applying high temperature and pressure externally exerts significant pressure on the formed grating area, causing deformation of the grating period and permanently altering its diffraction angle and optical performance. Utility Model Content

[0004] The present invention aims to overcome at least one defect (deficiency) of the prior art and provide a vacuum bonding device for a volume holographic optical waveguide, which achieves the bonding process in a completely vacuum environment, completely eliminates air residue, fundamentally eliminates the possibility of bubble generation, and thus eliminates the need to apply external force to eliminate bubbles.

[0005] The technical solution adopted by this utility model is a volume holographic waveguide vacuum bonding device, including an upper cover plate, a lower cover plate, and a vacuum generating device. The upper cover plate is a box structure with an opening on the lower side, including a top plate and a first side plate disposed on the periphery of the top plate, and a first vacuum channel is provided on the top plate. The lower cover plate is a box structure with an opening on the upper side, including a bottom plate and a second side plate disposed on the periphery of the bottom plate, and a second vacuum channel is provided on the bottom plate. The upper cover plate can be molded with the lower cover plate to form a sealed chamber. The first vacuum channel and the second vacuum channel are respectively connected to the vacuum generating device through a first vacuum pipeline and a second vacuum pipeline. A first vacuum valve and a second vacuum valve are respectively provided on the first vacuum pipeline and the second vacuum pipeline. A connecting pipeline is provided between the first vacuum pipeline and the second vacuum pipeline, and a connecting valve is provided on the connecting pipeline.

[0006] The upper glass is adsorbed onto the upper cover plate through the first vacuum channel. After mold closing, the sealed chamber is evacuated to a high vacuum through the second vacuum channel. A connecting pipe connects the first and second vacuum channels, balancing the pressure on both sides of the upper glass and eliminating the adsorption force. The upper glass then falls steadily and vertically under its own weight in a pure vacuum environment, bonding with the lower glass. The entire bonding process is carried out in a vacuum, with no air residue, fundamentally eliminating the possibility of bubble formation. The entire process also requires no external force from airbags or mechanical pressure heads, completely avoiding glass bending and grating deformation caused by external pressure, achieving truly non-destructive bonding. Since there are no air bubbles in the bonded glass assembly, there is no need for post-processing with a pressure degassing machine, avoiding compression of the formed grating area and preventing deformation of the grating period.

[0007] Alignment mechanisms are installed on the upper and lower cover plates to achieve high-precision bonding. The grating structures on the upper and lower glass plates require precise alignment to ensure the optical performance (such as diffraction efficiency and field of view) of the final volume holographic waveguide. The alignment mechanisms on the upper and lower cover plates first achieve precise positioning, and then pressure balancing achieves disturbance-free release, jointly ensuring the high quality and high yield of the bonded product. The alignment mechanisms can employ high-precision guide rails, optical vision alignment systems, or mechanical positioning pins, etc.

[0008] When the connecting valve opens, the upper glass can only achieve synchronous, vertical, and lateral-disturbance free fall under gravity under the influence of gravity when the pressure is at an instantaneous equilibrium. Therefore, the connecting pipeline must be designed to ensure that the pressure on the upper and lower surfaces of the upper glass can achieve instantaneous and absolute equilibrium after the connecting valve opens. The diameter of the connecting pipeline is greater than or equal to the diameter of the first and second vacuum pipelines. When the connecting valve opens, the airflow can pass through instantaneously with extremely low flow resistance, allowing the pressure on the upper and lower surfaces of the upper glass to reach uniformity instantly, and the adsorption force to be removed instantly. If the diameter of the connecting pipeline is smaller than the diameter of the first and second vacuum pipelines, the airflow will encounter flow resistance within the connecting pipeline when the connecting valve opens, causing the pressure equilibrium process to become slow. This slow equilibrium will cause the adsorption force of the upper glass to gradually disappear rather than instantaneously, potentially leading to the glass tilting, sliding, or sticky detachment, resulting in a loss of alignment accuracy. Therefore, the diameter of the connecting pipeline should not be smaller than the diameter of the first and second vacuum pipelines.

[0009] During operation, the upper glass is adsorbed onto the lower surface of the top plate of the upper cover, while the lower glass rests on the upper surface of the bottom plate of the lower cover. When the connecting valve opens, the upper glass falls freely under gravity and adheres to the lower glass below it. Therefore, it is essential to ensure a safe and appropriate drop distance between the two to prevent glass breakage or damage to the grating structure due to collision or compression. For the volume holographic waveguide (used in AR glasses) targeted by this device, the optical glass used has typical specifications: the thickness of the upper glass (usually the cover glass) is approximately 0.5 mm, and the thickness of the lower glass (usually the base glass with the grating) is approximately 0.7 mm. Based on this, after mold closing, the net distance between the top and bottom plates is set to 2.0-3.0 mm. At this time, the net distance between the upper and lower glass is between 0.8-1.8 mm, ensuring that the final velocity of the upper glass falling under gravity is limited to an extremely low level, thereby effectively avoiding damage to the grating and glass surface.

[0010] When the device is in use, the connecting valve opens, the pressure on the upper and lower sides of the upper glass is balanced, and it falls freely under the action of gravity. If there is an excessively strong electrostatic attraction between the upper glass and the lower surface of the top plate, even if the vacuum attraction disappears, the upper glass may still not fall smoothly, or it may slip uncontrollably during the fall, leading to process failure. A low surface energy material layer on the top plate of the upper cover plate can greatly reduce the electrostatic attraction between the upper glass and the top plate. When the vacuum attraction is removed, the upper glass can be reliably and immediately released. A low surface energy material layer on the bottom plate of the lower cover plate facilitates the removal of the bonded glass assembly from the lower cover plate after the bonding process. If no low surface energy material layer is provided on the bottom plate, the bonded glass assembly may be difficult to remove due to the "suction cup effect," or stress may occur during removal due to uneven local force. Specifically, the low surface energy material layer is a polytetrafluoroethylene (PTFE) layer. The extremely low surface energy of PTFE gives it excellent anti-sticking and anti-adhesion properties, ensuring the smooth release of the glass to the greatest extent possible. Secondly, PTFE has an extremely low coefficient of friction, which effectively prevents the glass from sliding or shifting laterally, ensuring vertical drop and precise alignment. Furthermore, PTFE is chemically extremely stable and has excellent resistance to high and low temperatures, ensuring that its performance will not degrade under vacuum conditions and potential process temperature fluctuations, and that it will not release gases or substances that could contaminate the optical glass or vacuum chamber.

[0011] Reliable sealing is the cornerstone of obtaining a stable and uniform vacuum environment and a prerequisite for the entire bonding process. Seals are installed on the first and / or second side plates to ensure a reliable, airtight seal is formed when the upper and lower cover plates are closed, thus creating a sealed chamber. Seals may be installed on only the first or second side plate, or on both.

[0012] The requirements for vacuum level and speed for the top cover adsorption and the vacuuming of the sealed chamber may differ. Setting up a first vacuum source and a second vacuum source enables more efficient, reliable, and high-performance bonding. The first vacuum source is connected to a first vacuum line to provide adsorption force for the top cover, while the second vacuum source is connected to a second vacuum line to evacuate the sealed chamber. The two vacuum lines are completely independent and do not interfere with each other. The pumping rate, start / stop time, and vacuum level of each line can be independently controlled, providing greater flexibility for process optimization.

[0013] The first vacuum channel is used to adsorb the upper glass, and the second vacuum channel is used to evacuate the sealed chamber. Therefore, the first and second vacuum channels should be staggered. Both the top and bottom plates have bonding areas, which are used to support and fix the upper and lower glass. The bonding areas on the top and bottom plates are opposite to each other. The first vacuum channel is located in the bonding area of ​​the top plate to adsorb and fix the upper glass, while the second vacuum channel is located in the area outside the bonding area of ​​the bottom plate, i.e., the non-bonding area, to avoid interference with the lower glass and to achieve the function of evacuating the sealed chamber.

[0014] Compared with existing technologies, the advantages of this invention are as follows: The upper glass is adsorbed onto the upper cover plate through a first vacuum channel, and the sealed chamber formed after molding is evacuated to a high vacuum through a second vacuum channel. A connecting pipe connects the first and second vacuum channels, balancing the pressure on both sides of the upper glass, eliminating the adsorption force, and allowing it to fall steadily and vertically under its own weight in a pure vacuum environment, thus bonding with the lower glass. The entire bonding process is carried out entirely in a vacuum, fundamentally eliminating the generation of air bubbles. No external force is required from airbags or mechanical heads, completely avoiding glass bending and grating deformation caused by external pressure. It also eliminates the need for post-processing of the bonded glass assembly using a pressure degassing machine, preventing compression of the formed grating area and thus avoiding deformation of the grating period. Alignment mechanisms are respectively provided on the upper and lower cover plates to achieve precise positioning, ensuring high quality and high yield of the bonded product. The diameter of the connecting pipe is no less than that of the first and second vacuum pipes to ensure that the pressure on both sides of the upper glass can be balanced instantaneously when the connecting valve is opened, allowing the upper glass to achieve a synchronous, vertical, and lateral free fall under gravity. To prevent the upper glass from falling under gravity and damaging the grating and glass, the net distance between the top and bottom plates after mold closing is limited to 2.0-3.0 mm to ensure that the final velocity of the upper glass is kept extremely low. A low surface energy material layer is applied to the top plate of the upper cover plate, which greatly reduces the electrostatic attraction between the upper glass and the top plate, allowing the upper glass to be reliably and instantly released after the vacuum attraction force is removed. A low surface energy material layer is applied to the bottom plate of the lower cover plate, which greatly reduces the electrostatic attraction between the lower glass and the bottom plate, facilitating the easy and smooth removal of the bonded glass assembly. The low surface energy material layer is preferably a polytetrafluoroethylene (PTFE) layer, which has extremely low surface energy, ensuring the smooth release of the glass to the greatest extent possible. Simultaneously, it has an extremely low coefficient of friction, effectively preventing lateral sliding or displacement of the glass. To ensure a stable and uniform vacuum environment, sealing elements are provided on the first and / or second side plates. The vacuum generating device includes a first vacuum source and a second vacuum source, respectively connected to the first and second vacuum pipelines, forming two independent and non-interfering pipelines. The pumping rate, start / stop time, and vacuum level of each pipeline can be independently controlled. The first and second vacuum channels are staggered to achieve different functions. The first vacuum channel is located in the contact area of ​​the top plate and is used to support the adsorbed glass; the second vacuum channel is located outside the contact area of ​​the bottom plate and is used to evacuate the sealed chamber. Attached Figure Description

[0015] Figure 1 This is a structural diagram of the present invention.

[0016] Figure 2 This is a sectional view of the upper and lower cover plates.

[0017] Figure 3 This is a sectional view of the upper and lower cover plates when they are joined together.

[0018] Figure 4 A structural diagram showing how the upper and lower glass panes are fixed to the upper and lower cover plates.

[0019] 1. Top cover plate; 11. Top plate; 12. First side plate; 13. First vacuum channel; 14. Sealing ring; 15. Low surface energy material layer; 2. Bottom cover plate; 21. Bottom plate; 22. Second side plate; 23. Second vacuum channel; 3. Vacuum generating device; 31. First vacuum source; 32. Second vacuum source; 4. First vacuum pipeline; 41. First vacuum valve; 5. Second vacuum pipeline; 51. Second vacuum valve; 6. Connecting pipeline; 61. Connecting valve; 7. Sealed chamber; 8. Upper glass; 9. Lower glass. Detailed Implementation

[0020] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this invention. To better illustrate the following embodiments, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0021] In the description of this utility model, it should be noted that the terms "upper," "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use, or the orientation or positional relationship commonly understood by those skilled in the art. These terms are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this utility model. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0022] like Figure 1 , Figure 2 As shown, a volume holographic waveguide vacuum bonding device includes an upper cover plate 1, a lower cover plate 2, a vacuum generating device 3, and a control system (not shown). The upper cover plate 1 is a box structure with an opening at the bottom, including a top plate 11 and a first side plate 12 disposed around the top plate 11. A first vacuum channel 13 is provided on the top plate 11. The lower cover plate 2 is a box structure with an opening at the top, including a bottom plate 21 and a second side plate 22 disposed around the bottom plate 21. A second vacuum channel 23 is provided on the bottom plate 21. The upper cover plate 1 can rise or fall relative to the lower cover plate 2, thereby realizing mold opening or mold closing. When the mold is closed, the upper cover plate 1 and the lower cover plate 2 form a sealed chamber 7.

[0023] like Figure 2 , Figure 3 As shown, specifically, both the top plate 11 and the bottom plate 21 are provided with bonding areas and non-bonding areas, and the bonding areas on the top plate 11 and the bonding areas on the bottom plate 21 are arranged opposite to each other. The bonding areas are used to fix the upper glass 8 and the lower glass 9, and their size and shape are matched with the optical glass to be bonded. The non-bonding areas are the areas outside the bonding areas. The first channel 13 is located in the central area of ​​the bonding area of ​​the top plate 11 to ensure that the vacuum adsorption force acts evenly on the center of the upper glass 8, thereby making the upper glass 8 subjected to balanced force during adsorption. The second channel 13 is located in the non-bonding area of ​​the bottom plate 21, so that when the lower glass 9 is placed on the bottom plate 21, the lower glass 9 and the second channel 13 do not interfere with each other. The lower surface of the top plate 11 and the upper surface of the bottom plate 21 are respectively provided with a low surface energy material layer 15 to reduce the electrostatic adsorption force between the top plate 11 and the upper glass 8, and between the bottom plate 21 and the lower glass 9. The low surface energy material layer is preferably a polytetrafluoroethylene layer, which has extremely low surface energy, giving it excellent anti-sticking and anti-adsorption properties, as well as an extremely low coefficient of friction. At the same time, it has stable chemical properties and good temperature resistance.

[0024] like Figure 3 , Figure 4 As shown, during mold closing, the net distance D between the top plate 11 and the bottom plate 21 is 2.0-3.0mm to avoid damage to the grating and the surface of the bottom glass 9 when the upper glass 8 falls due to an excessively large net distance D. The volume holographic waveguide used in AR glasses uses optical glass with typical specifications. The upper glass 8 is usually a cover glass with a thickness of about 0.5mm, and the bottom glass 9 is usually a base glass with a grating on it with a thickness of about 0.7mm. When the upper glass 8 is adsorbed onto the top plate 11 and the bottom glass 9 is placed on the bottom plate 21, the net distance d between the upper glass 8 and the bottom glass 9 is 0.8-1.8mm. This distance limits the final velocity of the upper glass 8 under gravity to an extremely low level, thereby achieving a "soft landing" and effectively avoiding structural damage to the precision grating and the surface of the bottom glass 9.

[0025] like Figure 1As shown, the vacuum generating device 3 includes a first vacuum source 31 and a second vacuum source 32, both of which are vacuum pumps. The first vacuum source 31 is connected to the first vacuum channel 13 via a first vacuum pipeline 4, and a first vacuum valve 41 is installed on the first vacuum pipeline 4 to control the opening and closing of the first vacuum pipeline 4. The second vacuum source 32 is connected to the second vacuum channel 23 via a second vacuum pipeline 5, and a second vacuum valve 51 is installed on the second vacuum pipeline 5 to control the opening and closing of the second vacuum pipeline 5. A connecting pipeline 6 is provided between the first vacuum pipeline 4 and the second vacuum pipeline 5, and a connecting valve 61 is installed on the connecting pipeline 6 to control the opening and closing of the connecting pipeline 6. To ensure that the pressure on the upper and lower sides of the upper glass 8 can achieve instantaneous and absolute balance when the connecting valve 61 is opened, the diameter of the connecting pipeline 6 is set to be greater than or equal to the diameter of the first vacuum pipeline 4 and the second vacuum pipeline 5.

[0026] A driving mechanism (not shown) is provided on the upper cover plate 1. This driving mechanism drives the upper cover plate 1 to move up and down relative to the lower cover plate 2, thereby achieving mold opening and closing. When the upper cover plate 1 and the lower cover plate 2 are closed, a sealed cavity 7 is formed. Figure 1 As shown, in order to ensure that a reliable and airtight sealed chamber 7 can be formed when the mold is closed, a sealing ring 14 is provided at the bottom of the first side plate 12. Of course, a sealing ring 14 can also be provided at the top of the second side plate 22, or a sealing ring 14 can be provided at the bottom of the first side plate 12 and the top of the second side plate 22.

[0027] The control system is communicatively connected to the first vacuum valve 41, the second vacuum valve 51, the connecting valve 61, the first vacuum source 31, the second vacuum source 32, and the drive mechanism. Connected to the first vacuum valve 41, the second vacuum valve 51, and the connecting valve 61, the control system can drive these valves to achieve rapid opening and closing actions, with valve response time controlled within 0.1 seconds. Connected to the first vacuum source 31 and the second vacuum source 32, it can precisely control the start and stop of the first and second vacuum sources, and can automatically execute the entire process flow strictly according to preset vacuum thresholds, stabilization waiting times, and final bonding holding times by receiving feedback signals. Connected to the drive mechanism, it can control the upper cover plate 1 to rise, fall, and precisely position itself at a set speed, achieving smooth and accurate mold closing and opening with the lower cover plate 2. The control system completely eliminates the uncertainty and random errors of manual operation, ensuring absolute consistency of process parameters for each bonding operation. This provides a fundamental guarantee for the mass production and high-yield production of volume holographic waveguides.

[0028] In operation, the device first operates by controlling the drive mechanism to open the upper cover plate 1. The operator places the upper glass 8 into the mating area of ​​the top plate 11, then opens the first vacuum valve 41 and activates the first vacuum source 31. Vacuuming is then performed through the first vacuum channel 13 to adhere the upper glass to the upper cover plate 1. Simultaneously, the lower glass 9 is placed into the mating area of ​​the bottom plate 21. Next, the control system controls the drive mechanism to smoothly lower the upper cover plate 1, precisely closing it with the lower cover plate 2 to form a sealed chamber 7. After mold closing, the control system opens the second vacuum valve 51 and activates the second vacuum source 32, evacuating the sealed chamber 7 through the second vacuum channel 23. When the pressure inside the sealed chamber 7 reaches a set value (-100 kPa), a pressure stabilization waiting phase begins, with a 2-second countdown. This waiting phase ensures that the pressure inside the sealed chamber 7 is stably maintained within a set threshold range (-100 kPa ± 1 kPa). After the timing period ends, the control system opens the connecting valve 61, connecting the first vacuum line 4 and the second vacuum line 5. This achieves instantaneous pressure balance between the upper and lower sides of the upper glass 8, instantly eliminating the vacuum suction force acting on it. The upper glass 8 then falls vertically and smoothly under gravity, making air bubble-free contact with the lower glass 9 in a vacuum environment. A 10-second bonding timer is then initiated to ensure a tight fit between the upper and lower glass 8 and 9. After the bonding timer ends, the control system first closes the connecting valve 61, then opens the first vacuum valve 41 and the second vacuum valve 51, injecting gas into the sealed chamber 7 (breaking the vacuum). Finally, the drive mechanism raises the upper cover plate 1, allowing the bonded glass assembly to be removed.

[0029] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the technical solution of this utility model, and are not intended to limit the specific implementation of this utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A vacuum bonding device for volume holographic optical waveguides, characterized in that, The device includes an upper cover plate, a lower cover plate, and a vacuum generating device. The upper cover plate is a box structure with an opening on the lower side, including a top plate and a first side plate disposed around the periphery of the top plate. A first vacuum channel is provided on the top plate. The lower cover plate is a box structure with an opening on the upper side, including a bottom plate and a second side plate disposed around the periphery of the bottom plate. A second vacuum channel is provided on the bottom plate. The upper cover plate and the lower cover plate can be molded together to form a sealed chamber. The first vacuum channel and the second vacuum channel are respectively connected to the vacuum generating device through a first vacuum pipeline and a second vacuum pipeline. A first vacuum valve and a second vacuum valve are respectively provided on the first vacuum pipeline and the second vacuum pipeline. A connecting pipeline is provided between the first vacuum pipeline and the second vacuum pipeline, and a connecting valve is provided on the connecting pipeline.

2. The vacuum bonding device for volume holographic optical waveguides according to claim 1, characterized in that, Alignment mechanisms are respectively provided on the upper cover plate and the lower cover plate.

3. The vacuum bonding device for volume holographic optical waveguides according to claim 1, characterized in that, The diameter of the connecting pipeline is not less than the diameter of the first vacuum pipeline and the second vacuum pipeline.

4. The vacuum bonding device for volume holographic optical waveguides according to claim 1, characterized in that, After the upper cover plate and the lower cover plate are closed, the net distance between the top plate and the bottom plate is 2.0-3.0mm.

5. The vacuum bonding device for volume holographic optical waveguides according to any one of claims 1-4, characterized in that, The top plate and the bottom plate are respectively provided with a low surface energy material layer.

6. The vacuum bonding device for volume holographic optical waveguides according to claim 5, characterized in that, The low surface energy material layer is a polytetrafluoroethylene layer.

7. The vacuum bonding device for volume holographic optical waveguides according to any one of claims 1-4, characterized in that, The first side plate and / or the second side plate are provided with sealing elements for sealing the sealed chamber.

8. The vacuum bonding device for volume holographic optical waveguides according to claim 1, characterized in that, The vacuum generating device includes a first vacuum source and a second vacuum source, wherein the first vacuum source is connected to the first vacuum pipeline and the second vacuum source is connected to the second vacuum pipeline.

9. The vacuum bonding device for volume holographic optical waveguides according to claim 1, characterized in that, The first vacuum channel and the second vacuum channel are staggered.

10. The vacuum bonding device for volume holographic optical waveguides according to claim 9, characterized in that, Both the top plate and the bottom plate are provided with a bonding area, and the bonding area on the top plate is arranged opposite to the bonding area on the bottom plate; the first vacuum channel is provided in the bonding area on the top plate, and the second vacuum channel is provided in the area outside the bonding area on the bottom plate.

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